EPA 600/3-87/037b
September 1987
AIR POLLUTION EXPOSURE SYSTEMS AND EXPERIMENTAL PROTOCOLS:
VOLUME 2: DESCRIPTION OF FACILITIES
Appendices
William E. Hogsett
US EPA Environmental Research Laboratory
200 SW 35th Street
Corvallis, OR 97333
David Olszyk
Statewide Air Pollution Research Center
University of California
Riverside, CA 92521
Douglas P. Ormrod
Department of Horticultural Sciences
University of Guelph
Guelph, Ontario NIG 2W1
Canada
George E. Taylor, Jr.
Environmental Sciences
Oak Ridge National Laboratory
P. 0. Box X
Oak Ridge, TN 37830
David T. Tingey
US EPA Environmental Research Laboratory
200 SW 35th Street
Corvallis, OR 97333
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97333
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DISCLAIMER
The information in this document has been funded wholly by the United
States Environmental Protection Agency. It has. been subjected to the
Agency peer and administrative review, and it has been approved for
publication as an EPA document. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
ii
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Table of Contents
Volume II. Description of Facilities
I
Appendices
A.-
B.
C.
D.
E.
F.
G.
Descriptions of Facilities and Performance Evaluations — Plume
Systems for Gaseous Dry Deposition Research
Descriptions of Facilities and Performance Evaluations -- Air
Exclusion Systems for Gaseous Dry Deposition Research
Descriptions of Facilities and Performance Evaluations -- Outdoor
Chambers for Gaseous Dry Deposition Research
Descriptions of Facilities and Performance Evaluations -- Outdoor
Chamber for Gaseous Dry and Wet Deposition Research
Descriptions of Facilities and Performance Evaluations — Indoor
Chambers for Gaseous Dry Deposition Research
I. Chambers for Laboratory Use
II. Chambers for Greenhouse Use
III. Chambers for Laboratory and Greenhouse Use
Descriptions of Facilities and Performance Evaluations -- Systems
for Rainfall Simulation Research
I. Indoors
II. Outdoors
A. Non-Chambered Systems
B. Chambered Systems
C. Automated Exclusion Systems
Descriptions of Facilities and Performance Evaluations -- Systems for
Aerosol/Mist Simulation Research
I.
II.
Indoors
Outdoors
H. Descriptions of Facilities and Performance Evaluations -- Systems for
Dust and Particulate Exposure Research
I. Supplementary Reports: Some Basic Exposure Techniques
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J. Supplementary Reports: Recommended Environmental Monitoring Protocol
-- Controlled Environment Guidelines
K. Supplementary Reports: Suggested Measurements and Reporting Charac-
eristies of Dry Deposition Gaseous Exposure Systems
L. Supplementary Reports: Air Quality Data Bases
M. Supplementary Reports: General Trends in Dry Deposition
II. References
IV
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APPENDIX A
Descriptions of Facilities and Performance Evaluations --
Plume Systems for Gaseous Dry Deposition Research
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Publication: de Cormis, L., J. Bonte, and A. Tisne. 1975. Technique experi-
mental permenant Tetude de I1incidence sur la vegetation d'une pollution
par le dioxyde de soufre appliquee en permanence et a dose subnecotique.
Pollut. Atmos. 66:103-107.
Location: INRA Station d'Etude de la Pollution Atmospherique (INRA), France
Summary: A field exposure facility is described which consists of.an array of
vertical tubes positioned across a 2000 m2 rectangular plot and used to
expose small trees to sulfur dixoide.
1. Plots
The exposure plot is approximately 32 x 64 m with trees planted every
4.5 m.
2. Hardware
a. Emitters
The emitters are 2.75 m high PVC tubes located on a grid every
4.5 m across the plot. Sulfur dioxide is released from holes located
0.5 to 2.75 m along the tubes.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is dispensed from gas tanks to the emitters via
solenoids and a rotameter. There is an automatic shutoff system to
terminate the exposure if S02 becomes too high.
c. Environmental Control and Monitoring
Wind speed, air temperature, and rainfall are measured during
the exposures.
d. Data Aquisition
Recorders.
3. Performance Evaluation
a. Pollutant Uniformity
Sulfur dioxide concentrations vary by 25% vertically between 0.5
and 2.5 m in the plot. Horizontal variability is approximately 240%.
Temporal variability is approximately 100%, but varying with ambient
wind speed.
A-l
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r
b. Pollutant Control and Maintenance
The exposure system provides for relatively uniform exposure
conditions, especially vertically in the small tree canopy. However,
due to a single routine air sampling point it is difficult to assign
exposure doses to particular trees.
See original article for diagram of system (reprint permission not
obtained).
A-2
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Publication: Greenwood, P., A. Greenhalgh, C. Baker, and M. Unsworth. 1982.
A computer controlled system for exposing field crops to gaseous air
pollutants. Atmos. Environ. 16:2261-2266.
Additional Publication: Baker, C. K., M. H. Unsworth, and P. Greenwood. 1982.
Leaf injury on wheat plants exposed in the field in winter to S02. Nature
299:149-151.
Location: University of Nottingham, Nottingham, England
Summary: A facility is described for exposing grasses to S02 using a square
computer-controlled plume system. The pollutant is released from the four
sides independently, depending on wind direction.
1. Plots
The exposure plot is a 2-m square, bounded by emitters.
2. Hardware
a. Emitters
The emitters are 20-m long PVC tubes with 0.0024-m diameter
holes every 1.0 m along the length. The tubes are positioned 0.2 m
above the plant canopy.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is delivered from a heated tank to the pipes via
a gas regulator, flow controller, rotameter, and solenoid. The S02
enters a chamber at the base of the emitter tubes where the incoming
S02 is mixed with ambient air via a small fan. Excess pressure is
maintained in the tube at all times to avoid blockage of the release
holes. Sulfur dioxide concentrations are monitored sequentially in
five positions over the plot with solenoids and a flame photometric
analyzer. Sulfur dioxide is not released if wind speed is less than
1.0 m s-1.
c. Environmental Control and Monitoring
Wind speed and direction are monitored continuously by computer
and the determined values used to control pollutant dispensing.
d. Data Aquisition
All pollutant dispensing, monitoring, and data storage are
computer controlled.
A-3
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3. Performance Evaluation
a. Pollutant Uniformity
Sulfur dioxide concentrations vary by approximately 100% horizon-
tally across the plot on a growing season basis. The average hourly
concentration over an experiment varies by 20%. The central area of
the plot has a more uniform S02 concentration and could be used to
determine plant response to a more uniform S02 exposure.
b. Pollutant Control, and Maintenance ,
The exposure system allows for long-term controlled exposures of
plants to $62 under ambient environmental conditions. The good
relationship between observed and theoretical pollutant concentra-
tions with specified emission rates and wind speeds makes it possible
to model S02 exposure to plants distant from sampling points. Thus,
the system can provide not only a relatively uniform exposure for
some plants, but also a gradient of exposures if particular areas of
the grid are considered.
A-4
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- --O
o
A
Figure A-l. Schematic diagram of.computer-controlled plume system. A. Plant
treatment area with "0" symbols identifying air sample points;
B. emitters; C. mixing chamber; D. solenoid for controlling S0£
release; E. flowmeter; F. flow controlled; G. S02 gas regulator
(reprinted from Greenwood ^t aj^., 1982, with permission of
Pergamon Press).
A-5
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Publication: Lee J. J., and R. A. Lewis. 1976. Field experimental component.
pp. 95-101 In: R. A. Lewis and A. S. Lefohn (eds.). The Bioenvironmental
Impact of a Coal Fired Power Plant. First Interim Report Colstrip,
Montana -- December 1974. U.S. Environmetal Protection Agency, Corvallis,
Oregon. EPA-600/3-76-002.
Additional Publications: Lee, J. J., R. A. Lewis, and D. E. Body. 1975. A
field experimental system for the evaluation of the bioenvironmental
effect of sulfur dioxide. In: D. Wilson and F. Clark (eds.). Proceed-
ings of the Fort Union Coal Field Symposium. Volume 5, pp. 608-620.
Montana Academy of Science. Billings, Montana.
Preston, E. M., and J. J. Lee. 1982. Design and performance of a
field exposure system for evaluation of the ecological effects of S02 on
native grasslands. Environ. Monit. Assess. 1:213-228.
Laurenroth, W. K., D. G. Milchunas, and J. L. Dodd. 1983. Response
of a grassland to sulfur dioxide and nitrogen additions under controlled
S02 exposure. Environ. Exp. Bot. 23:339-346.
Location: U.S. Environmental Protection Agency, Colstrip Project, Colstrip,
Montana
Summary: A plume system was designed, tested and used for exposures of native
grasses to SOg in the field. The system consists of an array of emitter
tubes positioned over the plant canopy. Exposures are continuous over the
growing season. The system provides for controlled-exposures with vari-
ability in concentration such as may occur during S02 fumigation episodes
from coal-fired electrical generating stations.
1. Plots
The plots are 85 x 73 m with a plant growing area of 1891 m2.
2. Hardware
a. Emitters
The emitters are 0.0254-m diameter aluminum pipes 0.75 m above
the ground. Three tubes are 85 m long, and two are 73 m long;
additional 14-m length tubes are placed at right angles every 24 m.
The holes are 0.008 m in diameter and located every 3.1 m along the
length.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is dispensed from a heated tank of S02 via a
valve and compressor, and is monitored with a flame photometric
analyzer. ., Sulfur dioxide is measured in several plots with a time-
sharing device.
A-6
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c. Data Aquisition
Recorder.
d. Environmental Control and Monitoring
Not described.
3. Performance Evaluation
a. Pollutant Uniformity
Sulfur dioxide concentrations vary by up to 300% across plots.
Sulfur dioxide concentrations are highest near the tubes on days with
low wind speeds. Sulfur dioxide concentrations within plots vary by
up to 20 times over the growing season. The source of this variation
is most likely wind speed.
b. Pollutant Control and Maintenance
Pollutant control is electromechanical via an automatic shutoff
at a specified pollutant concentration. Continuous use of the system
with all wind speeds and directions results in the large horizontal
and temporal variability.
A-7
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Figure A-2.
Schematic diagram of plot layout for grid plume system (Zonal Air
Pollution System) (Lee and Lewis, 1976).
"A-8
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Publication: McLeod, A. R., J. E. Fackrell, and K. Alexander. 1985. Open-air
fumigation of field crops: criteria and design for a new experimental
system. Atmos. Environ. 19:1639-1649.
Additional Publication: McLeod, A. R., K. Alexander, and P. Hatcher. 1983. A
Prototype System for Open-Air Fumigation of Agricultural Crops. 2: Con-
struction and Description. Central Electricity Generating Board. Technol-
ogy Planning and Research Division. Report TPRD/L/2475/N83. Leatherhead,
United Kingdom.
Location: Central Electricity Research Laboratories, Leatherhead,,England
Summary: A plume exposure system was designed, tested, and used for exposure
of grasses to air pollutants in the field under variable wind direction
,, conditions. Design is by computer simulation to provide the best pollut-
:. -ant d-ispersipn. The system is circular with an array of emitters within
the.center. Pollutant .release is determined by,a .microcomputer to follow
predetermined episode patterns. .. -• ..,'••,•.
1. Plots
The exposure plots are 27-m diameter circles. Sampling areas within
the plots are 9-m diameter circles, resulting in 64 m2 sampling areas.
2. Hardware
a. Emitters
The PVC pollutant emitters consist of an outside circle 27 m in
diameter, with internal emitters located on a 3-m grid across the
circle. The circle emits S02 at 0.5 m above the ground, and the
internal tubes at 1.5 m above the ground. The circular tube releases
S02 through 0.0022-m diameter holes every 3.0 m around the perimeter,
and the vertical tubes release S02 from 0.0026-m diameter holes at
the top.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is obtained from heated tanks via a computer-
controlled system of solenoids and mass flow controllers. Sulfur
dioxide is monitored with flame photometric analyzer, with samples
sequentially obtained from different sampling points and plots.
Nitrogen dioxide is measured at the plots with chemiluminescent
analyzers and 03 with an ultraviolet analyzer.
c. Environmental Control and Monitoring
The environment is not controlled with this field system.
Environmental conditions during the exposure are measured, including
wind speed and direction.
A-9
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d. Data Acquisition
All data acquisition was via a microcomputer system.
3. Performance Evaluation
a. Pollutant Uniformity
Sulfur dioxide concentrations vary vertically by > 40% between
1.4 m and the ground, < 7% across the plots, and < 10% over time
within a plot.
b. Pollutant Control and Maintenance
The. system provides for uniform exposure of plants to SO;? within
the sampling area. The computer control system allows for episodic
exposure treatments patterned after ambient exposures. The facility
is flexible for exposures with other pollutants in addition to S02-
A-10
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HICK LEVEL SOUKES
LOU UEYEL SOURCES
CU L_J
IB
Figure A-3.
Schematic diagram of encircling plume system (top), and closeup of
emitter head (bottom) (reprinted from McLeod et a!., 1985, with
permission of Pergamon Press).
A-ll
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Publication: Miller, J. E., D. G. Sprugel, H. J. Smith, and P. B. Xerikos.
1980. Open-air fumigation system for investigation of sulfur dioxide
effects on crops. Phytopathology 70:1124-1128.
Additional Publications: Miller, J. E., W. Prepejchal, and H. J. Smith. 1981.
Relative sensitivity of field corn hybrids to ozone: a field study.
Report No. ANL-81-85-III. Argonne National Laboratory, Illinois, pp.
30-36.
Irving, P. M., and J. E. Miller. 1981. Productivity of field-grown
soybeans exposed to acid rain and sulfur dioxide and nitrogen dioxide
alone and in combination. J. Environ. Qual. 10:473-478.
Irving, P. M., and J. E.'Miller. 1984. Synergistic effect on field-
grown soybeans from combinations of sulfur dioxide and nitrogen dioxide.
Can. J. Bot. 62:840-846. ' ' -. .
Location: Argonne National Laboratory, Argonne, Illinois
Summary: A modified Lee et al. (1975) plume 'was extensively tested by Argonne
National Laboratory staTT" to simulate fumigation episodes from coal-fired
power plants on agricultural crops. Miller _et _a]_. (1980) developed a
simpler one- to five-pipe system to evaluate the response of soybeans to
S02 alone or in combination with nitrogen dioxide (Irving and Miller,
1984), or acidic rain (Irving and Miller, 1981). The system also has been
used by Miller et .al- (1981) to determine the response of corn hybrids to
03 exposure.
1. Plots
The plots are rectangular with approximately 783 m2 in the exposure
area and 24 m2 in each sampling area. For S02 exposures, soybeans are
planted in rows 1 m apart parallel to the release pipes. Plant responses
are based on plants from four approximately 6.1 m wide x 5 m long sub-
plots. Two subplots are located on either side of the central release
pipe.
For 03 exposures, the corn hybrids are planted in rows perpendicular
to the 03 release pipe. There are seven rows 0.76 m apart with 0.15 m
between plants in each of the 16.2 m long x approximately 4 m wide plots.
The hybrids are planted in single rows with seven hybrids per plot. Each
plot is a sub-block of four replicate blocks. The plots are separated and
surrounded by areas planted with seed from all 14 hybrids to ensure good
density of pollen for all hybrids. Each sub-block has a 5.2-m long
ambient control section to the south of the 03 release pipe, and an 11-m
long exposure section to the north of the pipe.
A-12
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2. Hardware
a. Emitters
For S02, individual systems are smaller than the Colstrip plume
system (Lee and Lewis, 1976) and the pipes are arranged in parallel
.to more easily fumigate row crops (Miller et al», 1980). As designed
in 1977, the system consists of five 29-m sections of release pipe
^.extending at 6.7-m intervals from one side of a 27-m long delivery
, ,.„. pipe. .The release pipes are parallel to the prevailing southerly
winds, encompassing a 29 m wide by 27 m long exposure plot. Holes
0.0008-m in diameter are drilled at 0.76-m intervals on alternating
sides of the release pipes horizontal to the ground. The pipe is
0.0254-m inside diameter, threaded-schedule 40 aluminum with aluminum
couplings and elbows. Each system is attached to metal fence posts,
and continually raised during the growing season to maintain the
tubes 0.30 m above the soybean canopy. Corresponding control plots
are located 10 m west of each plume. Three complete systems are
located at least 40 m apart in a 4-hectare soybean field. In 1978
, only the three southernmost sections of pipe were retained with the
holes drilled only on their north sides. There were five complete
systems located across the field. ..In both years of operation, each
. -,;• plume was assigned a different target S02 cpncentration.
The system was further adapted for 03 exposures of 14 hybrids of
field. cor;n (Miller et aJL, 1981). The plume.consists of a single gas
release pipe of (KOZJT-ni diameter, aluminum installed in a field
perpendicular to the prevailing southerly winds. The release pipe
is 95-m long with 0.0008-m diameter holes at 0.61-m intervals. Ozone
is produced from liquid oxygen with an OREC Model 03DV-AR 03 gener-
ator. The 03 is mixed with ambient air in a delivery pipe with the
. .force for release provided by a Dietz Model SV-80 ring compressor.
, • The 03-air mixture enters midway along the release pipe to minimize
the pressure differential along the pipe. Ozone is sampled at six
points, three times each at.distances of 1.8, 5.5, and 9.1 m from the
pipe in two locations. Ozone .concentrations.at locations between
sampling points are estimated from curves generated from the sampling
point data. Ozone concentrations at the six points are determined
through a time-sharing system, and measured with a Dasibi Model
. 1003AH 03 .analyzer. ...........
b,. Pollutant Dispensing and Monitoring.
:••-•• Sulfur, dioxide .is obtained from anhydrous tank S02 and intro-
duced into the air stream via a pressure regulator and solenoid
valve, followed by adjustable rotameters. The solenoid is operated
.: - manually whenever meteorological conditions are appropriate for
. -.exposures. In 1977, plants were exposed between 0900:,and 1600 only
when winds were southerly or northerly; .in 1978, only when winds were
southerly. Exposures have not been conducted when dew is present on
leaf surfaces or in case of rain. Sulfur dioxide is monitored in the
plots sequentially from sampling points via a timer-controlled
A-13
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electrical sequencer in conjunction with three-way solenoid valves.
ThermoElectron Model 43, Meloy S160A, and Meloy S285A S02 analyzers
are used. Sulfur dioxide data are processed manually.
c. Environmental Control and Monitoring
The system is used with an acidic rain dispensing system for
some studies. Wind speed and direction are monitored during the
exposures, however, no information is given concerning the frequency
of wind measurements or monitoring of other environmental conditions..
d. Data Acquisition
Not described.
3. Performance Evaluation
a. Pollutant Uniformity
There is a 34% decrease in S02 concentration between the top of
the plant canopy and soil. Concentrations of S02 vary by 5 to 10%
horizontally across the plots. Over the course of a number of
exposures, hourly-average S02 concentrations vary approximately 50%.
There is a 10 to 20% difference in average concentrations between
replicate systems. In 1978 there were 18 exposures between 19 July
and 27 August with an average duration of 250 min, and ranging from
63 min to 370 min. Averages and standard deviations across the five
systems were 234 ± 131, 262 ± 131, 498 ± 210, 655 ± 367, and 943 ±
498 ug nr3.
The 03 was released between 0900 and 1600 from 29 June to 31
August, whenever wind direction was from a 90 degree sector from the
southeast to southwest. These conditions were present for 15 days
totaling 65 hours of exposure. The average 03 concentrations across
the plots ranged from 129 to 838 ug nr3 with an average ambient
concentration of 105 ug nr3 during exposure hours.
b. Pollutant Control and Maintenance
Tests indicated that the system could produce simulated S02
exposures with temporal and spatial fluctuations similar to ambient
fumigations. The magnitude of the fluctuations could be controlled
• to some extent by the S02 flow rate through the system. Interpreta-
tion of the results from plume effects required careful characteriza-
tion of the S02 concentration and duration of exposure for specific
locations across the plots. However, once the exposure was quanti-
fied, it could readily be used for regression equations to evaluate
plant responses. The system was flexible and could be adapted for
different uses by altering the number of pipes in the array.
A-14
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The system performed well with 03 exposures as well. The main
drawbacks were the amount of 63 which would be required to be gener-
ated for any long-term study, and the inability to produce an 03
treatment at a concentration lower than ambient.
A-15
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SO2 SO2 and NO2 NO2
78 - - - ifi4]i iTi :fd=|= i -: in Mi ifi iPfli i r.: 111 ifiQli ifi iBit 11:
56 111 i[i£|i :li :|^:Ji 11: in I|:Q|I iji i^iji 11: 111 r^li iji ijoij: 11:
4 --Z ifi4|i ifi if^-ili 11: S°2111 iFi^li iTi i[Pi]i 11: 111 i[iQ]i iTi ipit 11:
^ : 11 I[IAP -L- -lAl- - -: z - - -Lr0l- -1- -IQ-J- - -: - -= =L-nl- -l^ -\n-f- - - -
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Row *
t
5m
Wind direction
37m
A
a
fumigated
plots
Fumigation pipe
Soybean row
Harvested segment for
yield determination
SO2 monitoring point
NO2 monitoring point
Figure A-4.
Schematic diagram of plot layout for linear plume system for S02
and NOg interaction exposures (reprinted from Irving and Miller,
1983, with permission of Canadian Journal of Botany).
A-16
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Publication: Moser, T. J., T. H* Nash, and W. D. Clark. 1980. Effects of
long-term field sulfur dioxide fumigation on Arctic caribou forage
lichens. Can. J. Bot. 58:2235-2240. .
Location: University of Arizona, Tempe, Arizona; site at.Anaktuvuk Pass,
Alaska
Summary: A plume exposure system is described to expose Arctic lichens to S02
in situ. The system is a single length of pipe delivering SOg from a tank
of" $02 equipped with a regulator valve. Lichens are sampled from a grid
south of the pipe. Concentrations of S02 over the grid are checked under
a range of meteorological conditions.
1. Plots
The exposure plot is 1.0 x 5.0 m. Five 0.2 x 0.6-m sampling areas are
established in the center of the plot at 0.3-0.5, 1.0-1.2, 2.0-2.2,
3.0-3.2, and 4.0-4.2 m from the S02 source.
2. Hardware
a. Emitters
The aluminum emitter tube is 1.0 m long with 0.0008-m diameter
holes paired every 0.1 m along the bottom of the pipe. The pipe is
fitted with adjustable legs and positioned 0.05 m above the lichen
mat.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is supplied to the pipe from a tank of SOg via a
regulator valve. The S02 exposure is continuous for 36 days. An
electroconductimetric analyzer is used for S02 monitoring. Monitor-
ing is not continuous, but rather conducted under a variety of
weather conditions to establish the general pattern of S02 exposure
over the plot.
c. Environmental Control and Monitoring
The environment is neither controlled nor monitored.
d. Data Aquisition
Manual.
3. i Performance Evaluation
a. Pollutant Uniformity
Sulfur dioxide is monitored for over 55 h including 43.4 h of
downwind analysis and 11.9 h of upwind analysis. The mean S02
concentration upwind of the source has ranged from 231 ug nr3 near
A-17
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b.
the pipe to 1.8 ug nr3 when measured 4.1 m from the pipe. The mean
downwind concentrations have ranged from 2699 ug nr3 near the pipe to
173 ug nr3 at 4.1 m from the pipe. Variation in concentration at the
sampling points over time is > 100% upwind of the pipe and 50-70%
downwind of the pipe.
Pollutant Control and Maintenance
Not described.
A-18
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Publication: Northrop Services, Inc. 1983. Work Assignment 5. Air Quality
Related Values. Air Pollution Fumigation Studies #1. PX-0001-2-0725.
FinaVProject Report SP-4162-813-08. For National Park Service, Air and
Water Quality Division, Under Contract CX-0001-1-0112. Bennett, J.
Personal communication.
Location: National Park Service, Denver, Colorado
Summary: A portable plume system for use in native plant communities has been
designed and tested under contract to the National Park Service. The
system consists of a series of three emitter tubes that can be positioned
horizontally or vertically depending on vegetation type. The system is
controlled by a computer.feedback system to emit S02 or 03 depending on
wind speed and direction. The theoretical basis and testing of the system
in several different environments is described in detail.
1. Plots
The system could be placed horizontally to enclose a 8 x 15 m area
with the plume extending downwind, or vertically to provide a plume
emitted between 0 and 10 m high on one end of the plot.
a. Emitters
The emitters are three 15-m long PVC delivery pipes attached 4 m
apart to a head pipe. The pollutant is released from 0.003-m diameter
holes every 0.5 m along one side of the pipe.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is obtained from a tank of liquid S02, and
delivered to the emitters via a pressure regulator, rotameter, and
solenoid for computer control. Ozone is generated by UV irradiation
of air, with the emission rate determined by the number of bulbs in
operation. Dilution air is provided to the polluted air by a 2.8 m3
min~l capacity blower. The pollutants from a number of sample points
are analyzed via a series of solenoids.
c. Environmental Control and Monitoring
Wind speed and direction, temperature, relative humidity, and
solar irradiation are monitored continuously.
d. Data Acquisition
Pollutant concentration data are processed and controlled by an
interface and microcomputer. The microcomputer system also stores
environmental data.
A-19
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3. Performance Evaluation
a. Pollutant Uniformity
Pollutant concentrations over the exposure plot vary five-fold
over 10 days of fumigation when the system was used in the horizontal
mode. No information is available on dispersion with the vertical
mode, or for exposures over an extended period.
b. Pollutant Control and Maintenance
Further development and testing are suggested for this plume
system. A major drawback of the system is the inability to model the
pollutant plume in natural ecosystems, especially a forest canopy.
This results in a lack of definition of pollutant doses to target
plant material over the entire exposure area.
A-20
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POLLUTANT GENERATION
DILUTION 'WASTE
AIR BLOWER
GATE
POLLUTION DISTRIBUTION GRID
SAMPLE
COLLECTION/
MONITOR
COMPUTER
DATA ACQUISITION/CONTROL
SUPPORT
Figure A-5.
Schematic diagram of plume system developed for the National Park
Service (Northrop, 1983).
A-21
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Publication: Roberts, T. M. 1985. Open Air Forest Fumigation Experiment.
Personal communication.
Location: Central Electricity Research Laboratories, Leatherhead, England.
Experimental plots at Liphook.
Summary: A large-scale plume system is being constructed to expose trees to
S02 and/or 03 in the field for up to five years.
1. Plots
Five 50-m diameter exposure plots will be established, each with a
central 25-m diameter sampling area.
2. Hardware
a. Emitters
The pollutant emitters will be in a 50-m diameter circle with
heights of 1.0 and 2.5 m. The emitters will be PVC pipes in four
individually controlled sections.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide will be delivered from tanks through mass flow
controllers, with flow to each emitter controlled by solenoid valves.
Ozone will be produced by a large generator with output proportion-
ally controlled by a computer, and delivered to the emitters via
solenoids. Air samples will be moved by sampling pumps and valves to
analyzers.
c. Environmental Control and Monitoring
Environmental conditions will be monitored during the exposures.
d. Data Aquisition
All pollutant dispensing, control, monitoring, and data storage,
as well as environmental monitoring, will be by microcomputer.
3. Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Pollutant Control and Maintenance
Not described.
A-22
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Publication: Runeckles, V. C., K. T. Palmer,-and H., Trabelsi. 1981. Effects
of field exposures to S02 on Douglas fir, Agropyron spicatum, and Lo 1 iurn
perenne. Sil. Fen. 15:505-515. ,-.-,•• , ~
Location: University of British Columbia, Vancouver, British Columbia
Summary: Research at the University of British Columbia has focused on devel-
opment of a field exposure system relevant to the crops and environmental
conditions of the province. Open-top field chambers have not proven
useful especially due to the enhanced greenhouse effect during cool
months. A plume was developed first for use with S02, and has been
subsequently adapted for 03. The .system uses a grid of emitter points on
perpendicular and parallel tubes on a horizontal plane, similar to the Lee
et.jfL (1975) system. . - - . .. •
1. Plots
Exposure plots are rectangular, 10 x 12 m, with four plots.located
25 m apart in a field.
2. Hardware
a. Emitters
The plume system consists of an array of PVC tubes positioned
horizontally, parallel and perpendicular to each other as described
by Lee et al. (1975). The tubes are 1.0 m above the soil. There are
two outer T2~-m long tubes and an inner 10-m long tube. Other 3.0-m
long tubes cross the longer tubes at 3.0-m intervals. The pollutant
is emitted at 1.0-m intervals from 0.0008 m diameter holes. The
system originally was constructed for S02 exposures, but is currently
being used to expose plants to 03.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is dispensed from a tank of pure S02 diluted with
compressed air via a manifold to low, medium, and high concentration
plots. Samples of S02 are drawn from each plot via a time-sharing
device and analyzed with a pulsed fluorescence analyzer. For the
current 03 studies the pollutant concentration is controlled by a
computer feedback system.
c. Environmental Control and Monitoring
Measurement of meteorlogical variables is discussed in the text,
but no indication of conditions is given.
d. Data Acqusition
Pollutant concentrations and environmental conditions are
recorded by a datalogger and microcomputer system.
A-23
-------
3. Performance Evaluation
a. Pollutant Uniformity
Sulfur dioxide concentrations vary by 5-15% across plots. No
indication of vertical or temporal variation is given; however, a
frequency distribution is presented of the sulfur dioxide concentra-
tions through the growing season.
b. Pollutant Control and Maintenance
There is considerable variability in S02 concentrations through-
out the growing season. However, distributions are log-normal for all
three plots providing variability in S02 concentrations that could be
representative of fumigation episodes.
See original publication for schematic of exposure system (reprint per-
mission was not obtained).
A-24
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Publication: Thompson, C. R., D. M. Olszyk, G. Kats, A. Bytnerowicz, P. J.
Dawson, and J. W. Wolf. 1984. Effects of 03 or S02 on annual plants of
the Mojave Desert. J. Air Pollut. Contr. Assoc. 34:1017-1022.
Location: University of California, Riverside; field site at at Daggett,
California
Summary: A computer-controlled plume system was designed, constructed, and
tested for use with annual and perennial vegetation in the Mojave Desert.
The system has a linear configuration, releasing the plume over plots only
when the wind is from the west. The system is computer controlled depend-
ing on wind speed, wind direction, and pollutant concentration at a
dedicated point. The system has been used for S02 exposures and is being
adapted for 03 exposures.
1. Plots
The exposure plots are rectangular, 3.1 x 7.6 m, with a total area of
23.6 m1. Four to seven plots are positioned north to south at the
research site.
2. Hardware
a. Emitters
The system consists of a single bank of two levels of emission
tubes at one end of each exposure plot. The system is greatly
simplified from that of Lee and Lewis (1976) as it is designed for
use in the Mojave Desert where the prevailing wind direction is
usually from the west. Each system is fabricated from two 3.1-m long
x 0.0013-m diameter PVC tubes placed parallel 0.25 m apart with the
lower tube 0.45 m above the ground. The tubes have pin-hole perfora-
tions 0.15 m apart on the side facing the exposure plots. The
emission tubes are placed 7.1 m from the west edge of the plots.
b. Pollutant Dispensing and Monitoring
The S02 is released from the plume system only with the pressure
from the compressed S02 tank. The system relies solely on ambient
wind movement for pollutant dispersion. The plume has been operated
with a computer-controlled feedback system to provide exposures only
when wind is blowing within a specific range of degrees from the
west. For one desert plant study three Zonal Air Pollution plots were
used with target average concentrations of 1310, 2620, and 5240
ug m~^ SO^. The S02 concentrations are controlled via a dedicated
sample point in the low concentration plot. The air sample from this
point is analyzed via a dedicated Meloy Model SA85 sulfur analyzer.
The signal from the S02 analyzer is processed by an Issac® S91A
interface and Apple lie® microcomputer system where it is compared to
a set point. Based on relationship to the set point (1310 ug m~3
SO2), wind direction (west), and wind speed (> 5 mph); a mass flow
controller is activated to release more or less S02 from the system.
A-25
-------
Sulfur dioxide is dispensed from a cylinder of 100% gas enclosed in
an insulated, thermostated galvanized steel can via a pressure
reducer prior to the mass flow controller. From the controller S02
enters a manifold. Sulfur dioxide is monitored continuously with an
array of sampling points across the plots. The samples are processed
by a scanning valve and Meloy SA85 sulfur analyzer.
c. Environmental Control and Monitoring
In one study, soil moisture level is controlled by differential
watering. Environmental conditions are continuously monitored for
all studies, including air temperature, dewpoint, wind speed, and
wind direction.
d. Data Acquisition
Pollutant dispensing, monitoring, data storage, and processing
are controlled by an interfaced-microcomputer system. Environmental
conditions are monitored and the data stored and processed by the
computer system.
3. Performance Evaluation
a. Pollutant Uniformity
The plume has worked well to produce three levels of SOj? expo-
sure similar to events that could occur from a point source in the
desert. Initially, the exposures lacked precision and the system
•could not attain the desired concentrations and resulted in exposures
to 1048,. 2096,-and 2620 ug m~6 S02 in the low, medium, and high
plots. The exposures have occurred over 37 hours spread over 6
exposure days. The variability among hourly-average concentrations
has ranged up to 70% per treatment, and from 40-90% horizontally
across entire plots. •
b. Pollutant Control and Maintenance
Subsequent testing has resulted in increased precision by
increasing the distance between the plume and end of the plots to
reduce variability across the plots, decreasing the range of degrees
for which S02 would be released, and placing Dustamer® "snow fence"
material between' plots to a height of 1.0 m to "channel" the pollut-
ants down the plots. Also, enhanced pollutant sampling across the
plots allows for more precise identification of the pollutant concen-
trations which a particular plantMn the plot receives. Thus,
variability in pollutant concentration can be used to provide a wider
range of exposures for statistical analysis of the plant responses by
regression analysis of individual plant data.
Currently the plume system is being modified to provide expo-
sures to 03 in the Mojave Desert. An Orec Model 03 generator with
tank oxygen will be used as the 03 source. The same plume configura-
A-26
-------
tion and computer feedback control system is being used as described
for S02. A set point of 198 ug m~6 will be used to test the system.
The system is being tested to evaluate the amount of 03 required to
simulate ambient 03 episodes, the dispersion of 03 over the plots,
ability to control the 03 generator via an electronic signal, deter-
ioration of the PVC pipe with 03 exposures and other considerations.
Use of this simplified plume system for 03 exposure appears to
be appropriate for the Mojave Desert where 03 episodes are periodic;
following transport of pollutants from the Los Angeles basin to the
west. This plume configuration would not be appropriate for areas
where 03 episodes are a regional phenomenon occurring with winds from
different directions. Furthermore, this system has not been tested
for daily exposures over a .growing season, as would occur in many
regions of the U.S.
A-27
-------
w
\
CONTROL
PLOT
\
S02
AND
MONITORING (—
EXPOSURE (• —) CONTROLS
Figure A-6.
Schematic diagram of linear plume system for desert plants
(reprinted from Thompson _et a!., 1984, with permission of Air
Pollution Control AssociatiofiT.
A-28
-------
APPENDIX B
Descriptions of Facilities and Performance Evaluations --
Air Exclusion Systems for Gaseous Dry Deposition Research
-------
-------
Publication: Jones, H. C., N. L. Lacasse, W. S. Liggett, and F. Weatherford.
1977. Experimental air exclusion system for field studies of S02 effects
on crop productivity. U.S. Environmental Protection Agency, Washington,
D.C. EPA-600/7-77-122.
Location: Tennessee Valley Authority (TVA), Muscle Shoals, Alabama
Summary: A non-chambered air exclusion system was designed and tested to
determine the effects of ambient S0£ on crops. The system uses a high
pressure blower and PVC ducts between rows to blow filtered air over a
soybean canopy only during S02 fumigation episodes. The system is success-
ful in excluding up to 85% of the ambient S02-
1. Hardware
.a. Ducts .•••-•.•-.., '
The system consists of, a blower box and four PVC ducts lying
between and alongside four rows of soybeans. The ducts are 7.6 m
long and 0.33 m in diameter with 0.0025-m diameter holes spaced 0.31
m apart. For one test the ducts had one row of, 24, holes directed
perpendicularly up from the ground. For other tests the ducts had
two rows of 24 holes each at 45° angles from horizontal for two
middle ducts and the center facing sides of the outer ducts, holes at
90° angles for the outer sides of the outer ducts. The ducts are
inflated by a 1.5 hp blower delivering 122
min
~l flow. Filtered
air systems are equipped with charcoal filters and all systems are
equipped with dust filters.
Pollutant Dispensing and Monitoring
Pollutants are not added to this system. Sulfur dioxide is
monitored with a Phillips S02 analyzer, ozone with a chemiluminescent
analyzer.
Environmental Control and Monitoring
The environment is not controlled by the system; however, soil
moisture, air temperature, solar radiation, and relative humidity are
measured during the exposures.
Data Acquisition
Pollutant data are saved with a datalogger.
B-l
-------
2. Performance Evaluation
a. Pollutant Uniformity
The system excludes up to 83% of the ambient $62 at the top of
the plant canopy. Sulfur dioxide is to some extent trapped beneath
the plant canopy, and concentrations increased by 10% nearer to the
soil.
b. Environment Uniformity
Not described.
c. Pollutant Control and Maintenance
The feedback relay system works well for turning on the air
exclusion system only during SOg fumigation episodes. Further tests
of the system are suggested, especially to characterize the vertical
distribution of pollutants in the canopy.
d. Environmental Control and Maintenance
Not described.
B-2
-------
CROSS SECTION OF TUBES AS PLACED IN FIELD
(Projections show orientation-of holes)
Left Right
A. Twenty-four holes, 2.5 cm diameter each,-spaced 30.5 cm apart along length
B. Forty-eight holes, 2.5 cm diameter each, spaced 30.5 cm apart along length
SIDE VIEW OF AIRrEXCLUSION TUBE (LEFT)
/ <
3 C
30.5 cm
) 0
> o o ° A y o o o o o
ft/
. 7.6 m
Figure B-l.
Schematic diagram of emitter tubes for air exclusion systems
(Jones et al., 1977).
B-3
-------
Publication: Laurence, J. A., D. C. Maclean, R. H. Mandl, R. E. Schneider, and
K. W. Hansen. 1982. Field tests of a linar gradient system for exposure
of row crops to S02 and HF. Water, Air, Soil Pollut. 17:399-407.
Additional Publication: Reich, P. B., R. G. Amundson, and J. P. Lassoie.
1982. Reduction in soybean yield after exposure to ozone and sulfur
dioxide using a linear gradient exposure technique. Water, Air, Soil
Pollut. 17:29-36.
Location: Boyce Thompson Institute, Ithaca, New York
Summary: An exposure system is described for adding 03, S02, or HF to a plant
canopy. The system has a blower and mixing box, and three ducts alongside
two rows of test plants.
1. Hardware
a. Ducts
The blower box contains two 14 m3 min-1 blowers and a box where
ambient air mixes with injected pollutants. Three PVC ducts are
attached to exit ports on the mixing box. The ducts are 0.15 m in
diameter and 13 to 15.4 m long, depending on pollutant. Air exits
the ducts from a combination of 0.009- and 0.00625-m diameter holes
in two rows. The hole surface area ranges from 0 to 0.232 m^ m~l
along the length of the duct. The center duct has holes on both
sides, the outer duct only on the side facing plants.
b. Pollutant Dispensing and Monitoring
The pollutants are injected into the meter of the mixing box.
Sulfur dixoide is supplied from a tank, gaseous HF from a heated
solution of aqueous HF, and 03 from oxygen gas passing over an
ultraviolet light source. Sulfur dioxide is monitored with flame
photometric or pulsed-fluorescent analyzers, HF flux to static
samples is measured by wet chemistry methods, and 03 is measured with
a chemiluminescent analyzer. Multiple pollutant sampling locations
are distributed over the exposure plot. Air is sampled from each
point with a sequential sampler.
c. Environmental Control and Monitoring
Not described.
d. Data Acquisition
Not described.
B-4
-------
2. Performance Evaluation
a. Pollutant Uniformity
Pollutant concentrations increase linearly along the length of
the ducts. Sulfur dioxide concentrations increase from 0 to 1572 ug
m-3 along the duct. This increase is reflected in a doubling of leaf
total sulfur content. There is a similar increase in static HF
concentrations and fluoride content of leaf tissue. At a monitoring
point 11 m from the blower box, S02 concentrations decrease by 50 to
67% with an increase in height from 0.2 to 0.9 m above the outside
ducts, but remain the same with an increase in height above the
middle duct. Sulfur dioxide and 03 concentrations in plots vary by
100 to 400% over low, medium and high pollutant zones of a linear
gradient system based on frequency distributions, with the greatest
variation in the high concentration zones.
b. Environment Uniformity
Not described.
c. Pollutant Control and Maintenance
The duct system provides for a controlled gradient of pollutant
concentrations within a plant canopy. The gradient is reflected in
flux of pollutants to leaves. However, the pollutant was added
beneath the plant canopy and not at the top as occurs in ambient air.
A comprehensive network of air sampling is reauired to define the
pollutant exposure to particular plants.
d. Environment Control and Maintenance
Not described.
B-5
-------
20'M
ISM
^^f_ ,^^_ .^^t ^^f. ^^£. .^fe. ,^^£. ^fe_ _^^_ .^fe. _^^_ .^^. .^^. .^k. *vl^ ^fc. .^^ /
^^> ^^> .^fe. J^^. .^fe. ^^£. .^^t _^^. .^^^. ^^.' .^^. .^fe. ^^. .^^_ _^^_ *i^* ^^£. i
^^f. ^^£. .^fe. .^^£. i^^£. ^^. .^k. .^k. .^^. ^^. ^fa. .^k. .^^£. .^fe.
•| / / I-.
*1V IV *I* ^T* *I* ^T* *I^ ^1^ 1^ T^ ^^ •T^ *T^ *T*
Border
rows
• Tubes
Exposed Plonts
Figure B-2.
Schematic diagram of air exclusion system for exposure of plants
to linear gradients of pollutants (S02, HF, 03) (reprinted
Laurence et al., 1982, with permission of D. Reidel Publishing
Co., DordrechT, Holland).
B-6
-------
Publication: Shinn, J. H., B. R. Clegg, and M. L. Stuart. 1977.. A linear-
gradient chamber for exposing field plants to controlled levels of air
pollutants. .UCRL. Reprint No. 80411. .Lawrence Livermore Laboratory,
University of California, Livermore.
Additional Publications: Bennett, J. P., K. Barnes, and J. H. Shinn. 1980.
Interactive effects of H2S and 03 on the yield of snap beans (Phaseolus
vulgaris L.). Environ. Exp. Bet. 20:107-114.
Shinn, J. H. 1979. Problems in assessment of air pollution effects
on vegetation. In: Advances in Environmental Science and Engineering, J.
R. Pfaffling and E. N. Ziegler (eds.). Gordon and Breach Science Publish-
ers, Inc. New York. pp. 88-105. ,...•,
Shinn, J. H., B. R. Clegg, M. L. Stuart, and S. E. Thompson. 1976.
Exposures of field-grown lettuce to geothermal air pollution -- photo-
synthetic and stomatal responses. J. Environ. Sci. Health (Part A).
11:603-612.
Location: University of California, Livermore, California
Summary: An air exclusion system was designed and tested for exposure of
plants to a linear gradient of 03 and/or H2S in the field. The system has
three rows of ducts, and a high pressure blower to inflate the ducts and
blow filtered or unfiltered air plus added pollutants over the plant
canopy. The system is surrounded by a fiberglass wall to inhibit incur-
sion of ambient air into the exposure plot.
1. Hardware
a. Ducts
There are three ducts lying between and alongside two rows of
plants. The ducts are 7.5 m long and 0.15 m wide, with 1.0 m between
ducts to provide a total plant growing area of 15.0 m per system.
The ducts have one row of holes oriented perpendicular to the ground
and toward the crop rows. The hole sizes increase moving away from
the blower box, from 0.00254 m to 0.00559 m in diameter. The flow
rate in the center of the ducts decreases-from the blower box.,to the
end of the duct, but the air speed exiting the holes remains 10 m
s~l. Air is supplied from a blower assembly delivering 28.3 m^ min~l
to the system. The blower is equipped with charcoal filters.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide or H2S are delivered to the system from tanks via
regulators, a stainless steel capilary tube, and an injection tube
downstream from the charcoal filter. Ozone is generated by ultra-
violet lamps controlled by a variable transformer. Concentrations of
were measured with a flame photometric analyzer, S02 with a
B-7
-------
pulsed-UV fluorescent analyzer, and ozone with a UV absorption
analyzer. Monitoring from various sampling points is via a time-
sharing system. Pollutant dispension is controlled with time clocks.
c. Environmental Control and Monitoring
The environment is not controlled in this system; however,
ambient irradiance, air temperature, wind speed and direction are
measured during exposures.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
The air exclusion system produces a gradient of S02, H2$, or 03
concentrations along the ducts. Horizontal variability in concentra-
tions is from 300 to 2300% along the duct. Vertical variability is
approximately 250 times from emission holes to the soil. Average
pollutant concentrations in the system as a whole vary by 20% over
time.
b. Environment Uniformity
There are no differences in irradiance or air temperature in the
air exclusion system compared to outside.
c. Pollutant Control and Maintenance
The air exclusion system maintains a gradient of pollutant
concentrations over the exposure plot. The concentrations are more
variable than in a system purposely designed for uniform plant
exposures throughout the plot; however, the gradient system provides
pollutant exposures for regression analysis of pollutant responses.
d. Environmental Control and Maintenance
Not described.
B-8
-------
Capillary tube-
Blower-. Air inroke-.
110 Vac
Bbow \ *- Transformer
UV ozone
•Stovepipe duct
•Inflated polyethylene plenums
Figure B-3.
Schematic diagram of air exclusion system for exposure of plants
to H2S and 03 (reprinted from Shinn. _et a!., 1977, with permission
of University of California, Lawrence LTvermore National Labora-
tory).
8-9
-------
Publication: Spierings, F. 1967. Method for determining the susceptibility
of trees to air pollution by artificial fumigation. Atmos. Environ.
1:205-210.
Additional Publication: Mooi, J. 1972. Investigation on the sensitivity of
trees and shrubs to air pollution. (In Dutch). Inst. Phytopath. Res. Wag.
Ann. Rep. 1971. pp. 169-173, 195..
Location: Institute of Phytopathological Research, Wageningen, Netherlands
Summary: A unique apparatus is described to expose portions of trees and
shrubs to air pollution in the field. The system has a blower which
directs polluted air towards a target branch in a "gun-like" fashion. The
apparatus is a variant of an air-exclusion system with transparent plastic
plates directing the air flow while blocking ambient air incursion.
1. Hardware
a. Blower
The blower box consists of a U-shaped tube with the air inlet at
one end and a flaring air outlet at the other end. The tube is 0.25 m
internal diameter, flaring to 0.38 m diameter at the outlet. Air
flow through the tube is 30 m^ min"1. The blower is positioned so
that the direction of the air flow to the branch parallels the wind
direction. Clear square plastic baffles extending from the flared
outlet of the blower direct the air stream toward a particular branch
and prevent a change in ambient wind direction from altering the air
flow.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is injected into the blower through four holes
equidistant around the perimeter of a PVC tube encircling the inside
of the tube near the inlet and just before the fan. The sulfur
dioxide concentration of the air stream at the target branch is
determined by wet chemistry.
c. Environmental Control and Monitoring
Air temperature and relative humidity are recorded during
exposures.
d. Data Acquisition
Not described.
B-10
-------
2. Performance Evaluation
a. Pollutant Uniformity
c.
d.
The average pollutant concentrations for target branches vary by
approximately 5 to 9% over a wide range of exposures with 1310 to
3747 ug m~6 S02.
b. Environment Uniformity
Not described.
Pollutant Control and Maintenance
Not described.
Environmental Control and Maintenance
Not described.
B-ll
-------
ilr rtjuUtlon nln
p.v.c. tube 6 4 re. ins.
4 holes of 0,5 •
-»- air ootlet
baffle phte
Figure B-4.
Schematic diagram of "gun" air-exclusion system showing top view
(top) and side view (bottom) (reprinted from Spierings, 1967, with
permission from Pergamon Press).
B-12
-------
Publication: Thompson, C. R., and D. M. Olszyk. 1985. A Field Air-Exclusion
System for Measuring the Effects of Air Pollutants on Crops. EPRI
EA-4203. Final Report for Project 1908-3. Electric Power Research
Institute. Palo Alto, California.
Location: University of California, Riverside, California
Summary: The system has been designed to exclude ambient pollutants and add
pollutants along a linear gradient. The system is based on the Tennessee
Valley Authority (TVA) system (Jones et _al_. , 1977), but has been substan-
tially modified to increase the efficiency of air exclusion, provide for
exposure of greater numbers of plants, and be more portable and flexible
for different uses. This air-exclusion system has been compared to open-
and closed-top chambers for the degree of environmental modification and
plant response to air pollutant with exposures during all seasons of the
year.
1. Hardware
a. Ducts
The basic system consists of four major components: a module
containing the filters, a blower for air supply, a manifold for air
distribution, and perforated ducts to deliver the air to the target
area. The filter module is fabricated of galvanized sheet-metal to
form an approximate 0.6-m cube. The module contains three 0.61 x
0.61 x 0.2 m corrugated activated carbon filters each with 20.4 kg of
6-mesh coconut charcoal. Glass furnace filters and strainer mats
protect the charcoal-filters from dust. A 2-hp, three-phase blower
(0.8-m diameter wheel with backward curved blades) is installed in an
adjacent approximate 0.6-m cube area. A sheet metal duct leads from
the blower to a 1.82 x 0.61 x 0.61 m mixing manifold. The manifold
has four short galvanized metal exha.ust ports for attaching plastic
duct. Butterfly valves are installed in each exhaust port to
regulate the flow into each duct. The free air delivery into the
entire system is 57
mn
~l
There are four ducts for all pollutant exposures, with three
rows of holes pointed at 45° down, 90° and 45° from horizontal.
There are rows of holes on either side of the two center ducts and on
the plant canopy side of the outer ducts. The ducts are 0.32 m in
diameter, and made of PVC with a metal bar placed inside to stabilize
them against wind. The ducts- are 0.41 m apart. The length of the
ducts, hole spacing, hole diameter, and division of the duct into
sections for a gradient differs for each experiment. A general
configuration for ambient 03 exclusion studies has 9.1-m long ducts,
and 0.022-m diameter holes 0.15 m apart. The system provides a
gradient of ambient 03 exclusion by dividing the duct into three
sections with sequentially larger holes of 0.011, 0.019, and 0.032 m
diameters. A sulfur dioxide linear gradient is provided by dividing
3-13
-------
the duct into four sections with metal baffles, and injecting S0£
into the duct at different distances from the blower to achieve 0,
79, 183, and 393 ug m~3 concentrations.
b. Pollutant Dispensing and Monitoring
No pollutant dispensing is required for the ambient 63 exclusion
test. Ozone is measured at a number of sample points with a scanning
valve and UV absorption analyzer. For S02 gradient studies, S0£ is
supplied from a heated tank via a mass flow controller and needle
valve to a mixing Venturi filled with dried, compressed air. " The S02
is injected into metal baffles at the beginnings of the low, medium,
and high S02 concentration portions of the duct. Each injection tube
is equipped with hypodermic tubing and a length of 0.0032-m diameter
PVC tubing. The gas dispensing rate into a1 particular baffle is
regulated by varying the length of the hypodermic tubing at a con-
stant S02 gas pressure. Sulfur dioxide at a number of sampling
points is measured with a scanning-valve and interface-microcomputer
system.
c. Environmental Control and Monitoring
1 . . - ': *' '* ~ . .' L'. ' ' V* ' '' "• '
The environment is not controlled in this system. However,
controlling the air flow'from the duct holes can alter dew formation
and fog intercept by le'aves. Wind speed, air temperature, soil
temperature, leaf temperature, irradiancey and relative humidity are
measured routinely during exposures.
d. Data Acquisition
Ozone and S02 are monitored and S02 exposures are controlled by
an interface-microcomputer system. All pollutant- concentrations, and
air and leaf temperature data are processed and stored by the
computer-system.
2. Performance Evaluation .
a. Pollutant Uniformity
The air-exclusion systems effectively exclude up to 80% of the
ambient pollution from the plant canopy based on ambient 03 and CO
addition tests. Within the plant canopy (0.05 to 0.4 m above the
ground) there is a 10% difference in pollutant concentrations. Over
entire growing season there is 10% variability in added pollutant
concentrations to plots based on hourly-average values for S02-
b. Environment Uniformity
The air speed over the plant canopy is approximately 1 m s~!.
Air temperature is similar in the air-exclusion systems and outside
plots (ambient) during the summer and fall, and up to 1.5°C warmer in
the air-exclusion systems during the winter compared to outside
8-14
-------
plots. Soil and leaf temperatures are similar in the air-exclusion
systems and the outside plots during the summer, and 1 to 2°C higher
in the air-exclusion systems in the winter. Irradiance generally is
> 94% of ambient during most periods of time. Relative humidity is
the same in the air-exclusion systems and outside plots.
Pollutant Control and Maintenance , "I .-. .
, Pollutant concentrations are similar to those that could be
achieved in open- or closed-top chambers, in terms of both ambient
and added pollutants. There generally is greater variability in
pollutant concentrations in the air-exclusion system than chambers
due to more ambient incursion with high winds. However, the vari-
ability is more representative of ambient conditions and can be
monitored'and documented with the microcomputer data-aquisition
system. . " > •:
Environmental Control and Maintenance .. , ;
Uniform environmental -conditions .can be maintained .as easily ;
with the,duct-systems as with.open-top field chambers. Wind speeds
over the crop^canopy are much more variable with air-fexclusion ;
systems.than chambers due1 to ambient wind incursion; however,' ttm
variability may be more representative of ambient conditions than a
constantly uniform air flow rate over a plant canopy.
B-15
-------
Flushing Pump
Perforated Polyethylene Ducts
Manifold
Blower
Box
Activated
Charcoal
Filters
Blower
Exhaust Port
Fiberglass Mixing
Tunnel
IF
Ambient Air
Flowmeter
Regulator
Tank
CO
Figure B-5.
Schematic diagram of air exclusion system for oxidant exclusion
and S02 addition (reprinted from Thompson and Olszyk, 1985, with
permission of authors and Electric Power Research Institute).
B-16
-------
APPENDIX C
Descriptions of Facilities and Performance Evaluations --
Outdoor Chambers for Gaseous Dry Deposition Research
-------
-------
Publication: Brewer, R. F. 1978. The Effects of Present and Potential Air
Pollution on Important San Joaquin Valley Crops: Sugar Beets. Final
Report to California Air Resources Board. Project A6-161-30. Sacramento.
Location: University of California Experiment Station, Parlier, California
Summary: A square base, circular top, open-top field chamber has been designed
for use with sugar beets and other crops.
1. Hardware , , ..
2.
a. Chambers . •.' ; •- • .
The chambers are 3.8,m2 at the base and .2.4 m high. The sides
taper upward to a 3.1-m circular open top. The chambers are covered
with PVC film. Blowers equipped with charcoal filters deliver 34 m^
min"1 to each chamber. Air is delivered to the chamber between rows
of plants via 0.15- and 0.20-m diameter perforated PVC pipe.
b. Pollutant Dispensing and Monitoring
Combinations of filtered and nonfiltered air are used as treat-
ments; pollutants are not added to the chambers. Ozone is monitored
in different chambers via solenoid valves and an ultraviolet analyzer.
c. Environmental Control and Monitoring
The environment is not controlled in these chambers. Air
temperature, relative humidity, irradiance, and air speed are
measured during exposures.
d. Data Aquisition
Manually by recorders.
Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Air temperatures are 0.5 to 1.0°C higher in chambers than
outside. Relative humidities are 3 to 4% higher than outside at
night and 4 to 5% lower than outside from midday to 6 p.m. Irradi-
ance is within 85 to 93% of outside. Air speed over the plant canopy
is approximately 0.3-m s-1 in chambers.
C-l
-------
c. Pollutant Control and Maintenance
The chambers effectively exclude over 75% of the ambient ozone.
The square design apparently provides for exposures similar to
cylindrical chambers, but with more plant growing area.
d. Environmental Control and Maintenance
The open-top chambers provide environmental conditions similar
to outside and relatively uniform over time.
e. Chamber Equilibration
There are 2 air exchanges per minute.
C-2
-------
Figure C-l.
Schematic diagram of open-top field chamber for sugar beets
(Brewer, 1978).
C-3
-------
Publication: Brewer, R. F. 1983. Effect of Ambient Air Pollutants on
Thompson Seedless Grapes. Final Report to California Air Resources Board.
Project Al-132-133. Sacramento.
Location: University of California Experiment Station, Parlier, California.
A similar 7.32 m long, 2.74 m wide, and 4.27 m high rectangular chamber
with a frustum has been developed at the Boyce Thompson Institute, Ithaca,
New York.
Summary: A large rectangular open-top chamber has been designed for use with
grapevines. The chamber has been used for filtered and nonfiltered
exposures over a four-year period.
1. Hardware
a. Chambers
The open-top chambers are rectangular, 3.1 x 7.3 m, and 3.1 m
high. They have aluminum frames, a redwood base, and are covered by
PVC film. Air enters the chamber from a plenum (double-walled PVC)
around the lower 1.2 m of the chamber wall. Either charcoal-filtered
or nonfiltered air is blown into the chambers at 127 irp min~l.
b. Pollutant Dispensing and Monitoring
No pollutants are added to the chambers. Ozone is monitored
with an ultraviolet absorption analyzer using clock-controlled
solenoids.
c.
d.
Environmental Control and Monitoring
The environment is not controlled in the chambers. Air tempera-
ture, irradiance, and air speed are measured during exposures.
2.
Data Acquisition
Manually with recorders.
Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Air temperatures are 0.5 to 1.0°C higher in chambers versus
outside. Irradiance is slightly lower in chambers than outside. Air
speed is greater in chambers than outside during the night and early
morning, but lower in chambers during the day.
C-4
I i^BHBHiB " FF
I- 11
-------
c. Pollutant Control and Maintenance
No information on 63 concentrations is given.
d. Environmental Control and Maintenance
The environment in the chambers is similar to outside. The only
apparent chamber-related plant growth response is 7 to 10 days
earlier bud break and bloom.
e. Chamber Equilibration
There are 2 air exchanges per minute.
C-5
-------
GRAPE CHAMBERS
B
RlrMMor
DIOWoi
Assembly
i
.Door Post H
(one end only)!
Double Wall .
*^t North side)
i
i
i
i
! ^
!
i:;:iii:i:|:;:::i:i:i:i^i:^:i:::;::::i:i:
5'
¥
.
^3/4"Th!nwa!l tubing
•Redwood Base
Double 4* Panel
on bottom
Extruded
Aluminum
* Tube Lock
2"x 12"
Redwood Basl
Figure C-2. Schematic diagram of open-top field chamber for grapes (Brewer,
1983).
C-6
-------
Publication: Buckenham, A. H., M. A. Parry, C. P. Whittingham, and A. T.
Young. 1981. An improved open-topped chamber for pollution studies on
crop growth. Environ. Pollut. (Series B) 2:275-282.
Additional Publication: Buckenham, A. H., M. A. J. Parry, and C. P.
Whittingham. 1982. Effects of aerial pollutants on the growth and yield
of spring barley. Ann. Appl. Biol. 100:179-187.
Location: Rothampsted Experimental Station, Harpenden, England
Summary: An open-top field chamber has been designed and tested for use with
grasses. The design is based on wind tunnel tests and incorporates a
frustum at the top. The environmental conditions in the chamber are near
ambient, but still show detrimental effects on plant growth. A filtered
chamber effectively excludes 60-70% of ambient air pollutants.
1. Hardware
a. Chambers
Extensive wind tunnel tests with model chambers of different
dimensions have been made to determine the optimum shape and size of
the chamber before construction. The chambers are hexagonal, 2.4 m
in diameter and 2.3 m high. The frame is horizontal bars of aluminum
with vertical aluminum glazing bars. The covering is Novolux
sheeting. The area within the chambers is 5.5 m^, but plants are
sampled only from an area 2.5 m^ between the air dispersion ducts. A
frustum inclines at 30° above the horizontal, and a lip projects into
the chamber 0.5 m below the frustrum. Large axial flow fans supply
116 m3 air/min into the chambers. Air entering the filtered chambers
passes through a unit containing 16 activated-charcoal filters
positioned in parallel. Two flexible ducts connect the filter unit
to a set of six rigid ducts arranged in parallel across the floor of
the chamber. Air is emitted from 0.01-m diameter holes located 0.03
m apart on both the upper and lower sides of the ducts. Air moves
vertically up through the chamber.
b. Pollutant Dispensing and Monitoring
The chamber is used only for ambient air-exclusion studies,
pollutants are not added. Ambient SOg concentrations are determined
with a flame photometric analyzer, sampling at canopy height (up to
0.6 m). Hydrogen fluoride is measured by wet chemistry. Ozone is
measured with an UV absorption analyzer.
c. Environmental Control and Monitoring
The environment is not controlled in the chamber. Air tempera-
tures, relative humidty, and light intensity are measured in the
chambers and outside.
C-7
-------
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
The filtered chambers exclude 63% of the ambient $03, and the
unfiltered chambers exclude 8%. Filtered chambers exclude 43% of the
ambient HF compared to unfiltered chambers based on fluoride content
of barley leaf tissue. There was no information on 03 distribution
in the chambers.
b. Environment Uniformity
Air temperature is 0.5 to 1.4°C higher in chambers than outside.
Irradiance is 10 to 20% lower in chambers than outside. Vertical air
speed rate through the chamber is 0.25 m s~*. Relative humidity is
reduced 10% from outside.
c. Pollutant Control and Maintenance
At low wind speeds, the filtered chambers greatly reduce S02
concentrations; however, with moderate wind speeds S02 concentrations
in the chamber can be reduced to only 50% of ambient.
d. Environmental Control and Maintenance
The chambers themselves result in altered plant growth compared
to outside plots. Barley grown in unfiltered chambers compared to
plants from outside have earlier anthesis, fewer shoots per unit
area, fewer ears, lower straw dry weights, and a smaller photosyn-
thetic area.
e. Chamber Equilibration
There are 3.5 air exchanges per minute.
C-8
-------
vertical section
90'
AB,
transverse section
1m
N
Air ducts
Holes
Crop rows
1m
Figure C-3.
Schematic diagram of open-top chamber (top), and chamber air
dispensing system (bottom) (reprinted from -Buckenham _et £l_., 1981,
with permission of Elsevier Applied Science Publishers, Ltd.).
C-9
-------
Publication: Farrar, J. F., J. Relton, and A. J. Rutter. 1977. Sulfur
dioxide and the growth of Pinus sylvestris. J. Appl. Ecol. 14:861-875.
Additional Publications: Garsed, S. G., and A. J. Rutter. 1984. The effects
of fluctuating concentrations of sulphur dioxide on the growth of Pinus
sylvestris L. and Picea sitchensis (Bong.) Carr. New Phytol. 97:175-189.
Lane, P. I., and J. N. B. Bell, 1984a. The effects of simulated
urban air pollution on grass yield: Part I —• Description and simulation
of ambient pollution. Environ. Pollut. (Series B) 8:245-263.
Mueller, P. W., and S^G. Garsed. 1984. A microprocessor-controlled
system for exposing plants to fluctuating concentrations of sulphur
dioxide. New Phytol. 97:165-173.
Location: Imperial College, Silwood Park, Ascot, England
Summary: The facility consists of eight closed-top field chambers used to
study the effects of S02 and N02 on grasses and trees.
1. Hardware
a. Chambers
The chambers are 1.5 x 1.5 m base and 1.0 m high gabled closed-
top chambers with a wood base and Perspex® plastic covering. The air
inlet is 0.1-m bore tubing at a height of 0.6 m and directed towards
the chamber roof. A high capacity fan blows air through the
chambers.
b. Pollutant Dispensing and Monitoring
Pollutant dispensing is computer controlled via a micro-
processor, flow-controllers,and valves. Sulfur dioxide was obtained
from a tank of 5% S02 in nitrogen. Nitrogen dioxide and nitric oxide
also are obtained from tanks. Sulfur dioxide is monitored with a
flame photometric analyzer,, and NOx'with a chemiluminescent analyzer
and wet chemistry methods.
c. Environmental Monitoring and Controls
The chambers are covered, with green plastic netting to absorb
visible radiation when used with pine trees. There are no other
environmental controls. Temperature is monitored with shielded
thermistors and copper-constantan thermocouples, radiant flux with
, solarimeters, and airflow with an electronic vane anemometer.
d. Data Aquisition
Manual and computer.
C-10
-------
Performance Evaluation
a. Pollutant Uniformity
Sulfur dioxide concentrations vary by 7 to 15% over time, and by
less than 5% between replicate chambers. In a different study, SC>2
and NOx concentrations varied according to an exposure regime repre-
sentative of central London.
b. Environment Uniformity
The plastic netting absorbed approximately 40% of the visible
radiation. The chamber air temperature is 1 to 3°C higher than
outside at night, and up to 8 to 10°C higher with bright sunshine
during the day. Air temperature varies by + 0.2°C between chambers
in winter, and +_ 0.35°C in summer. Vapor pressure deficit was
greater in chambers than outside. Air speed through is adequate to
provide a boundary layer resistance of 23 to 37 s m~l across the
chambers.
c. Pollutant Control and Maintenance
The computer control system effectively maintains the S0£
concentrations at the desired frequency distribution.
d. Environment Control and Maintenance
The environment is different in chambers vs. outside, however,
the extent of this variation has been documented.
Chamber Equilibration
There are 2 air exchanges per minute.
C-ll
-------
Publication: Ashmore, M. 1985. Personal communication.
Location: Imperial College, Silwood Park, Ascot, England
Summary: A system of eight small open-top field chambers is being used to
study the effects of ambient and filtered air on plants.
1. Hardware
a. Chambers .' ... -
The chambers have open-tops and are cylindrical, 1.5-m diameter
and 1.5-m high. They have aluminum frames covered with clear plast.ic
sheet. Air is supplied from 1.1-kw fans for ambient air and 2.2-kw
fans for filtered air; with each fan supplying two chambers. Air
enters the chambers through ducting leading to an essentially closed
vertical acrylic tube at the side of the chamber. A 0.1-m diameter
horizontal polyethylene torus is attached to the vertical tube to
bring air around the chamber. Thevtorus has 0.02-m diameter holes
punched at 0.15-m intervals. The height of the torus is adjusted
upward toward the top of the chamber as the plants develop during the
growing season. The amount of air flowing into the chambers is
controlled via butterfly valves.
b. Pollutant Dispensing and Monitoring
No pollutants are dispensed; the chambers are used only for
ambient and filtered air. Air is.sampled for S02, 03, and N02 just
above the plant canopy.
No environmental control.
have not been described.
Methods for environmental.monitoring
2.
c. Environmental Monitoring and Controls
d. Data Aquisition
Microcomputer system.
Performance Evaluation
a. Pollutant Uniformity
The filter efficiency for the chamber is 50 to 60% of ambient
S02, N02, and 0$, but NO is not removed. Pollutant concentrations
were not described.
b. Environment Uniformity
Air temperatures are 0 to 2°C higher than outside depending on
environmental conditions.
C-12
-------
3.
c. Pollutant Control and Maintenance
Not described.
d. Environment Control and Maintenance
Not described.
Chamber Equilibration
There are 4 to 5 air exchanges per minute,
C-13
-------
Publication: Fowler, D. 1986. Specifications of Open-Top Chambers Used in
Barley Studies at the Institute of Terrestrial Ecology. Personal communi-
cation, 1986. Also in Proceedings of European Open-Top Chamber Workshop.
1986. Commission of the European Communities. Freiberg, Federal Republic
of Germany.
Location: Institute for Terrestrial Ecology, Glasgow, Scotland
Summary: An open-top field chamber system is described for determination of
the effects of ambient air pollutants on plant growth. The system is
desiqned to maximize air flow over the plant canopy and can be used for
pollutant flux measurements. Fluxes of N02, S0£, CQz, NO, and 03 to the
canopy have been measured continuously for periods of up to several days,
indicating its potential use for linking longer-term (growing season)
effects studies to physiological response studies. The system has
extensive pollutant and environmental condition monitoring, and computer-
ized data acquisition.
1. Hardware
a. Chambers
The chambers are 1.6-m diameter x 1.24-m high cylinders with
fiberglass walls. The ground surface area in the chamber is 1.21 m2
and volume is 1.93 m3. There is a frustum at the top of the chamber
which reduces the top open diameter to 0.9 m. Air is supplied to the
chamber from a blower box containing four 0.8 x 0.8 x 0.04 m acti-
vated-carbon filters treated with chemicals to absorb N02 and S0£ as
well as 03. Air is pumped into the chamber at a variable rate of
1 to 9 m3 min'1, but generally with 6 m3 min'1. Air is distributed
within the chamber through a vertically adjustable plastic pipe
supplying a perforated, 0.10-m diameter plenum. The plenum generally
has been positioned at 0.6 m above the ground.
b. Pollutant Dispensing and Monitoring
The chambers have been used only for ambient exclusion studies;
pollutants have not been added to the system. Pollutants monitored
include S02, NO, NOX, and 03. Solenoids switch between filtered and
ambient chambers every 20 minutes for air sampling; only the average
for the last 5 minutes of sampling is saved by the microcomputer
system.
c. Data Acquisition
Microcomputer system for storage and processing of data; concen-
trations are summarized in graphical form.
C-14
-------
d. Environmental Controls
Environmental conditions are not controlled in the chamber. Air
temperature, CC>2 concentration, wind speed, wind direction, and short
wave radiation are monitored continuously, stored, and processed by
microcomputer. Chemistry of rainfall events is monitored.
2. Performance Evaluation
a. Pollutant Uniformity
The filters remove approximately 95% of the ambient S02, 90% of
the NC>2, 95% of the 03, but none of the NO. The exclusion efficiency
of the chambers for S02, N02, and 03 is approximately 80%, but
decreases to 67% with higher ambient wind speeds. Air flow rates
into chambers have been adjusted to within 5% between chambers to
provide similar pollutant exposures. Concentrations of pollutants
are monitored continuously in one filtered and one ambient chamber.
Uniformity in pollutant concentrations between all chambers is
checked once per month.
b. Environment Uniformity
Air temperature inside the chamber exceeds ambient by < 1°C for
short-wave radiation flux of <50 W nr2. For flux between 200-700,
the air temperature difference is 1 to 2°C. Leaf temperatures within
chambers are only slightly higher than external leaf temperatures.
The air speed over the plant canopy is approximately 3 m s-1, result-
ing in very small temperature differences between chamber air and
leaves.
c. Pollutant Control and Maintenance
The pollutant monitoring system has been in continuous operation
for over one year.
d. Environmental Control and Maintenance
The environment is similar to ambient year-round, primarily due
to the high air speed rate.
e. Chamber Equilibration
There are 10 chamber air exchanges per minute.
C-15
-------
19 Seepage trench
20 Reserve pipes for
further development
21 Vacuum pump
22 Exhaust chimney
23 Turn table
1 Freeze drier
2 Pump for carrier gas
S02 generator
HCI generator
5 Cooling pump
6 Membrane pump
Container for HCI solution
8 HF generator
9 HF solution
10 Collection pipe for carrier gas
11 Branch pipe to fumigation chambers
12 Flow meter
13 Pollutant input in carrier gas pipe
16 Mixing chamber
15 Pollutant carrier gas mixture
16 Distributor head
17 Suction pipe with damper
18 Exhaust pipe
Figure C-4. Diagram of open-top field chamber designed by Institute for
Terrestrial Ecology staff (D. Fowler,.personal communication)
Volume A = 1.21 m3; B = 0.72 m3; Flow Rate = 0.10 m3 sec'1.
C-16 '
-------
Publication: Garrel, J. P. 1986. Personal communication.
Additional Publication: Heagle, A. S., R. B. Philbeck, and W. W. Heck. 1973.
An open-top chamber to assess the impact of air pollution on plants. J.
Environ. Qua!. 2:365-368.
Location: Laboratoire d'Etude de la Pollution Atmospherique, Institut National
de la Rechereche Agronomique, Champenoux, France.
Summary: Two open-top field chambers designed to study the effects of gaseous
air pollutants on tree seedlings at an altitude of 1000 m in Northeastern
France.
1. Hardware
a. Chambers
Two chambers were constructed according to the design of Heagle
et al. (1973). Each chamber is 2.4 m high, 3.0 m diameter, with an
"aluminum frame and PVC film covering. The chambers are cylindrical
with open tops and no frustrum. The filtered chamber has an
activated-charcoal filter which removes S0£, N02, and hydrocarbons,_
and catalytically converts 03 to oxygen. The filters do not remove
NO.
b. Pollutant Dispensing and Monitoring
Pollutants are not added to the chambers; they have only fil-
tered or ambient air. No information is available on pollutant
dispensing and monitoring, nor on efficiency in pollutant removal
with chamber filtration system.
c. Data Acquisition
Not described.
d. Environmental Control and Monitoring
The environment is not controlled, and no information is avail-
able on any routine environmental monitoring.
2. Performance Evaluation
a. Pollutant Uniformity
Not descrited.
b. Environment Uniformity
Not described.
C-17
-------
3.
c. Pollutant Control and Maintenance
Not described.
d. Environmental Control and'Maintenance
Not described.
Chamber Equilibration
There are 4 air exchanges per minute.
C-18
-------
Publication: Guderian, R. 1977. Air Pollution. Phytotoxicity of Acidic
Gases and Its Significance in Air Pollution Control. Ecol. Stud. 22.
Springer-Verlag, New York.
Location: Landesanstalt fur Immissionsschutz, Essen, West Germany, Large
Gabled Greenhouses
Summary: Large, square, closed chambers have been designed to investigate the
effects of S02, HF, and HC1 on plants. A central building houses instru-
mentation for taking in ambient air, generating the air pollutants, and
delivering them to the chambers via an underground piping system.
Polluted air is pumped into the tops of the chambers and mixes in the
chamber with filtered air drawn into the chambers.
1. . Hardware
a. Chambers
The facility includes 32 large, square chambers with a central
peaked roof. The chambers are covered with Mylar polyester film.
Outside carrier air enters a central building and goes through a
freeze-drier to remove moisture. Sulfur dioxide, HF, and/or HC1 are
generated in the building and enter the carrier air stream. The
polluted air is pumped through underground plastic ducts and enters
the chambers through a head manifold at the center of the top of the
chamber. Outside air is drawn into the chamber through charcoal-
filters by a pump beneath the center of the chamber. A turntable at
the base of the chamber rotates the plant pots. The air mixture is
then pumped underground, and after washing, exits though an exhaust
duct at the top of the control building.
b. Pollutant Dispensing and Monitoring
A comprehensive system is described for generating S02, HF, and
HC1. Specific pollutant concentrations are produced by regulation of
the amounts generated and amount of make-up air used for dilution.
The volume of charcoal-filtered ambient air for dilution of added
pollutants is regulated by a variable damper in the incoming air
stream. Pollutant monitoring is by continuous sampling for S02 and
HC1 and by a wet chemistry method for HF.
. c. Environmental Control and Monitoring
Not described.
d. Data Aquisition
Not described.
C-19
-------
2. Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Environmental conditions were "slightly altered" from ambient,
but specific changes were not described.-
c. Pollutant Control and Maintenance
Pollutant control is limited, i.e. of concentrations and
exposure times.
d. Environmental Control and Maintenance
Not described.
e. Chamber Equilibration
There are 1.3 to 1.7 air exchanges per minute.
C-20
-------
OPEN-TOP CHAMBER
FILTER/PUMP UNIT
•92
160
T
-300.
Figure C-5. Diagram of closed field chamber (reprinted from Guderian, 197.7,
with permission of Springer-Verlag).
C-21
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Publication: Heagle, A. S., R. B. Philbeck, and W. W. Heck. 1973. An open-
top chamber to assess the impact of air pollution on plants. J. Environ.
Qual. 2:365-368.
Additional Publications: Davis, J. M., and H. H. Rogers. 1980. Wind tunnel
testing of open-top field chambers for plant effects assessment. J. Air
Pollut. Contr. Assoc. 30:905-907.
Heagle, A. S, and M. B. Letchworth. 1982. Relationships among
injury, growth, and yield responses of soybean cultivars exposed to ozone
at different light intensities. J. Environ. Qual. 11:690-694.
Heagle, A. S., and R. B. Philbeck. 1978. Exposure Techniques. In:
W. W. Heck, S. V. Krupa, and S. N. Linzon (eds.). Handbook of Methodology
for the Assessment of Air Pollution Effects on Vegetation. Air Pollution
Control Association, Pittsburgh, pp. 6-1 to 6-19.
Heagle, A. S., R. B. Philbeck, H. H. Rogers, and M. B. Letchworth.
1979. Dispensing and monitoring ozone in open-top field chambers for
plant effects studies. Phytopathology 69:15-20.
Heck, W. W., 0. C. Taylor, R. Adams, G. Bingham, J. Miller, E.
Preston, and L.H. Weinstein. 1982. Assessment of crop loss from ozone. J.
Air Pollut. Contr. Assoc. 32:353-361.
Heck, W. W., W. W. Cure, J. 0. Rawlings, L. J. Zaragoza, A. S.
Heagle, H. H. Heggestad, R. J. Kohut, L. W. Kress, and P. J. Temple.
1984. Assessing impacts of ozone on agricultural crops: I. Overview. J.
Air Pollut. Contr. Assoc. 34:729-735.
Heggestad, H. E., R. K. Howell, and J. H. Bennett. 1977. The
Effects of Oxidant Air Pollutants on Soybeans, Snap Beans, and Potatoes.
U.S. Environmental Protection Agency, Corvallis, Oregon. EPA-600/3-77-
128.
Olszyk, D. M., T. W. Tibbitts, and W. M. Hertzberg. 1980. Environ-
ment in open-top field chambers utilized for air pollution studies. J.
Environ. Qual. 9:610-615.
Unsworth, M. H., A. S. Heagle, and W. W. Heck. 1984a. Gas exchange
in open-top field chambers. I. Measurement and analysis of atmospheric
resistances to gas exchange. Atmos. Environ. 18:373-380.
Unsworth, M. H., A. S. Heagle, and W. W. Heck. 1984b. Gas exchange
in open-top field chambers. II. Resistances to ozone uptake by soybeans.
Atmos. Envion. 18:381-385.
Weinstock, L., W. J. Kender, and R. C. Musselman. 1982. Micro-
climate within open-top air pollution chambers and its relation to grape-
vine physiology. J. Amer. Soc. Hortic. Sci. 107:923-926.
C-22
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Location: Developed at North Carolina State University with funding from the
U.S. Environmental Protection Agency (EPA)
Summary: A detailed description is provided by Heagle ^t _al_. (1973) for
construction and operation of one of the first opeTPtop" field chambers
designed for exposures of vegetation to gaseous pollutants in the field.
The chamber was adaptable for both pollutant exclusion and addition
studies. Tests at multiple sites with many crops indicated the near
ambient environmental conditions in the chambers and uniformity of pollut-
ant dispersal. Tests also indicate the usefulness of the chamber for crop
loss assessments on a growing season basis. This generic .description is
applicable to the basic chamber design as tested by a number of research-
ers. Table C-l summarizes some basic characteristics of the EPA-designed
chamber as it is used by a number of research groups throughout the U.S.
and Canada.
1. Hardware
a. Chambers
The chambers are open-top cylinders 2.4 m high x 3.0 m in
diameter with an interior plant growing area of 7.1 m^. The frame is
of three rolled-aluminum hoops 1.2 m apart with vertical and oblique
aluminum crossbars. The chamber is covered with PVC plastic in
separate upper and lower panels. The lower panel is two layers, an
inner layer perforated with 250 0.025-m diameter holes, and an outer
layer without holes. The lower panel inflates with forced air and
acts as a plenum or diffuser. Air flows from the plenum across the
plant canopy and out the top of the chamber. The original chamber
design ended abruptly at the top of the cylinder, resulting in a
turbulent flow of ambient air into the chamber which increased with
increasing wind speed. Addition of a conical nozzle or frustum at
the top greatly reduces the rate of ambient air incursion, and makes
chamber pollutant concentrations more uniform both vertically within
the chamber and at different ambient windspeeds (Davis and Rogers,
1980). The frustum is at a 45° angle rising from the top of the
chamber resulting in a total chamber height of 2.9 m. This reduces
the effective open-top of the chamber to 2.1 m in diameter. Slight
modifications of the frustum are often made for the chamber based on
local site conditions.
Air is supplied by a 0.63 hp axial-blade fan located in a sheet-
metal blower box. The box is equipped with dust-filters and charcoal-
filters when supplying filtered air. Air is blown into the chamber
at a rate of 70.8 m3 min-1.
b. Pollutant Dispensing and Monitoring
Pollutant dispensing varies~with the chamber installation. A
system for dispensing and monitoring 03 for the chamber has been
described in detail by Heagle^t jf[. (1979). Ozone is produced from
oxygen with a "silent arc" generator controlled by a timer. Oxygen
C-23
-------
to
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C-24
-------
flow is adjusted with a pressure regulator, needle valve, solenoid,
time clock, and rotameter. Safety switches in the 03 generator
stop the operation automatically if required. Ozone is dispensed
from a manifold to individual chambers via rotameters. Pressure is
regulated in the manifold to stabilize the rotameters.
Pollutant monitoring (03) is via individual air samples drawn
through teflon tubing from each chamber through solenoid valves to
either a sampling manifold or exhaust manifold by vacuum pumps. Both
vacuum pumps exhaust 03 to the atmosphere through charcoal filters.
Sequential activation of the solenoids by a timer (scanner) causes
the sample to be delivered to the sampling manifold. Samples are
drawn from the sampling manifold by a chemiluminescent 03 analyzer.
c. Environmental Control and Monitoring
The original EPA chamber has been designed,to provide minimal
environmental modification but without an initial capacity to control
either the atmospheric or soil environment. Stretching polypropylene
shade cloth (rated for different degrees of light reduction) across
the top of the chamber allows for manipulation of radiation intensity
x 03 interaction studies (Heagle and Letchworth, 1982). Alteration
of soil moisture through manipulation of irrigation allows for water
stress x 03 interaction studies (Temple et al., 1985). Placement of
the chambers over controlled salinity soTT profile plots allows for
soil salinity x 03 interaction studies (D. Olszyk, personal communi-
cation). Air flow rate through the chamber can be modified by
placing baffles upstream of the fan (Unsworth et ^1_., 1984a,b).
d. Data Aquisition . .
Data aquisition varies with the installation, but may include
manual reduction from recorder charts, or use of a datalogger or
interface-computer system for continuous storage of data.
2. Performance Evaluation
a. Pollutant uniformity
Vertical variation in 63 concentrations is less than 6% of the
mean between 0.3- and 1.2-m heights in the chamber. Horizontal
variation across the chamber is less than 6, 12, and 14% of the mean
at heights of 0.3, 1.2, and 1.8 m. This variation is based on wind
speeds less than 4.2 m s"1 for a chamber without a frustum (Heagle ^t
al., 1979). At higher wind speeds, uniformity decreases greatly
unless a frustum is added. Ambient 03 exclusion rates ranges from
75% at- low wind speeds to 57% at high wind speeds.
C-25
-------
b. Environmental Uniformity
Environmental conditions in the chambers vary slightly from
outside conditions (Heagle £t j^K, 1973; Heagle and Philbeck, 1978;
Heagle etjH., 1979; Heggestad et jH., 1977; Olszyk et_al_., 1980;
Weinstock et al., 1982). Air temperature generally is < 2°C warmer
than outsicfe" "Erased on peak temperatures > 32°C. Relative humidity is
generally the same as outside, but may be a few percent lower if
chamber air tempertures are.greater than outside, or slightly higher
if air flow is reduced or the chamber contains a great deal of plant
material. Irradiance is usually within 85-95% of ambient. Irradi-
ance is decreased with dirty chamber plastic or during spring or fall
months with low sun angles. Irradiance can also be temporarily
increased with certain sun angles and clean plastic covering. Air
movement over the plant canopy at the center of the chamber is approx-
imately 0.6 m s"1. The rainfall pattern inside the chambers varies
from outside depending on wind speed.
c. Pollutant Control and Maintenance
The 03 dispensing and monitoring system of Heagle et aJL (1979)
performs well over continuous growing season studies. Additional
modifications to the original dispensing system, such as feedback
control to the 03 generator via a computer, provide for proportional
control of 03 concentrations as some percentage of ambient (Temple et
al., 1985). Computer-control also permits programmed dynamic
exposures (Hog sett _et al_., 1985). Fine tuning of the solenoid system
and/or use of critical orifices can further reduce variability in
ozone concentrations between chambers and over the growing season (E.
Pell, personal communication).
d. Environmental Control and Maintenance
The environmental conditions are similar to ambient (see 2b) at
least during the growing season. Maintenance of the plastic film for
transparency and the blower for maximum flow rate help keep the
chamber environment near outside conditions.
e. Chamber Equilibration
The chamber air exchange rate is approximately 4 chamber volumes
per minute.
C-26
-------
Charcoal Filter
Figure C-6.
Diagram of open-top field chamber originally designed by North
Carolina State University staff under a contract from the U.S.
EPA.
C-27
-------
Publication: Hogsett, W. E., D. T. Tingey, and S. R. Holman. 1985. A
programmable' exposure control system for determination of the effects of
pollution exposure regimes on plant growth. Atmos. Environ. 19:1135-1145.
Location: U.S. Environmental Protection Agency, Con/all is, Oregon
Summary: A field exposure facility was designed and constructed to control the
atmosphere around the plant canopy for investigations of pollutant
dynamics. The chamber is a modification of the Heagle et al. (1973)
design with a truncated cone top frustum and a rain cap. The chamber is
operated with a microcomputer system which controls pollutant exposures,
pollutant and environmental monitoring, and irrigation.
1. Hardware
a. Chambers
The chambers are cylindrical, 3.0 m in diameter and 2.4 m high,
with aluminum frames and PVC coverings. A cone-shaped frustum is at
the top, reducing the chamber opening to 2.0 m. A 3.0-m diameter rain
cap is added 0.3 m above the top to exclude ambient rain. Air flow
into the chambers is through charcoal-filters via an axial-blade fan.
Airflow into the chambers is 305 m3 min"1. Air enters the base of
the chamber through a l;2-m high double-walled plenum.
b. Pollutant Dispensing and Monitoring
Ozone is produced by a spark discharge generator using pure
oxygen. The desired 03 exposures are programmed.into the computer as
hourly concentration values over the 7-month growing season. Up to
14 different exposure profiles can be controlled. The hourly 03
concentrations are regulated by the microcomputer through feedback
control, and 03 enters the chambers via rotameters. Ozone is sampled
sequentially from the chambers and monitored with ultraviolet
analyzers.
c. Environmental Control and Monitoring
A microprocessor-controlled drip irrigation system is used for
watering and fertilizing the plants. Environmental conditions are
monitored in chambers and outside, including air and soil tempera-
ture, relative humidity, and irradiance.
d. Data Acquisition
Data acquisition is with an interface and microcomputer. All
pollutant dispensing, pollutant and environmental monitoring, and
irrigation are controlled by the system. Extensive development of
software allows for pollutant episode programming and control.
C-28
-------
2. Performance Evaluation
a. Pollutant Uniformity
Hourly-averaged ozone concentrations are within 3 to 13% of the
programmed values for all pollutant patterns over the season. Lonq-
term distribution of ozone within the chambers is stable with outside
wind speeds of 2.2 to 5.5 m s"1. Ozone concentrations vary by <10%
between 0.2 and 0.5 m high in the chamber. Ozone varies by < 15%
horizontally across the chamber, except for a few points near the
periphery which varied by 20%.
b. Environment Uniformity
The average daily air temperature within the chamber was about
2°C warmer than ambient with the largest variation on cool, sunny
days. Daily solar radiation was 13-22% less than ambient during the
growing season. . .
c. Pollutant Control and Maintenance
Pollutant exposure profiles are carefully controlled by this
system, in terms of both achieving target levels and between repli-
cate chambers. Weekly span checks are made on analyzers. Sample
line loss determined at beginning and end of season.
d. Environmental Control and Maintenance
Not described.
e. Chamber equilibration
There were 1.5 air exchanges per minute.
C-29
-------
to Control Building
Charcoal Filter
Figure C-7.
Diagram of open-top field chamber with rain cap for facility
located at the U.S. EPA Environmental Research Laboratory in
Corvallis, Oregon (reprinted from Hogsett et_ a}_., 1985, with
permission of Pergamon Press).
C-30
-------
Publication: Kats, G., D. M. Olszyk, and C. R. Thompson. 1985. Open-top
experimental chambers for trees. J. Air Pollut. Contr. Assoc. 12:1298-
1301.
Location: University of California, Riverside, California
Summary: A large open-top field chamber has been developed for use with young
Valencia orange trees for long-term growth and yield studies. The
chambers have been used continuously for two years. Ozone and sulfur
dioxide concentrations are uniform within and between chambers. Environ-
mental conditions are modified only slightly from ambient; however, these
differences are associated with increased growth of trees in the chambers
versus outside.
1. Hardware
a. Chambers
The chambers are 2.94 m high and 4.27 m in diameter. Each
chamber has a lower base fabricated from two galvanized metal hoops
with 10 0.91-m metal uprights and is covered with corrugated fiber-
glass panels. One fiberglass panel is left unattached and hinged as
an entrance to the chamber. The hemispherical domes are fabricated
from 10 panels of UVEX plastic which are popriveted together and
popriveted and glued with sealant to the upper hoop of the base.
The chambers are equipped 0.61-m height x width x depth blower
boxes containing 3/4-hp propeller fan blowers, particulate filters,
and corrugated charcoal filters. A 0.53-m diameter x 0.61-m long
cylindrical baffle leads from the blower box to the chamber. The ,
baffle contains four crescent-shaped baffles for air mixing. The
incoming air flow is directed toward the citrus trees through a sheet
metal diffuser containing three vertical and six horizontal rows of
0.076-m diameter holes. Air flow into the chamber is approximately
56 ITH min-1.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is dispensed into the chambers via rotameters and
a flow controller from a heated tank of pure S02- Oxidant treatments
are achieved by blocking off part of the air flow through the
charcoal filters. Sulfur dioxide is monitored with a pulsed fluor-
escence analyzer and 03 with an ultraviolet absorption analyzer.
Samples are taken sequentially from chambers with a scanning valve.
c. Environmental Control and Monitoring
The environment is not controlled in the chambers. Air tempera-
ture, leaf temperature, relative humidity, and irradiance are
measured continuously.
C-31
-------
d. Data Aquisition
All pollutant and environmental monitoring is via an interface-
microcomputer system.
Performance Evaluation
a. Pollutant Uniformity
Filtered chambers effectively exclude 85% of the ambient 63.
b. Environment Uniformity
Irradiance in the chamber averaged over 90% of outside over a
period greater than one year. Leaf temperatures inside chambers
averaged 1 to 3°C greater than outside, even with outside tempera-
tures > 40°C. Relative humidity is the same in chambers as outside.
Air temperature and dewpoint data are being processed. Air speed
within the tree canopy is approximately 0.5 m s~l.
c. Pollutant Control and Maintenance
The chambers provided for good control of pollutant concentra-
tions, effectively excluding ambient air and delivering S02 exposures
within 10% of the target levels. The major design change over the
course of chamber testing is the addition of a pollutant diffuser
instead of a baffle. The diffuser is more efficient in providing air
flow to the tree canopy than the standard lower chamber plastic duct
used in EPA design chambers. The chambers originally were equipped
with a 0.91-m diameter duct around the inside of the chamber base.
The duct has four horizontal rows of 0.051-m diameter holes, 0.23 m
apart. A series of air flow measurements with a grid across the
chamber has indicated that air flow across the tree canopy is the
same or slightly greater with the metal diffuser than the duct. A
"diffuser is installed in each chamber as it is simpler to construct
and will not deteriorate compared to a plastic duct.
d. Environmental Control and Maintenance
Environmental conditions are uniform between chambers and
similar to outside on an annual average basis. However, the differ-
ences in environment that did occur resulted in increased vegetative
growth for chamber versus outside trees.
e. Chamber Equilibration
There are approximately 1.8 air exchanges per minute.
C-32
-------
2.44 m
2.03 m
<
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1
J.3I(T
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i
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Figure. C-8.
Diagram of side view of open-top field chamber for citrus trees
(reprinted from Kats et al., 1985,- with permission-of the Air
Pollution Control Association). ,- .-:•
C-33
-------
CHARCOAL
FILTER
BLOWER
ASSEMBLY
UPRIGHT FRAME
SECTION
0.91 m
7-1.2 7m
Figure C-9.
Diagram of cross-section of open-top field chamber for citrus
trees (reprinted from Kats et_ al_., 1985, with permission from the
Air Pollution Control Association).
C-34
-------
Publication: Keller, T. 1976. Auswirkungen niedriger S02-Konzentrationen auf
junge Fichten. Schweiz. Zeit. Forstwes. 127:237-251. and T. Keller,
personal communication.
Location: Swiss Federal Institute of Forestry Research, Birmensdorf,
Switzerland
Summary: A description is provided for a large-scale field chamber facility
designed for year-round investigations of S02 effects on small trees, and
recently modified for studies on the effects of 03. The trees are clonal
material growing in 10-liter pots. The site includes 20 round, closed-top
chambers and a movable cover to shade plants from full sunlight. The
careful control of pollutant exposures within the site is described, and
the effect of the chambers on air temperature and relative humidity is
documented.
1. Hardware
Chambers
The chambers are cl
2.5 m high. The top is
top. The chambers have
Air-flow is from a 50 m^
chambers, or 10 m min
air, studies with added
controls. A cover over
during full sunlight and
osed-top cylinders, 2.0 m in diameter and
not airtight to allow for air flow from the
steel frames and plexiglass walls and tops.
min~l capacity blower servicing five
per chamber. Studies with SOp used ambient
03 use carbon-filtered air with ambient air
the entire chamber facility provides shade
is controlled by a selenium cell.
Pollutant Dispensing and Monitoring
Sulfur dioxide exposures use manual dispensing of tank S0£, with
monitoring by a Philips PW 9700 S02 analyzer. Ozone exposures use a
Fischer ozone generator supplied with pure oxygen, manually dispensed
into filtered chambers at 100 or 300 ug nr3 for 9 h day1 (0800-
1700), 5 day week~l. Ozone is monitored with a Monitor Labs analyzer.
For the S02 studies, 03 and NOX also are routinely monitored, and for
the 03 studies, S0£ and NOX are monitored.
Environmental Control and Monitoring
Light intensity is controlled by the shade cover to simulate the
lower light conditions for young trees of some species. All other
conditions are not controlled, but are designed to be as close to
ambient as possible.
Data Aquisition
Manually by strip-chart recorders.
C-35
-------
2. Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Air temperature in chambers is approximately 1 to 5°C higher
than-outside air depending on month. The difference occurs at night
as well as during the day. The difference between chambers and
outside tends to be greater in winter than summer. Relative humidity
is 1 to 10% lower in chambers than outside during the day. At night,
relative humidity reaches 80 to 90% in chambers compared to 100%
every night outside.
c. Pollutant Control and Maintenance
The chambers are durable and the dispensing system has provided
carefully-controlled exposures over several years.
d. Environmental Control and Maintenance
Light intensity is controlled constantly with a cover operated
by a photosensitive cell. The cell is sensitive to changes in
sunlight, resulting in repeated changes in light intensity over the
day. Over the day, 'air temperature and relative humidity are more
constant in the chambers than outside.
e. Chamber Equilibration
There are 1.5 air exchanges per minute.
C-36
-------
Publication: Laurence, J. A,, and R. J. Kohut. 1984. Lake Erie Generating
Station Grape Study. Phase I and II. Contract #GF127.1T123083. Niagara
Mohawk Power Company of the New York State Public Service Commission/
Albany.
Additional Publications: Heck, W. W., W. J. Clore, I. A. Leone, D. P. Ormrod,
R. M. Pool, and 0. C. Taylor. 1985. Multi-Year Research Plan for the
Lake Erie Generating Station (LEGS) Grape Study. Vol II. — Technical
Report. State Board on Electrical Generation, Siting, and the Environ-
ment, New-York Department of Public Service, Albany.
Mandl, R. H., J. A. Laurence, and R. J. Kphut. 1987. Development
and testing of new open-top chambers for exposing large perennial plants
to air pollutants in the field. Phytopathology. In Press.
Location: Boyce Thompson Institute, Ithaca, New York
Summary: Two new designs of open-top field chambers have been developed for
exposures of grapevines to air pollutants. One design is a modified
cylindrical chamber enlarged to 4.6-m diameter x 3.7-m high. The other is
a modification of the rectangular grapevine chamber (Brewer, 1983). The
objectives of the designs are to enclose grapevines trained to an umbrella
system, to provide uniform distribution of pollutants through the grape-
vine canopy, to minimize intrusion of ambient air, and to minimize environ-
mental modification.
1. Hardware •-,.,-
a. Chambers , .
The chamber designs are based on extensive testing of models in
a wind,tunnel. The cylindrical, chamber is 4.6 m in diameter x 3.7 m
high with a frustum reducing the open top by 50% and baffles between
the frustrum and top of the cylinder. The rectangular chamber is
7.3 m long x 2.7 m wide x 3.7 m high with a frustum, baffles and wind-
actuated louvers at the top. Both chamber designs have aluminum
frames and PVC coverings. A blower equipped with charcoal filters
. pumps air into a PVC plenum around the lower one-third of the
chambers (1.2 m high). ,, , ;
b. Pollutant Dispensing and Monitoring .,, -
The chambers have been tested with the addition of 03 and HF
gases, but no information ;is given on dispersion or performance.
Ozone was monitored with a Teco analyzer and HF was measured by
••wet-chemistry. ..,..,- „ ,
C-37
-------
c. Environmental Control and Monitoring
The environment is not controlled in the chambers. Irradiance,
rainfall, and leaf temperature are measured inside the chambers and
outside by LICOR® sensors, rain gauges, and leaf thermocouples,
respectively.
d. Data Acquisition
Acquisition of monitoring data is done on a time-sharing system.
2. Performance Evaluation
a. Pollutant Uniformity
Ozone and HF concentrations vary horizontally in the chambers by
up to 33%. In general 03 concentrations in the rectangular chambers
are lowest at the blower end and at 0.6 and 1.8 m above ground at the
opposite end of the chamber. Flux of HF is uniform throughout
chambers. The pollutants vary by 10-100% vertically in the chambers
between heights of 1.8-3.1 m.
b. Environment Uniformity
Irradiance is reduced by up to 30% in the cylindrical chambers
and 50% in the rectangular chambers compared to outside. Irradiance
distribution is not uniform within either chamber design, but is
especially variable in the rectangular chambers. There is a substan-
tial rain shadow effect with both types of chambers. Rain is 10-15%
of ambient at the north ends and 50-70% of ambient at the center.
Mean air temperature differences are 2.5°C higher in the chambers
compared to the outside, however, leaf temperatures occasionally are
as much as 9°C higher in the chambers compared to outside.
c. Pollutant Control and Maintenance
Both types of chambers are effective in excluding ambient
oxidants. Based on the wind tunnel test, the circular chamber is
designed with a 50% frustum which minimizes incursion of ambient air
from the top. The rectangular chamber is designed with louvers in
addition to baffles and frustum to further decrease ambient air
incursion.
d. Environmental Control and Maintenance
The environment is modified from ambient and is variable within
chambers.
e. Chamber Equilibration
Not described.
C-38
-------
Frustum
Baffle
Plenum
Door
Vine
Figure C-10.
Schematic diagram of large cylindrical open-top chamber for
grapevines (Laurence and Kohut, 1984).
C-39
-------
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C-40
-------
Publication: Lucas, P. 1985. Hemispherical Domes for Fumigation of Plants.
University of Lancaster, United Kingdom. Personal communication.
Location: University of Lancaster, Lancaster, England
Summary: A facility with eight large closed dome chambers was designed,
constructed, and tested for studies with S02, N0£, and 03 air pollutants.
1. Hardware
a. Chambers
There are eight chambers, each 4.6 m in diameter, and 2.0 m high
for a volume of 20 m3. The frame is anodized aluminum with glass
panels. The plant growing area is 12.6 m2. The air handling system
operates by both pushing air into the dome and pulling air from it.
A large fan pumps 1700 m3 min~l through ducts and large charcoal-
filters to four domes. Pollutants are added via 0.59-m diameter
tubes in the mixing-chamber immediately before the air enters the
domes. After mixing, polluted air at a flow rate of 280 m3 min"1
enters each chamber via a horseshoe-shaped duct around the inside of
the base of the dome. Resistance of the system reduces the air flow
through the dome to 40-60 m3 min"1. Polluted air is pulled through
the chamber by a central fan mounted at the top of the dome center
arid exhausted to the outside.
b. Pollutant Dispensing and Monitoring
Ozone is generated from dry air by electrical discharge and is
dispensed to the chambers via a manifold and rotameters. Pure S02 is
fed through a rotameter and diluted with compressed air before
entering chambers via a manifold and rotameters. Nitrogen dioxide
comes from a heatec! tank of pure N02 maintained at 35°C, with control
valves and rotameters maintained at 40°C.
c. Environmental Control and Monitoring
Large capacity cooling units have been added to reduce summer
temperatures to outside levels. Other environmental factors are not
controlled.
c. Data Acquisition
The system is being computerized.
2. Performance Evaluation
a. Pollutant Uniformity
Ozone concentrations vary by < 10% around the perimeter of the
chamber and at the center.
C-41
-------
Environment Uniformity
Air temperatures in the chambers average 3 to 5°C warmer than
outside. Relative humidity in the chambers generally is < 2% less
than outside. Irradiance is approximately 80% of ambient. Air speed
around the perimeter of the dome averages 0.9 m s"1, and 0.18 m s"1
at 0.15 m above the ground in the center of the dome. Leaf boundary
layer resistance is estimated at 0.09 s cnr1 around the perimeter of
the dome based on filter-paper model leaf measurements.
Pollutant Control and Maintenance
Pollutant levels are uniform and the center of the chamber is
chosen as an acceptable sampling location. Weekly span checks are
made for the 03, S02, and N02 analyzers; and weekly zero checks are
made for the S02 and N02 analyzers. All analyzers are calibrated
monthly.
Environmental Control and Maintenance
The possibility exists that the large surface area of the duct
absorbs heat, contributing to the increase in internal air tempera-
ture vs. outside. A coating of reflective paint has been proposed to
correct this problem. The center of the dome is not used for growing
plant material due to the low air speed.
Chamber Equilibration
There are 2 to 3 air exchanges per minute.
C-42
-------
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C-43
-------
Publication: Mandl, R. H., L. H. Weinstein, D. C. McCune, and M. Keveny.
1973. A cylindrical open-top field chamber for exposure of plants to air
pollutants in the field. J. Environ. Qual. 2:371-376.
Additional Publication: McCune, D. C., D. C. Maclean, and R. E. Schneider.
1976. Experimental approaches to the effects of airborne fluoride on
plants. In: T. A. Mansfield (ed.). Effects of Air Pollutants on Plants.
Society for Experimental Biology Seminar Series, Vol. 1, Cambridge
University Press, Cambridge, pp. 31-46.
Location: Original design developed at Boyce Thompson Research Institute,
Ithaca, New York. Chambers of the same design are located at Riverside,
California.
Summary: A detailed description is provided by Mandl ^t _aj_. (1973) for
construction and operation of the other early open-top field chambers
designed for exposures of vegetation to gaseous pollutants in the field.
The chamber is adaptable for both pollutant exclusion and addition
studies. Features different from the EPA chamber include fiberglass
covering, an adjustable plenum for air dispersion, and a different design
for the air handling system. Tests indicate near ambient environmental
conditions in the chambers, uniformity of pollutant dispersal, and flux of
HF to plants in the chamber. Tests also indicate the usefulness of the
chamber for oxidant-exclusion studies on a growing season basis.
1. Hardv/are ,
a. Chambers
The chambers are open-top cylinders 2.4 m high x 2.74 m in
diameter with an interior plant growing area of 5.9 m^. The frame is
of three rolled aluminum hoops 1.2 m apart dividing the chamber
horizontally into two separable modules for different heights of
plants. The chamber is covered with corrugated fiberglass panels
attached to the hoops with nylon nuts and bolts. There are upper and
lower panels. A donut-shaped PVC plenum, 8.53 m long x 0.20 m
outside diameter, is attached to the inner wall,"of the base of the
chamber. The plenum is perforated with 0.025-m diameter holes at
0.076-m intervals, oriented to direct the air stream horizontally and
toward the center of the chamber. Air flows from the plenum across
the plant canopy and out the top of the chamber. The original
chamber design ended abruptly at the top of the cylinder, resulting
in turbulent flow of ambient air into the chamber which increased
with increasing wind speed. Addition of a baffle at the top of the
chamber greatly reduces the rate of ambient air incursion, and makes
chamber pollutant concentrations more uniform both vertically in the
chamber and with different ambient windspeeds (Kats et _a_l_., 1976).
The base of the baffle is 0.10 m from the side of the chamber, rising
at a 45° angle 0.6 m to just above the top of the chamber. The
original chamber design has a polypropylene yarn netting (0.016-m
mesh) stretched over the top.
C-44
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Air is supplied by a 0.75-hp nonoverloading blower located in a
sheet metal blower box mounted on a trailer. The box is equipped
with dust filters and charcoal filters when supplying filtered air.
Air is blown into the chamber at a rate of 28.3 ITH min-1.
b. Pollutant Dispensing and Monitoring
The original chambers have been used for ambient oxidant effects
studies and HF studies. No added ozone and HF, are supplied to the
chambers by volatilization of aqueous HF solutions. Oxidants are
measured with Mast Ozone analyzers and HF by wet chemistry.
c. Environmental Control and Monitoring
The environment te not controlled in the chamber. Air tempera-
ture and relative humidity are measured by spot checks during the
day, but frequency and methods are not described.
d. Data Acquisition
Data aquisition is manual.
2. Performance Evaluation
a. Pollutant Uniformity
Fluoride accumulation indicates that pollutant concentrations
vary vertically by 63% from 0.15 m to 1.2 m high in ttie chamber.
Horizontal variation is 7 to 15% across the chamber. Oxidant exclu-
sion is 60 to 70% of ambient. No gradient evaluation for ozone
given.
b. Environment Uniformity
Environmental conditions in the chambers vary slightly from
ambient (Heagle et jil_., 1978; Mandl et al., 1973). Air temperature
generally is < 2T warmer than outsidfe "bTsed on peak temperatures
> 90°C. Relative humidity is generally the same as outside.
Irradiance is usually within 70-95% of outside in free sunlight.
Yellowing of the chamber fiberglass and low sun angles of spring and
fall decreases irradiance. Air movement over the plant canopy in the
chamber center is approximately 0.24 m s*1.
c. Pollutant Control and Maintenance
Dynamic sampling methods of gas concentrations in the air
indicate that concentrations within chambers can be relatively
uniform across chambers {7 to 15% variabiltiy) (McCune e^t £K, 1976).
However, flux measurements for HF show that the actual flux of
pollutants can vary considerably within chambers due to differences
in air flow rates across chambers. Thus increasing the uniformity of
air flow in the chambers is desirable to equalize fluxes. Within the
C-45
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lower 1.2 m of the chamber, flux is most uniform when the air is
blown at a 45° angle up and away from the plenum. Other modifica-
tions of flow direction and pattern are suggested to provide a
vertical pollutant flux profile specific for different types of plant
canopies.
Environmental Control and Maintenance
The environment modification in the chambers is uniform over
summer growing seasons but can change as the fiberglass yellows with
age. The mesh top does not exclude -ambient'rain; however, the amount
of rain is still less in the chamber than outside depending on angle
of incidence.
Chamber Equilibration
The air exchange rate is 2 per minute.
C-46
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LOUVER
PAD FILTER IN FRAME
CHARCOAL FILTER
£ PLASTIC COATED PLYWOOD
ON 2W FRAME
SHEET METAL FILTER HOUSING
TO SLOWER INLET
HP BELTED VENT BLOWER
WITH WEATHERPROOF HOUSING
OUTLET REDUCER
TO 10" O D
Figure C-13.
Construction details for open-top field chamber (top) and blower
assembly (bottom) (reprinted from Mandl £t _al_., 1973, with
permission of Soil Science Society of America).
C-47
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Publication: Musselman, R. C., P. M. McCool, R. J. Oshima, and R. R. Teso.
1986. Field chambers for assessing crop loss from air pollutants. J.
Environ. Qual. 15:152-157.
Location: University of California, Riverside, California
Summary: A field exposure facility of 18 closed-top, octagonal, teflon-covered
chambers has been developed. Each chamber is supplied with filtered air,
ambient air, or a gradient of filtered plus ambient. The chamber provides
precise control of pollutant levels with slight modification of the
environment.
1. Hardware,
a. Chambers
Each chamber is 2.5 in diameter, and 2.4 to 2.1 m high (top
tapers diagonally down). The chamber frame is aluminum with teflon
covering. Air is supplied from two 5-hp blowers. Air from one
blower is pulled through charcoal filters; nonfiltered air goes
through the other blower. Underground ducting leads from both
blowers to each chamber. The amounts of filtered and nonfiltered air
are adjusted with a butterfly damper at each chamber outlet.
b. Pollutant Dispensing and Monitoring
The chambers have been used primarily with filtered and nonfil-
tered air. However, 03 or SOg can be added manually at each chamber
inlet. Air sampling is done with a scanning valve interface-micro-
computer system.
c. Environmental Control and Monitoring
The environment is not controlled in the chambers. Air tempera-
ture and irradiance are measured.
d. Data Aquisition
All pollutant and environmental monitoring is via an
interface and microcomputer.
2. Performance Evaluation
a. Pollutant Uniformity
Pollutant distribution has been determined with CO as a test
gas. Both horizontal CO concentrations and vertical (0.3 to 0.9 m
high) concentrations vary by < 2%.
C-48
-------
b. Environment Uniformity
Irradiance averaged 11% lower in chambers than outside after-
three years of chamber use. Chamber air temperatures were 2-4°C
warmer than outside during the day, and varied < 1-1.5°C across
chambers.
c. Pollutant Control and Maintenance
Pollutant concentrations are very uniform in the chambers and
independent of ambient wind speed.
d. Environmental Control and,Maintenance
The environment is relatively uniform within and among chambers,
e. Chamber Equilibration
The number of air:exchanges per minute is adjustable.
C-49
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Figure C-14.
Field exposure chambers. A. Air inlet mixing box. B. Air inlets
from filtered and nonfiltered blowers with butterfly valves to
adjust flows. C. Aluminum inlet duct to chamber from mixing box.
D. Louvers for air-exiting chamber. E. Chamber door. F. Teflon
film on chamber wall. G. Chamber teflon top panel. H. Aluminum
conduit post for attaching wall panels. I. Impeller. J. Impeller
motor and mount. K. Impeller support frame. L. Pollutant air
sample tube. M. Chamber top frame support. N. Thermocouple
sensor. 0. Aluminum bar to secure teflon film to aluminum angle.
P. Aluminum wall frame. Q. Weather strip (reprinted from
Musselman et al., 1986, with permission from Soil Science Society
of AmericaTT
C-50
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Publication: Semi-open-top chambers for use in remote, high-wind areas. D.
Olszyk, personal communication; and P. Miller, personal communication.
Location: University of California, Riverside, California. The chambers have
been operated at the Tanbark Flats Experimental Forest, San Gabriel
Mountains, California; Daggett, California in the Mojave Desert; Sequioa
National Park, California; and at the University of Geneva, Switzerland.
Summary: The chamber is a smaller, modified version of the Heagle et al.
(1973) chamber developed for use with small shrubs and trees. The chamber
has been used to expose whole shrubs of Larrea tridentata, a desert
perennial (D. Olszyk, UCR, personal communication), and Ceanothus
crassifolius, a chaparral perennial from Southern California (A.
Bytnerowicz, UCR, personal communicatio i). The chamber also has been used
for multiple seedlings of conifer specfes both in Sequoia National Park
and in Switzerland at the University of Geneva (P. Miller, USFS, Riverside,
personal communication). The chamber has a closed top with four holes,
leaving approximately 40% of the surface area open.
1. Hardware
The chambers are 2.0 m in diameter x 2.5 m high cylinders modified
from the design of Heagle jet a]_. (1973). The surface area in the chamber
is 3.1 m2. Each chamber is covered with clear polyvinylchloride film.
The top has four 0.68-m diameter holes accounting for 40% of the surface
area. The semi-open top is required, since a totally open-top design is
physically unstable under the high wind speed conditions that can occur in
the desert. Air is blown into the chambers at a rate of at least 0.31 m
s~l from a 1/5-hp high pressure blower.
b. Pollutant Dispensing and Monitoring
For the Larrea-SOg studies the air is filtered to remove any
confounding ozone, since ambient air contained little S02 at this
site. Sulfur dioxide is metered into the incoming chamber air stream
from a tank of approximately 100% S02 enclosed in an insulated
galvanized steel can. Sulfur dioxide is monitored with a pulsed
fluorescent analyzer. For the Ceanothus or conifer oxidant studies,
filtered or ambient air is blown into the chambers with or without
added 03 from a generator. Ozone was monitored with a scanning valve
system and UV analyzer. Both S02 and 03 concentrations are con-
trolled with rotameters.
c. Environmental Control and Monitoring
The environment is not controlled in these chambers. Environ-
mental conditions, including irradiance, temperature, and humidity
are measured inside chambers and outside on an intermittent basis.
d. Data Acquisition
Data acquistion is by strip-chart recorders.
C-51
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2. Performance Evaluation
Pollutant uniformity
Not described.
Environmental Control and Maintenance
Air temperatures in the chambers are 1 to 5°C warmer than
outside, with the largest differences at ambient air temperatures
> 32°C. The chambers reduce irradiance, but the decrease has not
been determined.
Pollutant Control and Maintenance
Not described.
Environmental Control and Maintenance
The chamber air temperature can increase significantly above
ambient, possibly altering plant response to air pollutants. Photo-
synthesis is affected by the chamber itself in Larrea, likely due to
the increased air temperature. The chamber top prevents wind incur-
sion which can be especially significant in the desert and other open
areas. The top also helps alleviate damage at high wind speeds by
channeling the air over the chamber.
Chamber Equilibration
There are at least 2 chamber air volumes exchange per minute.
C-52
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Publication: Roberts, T. M., R. M. Bell, D. C. Horsman, and K. E. Colvill.
1983. The use of open-top chambers to study the effects of air pollut-
ants, in particular sulphur dioxide, on the growth of ryegrass Lolium
perenne L. Part I. Characteristics of modified open-top chambers used
for both air-filtration and S02-fumigation experiments. Environ. Pollut.
3:9-33.
Additional Publication: Colvill, K. E., R. M. Bell, T. M. Roberts, and A. D.
Bradshaw. 1983. The use of open-top chambers to study the effects of air
pollutants, in particular sulphur dioxide, on the growth of ryegrass
Lolium perenne L. Part I. The long-term effect of filtering polluted
urban air or adding S02 to rural air. Environ. Pollut. (Series A)
31:35-55.
Location: University of Liverpool, Liverpool, England
Summary: A low exposure chamber has been designed, tested, and used for
exposing grasses to filtered vs ambient air, and assessing the effects of
added $03. The chamber design meets two objectives: small size, and
divides the air flow so that filtered air passes over the grasses and out
through the base and top of the chamber. The chamber has a duct around
the top to blow air across the plant canopy. The chamber is used in
year-round studies which have indicated that SOg has detrimental effects
in the winter and spring, but not the summer.
1. Hardware
a. Chambers
Four chambers have been constructed, with a 1.3-m diameter,
0.7-m high cylinder, originally covered by PVC film. The PVC was
replaced by fiberglass after one year. A split air inlet channels
approximately 80% of the air at 0.5 m3 s~l into a collar with a PVC
strip duct inside the upper margin of the chamber. Air is directed
through 0.0025-m diameter holes at an angle over the plant canopy.
The other 20% of the inlet air passes across a flow corrector to
insure laminar flow. An exhaust fan slightly less powerful than the
inlet fan, pulls air out of the chamber. In two chambers the air is
filtered with a 1.0 x 0.3 x 0.1 m block of activated charcoal. In
the two ambient chambers the charcoal block has been replaced with a
polystyrene baffle to produce an equal distribution of air at the
inlet.
b. Pollutant Dispensing and Monitoring
For filtered vs ambient air studies, there is no controlled
pollutant dispensing. Controlled levels of S02 are added to chambers
from a tank of pure S02 fed through a rotameter and diluted with
compressed air in a stainless steel mixing chamber. The S02 is
injected into the inlet ducts between the fan and the polystyrene
baffels. Monitoring of S02 is with a flame photometric analyzer.
C-53
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c. Environmental Control and Monitoring
Environmental factors are not controlled. Detailed measurements
of air temperature, light intensity, relative humidity, and rainfall,
are made in chambers and outside. Air speed over the canopy is
checked periodically with a hot-wire anemometer.
c. Data Aquisition
Data acquisition is manual.
2. Performance Evaluation
a. Pollutant Uniformity
The air flow pattern effectively excludes ambient with a cone of
air blown upwards and inwards from the chamber edge.to minimize
ambient air incursion. Air is also passed over the grass canopy and
out through a ventilation fan at the rear of the chamber. The
seasonal mean added S02 levels vary by 60%. Exclusion of SC>2 in the
filtered vs ambient chambers has averaged 56% over a 3-year period.
Unfiltered chambers have S02 levels 93% of outside concentration.
Sulfur dioxide concentrations varied by < 20% horizontally across the
unfiltered chambers, and up to 50% across chambers with added SO?.
b. Environment Uniformity
Irradiance is 15-25% lower in chambers than outside. At low
temperatures, the air is 1 to 2°C warmer in chambers than outside.
Continuous air movement over the canopy prevents hoarfrost on leaves.
When outside air temperatures are above 10°C, it is similar in the
chambers. There is no appreciable difference in relative humidity
between chambers and outside plots. Rainfall in chambers is similar
to outside plots. Air flow over the grass canopy is 0.5 to 0.8
m s-1. The chambers caused a 29% reduction in early summer plant
growth, but had no effect on winter growth. There is some evidence
for greater S02 flux to plants in ambient chambers versus outside,
based on total sulfur content.
c. Pollutant Control and Maintenance
The main disadvantage of these smaller chambers is the reduced
ambient pollutant filtering efficiency compared to larger chambers
'(Heagle et a/L, 1973).
d. Environmental Control and Maintenance
The chamber has the advantage of a reduced rain shadow, and
laminar flow of air across the plant canopy instead of turbulent flow
up through the chamber as found in larger open-top chambers.
C-54
-------
e. Chamber Eain'libration
There are 6 to 7 air exchanges in the chamber per minute
C-55
-------
X
c^:
•air director
plenum
-chamber wall
CROSS-SECTION
/ Direction of air flow
...••"' Filtered air
1cm=17cm
.'/r,\\\
/ i \ \\
Exhaust Exit Casing
Fan i
^..^...^...-^.^....H
-^^O^^^
Open Top Chamber
(Charcoal I Split Air Inlet Casing I Inlet
I Filter | | Fan
Figure C-15.
Schematic diagram of low open-top field chamber for grasses
(reprinted from Roberts _et al., 1983, with permission of Elsevier
Applied Science Pub! isheFs",~Ttd.) .
C-56
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Publication: Roberts, T. M. 1981. Effects of stack emissions on agriculture
and forestry. CEGB Research July:ll-24.
Location: Central Electricity Research Laboratories, Leatherhead, England
Summary: Four large chambers have been constructed by Central Electricity
Generating Board research staff for air pollution studies. The 4.0-m
diameter dome-shaped chambers are designed to provide close control of
pollutant concentrations with minimal environmental variation compared to
outside. Chamber air flow is designed to ensure that gas flux rates to
plants are similar to outsfde. The air flow and pollutant injection rates
are computer-controlled to simulate concentrations of gas mixtures that
can occur around electrical generating stations. ; • , ;
1. Hardware . .
2.
a.
Chambers .
The four chambers are 4.0-m diameter closed^domes with a volume
of 30 m6 and floor area of 9 ,m2. The frame is aluminum and the
covering is glass. Air is blown into each chamber through an
underground duct by a 5-hp fan which sucks air through, a charcoal-
fiTter with surface area of 15.8 m2. Air at a flow rate of 120 m3
min"1 enters the chamber through the center ;of the bottom. The flow
is pointed toward a diffuser near the top of the chamber which
directs the air down over the plant canopy. = •
Pollutant Dispensing and Monitoring
Pollutants are injected into the incoming,,air,stream past the
fan. Monitoring is through a timesharing device. All pollutant
dispensing and monitoring is computer controlled. .,;•
Environmental Controls
Environmental conditions are not controlled. Air and soil
temperatures, irradiance, and relative humidity are recorded by
computer.
d.
Data Acquisition
All data acquisition is computerized.
Performance Evaluation
a. Pollutant Uniformity
Not described.
C-57
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Environment Uniformity
Irradiance is approximately 25% lower in the chambers than
outside. Daily air temperature is increased by approximately 0.7°C
across a range of outside temperatures from -2 to +23°C. The
cumulative degrees temperature over the winter are 10% greater in
chambers than outside. The daily soil temperature is 1°C higher in
the chamber than outside except for cold still periods when the soil
temperature is lower in the ventilated chambers than outside.
Relative humidity is lower in the chambers than outside with high
humidities (> 80%), but 10% higher at lower outside humidities (60%).
The air flow rate over the plant canopy is approximately 0.5 m s~l at
canopy height.
Pollutant Control and Maintenance
The charcoal filters remove approximately 90% of ambient SO? ancl
03, and 75% of ambient N02- Charcoal filters which have been
operated'over the winter released 100 ppb NO in the spring and early
summer with specific high temperature conditions.
Environmental Control and Maintenance
The chamber produces modifications in climatic conditions which
are comparable to those of open-top field chambers. The relative
humidity differences in chambers vs ambient also occurred when plants
were not present, indicating that charcoal filters were probablly
releasing moisture during the day and retaining it during the night.
Chamber Equilibration
There are 4 air exchanges per minute.
C-58
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Diffuser
Solardome
Site instrument hur
Land
drain
•Replaced
soil
6000cu.fr/min
Gas injection Gas sampling
'<"* line
Figure C-16.
Schematic diagram of dome chamber designed by staff of the
Central Electricity Research Laboratory, Leatherhead, England
(Roberts, 1981).
C-59
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Publication: Runeckles, V. C., L. M. Staley, and N. R. Bulley. 1978. A
downdraft chamber for studying the effects of air pollutants on plants.
Can. J. Bot. 56:768-778.
Location: University of British Columbia, Vancouver, British Columbia
Summary: A conical exposure chamber is described for gaseous air pollutant
exposures. The blower is located on the top of the chamber, providing a
downdraft of charcoal-filtered air and/or added polllutants to the plant
canopy.
1 . Hardware
a.
Chambers
The chamber is 4.9 m high, 1.2 m diameter at the top, and 2.4 m
diameter at the bottom. The base of the chamber is 0.4 m above the
soil., The chamber frame is steel pipe, with five hoops of seqii'en-
tially smaller diameter from bottom to top, and four side tubes. The
chamber -is covered with PVC and held in place , by guy wires. The
blower Is in a box supported by the top steel hoop. It contains a
rain cover, dust filters, activated-charcoal filters,, and a1 fan
providing 127 m^min-l 'down through the .chamber.
2.
b. Pollutant Dispensing and Monitoring ',";'
Ozone is produced by a Grace generator and injected into the
chamber immediately below the fan. Ozone is monitored with colori-
metric and chemiluminescent monitors.
c. Environmental Control and Monitoring
The environment is not controlled in this system. Wind speed,
irradiance, net radiation, relative humidity, and air and soil
temperatures are measured in chambers and outside to characterize the
environmental modification by the system.
d. Data Acquisition
Not described.
Performance Evaluation
a. Pollutant Uniformity
Ozone concentrations vary by 6 to 8% across the chamber, and
< 5% vertically between heights of 0.2 and 1.0 m within the chamber.
When ambient 03 concentrations are low, filtering the chamber
excludes 40% of ambient 03 under calm conditions, and 25% of the 03
under windy conditions. , With .higher ambient 03 exclusion is 70% of
ambient. . ' ,.'.'. . . .....
C-60
-------
b. Environment Uniformity '
The wind speed is 0.5 m s-1 vertically downward, at a position
in the center of the chamber 0.3 m above the soil surface. The
transmittance of the PVC is 90 to 93% of ambient irradiance. On
clear days irradiance is the same in chambers as outside, however, it
is 30% lower on cloudy days. Net radiation1 loss is negative outside
at night, but is 0 in the chamber due to lack of reradiation to the
sky. Air and soil temperatures are usually < 1°C warmer in the
chamber than outside. Relative humidity is 10% less in chambers than
outside. .
c. Pollutant Control and Maintenance
The chamber is useful for providing a pattern of air dispersion
over the plant canopy under representive conditions. Pollutant
distribution within the chamber is essentially uniform. The air-
exclusion capability of the chamber is least efficient for areas with
relatively low air pollutant concentrations.
d. Environmental Control and Maintenance
Environmental conditions in the chamber are similar to outside,
with the largest difference in relative humidity. The variability in
chamber conditions is similar to ambient variability.
e. Chamber Equilibration
Not described.
C-61
-------
dus; (liters
prooeter fan
zip fastener
guy wire
louvres
activated charcoal fitters
door
tent fastener
vinyl cover
level adjuster
Figure C-17.
Schematic diagram of downdraft chamber for field studies
(reprinted from Runeckles et a]_., 1978, with permission of
Canadian Journal of BotanyTT
C-62
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Publication: Seeliger, T., A. Wichmann, J. Schweckendiek, and R. Bornkamm.
Personal communication. 1985.
Location: Technical University of Berlin, Berlin, Germany
Summary: Equipment has-been designed, constructed, and tested to simulate
ozone exposures. The equipment consists of one open-top chamber and a
computer-controlled system for dispensing pollutants, monitoring, and data
aquisition. The chamber has been characterized for vertical and hori-
zontal ozone distribution.
1. Hardware
a. Chambers
The chamber is eight-sided, 2.5 m in diameter, and 2.4 m high.
The chamber has an aluminum frame, teflon covering, and no frustum.
The lower part of the chamber is double-walled, with air entering
around seven sides of the chamber through the perforated teflon wall.
Air is supplied from a blower at 42 m3 min"1 via ventilator, dust
filters, activated charcoal filters, and turbulator before entering
chamber.
b. Pollutant Dispensing and Monitoring
Ozone is supplied from a generator and monitored by an ultra-
violet photometer.
c. Environmental Control and Monitoring
The environment is not controlled in the chamber; however, five
environmental conditions are monitored.
d. Data Aquisition
A datalogger and microcomputer monitor air pollution concentra-
tions and environmental variables. The microcomputer also controls
03 dispensing based on a programmed episode.
2. Performance Evaluation
a. Pollutant Uniformity
Ozone concentrations varied by 28% horizontally across the
chamber which had a turbulator in the inlet duct to mix the air. Air
varied by 14% vertically between 0.2 and 1.75 m above the bottom of
the chamber.
b. Environment Uniformity
Not described.
C-63
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c. Pollutant Control and Maintenance
The system simulates .episodic air pollutant events. Asym-
metrical 03 concentrations were measured vertically and horizontally
in the chamber.
d. Environmental Control and Maintenance
Not described.
e. Chamber Equilibration
There are 3.5 air exchanges per minute.
C-64
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Publication: Skarby, L. 1986. Personal communication.
Location: Swedish Environmental Research Institute, Gothenburg, Sweden
Summary: Open-top field chambers have been designed and operated to study
effects of 03 on pine and spruce, trees, . .:'-,- •• •••• -.
1. Hardware . ,- -:,
a. Chambers -.. , :..•• . : •. - ,.-. ..- ;
Ten cylindrical open-top field chambers were constructed based
on the design of Heagle et _al. (1973). The chambers are 2.5 m high,
3.0 m diameter, with aluminum frames and PVC plastic (hard) cover-
ings. The chambers have 45° frustra, reducing the top diameter to
1.25 m. Air flow (40 m3 min-1) driven by an axial-b.lade fan enters
the base of the chamber through a 0.4-m circular tube manifold with
0.025-m diameter holes distributed to give an even air flow inside
the chamber.
b. Pollutant Dispensing and Monitoring
Ozone (0.22 ppm from 2300 to 0600) is dispensed into one chamber
from a Sonozaire electric discharge generator. The 03 is dispensed
into the chamber through a 0.4^m diameter, 2.5-m long manifold duct.
Ozone is monitored with a chemiluminescent analyzer and NOX with a
fluorescent analyzer. A microcomputer controlled the monitoring of
air pollutants with a solenoid valve system. Frequency of monitoring
is not described.
c. Environmental Control and Monitoring
The environment is not controlled in the chambers. Air tempera-
ture is routinely monitored with platinum resistance temperature
detectors. Humidity is measured with a psychrometer or a Pi tot tube.
d. Data Acquisition
Microcomputer system.
2. Performance Evaluation
a. Pollutant Uniformity
Ozone concentrations vary by less than 10% horizontally across
the chambers. Vertical distribution is not described.
b. Environment Uniformity
The average daily temperature -in the chamber was a maximum of
4°C warmer than ambient.
C-65
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c.
d.
Pollutant Control and Maintenance
Sample line loss was determined at the beginning and end of
exposure period, but the results were not described.
3.
Environmental Control and Maintenance
Mot described.
Chamber Equilibration
There are 2 to 3 air exchanges per minute.
C-66
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•1.75 m
rH
2.5m
3m
2.5m
Figure C-18.
Schematic diagram of open-top field chamber for air pollutant
exposure in Gothenburg, Sweden: (1) fan: (2) duct; (3) plenum
(manifold); (4) ozone/NOx measurements; (5).PVC corrugated hard
plastic; (6) Door (Skarby, Personal communication, 1986).
C-67
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Publication: Soja, G. 1986. Personal communication.
Location: Austrian Research Centre Seibersdorf, Institut fur Landwirtschaft,
Vienna, Austria
Summary: An open-top field chamber facility was constructed to evaluate
effects of filtered or ndnfiltered air to plants. Wheat and red clover
have been the experimental material to date.
1. Hardware
a. Chambers '.
Cylindrical open-top field chambers were constructed based on
the design of Heagle et a/L (1973). The chambers are 2.4 m high,
3.0 m diameter,.w-ith a frustum that.rises to a ,45° angle above the
chamber, effectively reducing the open-top to 1.5 m diameter. Air is
dispensed within the chamber,,v.ia a perforated pi asti.c .tube'around the
inner wall. Filtered chambers have charcoal filters which remove
approximately 97% of the ambient. N02 .and.S02, but none of the NO.
b. Pollutant Dispensing 'and Monitoring - '
Pollutants are not dispensed into the chambers — there are only
filtered and nonfiltered air treatments. Sulfur dioxide is monitored
with a pulsed fluorescence analyzer, NOX is monitored with a fluor-
escent analyzer.
c. Data Control and Monitoring -
..•• •-• • -, .' \. ' •'-,- / • • •
* -. • ' ' ., 'I*"*
.The environment is not controlled in' the chambers. Air temper-
ature, leaf temperature, relative1; humidity of the air, and irradiance
are measured periodically with,,a Lambda Instruments Corporation
LI-COR 6000 portable photosynthesis system. Air speed also is
checked periodically. Soil moisture is determined with tensiometers.
c. Data' Acquisition ' . ••
* .•""
Manual. , ?
2. Performance Evaluation
„..•'•'•• ..- - .-*"
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Not described. ' ... '.
C-68
-------
3.
c. Pollutant Control and Maintenance
Not described.
d. Environmental Control and Maintenance
Not described.
Chamber Equilibration
Not described.
C-69
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Publication: Thompson, C. R., and D. M. Olszyk. 1985. A Field Air-Exclusion
System for Measuring the Effects of Air Pollutants on Crops. EPRI
EA-4203. Final Report for Project 1908-3. Electric Power Research
Institute. Palo Alto, California.
Location: University of California, Riverside, California
Summary: The facility consists of 20 open-top field chambers constructed
according to the basic shape and design of the Heagle ^t _al_. (1973)
chamber, but with a top baffle instead'of a frustum and permanent support-
ing posts instead of a movable aluminum frame. The facility was con-
structed for, and is maintained under a contract with the California Air
Resources Board. The chambers modify the plant growing environment to a
similar extent as the Heagle et al. (1973) chambers, the chambers have
been used for year-round studies with a variety of crop and native plant
species.
1. Hardware
a. Chambers
The 20 chambers follow the basic design and shape described by
Heagle et al. (1973), chamber except that the installation is not
portable ami the chambers can not be removed for field planting of
crops. The chambers are cylinders 2.43 m high and 3.0 m in diameter
with rolled aluminum frames covered by PVC film. The upper half of
the chamber has a single layer of film and the lower half has a
double layer. The inner layer is covered with 0.03-m diameter holes,
positioned in six rows, with 0.15 between holes and rows. The chamber
has a cone-shaped baffle at the top (Kats et^ al., 1976) that reduces
the top hole diameter to 1.5 m. Each chamber is equipped with a
1.52-m long x 0.6-m wide x 0.6-m high blower box containing a fiber-
glass particulate filter, corrugated activated charcoal filter, and
3/4-hp IL6 propeller blowers. The chambers have side posts buried
0.15 m in the ground, and below ground air sampling, pollutant
delivery, and irrigation systems. The chambers have been used both
with potted plants and plants planted in the ground.
b. Pollutant Dispensing and Monitoring
The pollutant delivery system includes a Griffin ozone gener-
ator, and heated, insulated containers for tank gases such as sulfur
dioxide and nitrogen dioxide. The output of the tank gases is
controlled by a mass flow controller. The concentrations of all
gases added to individual chambers are controlled by individual
rotameters.
c. Environmental Controls and Monitoring
The environment in the chambers has not been controlled in past
studies. Recently, humidity variation has been added to determine
its effect on the sensitivity'of plants to air pollutants. A
C-70
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propane-fired boiler provides dry steam, a water-soften ing system
provides water, a humidity delivery system has been installed in two
chambers, and long ducts deliver the steam to.chambers with enough
mixing time to allow for any condensation prior to entry into the
chambers. A humidistat controls steam injection into the chamber
ducts. Dew point and air temperature sensors determine chamber
humidity, and a computer feedback system is being developed to
control the humidistats based on ambient and chamber humidities and
desired humidity set points.
When completely modified, the chamber apparatus will be able to
measure air, soil, and leaf temperatures, relative humidity, irradi-
ance, and air speed.
d. Data Acquisition
Pollutant concentrations in chambers are determined with a
scanning valve system associated with 03, SOg, or NC>2 analyzers.
Pollutant concentrations and environmental conditions are recorded,
stored and processed with an interface-microcomputer system.
2. Performance Evaluation
a. Pollutant Uniformity
Pollutant concentrations vary by < 2% between 0.05 and 0.41 m
vertically in the chambers. Horizontal concentrations have not been
determined. Concentrations of added pollutants vary by < 10% over
time based on growing-season averages of hourly data.
b. Environment Uniformity
Air speed is approximately 0.6 m s'1 over the plant canopy. Air
temperature generally is < 1°C warmer in the chambers than outside,
but can range up to 4°C warmer, especially in cooler months. Soil
temperatures are up to 3°C warmer than outside at depths of up to
0.10 m. Leaf temperatures are cooler than outside in early morning
and up to 3°C warmer than outside during mid-day. Irradiance is
still within 75% of ambient after more than two years use of the PVC
vinyl chamber covering. At mid-day during the summer, chambers have
3 to 4% higher relative humidities than outside.
c. Pollutant Control and Maintenance
Pollutant concentrations can be effectively controlled in the
chambers. The chambers exclude approximately 75 to 80% of ambient
d. Environment Control and Maintenance
Not described.
C-71
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e. Chamber Equilibration
There are approximately 2 air exchanges per minute.
C-72
-------
Publication: Van Haut, H. 1972.
Environ. Pollut. 3:123-132.
Test methods to prove phytocidal pollutants.
Location: Landesanstalt fur Immissionschutz-, Essen, West Germany
Summary: Small, closed plexiglass chambers have been'de'signed and used for
studies on the effects of ambient air pollutants on small seedling plants.
Each experimental unit consists of two chambers, one with filtered air and
the other with ambient air. The chambers are self-contained units with
individual air and water supply. ' ' - ' • -
1. Hardware '• ' •
a. Chambers
Each chamber is a 0.6 x 0.9 x 0.9 m closed plexiglass box. The
air supply system consists of an elevated air intake, charcoal
filter, and exhaust blower. Air flow is from the filter, into the
top of the chamber, through a top baffle, down through the chamber,
and pulled out through the system by an exhaust fan. The filtering
material is coated with silver and silver oxide to remove S02, HF and
HC1. A watering system continuously supplies the plants through a
closed system with water reservoir and pump.
b. Pollutant Dispensing and Monitoring
No dispensing occurs in the chambers and there is no information
on monitoring.
c. Environmental Control and Monitoring
Not described.
d. Data Aquisition
Not described.
Performance Evaluation
a. Pollutant Uniformity
The single pass-through system and top baffle disperses ambient
or filtered air through the system. No information is provided
concerning pollutant uniformity between systems.
b. Environment Uniformity
Not described.
2.
C-73
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c. Pollutant Control and Maintenance
The air filter is successful in removing ambient pollutants
based on studies with BEL W3 tobacco as a bioindicator plant.
d. Environmental Control and Maintenance
Not described.
e. Chamber Equilibration
Not described.
C-74
-------
Figure C-19.
Gaseous exposure chambers (reprinted from Van Haut, 1982, with
permission of Elsevier Applied Science Publishers, ltd.).
C-75
-------
-------
APPENDIX D
Descriptions of Facilities and Performance Evaluations --
Outdoor Chambers for Gaseous Dry and Wet Deposition Research
-------
-------
Publication: Ashmore, M. R. 1986. Personal communication.
Additional Publication: Ashmore, M. R., J. N. B. Bel'l, and1C. Dalpra. 1980.
Visible injury to crop species by ozone in the United Kingdom. Environ.
Pollut. (Series A) 21:209-215; .
Location: Imperial College, Silwood Park, England
Summary: An open-top field chamber was designed to investigate the effects of
ambient air pollutants on crops.
1. Hardware ;
a. 'Chambers .. , • :
The chamber consists of 2.3-m high, 3.3-m diameter cylinders
with aluminum frames and covered by transparent polyethylene. The
chambers, erected on a concrete platform, are used witfr'potted
plants. Air is blown into the chambers through a plenum around the
inside of the wall at a rate of 1.15 m s-1. The air entering fil-
tered chambers passes through activated charcoal filters, while other
chambers receive ambient air. The chambers are'being rebuilt as
semi-open-top chambers for studies on the effects of 03 and acidic
mist on trees. A curved roof, 3.45 m in diameter, is being placed
over the chambers to exclude ambient rain. The edges are 0.15 m
above the chamber rim and centers are 0.25 ffl above the top of the
chamber.
b. Pollutant Dispensing and'Monitoring ' •
The chambers originally had only filtered or ambient air, with
no extra pollutant dispensing. Ozone is monitored continuously with
an ultraviolet analyzer. For Oa-acid mist studies, ozone is added,
generated by a high voltage generator with concentrations controlled
by altering voltage and flow rate to chambers. Acid mist is gener-
ated by 2 spinning disc humidifiers in each chamber. Droplet size is
5-20 u, with a mean of 11 u. Each humidifier emits 0.4 1 hr-1.
c. Environmental Control and Monitoring
The chamber environment is not controlled.
temperature in the chamber are measured.
Irradiance and air
Data Acquisition
Ozone concentration is recorded every 5 minutes in a datalogger.
D-l
-------
2. Performance Evaluation
a. Pollutant Uniformity
Ozone exclusion at the top of the plant canopy in filtered
chambers is approximately 20% of ambient, but changes with outside
wind speeds. . • • . .
b. Environment Uniformity
Irradiance in the chambers is > 90% of outside. Air temperature
in the chambers is 3-4°C higher than outside on days with high light
intensity. Plant injury response to ambient air in chambers is
similar to the response to ambient air outside of the chambers. Air
velocity over the plant canopy is 0.35-0.55 m sec"1 for the acid mist
studies.
c. Pollutant Control and Maintenance
Not described.
d. Environmental Control and Maintenance
Not described.
e. Chamber Equilibration
There are 2.4 air exchanges per minute in the older chambers.
This is increased to 4.7 air exchanges per minute in the new chamber
design for the ozone-acid mist studies.
0-2
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Publication: Jager, H.-J. 1986. Personal communication'.
Location: Institut fur Produktions-und OkotoxikoTogie, < Bundesforschungsanstalt
fur-Landswirtschaft, Braunschweig, Federal Republic of Germany
Summary: A semi-open-top field chamber facility wa-& designed, constructed, and
put into operation for determining the effects of ambient air pollutants
and rain on plants. The chambers"currently are being irsed for an experi-
ment with winter barley.
1. Hardware • • >.- / -. :-••• »,-: .
a.
Chambers
'","•,• ' ; . '•';'* * ' * •', ' ' ' '"*• '
Eight cylindrical semi-open-top field chambers were constructed
The chambers are of the Heagle _et _al_. (1973). design as modified by
Hogsett et _al_. (1985). Each chamber is 3.5 m diameter, and 3.5 m
high, including a 45° frustum at the top and rain :cap. The1 frames
are aluminum, and coverings are a low density polyethylene which has
been UV Tight stabilized. Each chamber blower has a 'coarse particu-
late filter and fine particulate filter. Each filtered chamber has
activated charcoal filters impregnated with 10% KgCOs. The blowers
have a maximum air flow capacity of 43 m3 min-1 at a counter pressure
of 55 mm (550 Pa).
Pollutant Dispensing and Monitoring
Sulfur dioxide is dispensed into some of the chambers from a
tank of pure S02 via a mass flowmeter, mixing tank (for combination
with clean air), pumps, and enters at the lower outlet to the
chamber. The S0£ is routinely monitored with a fluorescent analyzer
Ozone is monitored with a UV-absorption analyzer. Nitrogen oxides
are measured with a chemiluminescent analyzer. A simulated rain
solution is dispensed in the center of the chambers at 2.6 m above
the ground.
c. Environmental Monitoring and Controls
Ambient rainfall is controlled in the chambers.
is given concerning other environmental factors.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
Not described.
No information
••D-3
-------
3.
b. Environment Uniformity
Irradiance is reduced 18-22% inside the chambers. Air'tempera-
ture in the chambers varies with irradiance: 2.2°-2.8°C warmer
during daylight with low-high irradiances. At night, chambers are
less than 1°C different from ambient.
c. Pollutant Control and Maintenance
Efficiency of charcoal-filtration showed 58-64% removal of SOa
for incoming ambient air. Data not given for N02 or 03. NO is not
removed.
d. Environment Control and Maintenance
Not described.
Chamber Equilibration
There are approximately 2.3 air exchanges per minute.
D-4
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S02 Dosage System
6. S02 gas tank
7. Heater
8. Mass-flow meter with potentiometer
and analog display
9. SO2 .mixing chamber
10. Ambient air inlet with particulate
and SO, filters
Membrane pump
Air-flow controller
\
SO, Monitor System
1.
2.
3.
4.
5.
Open-top chamber
Fan with filter system
SO2 monitor
Printer
Pump
Figure D-l.
Schematic diagram of semi-open-top field chamber and pollutant
dispensing system at Braunsweig (Jager, H.-J., 1586, personal
communication).
D-5
-------
Publication: Krause, G. 1986. Personal communication, and Pfeffer, H.-U.
1982. Das Telemetrische Echtzeit-Mehrkomponenten-Erfassungs-System TEMES
zur Immissionsuberwachung in Nordrhein-Westfalen, LIS-Berichte, 19,
Landesanstalt fur Immissionsschutz des Landes Nordrhein-Westfalen, Essen,
Federal Republic of Germany.
Location: Landestalt fur Immissionsschutz des Landes Nordrhein-Westfalen,
Essen, Federal Republic of Germany
Summary: A new semi-open-top field chamber facility has been designed,
constructed, and put into operation for determining the effects of ambient
pollutants on trees. -The chambers have either filtered or ambient air
treatments, and treatments of ambient rain collected on a large nearby
surface.
1. Hardware • : '
a. Chambers !
The facility consists of ei'ght semi-open-top field chambers
based on the design of Heagle___et al. (1973), as modified by Hogsett
et al_. (1985),, 'Each chamber is 370" m in diameter and 2.4 m high.
"Ab~ove each chamber is an, 8,.5 m high frustum which inclines inward by
45°; and 0.3 m above the:frustrum is a 2.7-m diameter, 0.6-m high
rain cap. The chambers have rigid aluminum frames, and are covered
with.PVC film which is temperature resistant between -25 to +50°C,
and UV light resistant. Air is blown into the chambers from a radial
blower at a variable rate ranging from 8.3 to 117 m^ min-1 at;
pressures of 0 ,to 870 Pa. A typical operating air flow raten's 58 m3
min-1. Air enters the chambers through a donut-shaped plenum-around
the base of the.chambers. The trees are placed in 1.0-m deep, 0.8-m
diameter lysimeters, with six lysimeters per chamber.
Ambient wet deposition is collected on a 30 m^ roof of fibrous
polyester material adjacent to the chambers.//The surface of the roof
is the same as the area within the four ambient rain chambers. The
rain is collected for 24-hour periods' for particular events, and
deposited in chambers at 0300 the next day. The blowers are turned
off during rain events. Four other chambers receive simulated rain
at the same time as the collected ambient rain treatment'. The
simulated rain is based on annual means for rain data collected in
the Italian Alps. All rain treatments are delivered through stain-
less steel nozzles with a mean droplet size of 0.5 mm at a rate of
0.17 mm m~2 min-1. The blowers are turned on again at 0600 following
the rain treatments.
b. Pollutant Dispensing and Monitoring
No gaseous air pollutants are dispensed into the chambers.
Routine monitoring of S02, NOX, CO, 03, coarse, and fine particulates
is via the automated TEMES measuring system (Pfeffer, 1982).
• D-6
-------
c. Environmental Monitoring and Controls
Simulated rain is dispensed in the chambers as described above.
Routine monitoring of environmental parameters (air temperature,
relative humidity, precipitation, solar radiation, wind speed, and
wind direction) is via the TEMES system.
d. Data Acquisition
Mainframe computer.
Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Air flow over the plant canopy is approximately 0.02 to 0.24
m s-1. Air temperature in the chambers is 1.5°C warmer than outside
with solar radiation and 35°C. Air temperature in chambers is 0.5°C
warmer than outside without solar radiation and an air temperature of
25°C. Irradiance is reduced by approximately 18% in the chambers
compared to outside, but light quality is the same in chambers and
outside. Relative humidity is lower in chambers than outside by the
same proportion as air temperature is increased.
c. Pollutant Control and Maintenance
Not described.
d. Environment Control and Maintenance
•" / ,>,
Not described. . ' ...
Chamber Equilibration
There are 0.4 to 4.6 air exchanges per minute, with a typical rate of
2.3 per minute.
0-7
-------
VI filtered air/ambient rain
V2 filtered air/simulated rain
V3 ambient air/ambient rain
V4 ambient air/simulated rain
R1-B1 reference without chambers
Figure D-2. Schematic diagram of semi-open-top field chamber facility of
L.I.S. (Krause, 6., 1986, personal communication).
D-8
-------
1. Aluminum frame with plastic covering
2. Plenum
3. Roof with plastic covering
4. Spray nozzle for simulated rain events
5. Cement cylinder for soil (planting bed/lysimeter )
6 . Soil
7. Plastic liner
8. Cloth layer
9. Gravel
10. Concrete slope
11. Cement well for sampling percolation water
12. Drainage tube for percolation water
13. Sample container for percolation water
14. Well cover
15. Collector for wet deposition
16. Collector for interception water
17. Air inlet
18. Iris air regulator
19. U-tube manometer
20. Fan
21. Activated charcoal filter
22. Coarse and fine particulate filter
23. Protective covering with grate (to stop leaves)
1
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x-^"
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Fiaure D-3.
Schematic diagram of seml-open-tqp field chamber, air handling
system, and soil solution sampling system of L.I.S. (Krause, G.
1986, personal communication).
D-9
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Publication: Kuja A., R. Jones, and E. Enyedi. 1986. A mobile rain exclusion
canopy and gaseous pollutant reduction system to determine dose-response
relationships between simulated acid precipitation and yield of field
grown crops. Water, Air, Soil Pollut. 31:307-315.
Location: Ontario Ministry of the Environment, Brampton, Ontario
Summary: A system has been designed, constructed, and tested to determine the
interaction between acidic rain and ambient oxidants on agricultural
crops. The system uses a duct air-exclusion system for reducing ambient
gaseous air pollutant levels (03, S02, NOX), and a cover to exclude
ambient rain while simultaneously adding acidic rain to a crop canopy. A
microcomputer controls both the inflation of the air-exclusion system
based on specified ambient air pollution concentrations, and rain exclu-
sion/addition based on ambient rain events. The computer system also
handles all air pollution and rain event data acquisition, as well as
meteorological data acquisition. The system has been tested in studies of
radish and soybean crops in 1984, and a soybean crop in 1985.
Rain exclusion is achieved by an automated exclusion shelter acti-
vated by an ambient precipitation sensor. During exclusion in sheltered
plots, rainfall is dispensed automatically through nozzles at a rate
equivalent to the natural rainfall rate. The shelter is basically a
modified greenhouse wrapped in plastic. The size of the plots sheltered
from ambient rainfall allows for replication within a single shelter unit.
1. Hardware
a. Ducts and Rain Exclusion/Addition System
The air exclusion system consists of three blower units, each
containing three low pressure fans. Two units are equipped with
activated-charcoal filters and particulate filters to supply filtered
air; the other unit supplies ambient air. The air is forced into two
15.2-m long by 0.30-m diameter perforated PVC ducts. Each system has
a mobile greenhouse shelter (19.5 x 9.1 x 4.6 m) constructed of
galvanized steel covered with PVC. The shelter rolls on wheels on
steel tracks over the duct systems during each ambient rain event.
Whirl-jet type, stainless steel nozzles deliver 1-mm diameter
simulated rain to the plots during the rain events. The entire
system is replicated three times. The surface area for planting is
174 m2, with a maximum height of 2.4 m.
b. Pollutant Dispensing and Monitoring
The gaseous pollutant treatments are ambient or charcoal-
filtered air; no other gases are added. Ambient air concentrations
of 03, S02, and NO/N02 are measured by monitors in a control trailer.
The simulated acidic rain included five pH treatments of 3.0,
3.4, 3.8, 4.2, and 5.6; each with mineral salts and a 2:1 S04/N03
ratio based on ambient rainfall chemistry. The simulated rain
D-10
-------
solutions were mixed immediately before eacji event by a computerized
system. The activation of the exclusion shelter is achieved by a
rain sensor monitored by a minicomputer.- -The-rate...of ambient
rainfall is monitored with a tipping-bucket rain gauge. Minimum
rainfall needed to trigger dispensing of the, rain-simulant is Q.5 mm,
Rain is dispensed from stainless steel nozzles that deliver droplets
in a square pattern. Rain simulant is delivered by pumps from
reservoirs, and the flow rate through the lines is controlled by PVC
needle valves and pressure gauges. All mixing of solutions is
achieved in the batch mode but is done automatically by a system of
light switches, pumps, and solenoid valves.
The method for chemically analyzing the simulated rainfall is
not specified. The reported chemistry is for batch or in-line
solutions and is calculated based upon recipe additions. The method
for measuring the rainfall distribution/application rate within the
shelter, either on a routine basis or as a means of evaluating
performance, is not reported.
c. Environmental Monitoring and Controls
Air temperature, relative humidity, wind velocity, and light
intensity are monitored continuously and the data stored by the data
acquisition system.
d. Data Acquisition
All aspects of the field system are controlled by a micro-
computer and data acquisition system. The data commonly logged
include status of mixing and treatment pumps, blower activation,
storage tank levels, air temperature, relative humidity, wind .
velocity, irradiance, and ambient levels of gaseous pollutants. For
the meteorological data, a 30-min averaging time is used.
2. Performance Evaluation
a. Pollutant Uniformity
Gaseous pollutant distributions not described. Rain chemistry
is calculated from the solution mixture. Soil deposition rates are
calculated rather than measured with rain events.
b. Environment Uniformity
Not described.
c. Pollutant Control and Maintenance
Not described.
D-ll
-------
d. Environment Control and Maintenance
Not described.
Diagram of the system was not available.
0-12
-------
Publication: Seufert, Von 6., and U. Arndt. 1985. Open- top kammern als tell
einer konzepts aur okosystemaren unter suchung der neuartigen woldschaden
Allg. Forstz. 40:13-20.
Additional Publication: Arndt, U. 1986. Proceedings of Open-Top Chamber
Workshop, Environmental management in open-top chambers. Freiburg,
Federal Republic of Germany. Commission of the European Communities.
Location: Institut fur Landeskuetur und Pflanzenokologie, University of
Hohenkiran, Stuttgart, West Germany
Summary: A system of six open-top chambers are part of model ecosystems with
lysimeters and protection from ambient rain to investigate long term
effects of SQ2, 03, and acid rain on mineral cycling, biochemistry,
ecophysiology, and anatomy of tree seedlings.
1. Hardware
a. Chambers
The chambers are 3-m diameter cylinders, 3 m in height, with a
frustrum and an inside area of 3.2 m*, UV-B stabilized PVC film
(Polydress SPR 3) cover the chambers. Each chamber has a blower fan
(56 m3 min-1) and filtration system of activated charcoal with KOH
and dust filters. The trees are planted in ground-level lysimeters.
b. Pollutant Dispensing and Monitoring
Only ambient gaseous pollutants and filtered chambers are in
use; no added pollutant except acid rain. The incoming air is
distributed from the center with three perforated PVC tubes extending
out along a footpath. Each chamber is monitored for S£>2, 032, and
N02, but frequency of sampling is not reported.
c. Environmental Monitoring and Controls
Chamber environment is not controlled except "rain cap" excludes
ambient precipitation. Relative humidity, evapotranspiration, soil
moisture, and soil temperature (at 10 and 30 cm) are routinely
measured in all chambers. The frequency of measurement of air
temperature and solar radiation is not described.
Data Acquisition
Not described.
D-13
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2. Performance Evaluation
a. Pollutant Uniformity
The chambers exclude between 60 and 95% of the ambient 03, the
average is 80%. No information on exclusion of other pollutants is
described. Ambient rainfall is excluded, but no information on
amounts is provided. There was no information on pollutant varia-
bility across the chamber or over.time.. ,
b. Environment Uniformity
The chambers have an irradiance 30% lower than outside without
the shadecloth,-and 45% lower thaji outside with the shadecloth. This
low irradiance is considered to be more representative of forest
environments than full sunlight. Chamber air temperature is 0. to 5°C
greater, and relative humidity is 0 to 15% greater than, outside if no
chamber modifications are made. The chamber has been adapted to
include fog nozzles which raise the relative humidity to within 5% of
the outside; this is accompanied by a decrease in chamber tempera-
ture. Air speed within the chamber is estimated at 0.5 to 1.0
m sec"1, which is adequate for high boundary layer conductances. No
information was described concerning the location or frequency of
environmental,measurements, or uniformity vertically,.horizontally,
or temporally across or between-chambers.
c. Pollutant Control and Maintenance
Ambient and charcoal-filtered air is put into the chambers.
Filtration efficiency is not described for 03, S0£, N02, and NO.
Intrusion of pollutants in the open top is a function of wind speeds
and varies between 70% with strong winds and not detectable with wind
speeds less than 0.5 m sec-1. Mean.chamber efficiency given as 80%
exclusion of 03 and S02.
d. Environment Control and Maintenance
Not described.
e. Chamber Equilibration
.' . •• I- ',''•'"
There are approximately 1.5 air exchanges per minute.
D-14
-------
1. basement of concrete
2. lysimeter-walls, concrete
80*9 cm. .0 3 m
3. sealing up of concrete
with PC-foil 2 m*
*. drain for percolating «ater
5. PC-tube J/V
6. PC-container 60 1
7. drainage-shaft, h s 110 cm
d * 60 cm
8. frawe of coated iron-tubes 1/2"
9. mounting for the frame
10. coated strip iron 30*3 am
11. holding device for
rain-shelter
12. rain outlet
13. line to strain the
rain-shelter-foil
14. fruslrum as*, SO c«
15. Al-profile for stabilisation
16. PVC-foil 3,2 irnn. UV-stabllircd
17. foil-door
' 18. 19. central suppport
for footbridge
20, 21. footbridge
22, 23. peripheral Support
for footbridge
2*. annular ventilation tube,
d s 125 mm
25. ventilation tube between center
and annulus
26. central air-distribution
27. air-duct fro« blo«r
28. blower 2200 V, 56 m'/min
29. filter element mln carbon-
30. dispensing teflon-line for qases
31. draining stowe-matenal
35.
36.
sampling-duct for crown
leachate
. keramtc candles for
soil solution
. bulk sampler
. rmrask ope -tube
. rain noizle
62. magnetic valve, pres:
sample-line to an?lysrrs
Figure D-4.
Schematic diagram of open-top chambers at University of Hokenheim
Stuttgart, West Germany (u. Arndt, personal communication, 1986).'
D-15
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Publication: Seufert, Von 6., and U. Arndt. 1985. Open-top kammenn als tell
einer konzepts aur okosystemaren unter suchung der neuartigen woldschaden.
Allg. Forstz. 40:13-20.
Location: Edelmannshof station in Welzheimer Wold at Aufbau, Germany
Summary: Four large open-top chambers built around four healthy mature spruce
trees in a diseased forest area. The chambers are designed to investigate
the long-term effects of ambient and filtered air on mineral cycling,
biochemistry, ecophysiology, and anatomy.
1. Hardware
a. Chambers
Each chamber is a 6 x 2.5 m cylinder with a ground area of 4.9
m2 and volume of 2.9 m3. Air is drawn into the chambers with two
blowers delivering air to the plenum at the lower and upper levels of
the chamber. Blowers run full speed for the upper level at all times
(18-20 m3 min-1); the lower level (0-20 m3 min"1) depends on ambient
wind speed and is off at night to allow dew formation. Charcoal
filters impregnated with KOH are in use on each blower fan.
b. Pollutant Dispensing and Monitoring
No dispensing occurs in the chambers, only filtered and ambient
air. Monitoring of 03 is by analyzer and monitoring of S02 and N02
is by surface active monitoring at 10 places within each chamber.
The frequency of sampling is not described.
c. Environmental Monitoring and Controls
Chamber environment is not controlled. Relative humidity,
evapotranspiration, soil moisture, and soil temperature (10- and
30-cm depth) are routinely measured in all chambers. Measurement of
air temperature and irradiance are not described.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
Distribution within each chamber is not described. Chamber
efficiency'in excluding ambient pollutant is improved by plastic
netting at the outlet. Initial measurements show incursion starting
at wind speeds of more than 1 m sec-1.
D-16
-------
Environment Uniformity
Variation within each chamber is not described. Inside versus
outside temperature and solar radiation show 2-3°C increases in
temperature and 10-25% reduction in photosynthetic active radiation
(PAR) inside the chambers. Wind speed at the twigs varies between
0-2 m sec-1. .
Pollutant Control and Maintenance , .-
Not described.
Environment Control and Maintenance
Not described.
Chamber Equilibration
There are 1-2 air changes per minute.
D-17
-------
wooden stake
frame of coated Al-T-profile
coated strip-Iron 30x3 am
Al-profile for stabilization
and working platform
mounting for the frame
frustrum 45°, 60 cm
plastic net
PVC-stnp 30xJ mm for mounting
the foil to the iron-strip
PVC-foil 0,2 mm, UV-stabilized
annulus of foil, perforated
with 1 cm holes
12. air duct from blower
blower 530 U, 28 m'/min
filter element with carbon
cartridges and particle-filter
platform for filter element
foil-door
steel cable for mounting
Figure D-5.
Design of open-top chambers at Edelmanshof for ambient air
pollutant exclusion (U. Arndt, personal communication, 1986)
D-18
-------
APPENDIX E
Descriptions of Facilities and Performance Evaluations --
Indoor Chambers for Gaseous Dry Deposition Research
-------
-------
I. Chambers for Laboratory Use
Publication: Adams, D. F. 1961. An air pollution phytotron. A controlled
environment facility for studies into the effects of air pollutants on
vegetation. J. Air Pollut. Contr. Assoc. 11:470-476.
Location: Washington State University, Pullman, Washington
Summary: This paper reports the design of a controlled
(phytotron) in which light, temperature, humidity,
pollutant concentrations may be controlled for the
responses to atmospheric pollutants.
/
1. Hardware
exposure facility
air circulation, and
studying of plant
2.
The facility uses plant growth chambers, an air handling system, a
lighting system, and a pollutant (fluoride) generating system.
a. Chambers
A controlled environment room is divided into three walk-in
chambers, one large and two small. The large chamber is used to
germinate and grow plants to any selected state of maturity. The
plant population is divided into the two smaller chambers for paired.
experiments of unexposed (control) and exposed plants. Incoming
filtered and conditioned air is introduced through a perforated
ceiling, creating a nearly uniform air flow into the chambers. The
exhaust ducts at floor level have numerous openings to help maintain
an even air flow. The light source is a combination of fluorescent
and incandescent lamps.
b. Pollutant Dispensing and Monitoring
Hydrofluoric acid vapor is generated and introduced into the
incoming chamber air stream.
c. Environment Controls
Not described.
d. Data Acquisition
Not described.
Performance Evaluation
a. Pollutant Uniformity
Ten bench locations had an average variation of + 5.9% from the
mean.
E-l
-------
b. Environment Uniformity
Light levels varied horizontally by about 30% .in the large
chamber and 20% in the small chambers.
c. Pollutant Control and Maintenance
Diurnal variations of the chamber fluoride concentration were
found and were associated with variations in incoming air tempera-
ture. There is more adsorption of fluorides on cooler chamber walls
at night than on warmer walls during the daytime. ,
d. Environment Control and Maintenance
Not described.
e. Chamber Equilibration
Not described.
E-2
-------
INLET
"CJ
u
-------
Publication: Aiga, I., K. Omasa, and S. Matsumoto. 1984. Phytotrons in the
National Institute for Environmental Studies. Res. Rep. Natl. Inst.
Environ. Stud., Japan 66:133-154.
Location: National Institute for Environmental Studies, Ibaraki, Japan
Summary: This paper describes two phytotrons, one with controlled greenhouses
and growth cabinets; the other with simulators to analyze the plant-
environment system. In the controlled greenhouses, there are four growth
cabinets for studying the effect of air pollutants on plants under natural
light and nine growth cabinets (described below) for studying air pollut-
ants under artificial light. The phytotron with two simulators (growth
rooms) reproduces a plant community's light, air, and soil, to examine the
effect of environmental deterioration on plants.
1. Hardware .
a. Chambers
Each controlled exposure chamber consists of a fresh air pro-
cessing unit, .a chamber for gas exposure experiments, and an exhaust
processing unit. The fresh air for ventilation is introduced through
an air conditioner and filters of both activated carbon and manga-
nese. Each simulator is a special wind tunnel .of the low wind
velocity type. It includes an air conditioner and profile units for
wind velocity, air temperature and humidity. There is a solar
simulator to control light spectrum and intensity and a soil environ-
ment control unit.
b. Pollutant Dispensing and Monitoring
The gas, supplied from a cylinder or an ozone generator, is
manipulated by a mass flow controller: A gas analyzer is used for a
feedback sensor. These can be programmed to control gas concentra-
tion for both single and mixed gases.
c. Environment Controls
Temperature from 15 to 40°C and relative humidity from 50-80%
are controlled by a central cold water and steam system. For light-
ing, metal halide lamps with the emission spectrum of tin halide are
used. Phosphide glass containing iron oxide is used as a heat-
absorbing filter. Mean wind velocity is 0.2'm sec"1 with 0-2800
m3 h"1 ventilation. In the simulator the profile unit for air
temperature and humidity is composed of 10 stages, each of which can
be independently regulated by computer control to provide any spatial
distribution of temperature up to 10°C and humidity up to 50%. The
wind velocity profile up to 8X minimum is produced by retardation
using a 10-stage profile unit after preconditioning by the main
blower. The light spectrum and intensity of 4 to 60 Klux are
regulated by various fluorescent lamps with different spectral
E-4
-------
d.
characteristics. Both soil temperature (-5 to +35°C) and water
content can be regulated. The range of wind velocity is 0.1 to 2.7
m s"1 with ventilation of 50-250 nH tr1.
Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
For the controlled exposure chamber the deviations of gas
concentration are: SO^ ±3.2 ppb (at 0.05 ppm), N0£ ±0.6 ppb (at
0.05 ppm), 03 ±0.2 ppb (at 0.01 ppm) and HC ±10 ppb (at 0.2 ppm).
For the simulator the corresponding values are: S02 ±3.2 ppb (at
0.05 ppm), N02 ±0.6 ppb (at 0.5 ppm), 03 ±0.2 ppb (at 0.01 ppm) and
HC ±10 ppb (at 0.2 ppm).
b. Environment Uniformity
For the controlled exposure the maximum temperature deviation is
±0.1°C and maximum distribution ± 0.3°C, humidity deviation ± 1% RH
and distribution ±2% RH, wind distribution ±0.1 m s~^-. For the
simulator the corresponding values are temperature ±0.1°C and
±0.3°C, humidity ± 0.1°C (dew point) and ± 0.2°C (dew point), and
wind ±0.1% and ±3% with turbulence intensity of ±3%. The devia-
tion in lighting is ± 0.1% and distribution ± 10 lux at 50 Klux.
Brine temperature deviation is ± 0.1°C for the soil temperature
control system.
c. Pollutant Control and Maintenance
Included above under uniformity.
d. Environment Control and Maintenance
Included above under uniformity.
e. Chamber Equilibration
Not described.
E-5
-------
fresh air
Figure E-2.
Sectional view of the growth cabinet for air pollutant exposure
(reprinted from Aiga £t _aj_., 1984, National Institute of Environ-
mental Studies). ~T
E-o
-------
Publication: Cantwell, A. M. 1968. Effect of temperature on..response of
plants to ozone as conducted in a specially designed plant fumigation
chamber. Plant Dis. Reptr. 52:957-960.
Location: Department of Plant Pathology, University of Delaware, Newark,
Delaware
Summary: A commercial plant growth chamber was modified for air pollution
studies in which temperature was to be a treatment factor.
1. Hardware
a. Chambers
Filtered air is provided to the chamber through an inlet blower
and filter system. About 90% of the air is recirculated and 10% is
ambient. The growth chamber contains an enclosed glass fumigation
chamber. Lighting is by the combination of fluorescent and incan-
descent lights in the chamber.
b. Pollutant Dispensing and Monitoring
Conditioned air in the growth chamber is mixed with a gaseous
pollutant and passed through a turbulence-inducing distribution tube.
The air pollutant then enters the fumigation chamber where it
contacts the plant, and subsequently is vented to the atmosphere.
Pollutant concentration within the fumigation chamber is continously
monitored by withdrawing samples through tubing to the appropriate
monitor.
c. Environment Controls
Temperature and humidity are controlled by the growth chamber
system.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Not described.
E-7
-------
c. Pollutant Control and Maintenance
Ozone levels of 0.1 to 100 pphm can be maintained in the fumiga-
tion chamber with a maximum variation of +_ 5%.
d. Environment Control and Maintenance
Not described.
e. Chamber Equilibration
About 2 hours are required before the unit operates at equili-
brium and the pollutant saturates the absorbing surfaces in the
tubing and chamber. Following this initial period, substantial
changes in pollutant concentrations can be stabilized within 10 to 15
minutes.
E-8
-------
'b
t
c
_^
^ X
'X 1
h
•
«
^
. —
j
a - air inlet to conditioning chamber
b - high pressure blower
c and d - activated charcoal filters
e - circulating fan
f - refrigeration unit
g - humidifying unit
h - inlet to fumigation chamber
i - distribution tube
j - air outlet tube
a1 - oxygen inlet
b1 - ozone generator
- ozone flow controller
- pure air pump
- pure air flow controller
- air pollutant flow controller
g1 - air pollutant inlet line
h' - pollutant sampling line
i' - pollutant analyzer
j' - pollutant scrubber
k1 - oxidant injection line
c1
d'
e1
f
Figure E-3. Controlled environment chamber for ozone research (reprinted from
Cantwell, 1968, Plant Disease Reporter).
E-9
-------
Publication: Hill, A. C. 1967. A special purpose plant environmental chamber
for air pollution studies. J. Air Pollut. Contr. Assoc. 17:743-748.
Location: Department of Botany, University of Utah, Salt Lake City, Utah
Summary: These controlled exposure chambers utilize an airtight, recirculating
air system with controlled addition of C02- Air velocity can be con-
trolled. Temperature and humidity are maintained by. a water temperature
control system. The air pollutant concentration is maintained by auto-
matic or manual additions.
1. Hardware
The facility consists of*an airtight controlled-environment chamber
with internal recirculation of air and provision for different wind
speeds. There is a carbon dioxide control system. Temperature and
relative humidity are controlled over a wide range with a combination of
cooling and heating coil temperatures and the circulating of air through a
water bath.
a. Chambers
Each chamber consists of a light bank, plant area, stands, and
conditioning unit bolted together, with joints sealed, and foam
insulation in the walls. Air is circulated through a perforated wall
across the plant area with a variable proportion circulated through
water coils. The light bank consists of fluorescent, quartz iodide,
and incandescent lamps, with infrared absorbing filters.
b. Pollutant Dispensing and Monitoring
In this chamber the pollutant concentration is controlled, once
the desired level is reached, by adding the pollutant to the chamber
at the same rate that it is being lost by the system. A glass
sampling tube on the exterior of the chamber connecting the two
plenums of the chamber has continuous air flow because of a pressure
differential. Ozone is injected into the chamber at the fan inlet to
facilitate thorough mixing with chamber air.
c. Environment Controls
Air flow rates can be modified by blocking off part of the inlet
and outlet walls. Carbon dioxide concentration in the chamber is
maintained by monitoring with an infrared analyzer controlling a
valve that admits CO? from a pressurized cylinder. Temperature is
controlled by water temperature in cooling coils. Humidity is
controlled over a wide range by a combination of circulating air
through cold and warm water coils for low humidities and by circulat-
ing air through a warm water bath to obtain high humidities. Oper-
ator experience is an important factor in control of environmental
E-10
-------
variables that are affected by percentage of air flowing through the
water coils, water flow rate through the coils, water temperature
and the number of cold coils in operation.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
4. ^ auohor reP°rted that relative humidity in the range from 20
to 96% at 27 C can be maintained within + 1%. Other variables not
described. —
Pollutant Control and Maintenance
Not described.
Environment Control and Maintenance
Not described.
Chamber Equilibration
Not described.
E-ll
-------
Figure E-4.
Air circulation and conditioning components of the controlled
environment chamber for air pollution research (reprinted from
Hill, 1967, with permission of the Air Pollution Control Associa-
tion).
-------
Publication: Jensen, K. F., and F. W. Bender. 1977. Seedling-size fumigation
chambers. Forest Service Research Paper NE-383. 4 p.
Location: Northeastern Forest Experiment Station, Research Laboratory,
Delaware, Ohio L
Summary: The design of fumigation chambers for forest tree seedlings is
described. Each chamber has individual temperature, humidity,, light, and
pollutant control. Temperature is variable from 15 to 35°C and controlled
within ± 1°C. Humidity is variable from 25 to 95% and controlled within
± 3%. Seedlings have been successfully grown in these chambers 'for up to
3 months.
1. Hardware
The fumigation system consists of four chambers with airflow, air
conditioning, lighting, temperature control, humidity control, and
pollutant addition components.
a. Chambers
The chambers are constructed of plywood painted with white
epoxy. The airflow is negative-pressure, single-pass by means of a
blower on each chamber. Air conditioning is by three separate
compressor and evaporator coil units.
b. Pollutant Dispensing and Monitoring
Two pollutants can be added, individually or in combination, to
each chamber. Additions are by micrometering valves to the air
stream about 150 cm before the pollutant enters the chamber to allow
ample mixing. Monitoring is by drawing a sample from the chamber.
c. Environment Controls
Lighting is by a bank of fluorescent and incandescent bulbs that
can be turned out selectively to provide six different light levels.
Temperature is monitored and controlled with shielded thermocouples.
Each chamber has a 24-hour programmable controller.
d. Data Acquisition
Monitors alternate automatically between chambers and are
connected to strip chart recorders. Temperature is also recorded.
2. Performance Evaluation
a. Pollutant Uniformity
Not described.
E-13
-------
Environment Uniformity
Light level decreases approximately 20 percent from the center
to the corners of each cabinet. Temperatures in the center and in
each corner 15 and 45 cm above the floor are within a range of +_ 1°C.
Relative humidity has a variation of +_3% at 23°C.
Pollutant Control and Maintenance
Pollutants can be added in a wide range of concentrations and
maintained with slight adjustments for long periods.
Environment Control and Maintenance
Light levels at 30 cm above the floor can be set for about 10 to
30 Klux, temperatures from 15 to 35°C, and humidity 25 to 95% with
the lower limit being higher at low temperatures.
Chamber Equilibration
Not described. -
E-14
-------
A, Light bank
B, 4-inch inlet duct
C, Door
D, Horizontal handle clamp
E, False bottom
F, Pollutant addition port
Gf Steam addition port
H, 12-inch inlet duct
li Heater
J, Charcoal filter
K, Butterfly valve
L, Orifice plate
M, Pressure tap
N, 4-inch aluminum outlet pipe
O, Exhaust duct to blower
P, Inlet duct from air conditioner.
Arrows show direction of air movement.
I J J O P
Figure E-5.
View of controlled environment seedling chamber for air pollution
research (reprinted from Jensen and Bender, 1977, U.S. Forest
Service). £
-------
Publication: Mclaughlin, S. B., V. J. Schorn, and H. C. Jones. 1976. A
programmable exposure system for kinetic dose-response studies with air
pollutants. J. Air Pollut. Contr. As'soc. 26:132-135.
Location: Tennessee Valley Authority, Muscle Shoals, Alabama
Summary: A programmable system for exposing plants to sulfur dioxide under
controlled and reproducible concentration regimes is described. The
system is capable of reproducing the rapid changes in pollutant concentra-
tions that occur in the field. The system relies on feedback control to
reproduce previously programmed exposure regimes within a controlled
exposure chamber.
1. Hardware
The main components of the system are an exposure chamber, pro-
grammer, analyzer and controller, and valves. The system operates on the
principle of feedback control whereby at any time the level of the pro-
grammed SOg concentration is compared with the actual concentration
occurring within the exposure chamber to determine the volume of S0£
injected into the chamber. Input and output signals are processed by a
controller that continously compares the two signals as a basis for
activating two low flow valves. The valves meter S02 into the air
supplied to the exposure chamber. Sample air continously drawn from this
chamber is analyzed to produce the output signal which is fed back to the
controller and concurrently recorded.
a. Chambers
The chamber frame is covered with clear teflon film and utilizes
an air sy-em incorporating both supply and exhaust blowers. Air is
introduced along one end of an inflatable teflon panel which covers
the entire chamber top. The panel is perforated on the lower side
with 0.6-cm holes spaced approximately 7.6 cm apart. When inflated
by air supplied to the chamber, the upper and lower surfaces of the
panel form an approximately 10-cm deep envelope within which air is
mixed and directed downward uniformly to the test plants in the
chamber below. Air is simultaneously removed from the chamber
through a peg-board floor covering a 20-cm deep false bottom. The
exposure chamber is located within a walk-in growth chamber. A
slightly negative pressure is maintained within the exposure chamber
to prevent escape of S02 into the growth chamber.
*
b. Pollutant Dispensing and Monitoring
The pollutant concentration programmer utilizes a probe- that
follows a program line drawn on the conductive surface of a revolving
program chart. The kinetics of a desired exposure regime are repro-
duced by scribing the program line on a chart, which is then attached
to a revolving drum. A new chart is required for each new program,
but the same chart may be used repeatedly.
E-16
-------
The controller responds to a variable resistance signal from the
programmer and a variable voltage output from the analyzer. The
controller may be operated in any of three modes: manual, automatic,
or cascade. In manual mode, the aperture of the valves may be
regulated by manually selecting the desired degree of valve opening.
In automatic, the desired concentration level may be preset and the
system will automatically maintain that level by changing the valve
apertures as needed. When rapid changes in concentration are
required, the cascade mode is used. In cascade, the input signal is
changed automatically in response to the specific program, and valve
apertures are varied by the controller to produce programmed pollut-
ant concentrations.
The valve system consists of two electropneumatic valves of
unequal size that operate in parallel. The apertures of the valves
are adjusted by compressed air in response to an electronic signal
from the controller. The volume of flow through the system at any
degree of valve opening may be increased or decreased by increasing
or decreasing the pressure of the S02 supply.
An adjustable teflon sampling line is oriented at plant height
and connected to the control system module located outside the growth
chamber. Wrapping.the tubing with heating tape reduced its equili-
bration time and eliminated absorption problems caused by condensa-
tion of water within the tubing.
c. Environment Controls
The programmable light, temperature, and relative humidity
controls on the walk-in growth chamber are adjusted to provide
desired conditions within the exposure chamber.
d. Data Acquisition
Sulfur dioxide concentrations are recorded and compared with the
programmed exposure kinetics.
Performance Evaluation
a. Pollutant Uniformity
When the sample probe was rotated around a circle within the
chamber, fluctuations in concentrations were not detectable at 4.0
ppm and were less than 0.01 ppm at an internal S02 level of 0.70 ppm.
b. Environment Uniformity
Not described.
E-17
-------
Pollutant Control and Maintenance
Criteria for control of rapidly changing S02 concentrations were
met. High concentrations could be produced rapidly within the
chamber (0 to 4.5 ppm in less than 2 min), and flushing time was
minimal (4.5 to 0.1 ppm in less than 3 min). Abrupt manual changes
in valve aperture could be seen as recorder deflections in 30 to 60
seconds. Recorder responses to rapid changes in concentrations were
smooth, indicating that mixing was thorough. With the controller in
the cascade mode there was a 1- to 2-minute lag time in reproduction
of programmed concentrations when program slopes were steep, but the
conformation of typical field exposures could be closely reproduced.
Comparison of programmed and reproduced exposure kinetics revealed an
accurate reproduction of individual program peaks, short-term aver-
ages, and the total exposure dosage. The principal shortcoming of
this sytem is that, in the cascade mode, the controller will maintain
a valve opening of not less than 10% even when the programmer calls
for less.
Environment Control and Maintenance
Not described.
Chamber Equilibration
Described in (c) above.
E-18
-------
Inject
S02
Supply air
Exhaust
air
/
/
-X
*r
/
'<",
*
^
&
1 - - -
-
s*
'.• .* .*
• .*•».* .* / .
•-»• • • •
i ^ —
' Sample
probe
i
Air
i
J^
_•? _ _/f]
U
/ToS
and
* .* ,* .' /V .'
..' / ^.^ /!.* /
i \ 1
movement
i i I
4 i J
» I
^IHI-rj
02 monitor
control system
>
• //
«
/
//
^
/ill
Figure E-6.
Diagram of exposure chamber showing single-pass air flow system
required for control of rapidly changing internal pollutant
concentrations. (Note double-walled teflon envelope on chamber
top.) Employed in sulfur dioxide exposures (reprintd from
Mclaughlin et_ jH., 1976, with permission of the Air Pollution
Control Association).
E-19
-------
Publication: Menser, H. A., and H. E. Heggestad. 1964. A facility for
ozone fumigation of plant materials. Crop Sci. 4:103-105.
Location: Agricultural Research Service, U.S. Department of Agriculture,
Beltsville, Maryland
Summary: A plant fumigation chamber used for ozone studies is described. The
installation consists of an ozonizer, an activated-charcoal air filter,
and an exposure chamber. A walk-in refrigerator is equipped with fluor-
escent lights, and provisions are made for control of temperature, rela-
tive humidity, and air flow rate.
1. Hardware
The principal components and accessory equipment are a large-capacity
ozonizer, an activated-charcoal air filter, and a fumigation chamber.
a. Chambers
The fumigation chamber is a modified walk-in type refrigerator
equipped with overhead lighting and provisions for control of tempera-
ture, relative humidity, and air movement.
b. Pollutant Dispensing and Monitoring
Filtered air and ozone pass into the chamber through ducting.
c. Environment Controls
Fluorescent lamps are mounted below the chamber ceiling.
Chamber temperature is regulated by a thermostatically controlled
refrigeration unit and circulating fan. Humidity is increased by
using vaporizing nozzles.
d. Data Acquisition
Temperature and humidity are recorded.
2. Performance Evaluation
a. Pollutant Uniformity
The maximum difference across the plant area was about 0.025 ppm
when the chamber was operated at 0.25 ppm. Slight changes in ozone
were thought to be due to temperature cycling.
b. Environment Uniformity
Temperature fluctuated about 1°C during fumigations. Relative
humidity fluctuated from 5 to 10% during temperature cycling.
E-20
-------
c. Pollutant Control and Maintenance
Ozone concentrations between 0.06 and 1.00 ppm were generated
readily.
d. Environment Control and Maintenance
Not described.
e. Chamber Equilibration ,"
Not described.
E-21
-------
AIR INTAKE
OZONE FUMIGATION
FACILITIES
SUPPLY
IIOV
1
..
/
/
-!S
::;
/
1FILTER AUXILIAR
HEAT
EXCHANG
a
COOLING
AIR-OZONE —
j
rf]
t
I
DUAL
OZONIZERS
^STEP-UP
/ 1 HAND
' FORMER
jrFLOW- M
:^XETER LTsTAT
I-WATER
r " j LINE
ER -J
UNIT — s. \ \
_ \ \
, j_| , ,—
INLET-'i !
. . . .__-.. . .-
;;TLUORES- PLANT
• "CENT ] EXPOSURE
.-LAMPS j AREAA
B * ! _^-^ 1
• ! ^ ^
11 , 1 ,
'I
II
^VAPORIZER
VOLTAGE
TRANSFORMER
-8'X6'X7' FUMIGATION
CHAMBER
Figure E-7. Design and arrangement of controlled environment chamber for ozone
research (reprinted from Menser and Heggestad, 1964, with per-
mission of Crop Science Society of America, Inc.).
E-22
-------
Publication: Oliva, M., and L. Steubing.
the photosynthesis, respiration, and
Angew Botanik 50:1-17.
1976. Effects of H£S fumigation on
water budget of Spinacia oTeracea.
Location: Botany Institute, Justus-Liebig University, Giessen, West Germany
Summary: A new installation is described for fumigation with very low concen
trations of HgS under defined climatic conditions. (In German language
with English summary.)
E-23
-------
/ \
-txj-
_ 1
I
-OO-
A-cH-
/ \
i _
L
QJ
o-
II C
1
Figure E-8.
Controlled environment chambers for hydrogen sulfide research
(reprinted from Oliva and Steubing, 1976, with permission of the
author).
E-24
-------
Publication: Payer, H. D., L. W. Blank, G. Gnatz, W. Schmolke, P. Schramel,
and C. Bosch. 1986. Simultaneous exposure of forest trees to various
pollutants and climatic stress. Water, Air, Soil Pollut. 31:485-491.
Location: Institute for Biochemical Plant Pathology, GSF, Munich, West Germany
Summary: This report describes a controlled-environment facility designed to
simultaneously generate the complex climatic and pollutant conditions
characteristic of field sites. The new facility consists of two environ-
mental chambers. The technical characteristics of the facility are
outlined on the basis of the design specifications and the performance
during the first test under experimental conditions.
1. Hardware
The system is based on the concept of a chamber-in-chamber facility.
Components include systems for lighting, air filtering and circulation,
gas exposure and analysis, and monitoring and control.
a. Chambers
The two large environmental chambers have a common monitoring
room but can be operated independently. Four smaller subchambers can
be placed within each large chamber. Light and climatic conditions
are identical for the four subchambers but gas supply and root
temperature control can be varied individually. The lighting system
consists of krypton, metal halide and xenon lamps, the former to
simulate dawn conditions, the latter two for simulating standard
daylight. A horizontal air recirculation system is used in the large
chambers. Subchambers use a vertical, single-pass-through air
circulation.
b. Pollutant Dispensing and Monitoring
Gases are diluted with fresh air to a preliminary concentration
not acutely toxic to plants. This pre-mixture is injected into the
fresh air supply of the chambers. High precision, mass flow control-
lers are used for mixing and dispensing. Different gas mixtures can
be added to each chamber and subchamber. Air samples are taken for
analyses from the unfiltered and prefiltered air, and from the
chambers.
c. Environment Controls
Cooling and heating of the chambers is carried out indirectly
using a brine system. Light levels up to 120 Klux may be obtained.
At high light intensities, an increased air exchange and circulation
rate is used to offset the greater heat load from the lights. Incom-
ing fresh air is preconditioned for 40 to 70% relative humidity
before filtration and entry into each large chamber.
E-25
-------
d. Data Acquisition
All chambers have a central monitoring and control system for
all pollutant and environmental factors.
2. Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Not described.
Pollutant Control and Maintenance
c.
d.
e.
The chambers are capable of operating with 0.01 to 1000 mg m~3
of SOg, NOX, 03, HC, C02, and other gases.
Environment Control and Maintenance
The temperature range is -20 to +40°C, humidity 20 to 95%, light
0 to 120 Klux, wind speed 0.05 to 0.7 m
4 chamber volumes per minute.
Chamber Equilibration
Not described.
, and air exchange 0.5 to
E-26
-------
Local area network
Temo. -controlled air Jacket
t=> 1
!
V
f
Room
FUln/M
Humidifier
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Brine
Brine
Cooling
Brine
Brine
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AAAr
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Figure E-9. Technical design of controlled environment chambers for air
pollution research (reprinted with permission of H.-D. Payer)
E-27
-------
Publication: Rogers, H. H., H. E. Jeffries, E. P. Stahel, W. W. Heck, L. A.
Ripperton, and A. M. Witherspoon. 1977. Measuring air pollutant uptake
by plants: A direct kinetic technique. J. Air Pollut. Contr. Assoc.
27:1192-1197.
Location: Agricultural Research Service, U.S. Department of Agriculture, North
Carolina State University, Raleigh, North Carolina
Summary: This paper describes the design of a chemical reactor system suitable
for plant growth and exposure, while meeting the criteria necessary to
apply the concept of a continuous stirred tank reactor (CSTR). This
system was the forerunner of the CSTR system described by Heck et al.
(1978). ,
1. Hardware
The complete CSTR plant exposure system consists of two cylindical
chambers. There is a common inlet and separate outlets for the two
chambers. Flow through the system is maintained by a pump on the down-
stream side. The chambers are mounted on a cart that is wheeled into a
controlled environment room.
a. Chambers
The cylindical chambers are each of 200-liter volume and
arranged side by side on a cart. All internal surfaces are made of
teflon or glass to minimize reaction and loss of gases to surfaces.
Plants are placed inside by lifting the chambers from their gasketed
bases. Welded steel frames are commercially coated with teflon.
Circular steel bands and rubber gaskets hold the teflon film to the
frame. Teflon-coated impellers are motor-driven from the lower level
of the cart. Inlet and outlet manifolds are fabricated from glass
tubing. Flow through the system is monitored by rotameters with
adjustable'valves.
b. Pollutant Dispensing and Monitoring
The main air stream enters the system through a glass fiber
filter after which the treatment gas is injected. The gas stream
enters a mixing bulb and, after it is mixed, the inlet monitoring
sample is taken. Sequential sampling of inlet and outlets, and
subsequent delivery of samples to the monitoring instruments is
controlled by solenoids. Air from the sampling points is taken
continously, but only one sample is analyzed at a time; the other
samples are bypassed to exhaust.
c. Environment Controls
Environmental conditions are dependant on those of the con-
trolled-environment room in which the chambers are placed.
E-28
-------
d. Data Acquisition
Not described.
2. Performance Evaluation
Under experimental conditions, the chamber system meets all design
criteria. Data obtained from the chambers shows a high precision for the
measurement of kinetic and biological processes.
a. Pollutant Uniformity
To test for uniform mixing, a tracer smoke of titanium tetroxide
is used. Mixing is visually uniform with no dead areas or pluming.
Uniform mixing was also verified with dynamic flow tests with nitro-
gen dioxide as a tracer gas. Mixing was nearly perfect and perform-
ance approximated that of an ideal CSTR.
b. Environment Uniformity
Essentially the same environment as the growth room is main-
tained throughout each CSTR chamber. Lighting is uniform in each
chamber.
Pollutant Control and Maintenance
The inlet concentration of N02 is
technique in which the gas is injected
capillary for flow control from a high
the air stream. This injection system
NOg levels over extended periods.
Environment Control and Maintenance
maintained by a dynamic
through a stainless steel
pressure calibration tank into
produces essentially constant
The single pass flow scheme and the spectral transmission
properties of teflon film prevent a large rise (< 0.5°C) in the
temperature of air moving through the system.
Chamber Equilibration
The chamber essentially follows the ideal CSTR chamber with
equilibrium reached in 6.6 residence times which was between 120 and
130 minutes for this particular system.
E-29
-------
©
*=Sample point
Flgur* 1. Schematic diagram of dual CSTR system.
1
I I
5
^
*rd
Lift assembly
"°-TW"ffysffl%WW4%/&f$Wffi£'±__ rt'frSy/s/£SSfpjyffl/rjirsfi2%s-£
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Figure E-10.
Schematic diagram of dual CSTR system (A) and cross-sectional
view (B) of CSTR for air pollutant uptake research (reprinted
from Rogers et al., 1977, with permission of the Air Pollution
Control Asso"cTatTon).
E-30
-------
Publication: Wood, F. A., D. B. Drummond, R. 6.
1973. An exposure chamber for studyinq the
plants. Penn. State Univ. Prog. Rep. 335.
7 pp.
Wilhour, and D. D. Davis.
effects of air pollutants on
University Park, Pennsylvania
Location: Department of Plant Pathology, Pennsylvania State University,
University Park, Pennsylvania
Summary: To study the effect of photochemical air pollutants (e.g., ozone and
PAN) on plants, a commercial plant growth chamber was selected that had
precise temperature and relative humidity control and was large enough to
accommodate 5- to 10-year-old trees. The chamber was modified to provide
a uniform concentration of fumigant throughout its interior, and interior
components were treated or modified to prevent corrosion by oxidants.
1. Hardware
The facility consists of a plant growth chamber modified for exposure
studies.
a. Chambers
The exposure chamber has two major components, the control
console and the chamber proper. The system includes a light cap
separated from the interior of the chambers by a plexiglass barrier,
highly reflective stainless steel and mylar-faced aluminum interior'
surfaces, air flow from ceiling to floor, and a vertically adjustable
plant bed. Modifications for exposure studies with ozone and PAN
included coating interior surfaces with epoxy base paints, installa-
tion of teflon-insulated wiring, and sealing of leaks. An air
exchange system, access ports, and a system for introducing pollut-
ants were installed.
b. Pollutant Dispensing and Monitoring
Air carrying the introduced pollutant moves downward over the
plants with some air continously removed near the ceiling. The
pollutant is introduced into the end walls of the chamber at six
different points, where it mixes with charcoal-filtered air. The
nature of routine monitoring is not described.
c. Environment Controls
Control features include a system for controlling temperature
and relative humidity jointly, with possible interlocking with light.
d. Data Acquisition
Temperature and humidity data are recorded on a multi-point
recorder. Data acquisition for pollutant concentrations is not
described.
E-31
-------
2. Performance Evaluation
a. Pollutant Uniformity
Uniformity and control of pollutant concentration was evaluated
by injecting 03 into the system and measuring concentrations at eight
different points along the long-control axis at five different
heights above the plant bed and at 24 points in a horizontal plane 36
cm above the plant bed. The 63 concentration fluctuated in the
vertical plane by a maximum of ±0.5 pphm at 7 to 9 pphm or approxi-
mately 5% and by a maximum of ± 1.0 pphm at 27 to 29 pphm or approxi-
mately 5%. Similar fluctuations occurred in the horizontal plane.
b. Environment Uniformity
Uniformity of temperature and relative humidity were checked
with the lights on, at different points along vertical and horizontal
planes within the chamber. Temperature was measured with copper-
constantan thermocouples connected to a strip chart recorder. Uni-
formity of temperature was evaluated with 24 thermocouples arranged
in a horizontal plane at 41-cm intervals along the long axis of the
chamber and 38-cm intervals along the short axis. During temperature
regimes of 10, 16, 21, and 27°C, temperature was measured in three
different horizontal planes at levels of 0, 46, and 91 cm above the
plant bed. There was a 0.6 to 2.2°C increase in temperature from the
front to the rear wall of the chamber interior. This pattern was
most obvious at lower temperatures and at lower levels in the
chamber. In most cases, the temperature did not vary by more than
1.1°C in the horizontal plane examined.
The uniformity of relative humidity was checked by measuring wet
bulb temperatures at 24 points in two horizontal planes within the
chamber. Thermocouples wrapped with cotton thread were used as wet
bulbs. The temperature of wet bulbs was recorded with a multi-point
strip chart recorder. Wet bulb temperature varied from 0.6 to 2.2 C
across the chamber. Corrections for differences in wind speed across
the chamber were not made and the temperature measuring and recording
system had an accuracy of only ± 0.6°C.
c. Pollutant Control and Maintenance
Fluctuations in 03 concentration with time were measured in the
same manner as for the uniformity evaluation. At 10 pphm the concen-
tration fluctuated by ± 0.5 pphm and at 50 pphm by ± 1.5 pphm. Since
this is essentially a closed system with a small rate of air exchange,
a steady concentration of pollutant was maintained by introducing the
pollutant at the same rate at which it was destroyed or otherwise
removed from the atmosphere within the chamber. There was a tendency
for the concentration to increase slowly over time but this was
easily corrected by periodic adjustment of the amount of pollutant
entering the system.
E-32
-------
Environment Control and Maintenance
Fluctuations in temperature with time (temperature control) were
measured at a single point in the horizontal plane at different
heights in the chamber. Temperature varied by ± 0.3° at 10°C, ± 0.4°
at 16°C, ± 0.7° at 21°C and ± 0.6° at 27°C, with a periodicity of
approximately 3 minutes. In general the fluctuation was lowest near
the plant bed and increased with height.
Fluctuations in relative humidity at a given point for a period
of time were measured with wet bulb thermocouples. Wet bulb fluctua-
tions represented ± 1.0%, ± 1.0%, ± 1.5%, and ±1.5% changes in
relative humidity at 10°, 16°, 21°, and 27°C, at relative humidities
of 53, 54, 60, and 63%, respectively. During exposures, relative
humidity was measured with lithium chloride sensors accurate to
± 1.5% relative humidity and found to be within these limits.
Chamber Equilibration
Not described.
E-33
-------
Exchange Air Outlet
102"
Filter
54'
Exchange Air Met
• Pollutant
Pollutant
Exchange Air Outlet
Figure E-ll.
Top and side views of controlled environment chamber for air
pollution research (reprinted from Wood ^t. jiJL, 1973,
Pennsylvania State University).
E-34
-------
II. Chambers for Greenhouse Use:
Publication: Berry, C. R. 1970. A plant fumigation chamber suitable for
forestry studies. Phytopathology 60:1613-1615.
Location: Southeastern Forest Experiment Station, Asheville, North Carolina
Summary: A lean-to greenhouse is used to expose potted trees to air pollutants,
1. Hardware
The greenhouse is fitted with environmental controls and a pollutant
dispensing system.
a. Chamber
The lean-to greenhouse has a volume of 8.4 m3 and can accommo-
date trees as tall as 2 m.
b. Pollutant Dispensing and Monitoring
Air pollutants are introduced into the chamber through tubes
leading into the air duct system and monitored with automatic
analyzers.
c. Environment Controls
Desired temperatures are maintained by an air-conditioner and
electric strip heaters. Pneumatic mist nozzles and steam are used to
keep relative humidity at specified levels. Sunlight is used for
radiation.
c. Data Acquisition
Recorders are used.
2. Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Not described.
c. Pollutant Control and Maintenance
Ozone concentrations from 0.0 to 1.0 ppm and sulfur dioxide
concentrations from 0.0 to 5.0 ppm can be maintained by manual
adjustment of flowmeters or by a recorder-controller.
E-35
-------
Environment Control and Maintenance
Temperature control can be maintained at ± 1.0°C and humidity at
± 5%. Humidities near saturation are possible when the air condi-
tioner-compressor is not needed; above 21°C, somewhat lower humidi-
ties must be used when cooling is necessary.
Chamber Equilibration
Not described.
E-36
-------
AIM COMOttlOMfM
Figure E-12.
Greenhouse for air pollution research. (1) Fumigation chamber:
(A) pneumatic nozzles; (B) instrument shelter containing wet- and
dry-bulb thermostats; (C) air inlet port; (D) air exit port; (E)
entrance to chamber; (F) air conditioner; (G) air ducts. (2)
Arrangement of air duct system to the chamber. (3) Side view of
chamber: (A) instrument shelter; (B) bench; (C) pneumatic
nozzles; and (D) air and water supply lines. Arrows indicate air
flow (reprinted from Berry, 1970, with permission of the American
Phytotoxicological Society).
E-37
-------
Publication: Hill, A. C., L. G. Transtrum, M. R. Pack, and A. Holloman, Jr.
1959. Facilities and techniques for maintaining a controlled fluoride
environment in vegetation studies. J. Air Pollut. Contr. Assoc. 9:22-27.
Location: Agricultural Department, U.S. Steel, Provo, Utah
Summary: This report describes greenhouses, equipment and techniques developed
to study the effects of fluoride on plants, with care being exercised to
maintain conditions comparable to those in the field.
1. Hardware
The facility consists of three greenhouses equipped with air condi-
tioning and portable chambers for isolating individual plots within the
greenhouses.
a. Chambers
The greenhouses are 11 m long by 2.8 m wide and 2.5 m high.
Incoming air is filtered and circulated through the greenhouses at
two air changes per minute. Portable chambers are of two different
sizes. They are constructed of plastic sheeting over aluminum
frames. The height of the larger chambers can be extended to
accommodate trees.
b. Pollutant Dispensing and Monitoring
Gaseous fluoride is injected into the air stream entering a
greenhouse or portable chamber. The rate of introduction is calcu-
lated for a particular air flow rate. Air in the chambers is sampled
continuously for fluoride analysis.
c. Environment Control
Solar radiation heating of the greenhouse is offset by a cooling
system in the incoming air .ducts. The temperature and humidity in
the portable chambers are maintained by using rapid air circulation.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
'Difference in fluoride content in the air in different parts of
the chamber were noted.
b. Environment Uniformity
Not described.
E-38
-------
Pollutant Control and Maintenance
The fluoride concentration in the air within a chamber was found
to be less than that of the incoming air because of absorption by the
plants and adsorption by the walls and soil.
Environment Control and Maintenance
The cooling system prevents the temperature from going more than
2 to 3°C above the outside temperature during the warmest months of
the year.
Chamber Equilibration
Not described.
E-39
-------
Publication: Lockyer, b. R., D. W. Cowling, and L. H. P. Jones. 1976. A
system for exposing plants to atmospheres containing low concentrations of
sulphur dioxide. J. Exp. Bot. 27:397-409.
Location: Grassland Research Institute, Hurley, England
Summary: A description is given of the construction and operation of a system
of chambers in which plants can be grown in filtered air, with or without
the addition of S02. Concentrations of S02 as low as 20 ug m~* , which can
be maintained in the chambers over prolonged periods, are monitored
automatically. The plants are grown in pots containing soil and watered
by remote control, allowing exposure to S02 for extended periods without
interruption. The method of watering is based on loss of weight and gives
an estimate of transpiration. The system is based on the design given by
Heck £t_al_. (1968) but with considerable modification.
1. Hardware
The main components of the system are: 10 chambers in which plant
pots are housed and through which filtered air is passed; apparatus to
supply and meter SOg to each chamber and water to each plant pot; and an
assembly for monitoring automatically the S02 concentration in the
chambers.
a. Chambers
The materials used are chosen to provide good transmission of
heat and light to allow satisfactory plant growth and to avoid
condensation of water and the consequent removal of S0£ from the air.
Materials having little capacity to adsorb, or to react with, SOg are
selected. Each chamber is a cube built of clear acrylic sheet
covered with polyester film and containing a perforated ceiling and
floor. The air supply to the chambers comes through a filtration
unit constructed of ABS plastic sheet and containing a nylon dust
filter and granular charcoal filter. The air duct system is con-
structed of ABS plastic fittings and pipes. Air is drawn from the
filtration unit and blown into an inlet manifold. It then passes to
the top of each chamber through an inlet duct and diaphragm valve.
From beneath the floor of the chamber the air is drawn through a
flowmeter and diaphragm valve to an outlet manifold, evacuated by a
second blower. The apparatus for supplying water to the plant pots
avoids opening the chamber and allows water use by the plants to be
measured. Water is supplied via nylon tubing under pressure from a
nitrogen cylinder. Each pot is mounted on a small, topioading
balance.
E-40
-------
b. Pollutant Dispensing and Monitoring
Supply of S02 to each chamber from a gas cylinder and manifold
containing an S02:N2 mixture is controlled by a flowmeter and
injected through a hypodermic needle inserted into the inlet duct
that contains a fast moving, turbulent air stream. Mixing occurs in
the duct and above the perforated ceiling.
Two systems are used to monitor the SO;? concentrations. Each
system is independent and involves the continuous, sequential
.sampling of the chambers and of two other sites which are respective
sources of air containing a known amount of S02 and of specially
filtered air, free of S02.
c. Environment Controls
The system is housed in a greenhouse with automatic heating and
ventilation. The filtration unit and the blowers are mounted
outdoors. Supplementary lighting is provided by a single lamp
mounted above each chamber. There are no additional environmental
controls incorporated into the system.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
Using a chamber without plants but receiving 50 ug m~^ S02,
samples of air were withdrawn from above the ceiling, i.e., the
normal sampling point; from the center and four corners of the main
compartment; and from beneath the false floor. No differences were
detected among these samples indicating that thorough mixing of the
added gas occurs and that it is uniformly distributed within the
chamber. In a similar study, but with plants included, no depletion
of S02 could be detected within the chamber.
b. Environment Uniformity
Not described.
c. Pollutant Control and Maintenance
Not described.
d. Environment Control and Maintenance
An experiment is reported in which the temperature range was
13.5 to 23.0°C and humidity range from 46 to 92% over the course of
the experiment.
E-41
-------
e. Chamber Equilibration
Not described.
E-42
-------
To exhaust
fan
From \
blower
\
Figure E-13.
Diagram of a chamber showing air, water, and S02 supply assem-
blies. Key: Arrows indicate direction of air flow A-K =
chamber components (see text); L = air inlet; M = air outlet- N
sampling port; 0 = water supply ports; P = auxiliary port. Air
supply components: Q = inlet manifold; R = inlet duct- S S1 =
diaphragm valves; T = flowmeter; U = outlet manifold; V ='water
reservoir; W = stop-cock; X = S02 flowmeter (reprinted from
Lockyer et aK, 1976, with permission of Oxford University
Press). ^
E-43
-------
Publication: Piersol, J. R., and J. J. Hanan. 1975. Effect of ethylene on
carnation growth. J. Amer. Soc. Hort. Sci. 100:679-681.
Location: Department of Horticulture, Colorado State University, Fort Collins,
Colorado
Summary: Chambers are constructed in a greenhouse. Temperature and humidity
are controlled in the chambers and ethylene is injected from a gas
cylinder.
1. Hardware
The exposure system consisted of four chambers, electrical heating,.
refrigeration, and a high pressure mist system to maintain humidity.
a. Chambers
Four chambers, covered with clear vinyl plastic, were con-
structed in a greenhouse covered with rigid PVC panels. A constant,
positive pressure was maintained in the chambers with a non-recircu-
1ating air system.
b. Pollutant Dispensing and Monitoring
A gas cylinder was evacuated and then pressurized to about 1000
psi with a diluted ethylene mixture. The gas flow was controlled by
three pressure regulators and glass capillary tubes, selected to
provide the desired ethylene concentration in the chambers. The
mixture was injected at the inlet to each chamber. A plexiglass
diffusion plate of cross-sectional area equal to the chamber provided
mixing. Periodically, 50-ml samples were taken from the exhaust end
of chambers.
c. Environment Controls
The controls for the single air intake to all chambers employed
an electrical heating system (three stages) with two refrigeration
stages, in conjunction with a high pressure mist system, to maintain
temperature and humidity in the chambers.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
Samples taken at various heights above the chamber floors
indicate ethylene concentrations occasionally differ as much as 14%
from top to bottom.
E-44
-------
b. Environment Uniformity
Temperature between chambers usually did not differ more than
1°C.
c. Pollutant Control and Maintenance
Not described.
d. Environment Control and Maintenance
Night temperatures are controlled between 11.1 and 12.8°C; day
temperatures vary between 16.6 and 18.3°C.
e. Chamber Equilibration
Not described.
E-45
-------
w
f
CONTROL
VINYL PARTITION
100 ppb
i
DOOR
3OO ppb
VINYL PARTPriON
500 ppb
*-h
N
Figure E-14.
Diagram of ethylene treatment chambers, a. Air-conditioning
compressors, b. Fans. c. Control panel, d. Three-stage heating
unit. e. Evaporators, f. Humidification unit. g. Diffusion
plates, h. Point of C2H2 injection, i. Greenhouse exhaust fan.
j. Air intake (reprinted from Piersol and Hanan, 1975, with
permission of American Society of Horticultural Science).
E-46
-------
Publication: Posthumus, A. C. 1978. New results from S02-fumigations of
plants. VOI-Berichte 314:225-230.
Location: Research Institute for Plant Protection, Wageningen, The Netherlands
Summary: This research uses long-term fumigation greenhouses. There are two
greenhouses contained within one larger greenhouse. One is ventilated
with S02-containing air; the other with charcoal-filtered air.
1. Hardware
The hardware consists of filters, blowers and greenhouse rooms.
a. Chambers
The greenhouses have a ground area of 12 m2, a volume of about
30 m3 and are ventilated twice a minute. This air volume (about 90
m3 min-1) passes through a charcoal filter and moves through the
greenhouses from top to bottom, coming in from a 60-cm wide nylon
sack hanging in the top of the greenhouse and moves out through
drains in the soil.
b. Pollutant Dispensing and Monitoring
Sulfur dioxide is injected in the air stream of one of the
greenhouses from a SOg container through a mass-flow meter, deliver-
ing a known and constant gas stream. The S02 concentrations in the
greenhouse are measured continuously.
c. Environment Controls
Not described.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
Not described.
b. Environment Uniformity
Not described.
c. Pollutant Control and Maintenance
Not described.
E-47
-------
d. Environment Control and Maintenance
Experiments are described in which temperatures are maintained
between 20 and 25°C, relative humidity between 54 and 74%, and light
level between 49 and 113 watts nr2 with.additional lighting from high
pressure mercury lamps.
Diagram of system not available.
E-48
-------
III. Chambers for Laboratory and Greenhouse Use:
Publication: Heck, W. W., J. A. Dunning, and H. Johnson. 1968. Design of a
simple plant exposure chamber. U.S. Dept. of Health, Educ., Welfare.
National Center for Air Pollution Control Publ. APTD-68-6. Cincinnati
Ohio.
Location: National Center for Air Pollution Control, Cincinnati, Ohio
Summary: Chambers for plant exposure studies use a dynamic, negative-pressure
single-pass flow system with uniformity of toxicant flow, mixing, and
distribution in the chamber. A relatively simple design permits easy
installation of several chambers in a single air-handling system while
still permitting individual control of chambers. The chambers can be
installed in greenhouses or in controlled-environment chambers.
1. Hardware
The system consists of banks of chambers constructed with a single
air-handling system.
a. , Chambers
There are two chamber sizes with identical construction details.
The chamber frame is wood finished with white glass enamel. The
frame is covered with mylar film. The air-handTing system has an
exhaust blower that maintains negative pressure in the exposure
chambers. Filtered air moves into the bottom of the chamber through
a perforated floor.: For controlled environment exposure the inlet
air has controlled temperature and humidity.
b. Pollutant Dispensing and Monitoring
Pollutants are added through ports in the inlet duct from a
pollutant dispensing system. The dispensing systems have an initial
dilution system, so that pollutants enter the inlet duct at dilutions
of about 100 to 1. Pollutant monitoring is not described.
c. Environment Controls
Greenhouse exposure chambers are normally maintained at green-
house conditions. Two controlled-environment chambers are mounted
as inserts inside each standard plant growth chamber. Temperature
and humidity are initially controlled in the growth chamber and more
closely controlled with each exposure chamber plenum. Light is
controlled by the growth chamber and can be varied by shading one
chamber. Wet- and dry-bulb thermistors are located in front of the
exhaust duct of each chamber to monitor temperature and humidity.
E-49
-------
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Pollutant Uniformity
Ozone was used to evaluate operating performance of the exposure
chambers. Four probes were centered vertically in each chamber
within 5 cm of the four corners and a fifth was placed in the center
of each chamber. Ozone concentration decreased as much as 11% with
the greatest decrease at the centrally located probe with plants
present. Ozone uniformity varied with environmental conditions and
chamber loading. Ozone uniformity was improved by using a perforated
delivery tube. Results of the uniformity test were interpreted to
indicate excellent mixing within chambers of both sizes.
b. Environment Uniformity
Environmental conditions s.imilar to those found in greenhouses
exist within greenhouse exposure chambers. Under bright sunlight,
the chamber temperatures ran from 2.2 to 3.3°C above greenhouse
temperatures a.t an airflow rate of one change every 2 minutes.
Measurements at several points within a chamber were consistent.
Environmental control within exposure chamber inserts inside
plant growth chambers was evaluated at an air change rate of two per
minute. Temperature fluctuation at a given level in the chamber was
less than 0.28°C. There was a consistent difference in temperature
between the top and bottom of the chamber of approximately 1.1°C at a
chamber temperature of 21°C. At higher temperatures the difference
was less. At any given location no temperature or humidity varia-
tions could be picked up by using a wet-bulb, dry-bulb thermistor
sensing device.
c. Pollutant Control and Maintenance
Not described.
d. Environment Control and Maintenance
Not described.
e. Chamber Equilibration
Only the rate of chamber equilibration after starting or
stopping pollutant flow into the chambers was evaluated. The equil-
ibration rate after starting the dispensing system and the decay rate
after stopping the dispensing system are the same, about 8 minutes
under the conditions of the test.
E-50
-------
MET HEADER
(Z> 18 by 18 tf
CHARCOAL FILTER
>.A!« HUM
18 bjr It tf 42
Figure E-15.
Schematic showing general orientation and construction of
exposure chambers in greenhouse (all dimensions shown are in
inches) (reprinted from Heck et a!., 1968, National Center for
Air Pollution Control).
E-51
-------
fBMt SICTICU »UW
SIM StCTtOI >!CU
Figure E-16.
Schematic showing two exposure chambers with conditioning plenums
inside a plant growth chamber, front and side views (all dimen-
sions shown are in inches) (Heck et a!., 1968).
E-52
-------
Publication: Heck, W. W., R. B. Philbeck, and J. A. Dunning. 1978. A
continuous stirred tank reactor (CSTR) system for exposing plants to
gaseous air contaminants. Principles, specifications, construction, and
operation. Agric. Res. Serv., U.S. Dept. Agric. Publ. ARS-S-181. New
Orleans, Louisiana.
Location: Agricultural Research Service, U.S. Department of Agriculture,
North Carolina State University, Raleigh, North Carolina
Summary: Detailed descriptions are provided for the construction and operation
of exposure chambers that use the principle of the continuous stirred tank
reactor (CSTR). A CSTR system for greenhouse use consisting of nine
chambers and one for controlled environment rooms of four chambers is
described.
1. Hardware
of
The system employs a pollutant (gas) dispensing unit for control
the test chemical(s), CSTR exposure chambers, and a shared-time gas-
monitoring unit. . - • • ,
a. Chambers ;
The response of plants to gaseous air pollutants is studied in a
uniformly-mixed cylindrical exposure chamber (reactor) within a
system that utilizes a dynamic, negative-pressure, single-pass
airflow for maintenance of plants. Uniform mixing within the chamber
is kept constant, regardless of air inlet velocity, by a rotating
impeller. Several pollutants can be injected at once. A number of
chambers can be installed into a single air-handling component with
individual controls for each chamber.
b. Pollutant Dispensing and Monitoring
The gas concentrations within chambers are maintained by means
of dispensing units which use rotameters and flow dilution for gases
or calibrated syringe pumps for liquids. The dispensing system and
chambers are integrated with a shared-time monitoring unit for
determination of gas (vapor) concentrations within the chambers.
Rates of pollutant gas uptake, net photosynthesis, and transpiration
can be determined by monitoring inlet and outlet gas streams for the
pollutant, carbon dioxide, and water vapor, respectively.
The dispensing units have three components: (1) a source of gas
or pollutant (high-pressure tank(s), an ozone generator, or liquid
chemical(s)); (2) precision rotameters; and (3) an air-dilution
component {air manifold). Teflon tubing is used throughout this
unit.
E-53
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The shared-time gas-monitoring unit has three components: the
monitoring lines and sampling manifold, the controller (scanner), and
the monitoring instruments. These components are an integral part of
the complete CSTR system.
c. Environment Controls
CSTR systems for use in environmental growth rooms utilize an
environmental control system designed to maintain temperature,
humidity, and light levels. CSTR systems for use in a greenhouse do
not have environmental controls, but they do have high-intensity
lamps so that a minimum irradiance can be maintained.
d. Data Acquisition
Each monitoring instrument is attached to a recorder for contin-
ous measurement. Temperatures are measured within chambers with
thermocouples attached to a 24-point temperature recorder.
2. Performance Evaluation
a. Pollutant Uniformity
Performance data were gathered to determine the uniformity both
within and across the test chambers. Sulfur dioxide and ozone were
the test gases. Ozone was dispensed into the greenhouse chamber
system and monitored by means of a chemiluminescent analyzer.
Although small variations in ozone concentration were found across
the chamber at a given height and vertically within the chamber, the
ozone uniformity was within the accuracy of the monitoring method.
Tests showed that the exhaust concentration was representative of the
chamber concentration.
Bush snap bean plants were used to determine the uniformity of
injury within and across the nine-chamber greenhouse system. Plants
were placed at several positions in each chamber. Positional effects
, were not significant in an analysis of variance. The chamber-by-
position interactions were tested and no interaction was found.
Bush snap beans were also used to determine the uniformity of
injury within and across the four-chamber controlled environment
system. There were generally no positional or chamber effects in a
statisical analysis of leaf injury data.
Ozone and sulfur dioxide were studied together to see if they
would react chemically in the chamber when dispensed simultaneously.
Neither gas affected the concentration of the other gas in these
tests.
E-54
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Environment Uniformity
In the greenhouse chambers light intensity, temperature, and
humidity were dependent upon the existing ambient conditions within
the greenhouse. Results of a temperature-distribution study within
a chamber showed both vertical and horizontal uniformity. On heavily
overcast days, with the lights on, a small temperature increase
(approx. 0.5°C) was found between the chamber inlet air and the
chamber exhaust air. This difference was 1.7 to 2.8°C with increased
natural light intensity. The inlet and exhaust temperatures across
the nine-chamber system were within 1%, with or without supple-
mental lights on a cloudy day. Light intensity was uniform both
across and within chambers on overcast days. When the supplemental
lights are used, light variation at 18 cm height within a chamber may
be as much as
and across chambers as much as 3%. Variations
were greater at a 60-cm height and less with lights off. The varia-
tions at 60 cm probably reflected shadow effects from structural
parts of the chambers.
Airflow velocities through each of the controlled environment
chamber inlet ducts were measured and set, by means of the exhaust
valves, to give uniform flow. These velocities were converted to the
number of air changes per minute. Sulfur dioxide was injected into
each of the controlled environment CSTR chambers to confirm uniform
airflows across chambers. The exhaust ducts were monitored for
approximately 20 min after an equal flow of sulfur dioxide gas was
dispensed into each chamber. There was a high uniformity of airflow
across the four chambers.
Pollutant Control and Maintenance
Gas-flow settings are noted to be fairly consistent for any
specific chamber concentration but to vary, especially in the green-
house system, with light, temperature, and humidity within the
greenhouse.
Environment Control and Maintenance
A study was conducted in the controlled environment chambers to
determine the degree and limits of control for chamber temperatures.
This study indicated that exposure chamber temperatures could be
maintained between 18.3 and 35 °C and from about 40 to 90 percent
relative humidity. At the higher temperatures,, the system would
permit lower relative humidities.
The high-gloss white-enamel aluminum covering for each con-
trolled chamber increased the maximum light intensity up to 25% and
improved light distribution within each chamber. Differences between
chambers reflected variation in lamp output. These differences were
smoothed out by placing discs on some of the lamp reflector centers.
E-55
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e. Chamber Equilibration
Ozone buildup and decay curves were determined for the four
controlled environment chambers. These were almost identical for the
four chambers. The first minute showed little buildup because of the
delay inherent in the dispensing system. The design criterion of 6.6
chamber air changes to reach a 99% buildup or decay was met. Other
checks have shown a 5% loss of ozone from inlet to exhaust in an
empty chamber, possibly because of small leaks and sorption or
reaction with wall surfaces.
E-56
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Figure E-17.
Schematic of a single greenhouse CSTR chamber unit (reprinted
from Heck et al., 1978).
E-57
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/v>vxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx//XxxxxxxXx
INLET
SAMPLE LINE
OAS
INJECTION
LINES
STtAM
INJECTION LINE
. •BUBATEX*
— INSULATION
Figure E-18.
Schematic of a single phytotron CSTR chamber unit (reprinted from
Heck et ail_.5 1978).
E-58
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APPENDIX F
Descriptions of Facilities and Performance Evaluations --
Systems for Rainfall Simulation Research
-------
-------
I. Indoors
.Publication: Chevone, B. I., Y. S. Yang, W. E. Winner, I. Storks-Colter, and
S. J. Long. 1984. A rainfall simulator for laboratory use in acidic
precipitation studies. J. Air Pollut. Contr. Assoc. 31:355-359.
Additional Publication: Chappelke, A. H., B. I. Chevone, and T. E. Burk.
1985. Growth response of yellow-poplar (Liriodendron tulipfera L.) seed-
lings to ozone, sulfur dioxide, and simulated acidic precipitation alone
and in combination. Environ. Exp. Bot. 25:233-244.
Location: Virginia Polytechnic Institute and State University Blacksburq
Virginia *
Summary: This rainfall simulator, developed on the principal of droplet
formation from needle tips, is designed for use in a glasshouse environ-
ment. Through changes in needle diameter, pump speed, and number of
radial arms dispensing the solution, the system can simulate a range of
physical rainfall characteristics including droplet size and rainfall
intensity without sacrificing other relevant features of rainfall events
The distributional uniformity of the system is maintained by a rotating
circular platform upon which pots or trays are placed. The system is
suitable for studies with crops and forest tree seedlings.
1. Hardware
a. Description
Each unit is 1.6 m long, 1.0 m wide, and 2.2 m n high. The
circular rotating platform has a surface area of 1.1 m2 and is
positioned 1.7 m below the dispensing system. The platform revolves
at a speed of 2 rpm. The effective target area on the platform is
1.06 m^. The system consists of four independently-operated units.
b. Methodology
(1) Dispensing
Rainfall solutions are under pressure from a variable speed
pump and delivered to the radial arms of the hub containing
hypodermic syringes (gauges 20, 21, and 22) positioned on the
underside of each arm in a distribution providing for uniform
delivery of solution. Although automation is not discussed, the
system is amenable to a programmed controller providing regu-
lated delivery according to desired rainfall intensity.
F-l
-------
2.
(2) Chemical Analysis and Application Rate
Methods for evaluating the concentrations of assorted
cations, anions, pH, and solution conductivity are outlined for
both in-line rain solutions and deposited rainfall. Application
rate in the methods paper is assessed by distributing beakers on
the platform.
(3) Protocol for Chemical/Temporal Exposure Dynamics
Chemical composition of rainfall is based on reported mean
electrolyte concentrations in rainwater as reported over a
4-year period in southwestern Virginia. Temporal features of
rainfall application are at the discretion of the experimental
design. The typical protocol is a constant inter- and intra-
event exposure regime.
c. Environment Controls
The environmental conditions are dictated by the glasshouse
environment, which is equipped with charcoal filtration, temperature
regulation, and photoperiod adjustment.
d. Data Acquisition
Not described.
Performance Evaluation
a. Wet Deposition
Incident hydrometeor diameter range of 2.5 to 3.4 mm with 2.7
to 3.1% coefficient of variation; mean droplet velocity = 60 to 70%
of terminal velocity. Distribution statistics: coefficient of
variation within a unit = 2 to 8.3%; among units = 1.2 to 2.6%.
Exposure dynamics: 0.75 cm Ir1 for 1-h event, 2 times wk.
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Radiation and temperature reported.
d. Deposition Parameters
Chemistry of deposition calculated.
F-2
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Figure F-l. Schematic diagram of a rainfall simulation unit: (a) central hub;
(b) radial tubes containing hypodermic needles; (c) structural
supports; (d) rotating table; (e) 1/20-hp gear motor; (f) tube
indicating hydrostatic pressure. Inset: schematic aerial view of
entire rainfall simulator system: (a) peristaltic pump; (b)
carboy containing rain solutions; (c) an individual rainfall
simulation apparatus (reprinted from Chevone et al., 1984 with
permission of the Air Pollution Control Association).
F-3
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Publication: Irving, P. M. 1985.
radish plants to acidic rain.
Modeling the response of greenhouse-grown
Environ. Exp. Bot. 25:327-338.
Location: Argonne National Laboratory, Argonne, Illinois
Summary: This system is designed for use in a glasshouse environment in which
the principal focus is the mechanism underlying the treatment effects on
productivity of low stature plants. The environmental conditions for
growth and rainfall addition are either controlled or accounted for in the
experimental design (i.e., micro-climate effects in the glasshouse).
Rainfall simulation is provided by stainless steel nozzles facing upward,
which deliver rain to plants maintained on a turntable to assure uniform-
ity in rainfall distribution.
1. Hardware
a. Description
Data on dimensions and specifications are not reported.
b. Methodology
(1) Dispensing
Rain simulants are dispensed by full jet nozzles that
produce a median drop volume of 1.1 mm. The degree of automa-
tion is not reported.
(2) Chemical Analysis and Application Rate
Chemical analysis of pH and conductivity is conducted on
each batch or stock solution and on the actual deposited rain-
water. The application rate is calculated assuming a uniform
distribution of rainfall delivered to the system.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of the rain simulant is based upon the
weighted-average ion concentration for National Acid Deposition
Proaram (NADP) sites in Pennsylvania, Ohio, and New York. The
pH of these solutions is adjusted using sulfuric and nitric
acids in the ratio reported by NADP (2.37:1). Individual
* rainfall events are 1 hour in duration but are applied in ten,
6-min on-off periods, producing a final rate of 0.76 cm h-1.
The time between rain events is 2 to 3 days.
c. Environment Controls
The glasshouse environment was monitored and/or controlled with
respect to temperature, vapor pressure, photoperiod, and photoperiod
intensity.
F-4
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d. Data Acquisition
Not described for the wet deposition component.
2. Performance Evaluation
a. Wet Deposition Event
pH and conductivity are measured; other variables are calcu-
lated. Median droplet diameter is 1 mm. A turntable method is used
with constant intra-event exposure.
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Only radiation and temperature described.
d. Deposition Parameters
Deposition rate to soil calculated.
Diagram of system not available.
F-5
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Publication: Jacobson, J. S., J. Troiano, and L. Heller. 1985. Stage of
development, responses, and recovery of radish plants from episodic
exposure to simulated acidic rain. J. Exp. Bot. 36:159-167.
Additional Publication: Troiano, J., and E. J. Butterfield. 1984. Effects of
simulated acidic rain on retention of pesticides on leaf surfaces.
Phytopathology 74:1377-1380.
Summary: This is a glasshouse system designed to investigate the influence of
rainfall chemistry on specific plant processes under well-controlled
environmental conditions. The system administers rainfall through nozzle
injection of solutions to plants positioned on a turntable to assure
uniformity. There are four independently-operated rainfall simulators.
1. Hardware
a. Description
The turntable diameter is either 1.0 or 2.0 m and rotates at 3
rpm. One nozzle per unit is mounted 3.0 m above the turntable.
Consequently, the surface area for pots is 0.78 m^ or 3.14 m^-, and
the maximum plant height (pot plus aboveground portion) is 3 m.
b. Methodology
(1) Dispensing
Rain simulant is dispensed through a stationary, hydraulic,
hollow-cone nozzle positioned 3 m above the turntable. The
degree of automation is not reported.
(2) Chemical Analysis and Application Rate
The method for chemical analysis is not reported. Simu-
lated rainfall is collected on the turntable to achieve depo-
sition rates of 1.0 cm h"-"-.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of the rainfall is based on reported concen-
trations of cations and anions in the MAP3S network taken near
Ithaca, New York, during the growing season. The acidity of the
solution is adjusted using sulfuric and nitric acids in a 2:1
ratio. 'Rainfall events are pre-scheduled according to the
experimental design with most events lasting 1 h.
c. Environment Controls
The glasshouse environmental conditions are monitored and/or
controlled for photoperiod, temperature, irradiance during photo-
period extension, and vapor pressure.
F-6
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d. Data Acquisition
Not described.
2. Performance Evaluation
a. Wet Deposition Event
Concentrations of the incident hydrometeor were calculated.
Droplet size diameter ranges from 200 to 500 urn. Coefficient of
variation for deposition = 20% on the turntable. A constant intra-
event time is employed.
b. Wet Deposition Environment
Not reported.
c. Non-Exposure Growth Environment
Only radiation and temperature reported.
d. Deposition Parameters
Deposition to soil has a coefficient of variation of 20%;
deposition chemistry is calculated.
Diagram of system not available.
F-7
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Publication: McColl, J. G., and R. Johnson. 1983. Effects of simulated acid
rain on germination and early growth of Douglas fir and ponderosa pine.
Plant Soil 74:125-129.
Additional Publication: Killham, K., M. K. Firestone, and J. G. McColl. 1983.
Acid rain and soil microbial activity: Effects and their mechanism. J.
Environ. Qua!. 12:133-137.
Location: University of Berkeley, Berkeley, Calfiornia
Summary This is an open-air rainfall simulator set up in four partitioned
rooms, open to the atmosphere but sheltered from ambient precipitation.
The system's air exchange is passive rather than active/forced air. The;
experimental designs have focused on changes in both tree growth and soil
properties as a function of rainfall chemistry. The influence of the
shelter on the radiant and heat energy properties of the system are not
reported.
1. Hardware
a. Description
Dimensions and specifications are not reported.
b. Methodology
(1) Dispensing
Not described.
(2) Chemical Analysis and Application Rate
The method for estimating deposition rates is inferential
(i.e., calculated based on delivery of solution to a given
surface area). Methods for chemical analysis are not reported
except for the pH of the rain simulant.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemical composition of the rain simulant is based on
the average rainfall chemistry in- northern California with pH
adjustment being achieved through addition of sulfuric and
nitric acid. The frequency of application is twice weekly at a
rate based on that reported in California. The temporal expo-
sure dynamics (i.e., time of day, duration of event, frequency
between events) are not reported.
c. Environment Controls
Reported only for soil properties.
F-8
-------
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Wet Deposition Event
Calculated chemistry of stock solution.
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Soil solution chemistry reported.
d. Deposition Parameters
Deposition to soil reported but methods not defined
Diagram of the system was not available.
F-9
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Publication: Raynal, D. J., J. R. Roman, and W. M. Eichenlaug. 1982.
Response of tree seedlings to acid precipitation. II. Effect of simulated
acidified canopy throughfall on sugar maple seedling growth. Environ.
Exp. Bot. 22:385-392.
Location: State University of New York, Syracuse, New York
Summary: This system consists of a single treatment chamber constructed of
wood framing and covered with polyethylene sheeting. Rain nozzles are
mounted in each corner, and solutions are injected toward the center of
the exposure area. Potted seedlings are manually repositioned on the
platform to maximize deposition uniformity. The system is suitable for
either crops or tree seedlings of low stature. ,The most unique feature of
the research is the selection of the simulant chemistry to represent that
occurring in throughfall rather than incident precipitation, which is a
legitimate method to address the issue of how acidified rainfall (after it
is chemically processed by passage through the canopy) may influence seed
germination and early seedling growth. Both of these biological processes
take place on the forest floor so that the chemistry of the bulk of the
wet deposition to the forest floor is more characteristic of throughfall
than incident rainfall.
1. Hardware
a. Description
The single unit is 1 m wideby 1 m in long by 1.5 m high. The
surface area for growing plants is 1 mz, while the maximum height to
assure even rainfall deposition is not reported.
b. Methodology
(1) Dispensing
Rainfall simulants under pressure are dispensed with
nozzles facing upward. Methods of automation are not reported.
(2) Chemical Analysis and Application Rate
The chemical analysis methods are not reported. The
rainfall application rate is estimated.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of the simulant is uniquely adjusted to match
that reported for throughfall at Hubbard Brook rather than
incident precipitation. The temporal aspects of application are
pre-scheduled and for fixed time intervals (20-30 ruin). The
total deposition rate is equivalent to 2.5 cm wk-1.
F-10
-------
c.
2.
Environment Controls
The conditions during rain events are defined relative to air
temperature and irradiance. The environmental conditions during
subsequent growth periods (i.e., photoper'iod, day and night tempera-
ture, and irradiance) are monitored and controlled.
d.
Data Acquisition
Not described.
Performance Evaluation
a. Wet Deposition Event
Data provided on stock solution recipe. Qualitative evaluation
of distribution statistics.
b. Wet- Deposition Environment
Only radiation and temperature reported.
c.' Non-Exposure Growth Environment
Only radiation, temperature, and soil solution chemistry
reported.
d. Deposition Parameter
Throughfal 1 chemistry reported. Soil deposition chemistry and
profile processing reported.
Diagram of the system was not available.
F-ll
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Publication: Rebbeck, J., and E. Brennan. 1984. The effect of simulated acid
rain and ozone on the yield and quality of glasshouse-grown alfalfa.
Environ. Pollut. (Series A) 36:7-16.
Location: Cook College, New Jersey Agricultural Experiment Station, New
Brunswick, New Jersey
Summary: This is a glasshouse system designed to simulate rainfall for plants
maintained in pots. The system is most suitable for low stature vegeta-
tion canopies (< 0.35 m). The environment during exposure is presumed to
be equivalent to that of the growing conditions in the glasshouse.
1. Hardware
a. Description
Dimensions and specifications are not reported.
b. Methodology
(1) Dispensing
Solutions are dispensed through four nozzles (2-mm dia.)
mounted above the potted plants. Methods of automation are not
reported.
(2) Chemical Analysis and Application Rate
Methods for chemical analysis are not reported except for
solution pH. The chemical composition of the tap water (makeup
water for the simulant) is reported.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of the rainfall simulant is adjusted to
provide a range of acidities by adding concentrated sulfuric
acid. The additional cations and an ions are those reported for
tap water concentrations. The temporal features of rainfall
application are pre-scheduled, providing 2.0 cm per rain event
delivered during a 15-min time period once per week.
c. Environment Controls
The glasshouse environment is monitored and controlled for
photoperiod, temperature, and trace pollutant levels (charcoal
filtration).
d. Data Acquisition
Not described.
F-12
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2. Performance Evaluation
a. Wet Deposition Event
Chemistry data on makeup water only.
b. Wet Deposition Environment
Not described.
• c. Non-Exposure Growth Environment
Only radiation and temperature reported. Charcoal-filtered air
for glasshouse.
d. Deposition Parameters
Soil deposition rate calculated by inferential method.
Diagram of system was not available.
F-13
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Publication: Shafer, S. R., L. F. Grand, R. I. Bruck, and A. S. Heagle. 1985
Formation of ectomycorrhizae on Pinus taeda seedlings exposed to simulated
acidic rain. Can. J. For. Res. TFiW-TT!
Location: North Carolina State University, Raleigh, North Carolina
Summary: This system is located in a greenhouse and intended to provide an
inexpensive method of delivering regulated amounts of simulated rain
solutions to seedlings grown in pots or flats. Depending on the glass-
house conditions, the system can accommodate either short- or long-term
exposure studies. The only limitation might be the. plant growing height
and canopy size. Randomization of the flats or pots during exposure and
growth is recommended. Given the stated objectives of the experimental
design, the exposure system meets the needs of the study.
1. Hardware
a. Description
No data are reported for this particular application except for
the 1.2-m height from bench to nozzle. Dimensions are flexible based
upon surface area of bench space requiring rainfall application. The
system consists of four independently-operated units.
b. Methodology
(1) Dispensing
Pressurized rainfall solutions are dispensed from two
stainless steel cone nozzles per unit suspended 1.2 m above the
bench. The system is manually activated.
(2) Chemical Analysis and Application Rate
The pH values of solutions prior to dispensing are meas-
ured. The application rate per plot is evaluated by collecting
the deposition in 5 beakers placed on the soil surface. The
application rate per plot is estimated by the mean of the 5
volumes. The chemistry of the incident rain is not reported.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of ra-infall solutions is based on reported
ionic concentrations in ambient rain (Cogbill and Likens, 1974)
and is adjusted by additions of sulfuric and nitric acids to
deionized water. The temporal exposure dynamics are pre-
scheduled, providing 1.1 cm of rain in a 30-min event with a
total of 36 events over a 16-week growing season.
F-14
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c.
2.
Environment Controls
The exposure system is located in an environmentally controlled
glasshouse providing regulated temperature, relative humidity, and
photoperiod.
d.
Data Acquisition
Not described.
Performance Evaluation
a. Wet Deposition Event
Calculated chemistry of the rainfall solutions. pH is measured
in mixed solutions.
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Not described.
Deposition Parameters
d.
Soil deposition rate calculated but statistics are not reported,
Deposition chemistry is calculated.
Diagram of system was not available.
F-15
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Publication: Shriner, D. S., C. H. Abner, and L. K. Mann. 1977. Rainfall
simulator for environmental application. Oak Ridge National Laboratory
Technical Publication No. 5151. Oak Ridge National Laboratory, Oak Ridge
Tennessee. 17 pp.
Additional Publications: Shriner, D. S., and J. W. Johnston. 1981. Effects
of simulated, acidified rain on nodulation of leguminous plants by
Rhizobium spp. Environ. Exp. Bot. 21:199-209.
Johnston, J. W., D. S. Shriner, C. I. Klarer, and D. M. Lodge. 1982.
Effect of rain pH on senescence, growth, and yield of bush bean. Environ.
Exp. Bot. 22:329-337.
Norby, R. J., and R. J. Luxmoore. 1983. Growth analysis of soybean
exposed to simulated acid rain and gaseous air pollutants. New Phytol.
95:277-287.
Location: Oak Ridge National Laboratory, Oak Ridge, Tennessee
Summary: This rainfall simulator is situated in a controlled environment
glasshouse and is designed to provide regulated rates of rainfall applica-
tion to agricultural crops and forest tree seedlings grown in pots. The
system consists of 12 nozzles per unit that inject rainfall solutions
upward with deposition achieved by gravity. Distributional uniformity is
achieved by a rotating platform. System performance has been character-
ized. The limitations of the systems are principally associated with
growing and maintaining plants in a controlled-environment greenhouse.
1. Hardware
a. Description
The system is 3 in high, 1.25 m wide, and 2.1 m long. It is
constructed of aluminum framing, while the platform is of wood
construction. The platform,-which has a surface area of 3.4 mf- and
is positioned 1.35 m below the rainfall nozzles, rotates at a rate of
2 rpm. The system consists of two independently-operated units.
b. Methodology
(1) Dispensing
Rainfall solutions are injected to the atmosphere by a
series of mist and rain nozzles mounted along radial arms from a
central hub. Droplets fall to the exposure table by gravity.
Solutions are mixed using deionized water and analytical grade
reagents. Dispensing is achieved either automatically by a
programmable controller or by manual.activation.
F-16
-------
(2) Chemical Analysis and Application Rate
Routine chemical analysis consists of solution pH measured
in both the stock solution and the deposited rain. More
complete analysis of cations and anions is at the discretion of
the researcher and commonly involves the deposited rain rather
than the stock solution. Application rate is monitored by a
volumetric cylinder fitted with a funnel and mounted at the same
height as the canopy.
(3) Protocol for Chemical/Temporal Exposure Dynamics
Rainfall chemistry is based upon reported rainfall electro-
lytes (Shriner, 1979). The temporal aspects of the exposure are
artificial and commonly selected to provide rates of application
that simulate ambient conditions.
c. Environment Controls
The environmental conditions are those of the glasshouse
environment which include charcoal filtration of air intake, steam
heat, evaporative coolers, and photoperiod adjustment.
c. Data Acquisition
Not described.
2. Performance Evaluation
a. Wet Deposition Event
The coefficient of variation over time for rainfall chemistry is
< 50%. Droplet size has maximum coefficient of variation of 20%.
Mean terminal velocity is 7.8 m s'1. Distribution has a coefficient
of variation of 4.0%. Exposure dynamics: intra-event time period is
usually constant.
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Only radiation and temperature reported. Charcoal-filtered air
intake for glasshouse.
Deposition Parameter
Soil deposition rate coefficient of variation of
tion chemistry coefficient of variation < 50%.
Deposi-
F-17
-------
SEE NOTE
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NOTE: THE SYSTEM CONSISTS OF THREE IDENTICAL SOLUTION
DISTRIBUTORS. FOR CLARITY, ONE IS SHOWN
Figure F-2.
Rain simulation system (reprinted from Shriner _et _aj_., 1977, Oak
Ridge National Laboratory).
F-18
-------
II. Outdoors
A. Non-Chambered Systems
Publication: Abrahamsen, G., K. Bjor, and 0. Teigen. 1977. Field experiments
with simulated acid rain in forest ecosystems. 1. Soil and vegetation
characteristics, experimental design, and equipment. Research Report No.
4, 15 pp. 1432 NISK, Aas-NLH, Norway.
Additional Publications: Hagar, S.,.and B. R. Kjondal. 1981. Decomposition
of birch leaves: dry weight loss, chemical changes, and effects of
artificial acid rain. Pedobiologia 22:232-245.
Ogner, G., and 0. Teigen. 1980. Effects of acid irrigation and
liming on two clones of Norway spruce. Plant Soil 57:305-321.
Stuanes, A. 0. 1984. A simple extraction as an indicator of soils'
sensitivity to acid precipitation. Acta Agric. Scand. 34:113-127.
Location: Norwegian Forest Research Institute, Oslo, Norway
Summary: This system is designed for field application of simulated rainfall
to an entire forest stand and has been used in a number of forest eco-
systems in southern Norway. The objective of the multiple-year research
project for which the system was devised is to characterize the influence
of acidic wet deposition (i.e., sulfate addition) on tree growth, ground
cover vegetation, and the chemical and biological dynamics of the soil
system. The system applies simulated rain in excess of that which is
deposited by natural events. Application is provided through a system of
pipes supported by a boom that rotates around a central tower. The height
of the tower can be adjusted to provide for variable canopy heights. The
system is not capable of rainfall simulation during the winter so that all
applications must be made during the May to September time period. Non-
irrigated plots serve as controls for the effects of irrigation alone on
ecosystem properties.
1. Hardware
a. Description
The system administers rain using a circular pivot irrigation
system that services plots ranging in size from 15 m^ to 625 m^. The
irrigation can be administered either above or below the canopy and,
in the case of the latter, is provided by a system of pipes inter-
spersed within the trunk space or on the forest floor.
F-19
-------
2.
b. Methodology
(1) Dispensing
Water is supplied to the forest through pipes lying on or
above the ground or above the canopy. The pre-mixed rain
simulant is fed through PVC pipes drilled at 0.1-m intervals and
fitted with 0.1-m long capillary tubes to equalize pressure and
maintain a constant delivery rate along the pipe's reach. The
addition of sulfuric acid to the makeup water is automated to
provide aliquots of concentrated sulfuric acid to a prescribed
volume of water (e.g., 1:100).
(2) Chemical Analysis and Application Rate
Chemical analysis is done on incident ambient rain, inci-
dent rain simulants, throughfall, and stemflow using a variety
of different collectors depending on the fraction required. The
degree of variation in chemical constitution of the incident
simulant is not reported as a function of time or residence, time
in the dispensing system. The methods for chemical anaysis are
reported as being "standard methods" and are fully documented in
various technical reports from the organization.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The application protocol depends on the experimental design
and is commonly done once a month, providing 25 to 50 mm rain
per month with variable event duration (e.g., 20 min to 8 h),
depending on plot size.and system capacity. The chemistry of
the rain simulant is commonly adjusted to provide increments in
sulfur or nitrogen deposition to the system in excess of that
delivered by ambient wet processes. Consequently, the simulant
is adjusted solely for the sulfur and/or nitrogen content and
pH.
c. Environment Controls
Typical ecological data are collected to provide climate and
edaphic variables. With the exception of the hydrologic inputs, none
of the variables is controlled.
d. Data Acquisition
Not described.
Performance Evaluation
a. Wet Deposition Event
Incident hydrometeor chemistry is reported.
F-20
-------
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Soil solution chemistry is described.
d. Deposition Parameter
Throughfall and stemflow chemistry is reported. Soil deposition
rate, chemistry, and chemistry processing within the soil profile are
reported.
Diagram of system was not available.
F-21
-------
Publication: Irving, P. M., and J. E. Miller. 1981. Productivity of field-
grown soybeans exposed to acid rain and sulfur dioxide alone and in
combination. J. Environ. Qua!. 10:473-478.
Location: Argonne National Laboratory, Argonne, Illinois
Summary: This system is designed to investigate the influence of rainfall
chemistry on the growth and productivity of crop species under field
conditions. It has the additional attribute of gaseous pollutant control
so that the interactive effects of rainfall chemistry and gaseous air
pollutants can be addressed through a zonal air pollution system of pipes
interspersed above the canopy. The gaseous air pollutant feature provides
for additions above ambient only rather than subambient. The system does
not exclude ambient rain so that a companion plot is maintained with which
to evaluate the influence of additional water input to the system.
1. Hardware
a. Description
A stainless steel spray head is suspended 2.4 m over each plot
and supplied with simulant under positive pressure. Each spray head
administers rain to one plot.
b. Methodology
(1) Dispensing
Simulant is dispensed through a stainless steel spray head.
The degree of automation is not reported.
(2) Chemical Analysis and Application Rate
The chemistry of the deposited rain is measured for sulfate
concentration using a barium sulfate precipitation method, while
free acidity is measured with a pH electrode. Application rate
is calculated, and adjusted to account for wind distribution.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of the rain simulant is selected based upon
that occurring in ambient rainwater and includes multiple
cations and anions. The measure of H+ ion, sulfate, and nitrate
deposition per plot takes into account the deposition via
natural and simulated rainfall. The amount of rain simulant
added is approximately 50% of the amount provided under ambient
conditions. Simulated rainfall events are 20 min in duration
providing 0.40 cm h-1.
c. Environment Controls
None reported except for sulfur dioxide concentrations.
F-22
-------
d. Data Acquisition
Not described for wet deposition component.
2. Performance Evaluation
a. Wet Deposition Event
Droplet size ranges from 0.6 to 3.3 mm diameter, with a median
of 1.8 mm. Qualitative distribution statistics are reported.
b. Wet Deposition Environment
Ambient conditions.
c. Non-Exposure Growth Environment
Not described except S02 monitored and controlled.
d. Deposition Parameters
Soil deposition rate calculated.
Diagram of system was not available.
F-23
-------
Publication: Shriner, D. S., C. H. Abner, and L. K. Mann. 1977. Rainfall
simulation for environmental applications. Oak Ridge National Laboratory
Technical Publication No. 5151. Oak Ridge, Tennessee. 17 pp.
Additional Publications: Heagle, A. S., R. B. Philbeck, P. F. Brewer, and R.
E. Ferrel. 1983. Response of soybeans to simulated acid rain in the
field. J. Environ. Qual. 12:538-543.
Brewer, P. F., and A. S. Heagle. 1983. Interaction between Glomus
eosporum and exposure of soybeans to ozone or simulated acid rain in the
TeTi:Phytopathology 73:1035-1040.
Location: North Carolina State University, Raleigh, North Carolina; Oak Ridg.e
National Laboratory, Oak Ridge, Tennessee
Summary: This system was designed in accordance with specifications developed
at Oak Ridge but set up at Raleigh. The system is suitable for field use
with low stature vegetation canopies and does not use an enclosure to
exclude ambient rainfall. Consequently, all simulant additions are in
excess of that delivered by ambient rain. The system does not control
ambient levels of gaseous pollutants. The system dispenses rain from a
single nozzle positioned at the end of a boom that pivots in a circle
around a center post. Each plot is serviced by four booms.
1. Hardware
a. Description
Each boom has a radius of 0.9 m providing spray in a circular
pattern. The maximum height of the boom is 1.5 m above the soil
surface, although there is no structural reason that the height could
not be extended to accommodate higher stature plant canopies. The
minimum displacement between the height of the canopy and the boom in
order to provide uniform distribution of the simulant is not
recorded. Given the published dimensions of one unit (4 booms per
unit), the effective spray area is 9.0 m2. The field plot at N.C.
State has 24 plots.
b. Methodology
(1) Dispensing
Rain simulant is dispensed under pressure to the cali-
brated, stainless steel rain nozzles that inject rain simulant
upward. One system of a common rain chemistry services six
field plots. The method and degree of automation are not
reported.
F-24
-------
2.
(2) Chemical Analysis and Application Rate
On-site evaluation of simulant water chemistry is achieved
through analysis of pH. More detailed analysis of simulant
chemistry was done for three separate rain events in which the
analysis was completed on deposited rain rather than the simu-
lant in the dispensing system. The method of chemical analysis
is not reported. The application rate of ambient rain is
measured using two rainfall collectors located 30 m from the
plot, while rainfall rates within plots are measured by six rain
gauges. Reported data are means only. Nozzles with delivery
rates that vary by more than 10% of the mean rate of 0.63
m min-1 at 400 Pa pressure for 30 s were rejected.
(3) Protocol for Chemical/Temporal Exposure Dynamics
Rainfall chemistry is based upon rainwater data for ambient
conditions (Cogbill and Likens, 1974) with pH adjustment
achieved through the addition of sulfuric and nitric acids. The
simulant provides multiple cations and anions.. The temporal
exposure dynamics are artificial in that all simulants are added
between 0600 and 0800 h for a total of 30 min (rain delivered in
three 10-min intermittent showers). The frequency of events and
the duration of inter-event periods are not reported.
c. Environment Controls
Not described.
d. Data Acquisition
Not described.
Performance Evaluation
a. Wet Deposition Event
Mean droplet size is 0.9 mm. Mean terminal velocity is 7.8
m s-1. There is little variation in distribution between rain
events, but there is a marked edge effect for each plot.
b. Wet Deposition Environment
Exposure is under ambient conditions.
c. Non-Exposure Growth Environment
Soil solution chemistry is reported.
d. Deposition Parameters
Not described except for chemical processing in soil profile.
F-25
-------
B. Chambered Systems
Publication: Irving, P. M. W. Prepejchal, and J. E. Miller. Experimental
facility for long-term studies of acidic deposition effects on plant/soil
systems. Personal communication.
Additional Publication: Irving, P. M. 1985. Biochemical transformations in
two plant/soil systems exposed to simulated acidic precipitation. In:
Proceedings of the Seventh International Symposium on Environmental
Biogeochemistry, Rome, Italy.
Location: Argonne National Laboratory, Chicago, Illinois
Summary: This facility is identified as the Microcosm for Acid Rain Studies
(MARS). It consists of a steel framework 57 m long and 9 m wide, support-
ing a polyethylene roof. The maximum height of the roof is 5 m; the
distance between the nozzles and soil surface is 2.44 m. The enclosure
cannot be operated during winter. Within the 516 m2 of surface area under
the enclosure, rectangular microcosms (2.4 x 1.2 x 1.4 m) are used to
study plant/soil responses to acidic precipitation. The microcosms are
equipped with ceramic soil-water samplers positioned at various depths in
each microcosm.
1. Hardware
a. Description
See above.
b. Methodology
(1) Dispensing
Rainfall is generated by stainless steel nozzles positioned
2.44 m above the soil surface. The nozzles produce a square
deposition pattern with uniform distribution. The source^water
is deionized just prior to the rain event. Simulant chemistry
is based on reported data from the Midwest and includes multiple
cations and anions, with pH adjustment achieved with sulfuric
and nitric acids. The mode of mixing is in-line rather than
batch and is achieved using fluid metering pumps.
(2) Chemical Analysis and Application Rate
Method for characterizing deposition is inferential.
Conductivity of the solutions are monitored and recorded.
Methods for chemical analysis are not reported.
F-26
-------
(3) Protocol for Chemical/Temporal Exposure Dynamics
Rainfall chemistry is based on reported data from NADP from
the Midwest region. The rainfall deposition rate is fixed at
0.06 cm min-1, and a controller is used to lengthen the "on" and
"off" periods to achieve the desired rain event duration. The
physical features of rain events are selected to simulate
ambient conditions (i.e., events/week, cm/event).
c. Environment Controls
Not described.
d. Data Acquisition
Capabilities for acquisition are mentioned but not described.
2. Performance Evaluation
a. Wet Deposition Event
Chemical data are not reported.
b. Wet Deposition Environment
Data are not reported.
c. Non-Exposure Growth Environment
Data are not reported.
d. Deposition Parameters
Soil deposition rates of the hydrometer are constant across
treatments. The chemical concentration of cations and anions vary
among microcosms.
F-27
-------
Inflated
Double Layer
of Polyethylene
Sheeting
<1 Surface
»:*£; Surface
$ T
B£f Subsoil |i
Figure F-3. Cross-section of microcosm facility with rainfall simulation over
two pairs of plots (P. M. Irving, personal communication).
F-28
-------
D.I. SYSTEM
THERMISTER
CHILLER \-
R.O. SYSTEM
SOFTENER HEATER
! L-HIGH LIMIT-
•••LOW LIMIT-i
_________j
ACID
CONCENTRATE
REGULATOR
30qpm
*NOTE: Any Number of Treatment Lines
May be Utilized. For Simplicity Only
the CONTROL and One ACID LINE
are Depicted Here.
BACKGROUND
IONS] j
T.J
^ELECTRODE
STATION
TO SPRAY NOZZLES
Figure F-4. Rain simulant metering and pumping system with feedback control
(P. M. Irving, personal communication).
F-29
-------
Publication: Kelly, J. M., R. C. Strickland, F. P. Weatherford, and J. C.
Noggle. 1984. Evaluation of simulated acid precipitation effects on
forest microcosm. Final Report to the Electric Power Research Institute,
RP-1632. EPRI EA-3500. Electric Power Research Institute, Palo Alto,
California.
Additional Publication: Kelly, J. M., and R. C. Strickland. 1984. CO? efflux
from deciduous forest litter and soil in response to simulated acid rain
treatment. Water, Air, Soil Pollut. 23:431-440.
Location: Tennessee Valley Authority, Muscle Shoals, Alabama
Summary: This system was used for a 30-month period to expose forest micro-
cosms to simulated acidic precipitation in a manner approximating field
conditions. The microcosms are sheltered from ambient rain via a rain-
activated lid system. Simulated rain is administered at the discretion of
the research staff. During periods of artificial rain, the plots are
sheltered on the top and sides to reduce ambient radiant energy, and the
rate of rainfall addition per week is adjusted to provide the plots with
the equivalent of the 30-year average per week for the region. Microcosm
analyses include vegetation (tree seedlings), soils, soil solution
(lysimeters), root growth, and leaf physiology. Treatments are maintained
throughout the year. The uniqueness of the system is its focus on inte-
grating responses of the vegetation and soil components.
1. Hardware
a. Description
Each microcosm is 1.2 by 1.2 by 1.0 m. The depth measurement is
solely for the soil component. The aboveground height for the
vegetation component is limited by the shelter lid and is < 1.5 m,
although none of the seedlings reached that height. The system
consists of five separate units, four microcosms per unit. The soil
component is sealed on the sides and bottom and fitted with a
lysimeter at the bottom for monitoring soil solution chemistry.
b. Methodology
(1) Dispensing
Dispensing is not automated for unattended operation.
Manual activation of the pumping system provides delivery of
rainfall simulants to each microcosm. The shelter-lid system is
automated for closure by a rain-activated sensor. The method of
dispensing is by calibrated spray nozzles mounted in each unit
on the shelter lid.
F-30
-------
(2) Chemical Analysis and Application Rate
The methodology for chemical analysis of incident precipi-
iation is not described; throughfall chemistry is well character-
ized for cations, anions, conductivity, and total nitrogen. The
rate of throughfall is measured in each microcosm by four
collection vessels.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of the rainfall simulants is based on ambient
rainfall chemistry and includes a balance of cations and anions
with pH adjustment via sulfuric and nitric acid additions. The
feed water originates from a tap and is then deionized. The pH
of each rainfall event is programmed to change (i.e., increase)
over the event period in a manner similar to that which occurs
during ambient rainfall events. The temporal exposure dynamics
are pre-scheduled to be one event per week with the duration of
the exposure selected to deliver rain in an amount equal to the
30-year average for that time of the year.
c. Environment Controls
No continuous monitoring or control of aboveground environmental
conditions is intended. Soil solution chemistry is monitored on a
regular basis.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Wet Deposition Event
Chemistry of stock solutions is recorded. Coefficient of
variation for rainfall distribution is « 20%.
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Ambient conditions. Coefficient of variation for soil solution
chemistry is < 50%.
d. Deposition Parameters
Coefficient of variation for throughfall chemistry is < 30%.
Coefficients of variation for soil deposition rate, chemistry, and
profile processing are < 30%.
F-31
-------
Oi (ORGANIC SOIL HORIZON)
0'2 (ORGANIC SOIL HORIZON)
20 em A MINERAL SOIL HORIZON
80cm 0 MINERAL SOIL HORIZON
POROUS CERAMIC PLATE
LYSIMETER (lOOem)
s
I
D
E
V
I
E
W
B
TULIP POPLAR SESDLIN6
VIRGINIA PINE SEEDLIN9
LYSIMETERS
WHITE OAK SEEDLINO
T
0
P
V
I
E
W
MICROCOSM
ACCESS
MICROCOSM
3
MICROCOSM
2
PIT
MICROCOSM
4
TYPICAL
MICROCOSM
GROUPING
T
0
P
V
I
E
W
Figure F-5.
Schematic drawing of the features of an individual microcosm as
well as the arrangement of microcosms within a shelter (reprinted
from Kelly et al., 1984, Electric Power Research Institute).
F-32
-------
Publication: Lee, J. J., G. E. Neely, S. C. Perrigan, and L. C. Grothaus.
1981. Effect of simulated sulfuric acid rain on yield, growth, and foliar
injury of several crops. Environ. Exp. Bot. 21:171-185.
Additional Publication: Lee, J. J., and D. E. Weber. 1979. The effect of
simulated acid rain on seedling emergence and growth of eleven woody
species. Forest Sci. 25:393-398.
Location: U.S. Environmental Protection Agency, Corvallis, Oregon
Summary: This field facility consists of three different types of chambers
from which ambient rain is excluded by a permanently-mounted transparent
plastic cover. The sides of the chambers are open for forced air ventila-
tion which is provided by plenum boxes. Because plants are grown in pots,
the facility can accommodate both agricultural crops and forest tree
seedlings. The selection of species is restricted to those species and
cultivars that grow well in the Willamette Valley. The plenum boxes were
not equipped with charcoal filters so that ambient gaseous pollutant
levels were experienced in all chambers.
1. Hardware
a. Description
Three different chamber designs are utilized. The four large
round chambers are 4.6 m in diameter by 2.4 m high providing a 16.6
m^ surface area for plots. The 20 square chambers are 2.4 m wide and
2.1 m in height, providing a 5.8 m2 surface area. The eight small
round chambers are 3.0 m in diameter and 2.4 m high, providing a
surface area of 7.1 m2. The only source of turbulence for the
chambers is the forced air system.
b. Methodology
(1) Dispensing
The source of water for rainfall solutions is that provided
for routine irrigation, which is subsequently deionized.
Simulant chemistry is based on published data for rainfall in
the northeastern United States, and acidity is adjusted by
addition of sulfuric and nitric acids. The temporal exposure
dynamics are fixed at three equal duration events per week. The
time of day for exposure is not specified. The method of
dispensing is through a stainless steel nozzle.
(2) Chemical Analysis and Application Rate
The chemistry is provided for the irrigation water but not
for rain solutions either in storage or after dispensing in the
system. The number of equivalents of assorted cations and
anions per liter added to the irrigation water is repeated. The
method of measuring application rate is not repeated.
F-33
-------
(3) Protocol for Chemical/Temporal Exposure Dynamics
Rainfall chemistry is based upon 7-year average as
described above. Temporal exposure simulates the intermittent
nature of the rainfall events relative to intervening periods of
dry deposition but the dynamics of exposure are pre-scheduled.
The rate of application is 30 mm wk-1 provided in three separate
events of equal duration.
c. Environment Controls
Information is provided on ambient pollutant levels for S02 and
03. Pollutant levels are not controlled. The development of visible
foliar symptoms of injury is monitored.
d. Data Acquisition
Not described.
2. Performance Evaluation
a. Wet Deposition Event
Chemistry data are available for irrigation water only.
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Air turnover rate is reported except for large chambers. Trace
pollutant levels and soil solution chemistry are reported.
d. Deposition Parameters
Soil deposition rate is reported.
Diagram of the system was not available.
F-34
-------
Publication: Troiano, J., L. Colavito, L. Heller, D. C. McCune, and J. S.
Jacobson. 1983. Effects of acidity of simulated rain and its joint
action with ambient ozone on measures of biomass and yield in soybean
Environ. Exp. Bot. 23:113-119.
Additional Publications: Troiano, J., L. Colavito, L. Heller, and D. C
McCune. 1982. Viability, vigor, and maturity of seed harvested from two
soybean cultivars exposed to simulated acidic rain and photochemical
oxidants. Agric. Environ. 7:275-283.
Troiano, J., L. Heller, and J. S. Jacobson. 1982. Effect of added
water and acidity of simulated rain on growth of field-grown radish
Environ. Pollut. (Ser. A) 29:1-11.
Location: Boyce Thompson Institute, Ithaca, New York
Summary: This facility consists of a traditional open-top chamber modified
with a loosely-fit clear tarpaulin hood to exclude ambient rainfall but
not restrict the normal exchange rate of ambient or charcoal-filtered air
Temperature and irradiance are affected by the tarpaulin and the degree of
change in each factor is reported. Rainfall solutions are delivered to
each chamber via a single nozzle mounted in the center of the plot The
facility is suited for evaluating the potential for interaction between
rainfall acidity and elevated levels of gaseous pollutants (e.g., ozone).
1. Hardware
a. Description
Each chamber is a traditional open-top 2.44 m in diameter and
2.44 m high. The surface area for growing plants inside the chambers
is 4.7 m^ and the maximum height for plant growth is 2.44 m The
nozzle dispenses rain only over a 3.14 m2 area so that the border
plants cannot be sampled.
b. Methodology
(1) Dispensing
The solution is under positive pressure to the raindrop
nozzles which are upward-facing. The degree of automation for
the dispensing is not reported.
(2) Chemical Analysis and Application Rate
The methodologies for chemical solution analysis and
evaluation of application rate within the chamber are not
reported.
F-35
-------
2.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of the rainfall simulant is adjusted to
different pH levels using sulfuric and nitric acids added to
deionized water. The levels of ammonium, chloride, and calcium
are constant among the treatments. The temporal dynamics are
adjusted to provide rainfall events in the early evening or on
cloudy days. The individual rainfall events were typically of 1
hr duration, providing 1.3 cm h"1 of rain.
c. Environment Controls
The environment inside the chamber is reported to be only
slightly modified with respect to that of normal open-top chambers.
The most marked changes are in air temperatures (< 3 C) and irradi-
ance (attenuated 25%). The ozone levels are monitored and controlled
to be either ambient or some percentage of ambient (5% or 6CU).
d. Data Acquisition
Not described.
Performance Evaluation
a. Wet Deposition Event
None reported.
b. Wet Deposition Environment
Light is attenuated 25%. Maximum temperature increase is 3°C.
Wind and turbulence are maintained during treatments.
c. Non-Exposure Growth Environment
Trace pollutant levels are well characterized.
d. Deposition Parameters
Mean deposition rate to soil is, 1 cm h-1.
F-36
-------
C. Automated Exclusion Systems with Scheduled Rainfall Addition
Publication: Johnston, J. W., D. S. Shriner, and C. H. Abner. 1986. Design
and performance of an exposure system for measuring the response of crops
to acid rain and gaseous pollutants in the field. J. Air Pollut. Control
Assoc. 36:894-899.
Additional Publications: Norby, R. J., B. K. Takemoto, J. W. Johnston, and D.
S. Shriner. Acetylene reduction rate as.a physiological indicator of the
response of field-grown soybeans to simulated acid rain and ambient
gaseous pollutants. Environ. Exper. Bot. (in press).
Takemoto, B. K., D. S. Shriner, and J. W. Johnston. Effects of
simulated acid rain and gaseous air pollutants on the physiological
responses of field-grown soybean. Personal communication.
Location: Oak Ridge National Laboratory, Oak Ridge, Tennessee
Summary: This system is designed to provide control of both wet and dry
deposition under field conditions and is suitable for both agricultural
species and forest tree seedlings. Open-top chambers are used in conjunc-
tion with an automated system for rain exclusion and addition with exclu-
sion being achieved by covers activated by a Wong rain sensor. The
system's current configuration can accommodate three different rainfall
chemistry treatments in addition to that of ambient rain. The ability to
• automatically dispense simulated rain during, and in the amounts equal to,
natural rain events is unique to this system.
1. Hardware
a. Description
The open-top chambers are the original design, i.e., an aluminum
frame 3.05 m in diameter and 2.44 m high and wrapped in two side
panels of polyvinyl chloride plastic fi1m. The lower panel is
double-walled and perforated on the inner wall with 2.5-cm diameter
holes. The air flow rate through the chamber is approximately 70
mj min-1, providing four complete air exchanges per minute. The
exclusion lids are 4.27 m2 fiberglass sheets mounted on a tract
' system 2.7 m above the 'ground. The exclusion lids do not cap the
chambers so that air flow through the chamber is maintained during a
rain event. The growing area dimensions are a cylinder of 7.3 m2
(basal area) and < 2 m (height). The system consists of 36 indepen-
dently operated units set out in 4 rows. The system is equipped for
ozone monitoring and addition using an IBM personal computer and a
site-specific software package.
F-37
-------
2.
b. Methodology
(1) Dispensing
Well water is sand- and charcoal-filtered and deionized.
Analytical grade reagents are mixed in a batch mode and stored
for periods of <2 weeks. Solutions of prescribed chemistry are
delivered under positive pressure to wide-angle, full cone spray
nozzles mounted on the underside of each exclusion lid (one per
lid or chamber). The mixing is done manually while the dispens-
ing is automated, directed by the minicomputer that logs the
rate of rainfall in an ambient plot.
(2) Chemical Analysis and Application Rate
The performance criteria for simulation were achieved using
beakers placed at ground level in each of the chambers. On-site
Sea/analysis is restricted to pH measurements jj'le Jjor*
detailed characterization is achieved using TCP and AA. On-site
application rate is monitored by a bucket rain gauge in one
ambient and one simulated rainfall plot.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry is based upon reported mean rainfall chem-
istrv for the growing season including multiple cations and
anions. The pH adjustment is made through sulfuric and nitric
acid additions. Rainfall rates in an ambient plot and one
simulant plot are monitored using tipping bucket rain gauges for
which the data are logged.
c. Environment Controls
Environmental conditions (edaphic, climatic, and atmospheric)
are monitored and logged. The only control is for wet and dry
deposition.
d. Data Acquisition
Continuous monitoring and data logging are conducted for rain-
fall rates, ozone concentration, air temperature, wind speed irradi-
ance, soil water potential, and S02 concentration. The duration of
individual rainfall events is also logged.
Performance Evaluation
a. Wet Deposition Event
Chemistry of incident precipitation is reported. Distribution
of rainfall among chambers is characterized qualitatively.
F-38
-------
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Ambient conditions are reported but no dispersion statistics
available except for ozone.
d. Deposition Parameters
Data for rainfall deposition rates and cumulative sulfur and
nitrogen are reported.
F-39
-------
RAIN EXCLUSION COVER
PRESSURE
GAGE
THROTTLING
VALVE
BOTTOM
PANEL
Figure F-6.
Detail of an open-top chamber, rain exclusion cover,
dispensing apparatus (reprinted from Johnston ^t al.
permission of the Air Pollution Control Association)
F-40
and simulant
, 1986, with
-------
JSIMULANT
LEVEL
MONITOR
RAIN SIMULANT
STORAGE TANK
CONTROLLER
I
MOVABLE COVER
-------
WELL
SYS
1
'1
•i
— £
— o
-N
_A
PUMP
TEM
^
%& SAND
%•> FILTER
// DEIONIZER - —
n ^
^r*~
) J PUMP
<] TWtOraiNG VALVE
vj CHECK VALVE
5 PRESSURE TOOTH
•^ GAUGE SIMULAN
(TOTAL OF
tX}— BALL VALVE
1 f r^\
CONDUCTIVITY T \_y '
METER K, INJECTION PORT f' S
^~* 1 ^ _,,..,to TO OTHFn PI r
vjj/ ^x MOVABLE COVER
t
-------
Publication: Kuja, A., R. Jones, and A. Enyedi. 1986. A mobile rain exclu-
sion canopy and gaseous pollutant reduction system to determine dose-
response relationships between simulated acid precipitation and yield of
field grown crops.
between
Air, Water,
and Soil Pollution 31:307-315.
See description in Appendix D.
F-43
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Publication: Lewin, K. F., and L. S. Evans. 1984. Design of an experimental
system to determine the effects of rainfall acidity on vegetation. Brook-
haven National Laboratory Report No. 34649. Upton, New York. 15 pp.
Additional Publications: Evans, L. S., K. F. Lewin, M. J. Patti, and E. A.
Cunningham. 1983b. Productivity of field-grown soybeans exposed to
simulated acidic rain. New Phytol. 93:377-388.
Banwart, W. L. 1985. Quality assurance plan for: Simulated acid
rain effects on yield and growth of corn and soybeans and on soil para-
jrtment of Agronomy, University of Illinois, Urbana, Illinois.
meters.
14 pp.
Department
Location: Brookhaven National Laboratory, Upton, New York. This shelter
design is replicated at the University of Illinois (4 units) and
Pennsylvania State University.
Summary: The principal component of this system is the rainfall exclusion
shelter capable of covering vegetation canopies within 50 to 60 s after
being activated by an electronc rain sensor. The rain distribution system
is attached to the shelter's infrastructure and dispensing usually is done
at night (1800 to 2400 h) or on cloudy days. The shelter is a commer-
cially-purchased greenhouse constructed of steel channels covered with
polyethylene sheets. The frame is modified to rest on a track/rail
system. Because the plants are exposed to ambient conditions except
during the ambient or simulated rainfall events, the system is suitable
for long-term studies under standard agronomic or forest practices. Given
the shelter's height and area dimensions, it is well suited for studies of
both agricultural crops and forest tree seedlings/saplings grown either in
pots or in the ground. The size of the facility also lends itself to
plot/subplot replication within a single shelter unit.
1. Hardware
a. Description
Each shelter is approximately 10 m wide, 30 in long, and 4.3 m
high above the soil. The openings at each end are partially covered
with plastic to limit incursion of wind-blown rain and mist. The
plant growing area is approximately 300 m2 while the maximum height
would depend on the vertical distribution of rainfall under each
shelter. The maximum height is not likely to exceed 3.5 m. This
shelter system is replicated twice at Brookhaven.
b. Methodology
(1) Dispensing
The exclusion shelter is automatically activated, while the
dispensing is manually initiated. Nozzles are mounted on the
shelter structure, and their specifications vary as a function
of the desired spray pattern and plot size. Premixed rain
F-44
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2.
solutions (either mixed in-line or as a batch and stored) are
delivered to the nozzles under pressure. The mixing of in-line
rainfall solutions is automated via a programmable pH controller,
(2) Chemical Analysis and Application Rate
The method for analyzing the simulated rainfall chemistry
is not specified. Reported chemistries are for in-line solution
and calculated with recipes. The temporal dynamics and chem-
istry of ambient rain are reported. The method for measuring
rainfall distribution/application rate within the shelter
either on a routine basis or as a means of evaluating the'
distributional performance of nozzles, is not reported although
deposition rates are provided in manuscripts.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of rainfall solutions is based upon reported
ambient mean rainfall chemistry in the northeastern United
States and includes major cations, major anions, and multiple
trace elements. The makeup water is deionized prior to mixing
of the solutions, and the pH of the solution is adiusted with
additions of sulfuric and nitric acids. The temporal features
of rainfall additions are pre-scheduled and usually administered
at night or on cloudy days to. avoid temperature effects in the
shelter. The rate of application is set to simulate realistic
rates of application on a weekly basis as determined from 24
years of consecutive records in the region.
c. Environment Controls
Local gaseous air pollutants are evaluated on a weekly basis
The shelters are not equipped to exclude ambient levels of gaseous
pollutants. The vegetation canopy experiences ambient conditions
except during natural or simulated rainfall events.
d. Data Acquisition
Air quality data under ambient conditions (rainfall and dry
deposition) are commonly logged. No other forms of data acquisition
are reported.
Performance Evaluation
a. Wet Deposition Event
Chemistry is calculated from solution mix.
b. Wet Deposition Environment
Not described.
F-45
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c. Non-Exposure Growth Environment
Not applicable.
d. Deposition Parameters
Soil deposition rate is calculated
F-46
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Figure F-9,. Cross-section view of wet deposition system shelter at a wheel
assembly showing major structural components. (1) Rafter bow; (2)
purl in;.(3) horizontal bracing; (4) knee bracing; (5) wheel
assembly; (6) track supports; (7) concrete foundation (reprinted
from Lewin and Evans, 1984, Brookhaven National Laboratory).
F-47
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TO NOZZLES
TO WASTE
TO WASTE
TO WASTE
Figure F-10.
Schematic of in-line simulated rain mixing system in use at
Brookhaven National Laboratory: (1) well; (2) well pump; (3)
pressurized storage tank; (4) 5-micron filter; (5) flow con-
troller; (6) mixed-bed deionizing units; (7) electronic flow
sensor; (8) mixing tank; (9) recirculating pump; (1) pressure
gauges; (11) electronic flow sensor/accumulator; (12) simulated
rain concentrate storage tank; (13) electronic micro-flow sensor;
(14) pulse dampener; (15) adjustable, positive displacement meter-
ing pump; (16) electrode station for pH monitor/controller; (17)
pH monitor/controller assembly; (18) electronic motor speed
controller; (19) electronically adjusted positive displacement
metering pump; (20) acid storage carboy; (21) laboratory grade pH
probe and automatic temperature compensator; (22) pH monitor for
Quality conrol; (23) two-pen chart recorder for pH (Lewin and
Evans, 1984, Brookhaven National Laboratory).
F-48
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APPENDIX 6
Descriptions of Facilities and Performance Evaluations —
Systems for Aerosol/Mist Simulation Research
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I. INDOORS
Publication: Gmur, N. F., L. S. Evans, and K. E. Lewin. 1983a. Effects of
ammonium sulfate aerosols on vegetation. I. Chamber design for long
duration exposures. Atmos. Environ. 17:707-714.
Additional Publication: Gmur, N. F., L. S. Evans, and K. F. Lewin. 1983b.
Effects of ammonium sulfate aerosols on vegetation. II. Mode of entry and
responses of vegetation. Atmos. Environ. 17:715-721.
Location: Brookhaven National Laboratory, Upton, New York
Summary: A plant growth chamber has been constructed to expose a large number
of plants to a uniformly distributed concentration of submicrometer
aerosols of known particle size distribution and chemistry for periods of
up to 3 weeks. The chamber design, with features controlled externally,
provides regulation of wind velocity, temperature, relative humidity, air
exchange, lighting, irrigation, and aerosol injection. This facility
provides adequate plant growth in the presence and absence of submicro-
meter ammonium sulfate aerosols in order to determine deposition rates,
mode of entry, and effects of submicrometer aerosols on vegetation.
1. Hardware
a. Description
The unit is 6 m long, 3 m wide, and 2.2 m high. The plant
growing area is a 2.1 m2 area turntable. Root zone manipulation and
studies in combination with other forms of wet and dry deposition are
possible.
b. Methodology
(1) Dispensing
Solution is atomized into a duct; the duration of atomiza-
tion is programmable.
(2) Chemical Analysis and Application Rate
Rate of deposition is characterized by elution of aerosol
from leaves and chemical analysis of eluted ammonia via elec-
trode. Aerosols in the atmosphere are collected via filter
sample for subsequent ammonium sulfate determination with
specific ion electrode.
(3) Protocol for Chemical/Temporal Exposure Dynamics
Chemistry is based on reported atmospheric concentrations
of ammonium sulfate.
6-1
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c. Environment Controls
Air is filtered and conditioned for temperature, relative
humidity, and aerosol concentration. Water is deionized.
d. Data Acquisition
Temperature, light, and duration of event are recorded.
2. Performance Evaluation
a. Wet Deposition Event
Distribution of aerosol sizes is well characterized spatially
and temporally. Distribution uniformity is based on a turntable
approach.
b. Wet Deposition Environment
Wind speed mean 0.25 m s~l.
c. Non-Exposure Growth Environment
Same as for (b).
d. Deposition Parameters
Foliar interception and retention of aerosols on leaves is
recorded; mean deposition velocity is 3.2 x 10~3 cm s'1.
Diagram of system not available.
6-2
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Publication: McCune, D. C., D. H. Silberman, R. H. Mandl, L. H.-Weinstein, P.
C. Freudenthal, and P. A. Giardina. 1977. Studies on the effects of
saline aerosols of cooling tower origin on plants. J. Air Pollut. Control
Assoc. 27:319-324.
Additional Publication: Silberman, D. H., and D. C. McCune. 1978. Some
factors affecting the response of plants to simulated cooling tower saline
mist. In: Proceedings of a Symposium on Environmental Effects of Cooling
Tower Emissions. WRRC Special Report No. 9, University of Maryland, pp.
L ~~_7 ,
Location: Boyce Thompson Institute for Plant Research, Ithaca, New York
Summary: This aerosol facility consists of three exposure systems located in a
remodeled glasshouse. The glasshouse is equipped to provide physical
protection for the aerosol chambers, buffer the environmental control
systems of the chambers, and provide a temporary holding area for the
plants before and after the exposure. The system is well characterized
with respect to the rate of deposition, atmospheric concentration, and
particle size distribution.
1. Hardware
a. Description
Each chamber consists of a 13.3 m3 enclosure formed by a footing
upon which a wood frame and aluminum channel are covered with Mylar
sheeting. The plastic dome is Quonset-shaped; air is discharged from
a tubular plenum positioned at the arc. Each chamber is equipped
with a turntable. Air flowing into the chamber from the plenum is
drawn out through a metal grilled floor.
b. Methodology
(1) Dispensing .
The principal method for particle generation in each
chamber is atomization by a pneumatic nozzle. Larger particles
are generated with hydraulic nozzles and suspended saline
particles are generated using pneumatic nozzles.
(2) Chemical Analysis and Application Rate
Deposition rate is estimated using parafilm positioned on
the edge of the turntable. Collected particles are eluted and
the saline content determined. Atmospheric concentration of
saline particles are estimated following collection on a filter
membrane sampling air at a fixed rate. Particle size distribu-
tion is estimated using a rotating drum impactor followed by a
filter membrane. Larger particles are collected on glass slides
coated with magnesium oxide.
G-3
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(3) Protocol for Chemical/Temporal Exposure Dynamics
A range of exposure dynamics was employed to provide
dose-response relationships for a variety of species.
c. Environment Controls
Air was conditioned to 27.5°C and 85% relative humidity.
Supplementary lighting was provided by two Sunbrella light fixtures
per chamber.
d. Data Acquisition
Methods for data acquisition are not described.
2. Performance Evaluation
a. Wet Deposition Event
Data regarding distributional uniformity are not described,
although plants were maintained on a rotating platform.
b. Wet Deposition Environment
See 2a.
c. Non-Exposure Growth Environment
Design utilized controlled environments before and after expo-
sure to minimize growth differences due to microclimatic variation.
Data are not reported.
d. Deposition Parameters
Coefficient of variation for foliar deposition was less than or
equal to 50%, with most of the values being less than 20%.
Diagram of the system is not available.
6-4
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Publication: Musselman, R. C., J. L. Sterrett, and A. L. Granett. 1985. A
portable fogging apparatus for field or greenhouse use. HortScience
20:1127-1129.
Location: Statewide Air Pollution Research Center, Riverside, California
Summary: This is a portable fogging system for use in growth chambers, glass-
houses, or field environments to deliver a chemically defined solution to
plant surfaces. The fogger consists of a solution cannister, fog nozzle,
and compressed air, and a frame enclosure covered with polyethylene film
to contain the fog. The system description provides engineering specifi-
cations only (i.e., no biological characterization).
1. Hardware
a. Description
Enclosure size is variable with typical size being 3.3 * 3.3 x
3.3 m. Plant growing area is variable. The number of units is
unlimited.
b. Methodology
(1) Dispensing
Pressurized solution is impinged on a pin to disassociate
solution into fog-sized particles. Dispensing can be activated
by a timer.
(2) Chemical Analysis and Application Rate
Not described.
(3) Protocol for Chemical/Temporal Exposure Dynamics
Chemistry is subject to the discretion of the research
objective. Fogging is most effective during night-time expo-
sures.
c. Environment Controls
The enclosure will significantly modify the atmosphere. Daytime
exposures are not recommended.
c. Data Acquisition
Not described.
6-5
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2. Performance Evaluation
a. Wet Deposition Event
Data on droplet size available from nozzle manufacturer only.
b. Wet Deposition Environment
No wind speed possible.
c. Non-Exposure Growth Environment
Not described.
d. Deposition Parameters
Not described.
Diagram of system is not available.
G-6
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Publication: Scherbatskoy, T., and R. M. Klein. 1983. Response of spruce and
birch foliage to leaching by acidic mists. J. Environ. Qua!. 12:189-195.
Location: University of Vermont, Burlington, Vermont
Summary: This system consists of indoor, polyethylene-lined chambers in which
mist droplets are generated. The enclosure provides a suitable environ-
ment for evaluating the potential for acidified mists to leach multiple
cations and anions from foliage. The system is not designed to accommo-
date long-term exposures to mist.
1. Hardware
a. Description
No specifications or design features reported.
b. Methodology
(1) Dispensing
Mist is dispensed to the chambers by impingement of solu-
tions on nozzles producing droplets ranging from 50-100 urn in
diameter, which are similar in size to those of fog. Misting is
not automated.
(2) Chemical Analysis and Application Rate
Chemical analyses of the incident mist and throughfall are
extensive and include pH, conductivity, inorganic anions and
cations, carbohydrates, proteins, and amino acids.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The exposure protocol is maximized to address the issue of
leachate chemistry. All misting is of a 4-h duration, with
treatments being 2-3 times within a 72-h period.
c. Environment Controls
The study is conducted in a glasshouse providing monitoring and
control of photoperiod and irradiance. During the misting events,
the temperature and irradiance are monitored and controlled.
d. Data Acquisition
Not described.
Diagram of the system is not available.
6-7
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Communication: Taylor, G. E., Jr. Carbon dioxide assimilation and growth of
red spruce (Picea rubens Sarg.) seedlings in response to ozone, precipita-
tion chemistry, and soil type. Personal communication.
Location: Oak Ridge National Laboratory, Oak Ridge, Tennessee
Summary: The system is metal-framed and wrapped in polyethylene on all sides
to form an enclosure. The system is portable, with use limited by the
power source for the dispenser. It is currently located in a glasshouse
on growth benches. During the non-exposure periods, the enclosure is
removed from the bench to eliminate heat buildup.
1. Hardware
a. Description
The unit is 1.1 m long, 1.0 m wide, and 1.2 m high. The plat-
form area is 1.1 m2 with 1.2 m height. There are four units indepen-
dently operated and positioned side by side on a bench. Root zone
manipulation is possible as part of the design.
b. Methodology
(1) Dispensing
Solution is atomized by rotating-disc impaction and forced-
air delivery; deposition is via gravity and interception.
Duration of events and the number of events per experimental
duration can be automated.
(2) Chemical Analysis and Application Rate
Deposition rate is adjusted to simulate ambient conditions.
Rate of deposition is total interception of cloud water by
foliage, stem, and pot individually as determined by gravimetric
method. Evaluation of deposition chemistry includes onsite
analysis of H+ concentration, with a more detailed description
of cations and anions via intermittent TCP analysis.
(3) Protocol for Chemical/Temporal Exposure Dynamics
Chemistry is based upon reported chemical composition of
cloud water. Temporal aspects are based upon reported frequency
in high elevation forests.
c. Environment Controls
Glasshouse air is coo-led by evaporative coolers, heated with
steam, and charcoal filtered'. Water is distilled and deionized.
Monitoring of glasshouse atmosphere is not routine except for temper-
ature, photoperiod, and relative humidity.
G-8
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d. Data Acauisition
Not described.
2. Performance Evaluation
a. Wet Deposition Event
Coefficient of variation for distribution uniformity is 49%.
b. Wet Deposition Environment
Not described.
c. Non-Exposure Growth Environment
Only radiation and temperature are reported; ozone levels are
_< 0.5 x ambient.
d. Deposition Parameters
Coefficient of variation for foliar interception is 100% among
plants. Coefficient of variation for soil deposition rate is 49%.
Diagram of system is not available.
G-9
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Publication: Van Voris, P. (publication date not reported). The toxic
aerosol research facility at Battelle's Pacific Northwest Laboratories.
Facility and Equipment. Battelle Pacific Northwest Laboratories,
Richland, WA.
Location: Battelle Pacific Northwest Laboratories, Richland, Washington
Summary: This aerosol exposure system is a modified special wind tunnel that
is sealed, recirculating, and designed for total P-3 containment. The
exposure cells provide controlled environments for plant exposure and the
facility is serviced by an analytical support laboratory. The system
provides computerized control of, and data acquisition for, the wind
tunnel exposure environment that includes temperature, vapor pressure
deficit, illumination, wind speed, gas species concentrations, and
airborne contaminant quality and quantity. The entire system operates
under negative pressure to ensure containment of toxic chemical species.
1. Hardware
a. Description
The wind tunnel is constructed of stainless steel, except for
the transparent Lexan walls and ceilings of the exposure cells. The
test section is 6.1 m long, 0.6 m in high, and 0.6 m wide. Wind
speeds of 0 to 65 mph are attainable in the exposure cells.
b. Methodology
(1) Dispensing
The principal methods of aerosol generation are a vibrating
orifice (1 to 3 urn) and a submicron generator that produces
monodisperse aerosols (0.04 to 1.0 urn).
(2) Chemical Analysis and Application Rate
Multiple intrusive and non-intrusive techniques for charac-
terizing the physical features of the aerosols are outlined.
Chemical analysis of collected aerosols is reportedly achieved
following size fractionation of the aerosol mass. Techniques
for chemical analysis are not reported. Techniques for charac-
terizing foliar deposition rates are not reported.
(3) Protocol for Chemical/Temporal Exposure Dynamics
Chemistry of selected aerosols is not reported.
6-10
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2.
c. Environment Controls
Air is filtered and conditioned for control of temperature,
vapor pressure deficit, aerosol concentration, and concentration of
trace and physiologically-important gases. Conditioning is computer
controlled.
d. Data Acquisition
Data acquisition is provided by a dedicated computer.
Performance Evaluation
Data are not described.
G-ll
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TOP VIEW
PNL AEROSOL EXPOSURE FACILITY
WIND TUNNEL TEST SECTION
2'x2"x20'
LIGHTED FOR PLANT GROWTH
CLEAR WALLS AND CEILING
AEROSOL LABORATORY
LABORATORY VENTILATION
BUILDING SEALED TO P-3
CONTAINMENT
SAFETY EXITS
Figure G-l.
Top view of Toxic Aerosol Exposure Facility showing recirculating
wind tunnel and building air filter systems (reprinted with
permission of Battelle Pacific Northwest Laboratories).
6-12
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Publication: Wood T., and F. H. Bormann. 1974. The effects of artificial
acid mist upon the growth of Betula alleghaniensis Britt. Environ.
Pollut. 7:259-268.
Additional Publication: Wood, T., and F. H. Borman. 1975. Increases in
foliar leaching caused by acidification of an artificial mist. Ambio
4:169-171.
Location: Yale University, New Haven, Connecticut
Summary: This is an inexpensive system for investigating the potential effects
of acid mist on foliar leaching and growth processes. The system is
situated in a glasshouse environment and is suitable for administering
mist solutions to low stature plants maintained in pots on glasshouse
benches. Both crops and forest tree seedlings have been used with this
system.
1. Hardware
a. Description
No specifications or design features reported.
b. Methodology
(1) Dispensing
Mist solutions are delivered under positive pressure to
impingement-type fog nozzles. The degree to which the system is
automated is not reported.
(2) Chemical Analysis and Application Rate
The acidity of the .mist is measured electrometrically,
although it is not clear whether the measurement is on the stock
solution or on the deposited mist in a collection vessel. The
concentration of other cations and anions are not measured since
the only chemical adjustment to the deionized water is_sulfuric
acid. The application rate is measured by estimating deposition
to an empty pot. There is no estimate of foliar interception.
(3) Protocol for Chemical/Temporal Exposure Dynamics
The chemistry of the mist solution is adjusted solely to
reflect acidity, with the adjustment of deionized water pH being
achieved through the addition of sulfuric acid. The temporal
features of the misting are at the discretion of the experi-
mental design and were 6 h wk-1 with the rate of deposition
being 0.5 cm wk-1 pot. This rate is roughly 20% of'that
deposited in rainfall in the Northeast.
G-13
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c.
d.
Environment Controls
The system exists in a glasshouse environment, and the degree of
environmental monitoring and control is reported only for the photo-
period.
Data Acquisition
Not described.
Diagram for system is not available.
6-14
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II. OUTDOORS
Publication: Reiners, W. A., and R. K. Olson. 1984. Effects of canopy
components on throughfall chemistry: An experimental analysis. Oecoloqia
63:320-330.
Location: Dartmouth College, Dartmouth, New Hampshire
Summary: This system is designed for field or laboratory studies focusing on
the basic mechanisms governing the chemical flux and fate of principal
ions in deposited rain as they come in contact with vegetation. Conse-
quently, the focus is on the exchange of ions between the rain and vegeta-
tion components as a function of water flow over vegetation surfaces,
duration of rainfall exposure, and temporal duration of antecedent dry
deposition period. The analytical basis is mass balance calculations of
input and output chemistry including the incident simulated rain, through-
fall, and stemflow. The flux estimates on an ion-specific basis take into
account vegetation surface area (e.g., needle, twigs, and epiphyte cover-
age) and rate of rainfall application. Only one level of rainfall acidity
was selected (pH 4.08), which approximated ambient rainfall pH.
1. Hardware
a. Description
Artificial rain is applied to live branches in the field and
dead branches in the lab. The only dimension figure provided is the
0.5-m height of the nozzle above the vegetation. The entire appar-
atus is shielded from incident ambient rain and particle deposition
by a clear plastic sheet erected 1 m above the branches. Access is
provided by a wooden observation platform.
b. Methodology
(1) Dispensing
Artificial rain is applied from a nozzle positioned 0.5 m
above the branches. The solution is under positive pressure,
and the application rate is regulated by manipulations of
pressure and the timing of spray bursts by an electric valve and
timer. The rate of application ranges from 0.3 to 3.5 cm h'1.
(2) Chemical Analysis and Application Rate
The chemistry of incident rain (deposited rain, not the
stock solution), stemflow, and throughfall is characterized with
respect to pH (within 24 h), ammonium/nitrate/sulfate (Auto-
analyzer), and sodium/potassium (flame photometry). The appli-
cation rate is characterized by collecting the drip from
branches in a 0.2-m diameter funnel positioned below the rain
application device.
6-15
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(3) Protocol for Chemical/Temporal Exposure Dynamics
The exposure dynamics are pre-scheduled in accordance with
the experimental design. The chemistry of the rain simulant is
comparable to the volume-weighted summertime average rain for
Mt. Moosilauke in New Hampshire, and includes adjustments for
pH, conductivity, total ion composition, and specific activity.
The duration of the rainfall event and the duration of the
intervening dry period are deliberately varied in the study.
c. Environment Controls
Temperature in the field is recorded.
d. Data Acquisition
Not described.
Diagram of the system is not available.
G-16
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Publication: Skeffington, R. A., and T. M. Roberts. 1985. The effects'of
ozone and acid mist on Scots pine saplings. Oecologia 65:201-206.
Location: Central Electricity Generating Board, Leatherhead, Surrey, England
Summary: This system consists of four individually-operated "Solardome" units
which provide an automated system for investigating chronic effects
of gaseous pollutants on agricultural crop and forest tree species. The
Solardomes are suitable for potted plants maintained for long term
periods. This facility was used for the reported study solely with mist
interception.
1. Hardware
a. Description
The solardome volume is 35 m3. There are four units, individu-
ally operated. Root zone manipulation is a deliberate part of the
design. Other forms of wet and dry deposition can be studied; a
major thrust of the research is pollutant interactions.
b. Methodology
(1) Dispensing
The'method of dispersing is by means of ASL "Killaspray 8"
spray gun. Dispensing is manual.
(2) Chemical Analysis and Application Rate
Throughfall is collected weekly and measured immediately
for hydrogen ion concentration; other cations and anions
are measured via ICP or autoanalyzer. Method for deposition
rate is not specified.
(3) Protocol for Chemical/Temporal Exposure Dynamics
Chemistry of mist adjusted for sulfur and nitrogen ratio to
yield desired pH. Mist application at 0900 and 1630 h daily 5
d wk-1 at a rate sufficient to saturate foliage.
c. Environment Controls
Charcoal-filtered air is used. Pollutant levels are monitored
and controlled. Above-canopy wind velocity is controlled.
d. Data Acquisition
Dry deposition data and environmental conditions are logged.
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2. Performance Evaluation
a. Wet Deposition Event
Chemistry of stock solution is reported. Distribution uniform-
ity is assessed qualitatively.
b. Wet Deposition Environment
Mean wind velocity 0.5 m/s.
c. Non-Exposure Growth Environment
Air mixing, turnover time, trace pollutant levels, and soil pH
are reported.
d. Deposition Parameters
Throughfall chemistry, soil deposition rate, and deposition
chemistry are reported.
Diagram of the system is not available.
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Publication: Thorne, P. G., G. M. Lovett, and W. A. Reiners. 1982. Experi-
mental determination of droplet impaction on canopy components of balsam
fir. J. Appl. Meteorol. 21:1413-1416.
Additional Publication: Lovett, G.M., W. A. Reiners, and R. K. Olson. 1982.
Cloud droplet deposition in subalpine balsam fir forests: Hydrologic and
chemical inputs. Science 218:1303-1304.
Location: Dartmouth College, Dartmouth, New Hampshire
Summary: This system is a closed-circulation wind tunnel capable of providing
wind speeds >^ 800 cm s'1. The system is most suitable for investigating
the biological (e.g., vegetation surface features) and physical factors
governing the impaction of cloud droplets on components of vegetation
canopies. The system utilizes a tracer -- monodispersed glycerin droplet
-- tagged with uranine (sodium fluorescein), with the deposition rate
being quantified by the intensity of fluorescence. The mass of the
glycerin droplet is set to a comparable mass of that of cloud water
droplets. The comparability in behavior of the glycerin droplet relative
to that of a typical cloud water droplet is evaluated empirically in the
wind tunnel. The capture efficiency of vegetation components may differ
as a function of needle-cluster morphology. The conclusion is that
capture efficiency of twigs of different sizes and needle-bearing branches
is explainable by a single empirically-derived mathematical expression so
that the data may be applicable to a broader range of component configura-
tion.
1. Hardware
a. Description
The closed circulation wind tunnel has an internal test platform
measuring 0.15 m in length and 0.21 by 0.21 m set perpendicular to
the flow. The maximum wind speed is 810 cm s"1 but experimental runs
were conducted at speeds of 30, 170, 340, and 725 cm s'1.
b. Methodology
(1) Dispensing
Glycerin droplets are formed by a vibrating orifice aerosol
generator dispersed 0.5 m upstream of the test platform.
Methods for automation are not reported.
(2) Chemical Analysis and Application Rate
Methods for analyzing the chemistry of the hydrometeor are
not applicable to this study or system. The method to evaluate
the capture efficiency of glycerin droplets is to remove by
elution with water the fluorescein tag from vegetation compo-
nents and subsequently quantify the amount of fluorescence in
G-19
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solution. The flux rate is calculated on a projected or geo-
metric area basis taking into account time of exposure in the
wind tunnel.
(3) Protocol for Chemical/Temporal Exposure Dyanmics
The chemistry of the droplet is not a variable in this
study. The exposure dynamics are not relevant except as related
to the wind speed component that effects impaction of droplets
to boles, twigs, needles, and epiphytes.
c. Environment Controls
Wind speed is monitored and controlled.
d. Data Acquisition
Not described.
Diagram of the system is not available.
G-20
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APPENDIX H
Description of Facilities and Performance Evaluation --
Systems for Dust and Particulate Exposure Research
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Reference: Darley, E. F., S. Lerman, and R. J. Oshima. 1968. Plant exposure
chambers for dust studies. J. Air Pollut. Contr. Assoc. 18:28-29.
Location: Statewide Air Pollution Research Center, Riverside, California
Summary: A description is given of plant exposure chambers which provide for
uniform application of dusts at rates simulating those of natural condi-
tions. One set of chambers receives artificial light and is used for
short-term exposures. A second set of larger chambers receives natural
light and provides for dusting plants daily to maturity.
1. Hardware
Chambers are constructed of plexiglas or Tedlar film-covered wooden
frames. A feeder assembly from a Bacho Microparticle Classifier serves as
the means of introducing the dust at the top of the chamber. A whirling,
counter-airflow stream is introduced several centimeters below the feed
nozzles to assist in lateral distribution of the dust. Distribution is
further enhanced by placing exposed plants on a turntable. Carbon-
filtered auxiliary air is,supplied through a distribution system below the
turntable.
a. Chambers
Two sizes of chambers have been developed that operate in the
same manner. The smaller chambers, measuring 75 cm2 by 105 cm high
and made of plexiglas, are used for short-term exposures where plants
are dusted for no more than a few days. The larger chambers, measur-
ing 135 cm2 by 180 cm high, consist of a wooden frame covered with
Tedlar film, and are used for dusting plants daily until they reach
maturity.
b. Pollutant Dispensing and Monitoring
Dust is introduced at the top of the chamber by means of a
feeder assembly from a Bacho Microparticle Classifier. This vibrated-
hopper, brush-fed system meters dust at very low rates. Uniform
distribution of dust on leaves is accomplished by a combination of an
air distributor near the top of the chamber and a turntable (1 rpm)
plant stage near the floor. As the dust drops from the feed nozzle,
just inside the chamber, it encounters vertical and lateral air flow
provided by the air distributor.
c. Data Acquisition
Not described.
d. Environment Controls
The small chambers are located in a darkened room and light is
supplied, through a water bath, by four 300 W cool-beam lamps placed
over the chamber. The larger chambers are in a greenhouse with
H-l
-------
natural light. In the smaller chambers, filtered air is piped in at
floor level and discharged through a circular manifold below the
plant stage, with air exchange once every 4 minutes. Auxiliary air
for the large chamber is supplied to a plenum chamber below the floor
with entry through a circular arrangement of holes. Air is exhausted
through small holes located near the top of the chamber walls with
air exchange from 1 to 1.5 per minute.
2. Performance Evaluation
a. Pollutant Uniformity
Deposition on the outer two-thirds of the revolving stage did
not vary by more than 5%. Deposits closer to the center varied by as
much as 15%.
b. Environment Uniformity
Not described.
c. Pollutant Control and Maintenance
Not described.
d. Environment Control and Maintenance
Not described.
H-2
-------
Figure H-l. Large dusting chamber. Dust is dispensed•with a Bacho feeder
assembly (1) and drops into the chamber against a whirling counter-
flow air stream (2). This action, coupled with the turntable
plant stage (3) provides for uniform dust deposit. Auxiliary air
from an activated carbon filter-cooler enters a plenum (4) and is
discharged into the chamber below the plant stage (5). Doors (6)
vent holes (7), and Tedlar film walls (8) are indicated (reprinted
from Darley_et a!., 1968, with permission of the Air Pollution
Control Association).
•-H-3
-------
Reference: Ormrod, D. P., J. C. Hale, 0. B. Allen, and P. J. Laffey. 1986.
Joint action of participate fallout, nickel, and rooting medium nickel on
soybean plants. Environ. Pollut. (Series A) 41:277-291.
Location: University of Guelph, Guelph, Ontario, Canada
Summary: A plexiglas chamber for particulate deposition is described. An air
stream into the top of the chamber carries particulate that drops on
plants.
1. Hardware
This chamber is based on the one described by Marple and Rubow
(1983). The chamber is constructed of plexiglass. A tube carries an air
stream into the top of the chamber. Particulate is introduced from a side
arm.
a. Chambers
Dimensions are 38 cm2 and 152 cm high. The chamber can accommo-
date 4 plants at a time. A 1.5-cm diameter tube carries an air
stream into the top of the chamber. A perforated deflector directs
the air flow downwards and a baffle is placed across the chamber to
linearize the flow of air and particulate for a more even and gentle
deposition on the plants.
b. Pollutant Dispensing and Monitoring
Particulate is introduced from a side arm with a burst of air
injected into the air stream that is moving into the top of the
chamber. A range of experimental concentrations is provided by
introducing weighed amounts of particulate.
c. Environment Controls
The chamber is set in a fume hood in an air-conditioned labora-
tory.
d. Data Acquisition
The particulate dose to each plant is estimated by analysis of
leaves for metal. Estimated dosage is the assayed metal concentra-
tion in and on the leaves multiplied by the leaf dry weight and
divided by the estimated leaf area at time of treatment.
H-4
-------
2. Performance Evaluation
a. Pollutant Uniformity
_ Distribution of particulate was evaluated with filter paper
simulated leaves and intact leaves. Position had a significant
effect on deposition so sufficient replicates were conducted to
eliminate variation due to position in statistical analyses.
b. Environment Uniformity
Not described.
c. Pollutant Control and Maintenance
Not applicable.
d. Environment Control and Maintenance
Not described.
Diagram of the system is not available.
H-5
-------
-------
APPENDIX I
Supplementary Reports:
Some Basic Exposure Techniques
-------
-------
Reference: Heagle, A. S., and R. B. Philbeck. 1978. Exposure techniques.
In: W. W. Heck, S. V. Krupa, and S. N. Linzon (eds.). Handbook of
Methodology for the Assessment of Air Pollution Effects on Vegetation,
Pollution Control Association, Pittsburgh, pp. 6-1 - 6-19.
Air
Summary: This report outlines some basic principles for exposing plants to
prescribed amounts of gaseous pollutants so that the results will be
meaningful and acceptable to others. Exposure system design, dispensing
systems, pollutant control systems, and time-sharing monitoring are
discussed.
Recommendations:
1. Chamber Requirements
a. Uniform Distribution of Concentration
A mean deviation of less than 10% should be acceptable for low
concentration studies and of less than 5% for high concentration
studies.
b. Uniform Environment
Variations in temperature of ± 0.5°C, relative humidity of ± 3%,
irradiance of ± 0.5 Klux, and air velocity of ± 1 m min'1 are gener-
ally attainable and possibly satisfactory for most uses. A plan of
random distribution of plants is advised as well as, in long-term
studies, changing the position of plants and the assignment of
treatments to chambers.
c. Non-Reactive Surfaces
Chamber surfaces should be covered with the most nonreactive
materials available.
d. Precise Control of Pollutant Concentrations
Common gaseous pollutants can be controlled accurately to within
+ 0.01 ppm for low concentrations and + 0.02 p'pm for high concentra-
tions.
e. Environment Resembling Ambient Conditions
Ranges of values are recommended for experimental use based on
occurrences in ambient air during plant growth and factors that
affect response of plant to oxidants.
f. Single-Pass System
Single-pass flow systems are recommended.
1-1
-------
g. Negative Pressure
Recommended as precaution against leakage of gases into green-
house or laboratory air.
h. Easily Portable
An important consideration only in certain field situations.
i. Transparent Covering
Clear teflon film is preferred to all other coverings.
j~. Chamber Calibration
Comparisons are required of pollutant concentration and environ-
mental levels within and between chambers in the same system to
ensure uniformity.
2. Basic Components of Acceptable Systems
a. Greenhouse Chambers
Exhaust air blower with charcoal filter to draw air through
system.
Inlet equipped with charcoal filter.
Inlet and exhaust system for each chamber.
Dispensing and monitoring system connected by teflon tubing.
Lights.
Cooling mechanisms for summer use.
b. Controlled Environment Chambers
As above except provide temperature, humidity, and light control
systems.
c. Dispensing Systems
Deliver easily-controllable concentrations to one or more
chambers.
Free of leaks.
Relatively free of concentration drift.
Constructed with nonreactive materials.
1-2
-------
d. Pollutant Control Systems
Control depends on experimental objectives.
Time-sharing monitoring may be used depending on the response
time of the monitor, and the degree of variability of the
pollutant concentration.
1-3
-------
-------
APPENDIX J
Supplementary Reports:
Recommended Environmental Monitoring Protocol --
Controlled Environment Guidelines
-------
-------
Controlled-environment Guidelines
Donald T. Krizek1
Plant Stress Laboratory, U.S. Department of Agriculture, ARS,
Beltsville, MD 20705
J. Craig McFarlane2
Corvallis Environmental Research Laboratory, Environmental Protection
Agency, Corvallis, OR 97330
Since publication of the "Guidelines for
Measuring and Reporting the Environment
for Plant Studies" in HortScience (2, 3, 4,
Received for publication April 27. 1983. The cost
of publishing this paper was defrayed in part by
the payment of page charges. Under postal regu-
lations, this paper therefore must be hereby marked
advertisement solely to indicate this fact.
'Plant Physiologist, Plant Physiology Institute, Rm.
206, B-OOI, BARC-W. BeltsvillV. MD 20705.
:Plant Physiologist. 200 S.W. 35th St.. Corvallis
OR 97330.
6), the guidelines have been refined, re-
viewed, and published in various journals (1,
7, 8, 9, 10. 11, 13. 14, 15).
In the course of this review process, sev-
eral changes have been made by the North
Central Region (NCR-101) Technical Com-
mittee on Growth Chamber Use since formal
presentation of the guidelines at a workshop
in Madison, Wis.. in 1979 (16). These changes
have been adopted by the ASMS Working
Group on Growth Chambers and Controlled
Environments and are presented here to bring
members of ASHS up to date.
Underlying most of the changes is the rec-
ognized need to adopt SI units of measure-
ment in their entirety (5, 1?). The changes,
with the rationale for each change, are shown
in Table 1. The guidelines as currently rec-
ommended are presented in Table 2.
Adoption of these modified guidelines by
researchers and adherence to these recom-
mendations by journal reviewers and editors
should facilitate comparison of experimental
results obtained in controlled-cnvironment
studies on a worldwide basis.
-------
Table I. Current changes in controlled-environmem guidelines.
Parameter
Former unit
Present unit
Rationale
photosynthetic photon flux
density (PPFD)
watering
|imol s"
The mol is the accepted SI unit.
SI convention.
nutrition
electrical conductivity
solid media
kg m"3
footnote
I dSirr1 =
1 mho cm"1
solid media
mol m"3 or mol kg"1
footnote
1 dSm"1 =
1 mmho cm ~ '
The mol is the accepted SI unit for
concentration.
Initial error in conversion factor.
Table 2. Guidelines for measuring and reporting environmental conditions in controlled environments.'
Measurements
Parameter
Typically used unit
Where to take
When to take
What to report
Radiation
Photosynlheiically active
radiation (PAR)
a) Pholosynthctic photon
flux density (PPFD)
400-700 nm with cosine
correction.
(imol s~'
or
u.Es"' m
At top of plant canopy.
Obtain average over
plant growing area.
At start and finish of each
study and biweekly if
studies extend beyond 14
days.
Average over containers at
start of study. Decrease or
fluctuation from average
over course of study.
Wavebands measured.
b) Photosynthetic Irradiance
(PI) 400-700 nm with
cosine correction.
Total irradiance
With cosine correction.
Indicate bandwidth.
Spectral distribution
a) Spectral photon flux
density X|-X2 nm in
< 20 nm bandwidths
with cosine correction.
Win"2
WnT
u,mol s"1 m~2 nm"1
(X,-X2 nm) (quanta)
At top of plant canopy. At start of each study.
At top of plant in center At start of each study as a
of growing area. minimum.
Average over containers.
Wavebands measured.
Spectral distribution of
radiation with integral (\i-
X2) at start of study. Source
of radiation and instrument/
or
b) Spectral irradiance
(Spectral energy flux
density) X|-X2 in < 20
nm bandwidths with
cosine correction.
Illuminance*
380-780 nm with cosine
correction
Temperature
Air
Shielded and aspirated
(> 3 m s"1) device
Soil or liquid
or
Wm-2nm-'
(X|-X2 nm)
klx
At top of plant canopy. At start of each study.
At top of plant canopy.
Obtain average over
plant growing area.
In center of container.
Hourly over the period of
the study, (continuous
measurement advisable).
Hourly during the first
24 hr of the study. Start
immediately after watering
(monitoring over the
course of the study
advisable).
Average over containers.
Wavebands measured.
Average of hourly average
values for the light and dark
periods of the study with
range of variation over the
growing area.
Average of hourly average
values for the light and dark
periods for the first day or
over entire period of the
study if taken. Location of
measurement.
Atmospheric moisture
Shielded and aspirated
(» 3 m s'') psychromcter,
dew point sensor or infrared
analyzer
% RH, dewpoint
temperature, or g m"
At top of plant canopy in
center of plant growing
area.
Once during each light and
dark period, taken at least
1 hr after light changes.
Monitoring over the course
of the study advisable.
Average of once daily
readings for both light and
dark periods with range of
diurnal variation over the
period of the study (or
average of hourly values if
taken).
-------
Table 1. (continued).
Measurements
Parameter
Typically used unit
Where to take
When to take
What to report
Air velocity
Carbon dioxide
Watering
Substrate
Nutrition
mmol m~
At top of plant canopy.
Obtain maximum and
minimum readings over
plant growing area.
At top of plant canopy.
Electrical conductivity
Solid media: mol m~3
mol kg"1
Liquid culture: u, or
mmol 1"'
pH units
dS m~' * (decisiemens
per meter)
or —
In saturated media,
extract from media, or
solution of liquid culture.
In saturated media,
extract from media, or
solution of liquid culture.
At start and end of studies.
Take 10 successive
readings at each location
and average.
Hourly over the period of
the study.
At times of additions.
At times of nutrient
additions.
Start and end of studies in
solid media. Daily in
liquid culture and before
each pH adjustment.
Start and end of studies in
solid media. Daily in
liquid culture.
Average and range of
readings over containers at
start and end of the study.
Average of hourly average
readings and range of daily
average readings over tHe
period of the study.
Frequency of watering.
Amount of water added per
day and/or range in soil
moisture content between
waterings.
Type of soil and
amendments. Components of
soilless substrate. Container
dimensions.
Nutrients added to solid
media. Concentration of
nutrients in liquid additions
and solution culture.
Amount and frequency of
solution addition and
renewal.
Mode and range during
study.
Average and range during
study.
Literature Cited
American Society of Agricultural Engineers.
1982. ASAE Engineering Practice: ASAE
EP411. Guidelines for measuring and re-
porting environmental parameters for plant
experiments in plant growth chambers, p.
406-409. In: 1982 Agricultural Engineers
Yearbook, Amer. Soc. Agr. Eng., St. Jo-
seph, Mich.
American Society for Horticultural Sci-
ence—Committee on Growth Chamber En-
vironments. 1972. Guidelines for reporting
studies conducted in controlled environment
chambers. HortScience 7:239.
American Society for Horticultural Sci-
ence—Working Group on Growth Cham-
bers and Controlled Environments. 1980.
Guidelines for measuring and reporting the
environment for plant studies. HortScience
15:719-720.
Berry, W.L., P.A. Hammer, R.H. Hodgson,
D.T. Krizek, R.W. Langhans, J.C. Mc-
Farlane, D.P. Ormrod, H.A. Poole, andT.W.
Tibbitts. 1977. Revised guidelines for re-
porting studies in controlled environment
chambers. HortScience 12:309-310.
5. Incoll, L.D., S.P. Long, and M.R. Ash-
more. 1977. SI units in publications in plant
science. Current Adv. Plant Sci. 28:331-343.
6. Krizek, D.T. 1970. Proposed guidelines for
reporting studies conducted in controlled en-
vironment chambers. HortScience 5:390.
7. Krizek, D.T. 1982. Guidelines for measur-
ing and reporting environmental conditions
in controlled environment studies. ASPP
Newsletter 9(6):7-8.
8. Krizek, D.T. 1982. Guidelines for measur-
ing and reporting environmental conditions
in controlled-environment studies. Physiol.
Plant. 56:231-235.
9. Krizek, D.T. 1983. Controlled-environment
studies, p. 170. In: Council of Biology Ed-
itors. The CBE Style Manual, 5th ed. Coun-
cil of BE, Bethesda, Md.
10. McFarlane, J.C. 1981. Measurement and re-
porting guidelines for plant growth chamber
environments. Plant Science Bui. 27(2):9-
11.
11. McFarlane, J.C. 1982. Letter to the editor:
measurement and reporting guidelines for plant
growth chamber environments. J. Envir. Qual.
11:719-720.
12. National Bureau of Standards (NBS). 1981.
The international system of units. NBS Spe-
cial Pub. 330. Washington, D.C.
13. Sager, J.C. 1982. Guidelines for measuring
and reporting environmental parameters for
plant experiments in growth chambers. ASAE
Paper No. 82-4056. ASAE Environment of
Plant Structures (SE-303) Committee. St. Jo-
seph, Mich.
14. Spomer, L.A. 1980. Guidelines for measur-
ing and reporting environmental factors in
controlled environment facilities. Commun.
Soil Sci. & Plant Anal. 11:1203-1208.
15. Spomer, L.A. 1981. Guidelines for measur-
ing and reporting environmental factors in
growth chambers. Agron. J. 73:376-378.
16. Tibbitts, T.W. and T.T. Kozlowski. 1979.
Controlled environment guidelines for plant
research. Academic Press, New York.
y The first is preferred because it follows the SI convention. However, since 1 Einstein = 1 mol of photons, the values are equivalent. It is inaccurate to re-
port that "radiation values are xx.x pmol s"nr'," for the same reason that reporting mol kg"1 is wrong without associating that value and units with the
element (Le., K was 300 mol kg"1). Thus, "the PFFD was 320 /anal s"1 m"'" is correct since it specifically associates a definition (i.e., photons within a certain
waveband) with the value and units.
* Report with PAR reading only for historical comparison.
uJ 1 dS m"' = tnmho cm"1.
-------
-------
.APPENDIX K
Supplementary Reports:
Suggested Measurements and Reporting Characteristics
of Dry Deposition Gaseous Exposure Systems -
-------
-------
Suggested Measurements for Characterization of Dry Deposition Gaseous Exposures
(all measurements at plant height unless otherwise indicated)
1. Non-Chamber Plume Exposures
A. Atmospheric Chemistry
(1) Gaseous Pollutant
a. Distribution
(i) Horizontal -- continuous at many points in a grid over
plot.
(ii) Vertical -- spot checks >_ 2 heights.
b. Temporal Patterns
Continuous at many points.
(2) Non-Pollutant Chemicals
a. Water Vapor (Humidity)
Continuous at 1 point in ambient air.
b. CC-2
None.
B. Physical Properties of the Atmosphere
(1) Irradiance (Quantum Level at 400-700 nm)
a. Distribution
None.
b. Temporal Patterns
Continuous at 1 point in ambient air.
(2) Heat Energy (Air Temperature)
Continuous at 1 point in ambient air.
(3) Air Movement
None, N/A (not applicable). '
C. Soil Temperature
None, N/A.
D. Air Exchanges
None, N/A.
2. Non-Chamber Air Exclusion Systems
A. Atmospheric Chemistry
- (1) Gaseous Pollutant
a. Distribution
(i) Horizontal -- Spot checks at many points linearly
along ducts.
(ii) Vertical -- Continuous at > 2 heights.
b. Temporal Patterns ~~
Continuous at 1 point per system.
(2) Non-Pollutant Chemicals
a. Water Vapor (Humidity)
Continuous at 1 point in ambient air.
b. C02
None.
K-l
-------
Physical Properties of the Atmosphere
(1) Irradiance (Quantum Level at 400-700 nm)
a. Distribution
None.
b. Temporal Patterns
Continuous at 1 point in ambient air.
(2) Heat Energy (Air Temperature)
Continuous at 1 point in ambient air.
(3) Air Movement
Spot Checks
Soil Temperature
Continuous at 1 point each in outside plot and in system at
_>_ 0.05 m depth.
Air Exchanges
None, N/A.
K-2
-------
3. Chambers -- Outdoors
A. Atmospheric Chemistry
(1) Gaseous Pollutant
a. Distribution
(1) Horizontal -- Before study at many points In a grid
across chamber.
(11) Vertical — Before study at >_ 4 heights.
b. Temporal Patterns
Continuous at 1 point per chamber or at least every 20
minutes for time-shared monitored systems.
(2) Non-Pollutant Chemicals
a. Water Vapor (Humidity)
Continuous at 1 point each In ambient air and 1
chamber.
b. C02
— None In open chamber, spot checks In closed chamber.
B. Physical Properties of the Atmosphere
(1) Irradlance (Quantum Level at 400-700 nm)
a. Distribution
Before study In grid across chamber.
b. Temporal Patterns
Continuous at 1 point in ambient air.
(2) Heat Energy (Air Temperature)
Continuous at 1 point each in ambient air and 1 chamber.
(3) Air Movement
Spot checks.
C. Soil Temperature
Continuous at 1 point each in outside plot and 1 chamber at
_> 0.05 m depth.
D. Air Exchanges
Spot checks.
4. Chambers — Indoors
A. Atmospheric Chemistry
(1) Gaseous Pollutant
a. Distribution
(i) Horizontal -- Obtain vertical distributions at suffi-
cient points to characterize horizontal distribution
before and after study.
(ii) Vertical — At top of plant canopy and at four levels
within the plant canopy including just above the
rooting medium, before and after study, and biweekly
if studies extend more than 14 days.
b. Temporal Patterns
Continuous at 1 point just above plant canopy or at
least every 20 minutes for time-shared monitoring
systems.
K-3
-------
(2) Non-Pollutant Chemicals
a. Water Vapor (Humidity)
Continuous at 1 point.
b. C02
Spot checks at least biweekly.
B. Physical Properties of the Atmosphere
(1) Irradiance (Quantum Level at 400-700 nm)
a. Distribution
Before study in grid across chamber.
b. Temporal Patterns
Spot checks at least biweekly at 1 point above plant
canopy.
(2) Heat Energy (Air Temperature)
Continuous at 1 point.
(3) Air Movement
Before study obtain horizontal and vertical distribution.
C. Soil Temperature
Spot checks.
D. Air Exchanges
Spot checks at least biweekly.
K-4
-------
Suggestions for Reporting Characteristics of Dry Deposition Gaseous Exposures
1. All Outdoor Systems -- Chamber and Non-Chamber (Measurements at Canoov
Height) vy
A.
Atmospheric Chemistry • ,
(1) Gaseous Pollutant
a. Distribution
(i) Horizontal — Averages and fluctuation across plant
growing area. For plume systems the continuous
horizontal averages will be used to assign pollutant
doses to specific areas of the plot.
(ii) Vertical -- Averages at different heights before study.
b. Temporal Patterns -- Average fluctuation over the entire
growing season based on daily time period important to
plants, e.g., 12 hours. Significaat high values will be
reported for ambient concentration. A frequency distribu-
tion of concentrations may be included for ambient expo-
sures and plume exposures. -
Non-Pollutant Chemicals -
a. Water Vapor (Humidity)
Average ± fluctuation over the entire growing season
for system and ambient air. A graphic presentation of
fluctuation is recommended.
(2)
CO?
Vertical and temporal variation based on spot checks
in chambers.
Physical Properties of the Atmosphere
(1) Irradiance (Quantum Level at 400-700 nm)
a. Distribution
Average ± fluctuation across plant growing area for
chambers.
b. Temporal Patterns
Average ± fluctuation over the entire growing season
for system and ambient air. A graphic presentation is
recommended.
(2) Heat Energy (Air Temperature)
Average ± fluctuation over the entire growing season for
system and ambient air.
(3) Air Movement
Average ± fluctuation based on spot checks.
Soil Temperature
Average ± fluctuation over the entire growing season for system
and outside plot.
Air Exchanges
Spot checks where applicable.
, K-5
-------
2. Chambers — Indoors
A. Atmospheric Chemistry
(1) Gaseous Pollutant
a. Distribution
(i) Horizontal — Average + fluctuation across plant
growing area.
(ii) Vertical — Averages at different heights before study.
b. Temporal Patterns
Averages presented graphically if continuously moni-
tored or in tabular form if monitored at 20-minute
intervals.
(2) Non-Pollutant Chemicals
a. Water Vapor (Humidity)
Follow Krizek and McFarlane (1983).
b. C02
Follow Krizek and McFarlane (1983).
B. Physical Properties of the Atmosphere
Follow Krizek and McFarlane (1983).
K-6
-------
(2)
Suggestions for Limits of Exposure and Experimental Variation in Dry Deposition
Gaseous Exposures
1. Non-Chamber Plume Exposures
A. Atmospheric Chemistry
(1) Gaseous Pollutant
a. Distribution
(i) Horizontal -- Maximum ± 10% variation from mean
pollutant concentrations at canopy height. May be
much greater if system is purposely used as a gradient.
(ii) Vertical -- Maximum* 25% variation from 0.3 m above
to 0.3 m below top of canopy.
b. Temporal Patterns
Maximum ± 20%. May be much greater in ambient system.
Non-Pollutant Chemicals
a. Water Vapor (Humidity)
No limits.
b. C02
No limits.
*
B. Physical Properties of the Atmosphere
(1) Irradiance (Quantum Level at 400-700 nm)
a. Distribution
No limits.
b. Temporal Patterns
— No limits.
(2) Heat Energy (Air Temperature)
No limits.
(3) Air Movement
N/A
C. Soil Temperature
No limit.
D. Air Exchanges
N/A
E. Ambient Air Exclusion
N/A
2. Non-Chamber Air Exclusion Systems
A. Atmospheric Chemistry
(1) Gaseous Pollutant
a. Distribution
(i) Horizontal -- Maximum ± 10% variation from mean
pollutant concentrations at canopy height.
(ii) Vertical -- Maximum ± 25% variation.
b. Temporal Patterns
Maximum ± 10% variation.
K-7
-------
(2) Non-Pollutant Chemicals
a. Water Vapor (Humidity)
No limits.
b. C02
No limits.
B. Physical Properties of the Atmosphere
(1) Irradiance (Quantum Level at 400-700 nm)
a. Distribution
No limits.
b. Temporal Patterns
No limits.
(2) Heat Energy (Air Temperature)
Maximum 1°C different from ambient.
(3) Air Movement .
Maximum 0.5-1.0 m s"1 constant air movement with blowers on.
C. Soil Temperature
Maximum 1°C different from ambient.
D. Air Exchanges
— N/A
E. Ambient Air Exclusion
At least 70% at canopy height.
3. Chambers — Outdoors
A. Atmospheric Chemistry
(1) Gaseous Pollutant
a. Distribution
(i) Horizontal -- Maximum! 10% variation from mean
polluant concentrations at canopy height.
(ii) Vertical -- Maximum ± 10% variation.
b. Temporal Patterns
Maximum ± 10% variation.
(2) Non-Pollutant Chemicals
a. Water Vapor (Humidity)
Maximum ± 5% variation from ambient.
b. C02
No limits.
B. Physical Properties of the Atmosphere
(1) Irradiance (Quantum Level at 400-700 nm)
a. Distribution
Maximum ± 10% variation from ambient.
b. Temporal Patterns
Maximum ±10% variation from ambient.
(2) Heat Energy (Air Temperature)
Maximum 2°C different from ambient.
(3) Air Movement
Maximum 0.5-1.0 m s~l constant air movement with blowers on,
K-8
-------
C. Soil Temperature
Maximum 1°C different from ambient.
D. Air Exchanges
Minimum 2-4 air exchanges per minute.
E. Ambient Air Exclusion
At least 70% at canopy height.
4. Chambers — Indoors
A. Atmospheric Chemistry
(1) Gaseous Pollutant
a. Distribution
(i) Horizontal -- Maximum ± 5% variation from mean pollut-
ant concentrations at canopy height.
(ii) Vertical — Maximum ± 10% variation.
b. Temporal Patterns
Maximum ± 10% variation.
(2) Non-Pollutant Chemicals
a. Water Vapor (Humidity)
Maximum ± 5% variation over time from desired level in
controlled environments and air conditioned green-
houses.
b. C02
Maximum ± 5% variation over time from desired level.
B. Physical Properties of the Atmosphere
(1) Irradiance (Quantum Level at 400-700 nm)
a. Distribution
Maximum ± 10% variation from the desired level in
controlled environments.
No limits in greenhouses.
b. Temporal Patterns
Maximum ± 10% variation over the course of the experi-
ment in controlled environments.
No limits in greenhouses.
(2) Heat Energy (Air Temperature)
Maximum ±1% variation from the desired level in controlled
environments and air conditioned greenhouses.
(3) Air Movement
Maximum 1 m s-1 constant air movement.
C. Soil Temperature
Maximum ± 1°C from the desired level.
D. Air Exchanges
Minimum 2-4 air exchanges per minute.
E. Ambient Air Exclusion
-- At least 95%.
K-9
-------
-------
APPENDIX L
Supplementary Reports:
Air Quality Data Bases
-------
-------
Air Qualify Data Bases
Criteria Air Pollutants:
The U.S. Environmental Protection Agency established an automated data
processing system, SAROAD (Storage and. Retrival of Aerometric Data), for the
collection and storage of ambient air quality data for several common air
pollutants. The data"are collected by various federal, state and local air
pollution monitoring programs and entered in the SAROAD system.
The data base contains information on a range of compounds that have been
measured in the atmosphere but the primary focus is on the criteria air pollut-
ants: ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, suspended
particulate matter and lead. Most of the data are stored as hourly average
concentrations but other averaging times have been used. Tapes of the .data
base can be ordered from the U.S. Environmental Protection Agency, Office of
Air Quality Planning and Standards, National Air Data Branch, Research Triangle
Park, North Carolina. ' .
The USEPA does not collect the air quality data but has established the
criteria for acceptable data and submission of the data to SAROAD. Because 100
percent reporting of all monitoring is not required, data for an individual
site may range from a few months within the year to essentially all the.
possible hourly concentration values (8760). Some of the monitoring sites have
data for only one or two years while others have a more extended record..- The
data base contains information concerning both sample site identification and
the ambient air quality data for specific pollutants.
Much of the monitoring data in SAROAD has been collected around population
or emission-oriented monitoring sites. However, there are approximately 350
ozone monitor-ings sites (between 1978 and .1984) designated rural or remote; and
for sulfur dioxide and nitrogen dioxide, there are 500 and 135 monitoring
sites, respectively, that have been,designated rural or remote. Usually only
one or two compounds are monitored at a .given site; consequently, it is diffi-
cult to determine how the concentrations of several compounds change, concur-
rently, over time at a given site.
As part of the Electric Power Research Institute (EPRI) SURE/ERAQS moni-
toring programs,, sulfur dioxide, nitric oxide, ozone, and total suspended
particulates were measured at the same sites for part of 1977 and all of 1978
and 1979 at nine sites (Table L-l). The data for the gaseous pollutants are
reported as hourly mean concentrations. Most of the sites are in rural
locations. Dr. Peter Mueller, Electric Power Research Institute, 3412 Hill-view
Avenue, Palo Alto, California, can provide information regarding the data base
and the availability of data tapes.
The Tennessee Valley Authority (TVA) has collected ambient air quality
data (hourly mean concentrations) primarily in association with their power
generation facilities in Alabama, Kentucky, and Tennessee. Sulfur dioxide,
ozone, and nitrogen dioxide are reported but not all pollutants have been
monitored at all sites. Most sites monitored sulfur dioxide but ozone and/or
nitrogen dioxide were monitored at only a few sites. Data are available from
L-l
-------
Table L-l. List of EPRI SURE/ERAQS monitoring sites for gaseous air pollut-
ants. a5°
Site Location
Montage, MA
Scranton, PA
Indian River, DE
Dundan Falls, OH
Rockport, IN
Giles County, TN
Fort Wayne, IN
Research Triangle Park, NC
Lewisburg, WV
Latitude
(° ' ")
42 43 00
41 35 29
38 34 50
39 51 02
37 52 50
35 17 06
41 02 08
35 53 00
37 46 27
Longitude
(° ' ")
72 32 08
76 04 21
75 14 45
81 53 05
87 03 32
86 54 07
85 19 30
78 50 03
80 20 00
Elevation
(m)
73
335
6
250
131
244
244
128
701
The site locations were originally identified in the Universal Time coordin-
ate system (UTM) and the units have been converted to latitude and longitude;
consequently there may be slight differences from the sites identified in the
wet deposition data base (Table L-3).
The elevations are approximate; they were obtained from the EPRI wet deposi-
tion data base for sites with the same name as in the gaseous air pollution
data base.
-------
some sites since the 1970s. However, the sites were frequently in operation
for only a few years. Some, but not all, of the TVA data have been submitted
to the SAROAD data base. Information on these data bases and data tapes can be
obtained from Mr. John Blackwell, Tennessee Valley Authority, Air Quality
Branch, 465 Multipurpose Building, Muscle Shoals, Alabama.
Recently (since 1982), the National Park Service initiated an air quality
monitoring program in some of the national parks (Table L-2). Ozone, sulfur
dioxide, ozone, and nitrogen dioxide are monitored; but not all pollutants have
been measured at all sites. Some, but not all of the National Park Service
data, have been submitted to the SAROAD data base. Information on the data
base and data tapes can be obtained from Mr. Miguel Flores, National Park
Service, Air Quality Division, Denver, Colorado.
Wet Deposition:
Wet deposition is the indirect transfer of compounds from the atmosphere
to vegetation or the soil surface within or on a hydrometeor (e.g., rain, snow,
fog, hail, etc.). A number of studies have attempted to measure and character-
ize wet deposition. Most of the efforts have focused on rain as the hydro-
meteor, with studies of deposition via clouds or fog receiving only limited
study. Wisniewski and Kinsman (1982) summarized the wet deposition monitoring
studies in North America by giving the name of the study, the funding organiza-
tion, the nature and geographical extent of the study, the type of samples used
and the period of operation as well as the location where the chemical analyses
were conducted, and the individual to contact for additional information.
Although numerous studies were listed, there are only three major wet deposi-
tion data bases available. Individual investigators,. however, may have addi-
tional information.
The most extensive wet deposition monitoring activity in the United States
is the National Atmospheric Deposition Network (NADP)/National Trends Network
(NTN). Monitoring started in the late 70s and additional sites have been added
with time, so that by August 1985, the Network had more than 180 operational
monitoring locations distributed across the United States (Figure L-l). Most
of the monitoring locations are east of the Mississippi river with a predomin-
ance of sites in the Northeast. Precipitation samples are collected weekly and
shipped uncooled to a central laboratory wbere electrical conductivity, pH,
^- - - - + ^+ z+
Na
and Mg are measured. Dr. Jim
Gibson, Program Coordinator, Natural Resource Ecology Laboratory, Colorado
State University, Fort Collins, Colorado, should be contacted for information.
The Electric Power Research Institute initiated a wet deposition monitor-
ing program in August 1978. In 1981, the EPRI sites were incorporated in the
Utility Acid Precipitation Study Program (UAPSP); currently there are 23
monitoring sites east of the Rockies (Table L-3). In contrast to the NADP
program, the precipitation samples (rain and snow) are collected on a daily
and/or event basis, cooled in 'situ and shipped to.a central laboratory where
pH, S04^-, NOo , NH4+, CT, Na+, K+, Ca^+, and Mg2+ are measured. Dr. Peter
Mueller, Electric Power Research Institute, 3412 Hillview Avenue, Palo Alto,
California, can provide additional information.
L-3
-------
Table L-2. National Park Service monitoring sites.
Sites
National Park, Site, State
Years
Grand Canyon, AZ
Sequoia, Ash Mt., CA
Sequoia, Lodgepole, CA
Sequoia, Lookout Pt., CA
Everglades, FL
Indiana Dunes, IN
Acadia, ME
Theodore Roosevelt, ND
Congaree Swamp, SC
Great Smoky Mt., Elkmont, TN
Shenandoah, Dickey Ridge, VA
Shenandoah, Big Meadows, VA
Shenahdoah, Sawmill Run, VA
Olympic, Port Angeles, WA
1982-83
1982-83
1982-83
1983
1982-83
1983
1982-83
1982-83
1981-83
1980-93
1983
1983
1983
1981-83
L-4
-------
to
03
s-
o
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s: oo
01
O) o
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i. •<-
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-------
Table L-3. Site operation dates, coordinates, and elevations for the combined
EPRI and UAPSP networks. From Mueller et al., 1984.
Site
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Site Location
Montague, MAa»b
Turner Falls, MAa
Scranton, PAb>c
Tunkhannock, PAC
Indian River, DEb
Zanesville, OHb>d
Rockport, INb
Giles County, TNb
Fort Wayne, INb»e
Raleigh, NCb
Lewisburg, WVb
Gaylord, MI
Clearfield, KY
Alamo, TN
Winterport, ME
Uvalda, GA*
Selma, AL9
Clinton, MS
Marshall, TX
Lancaster, KS1]
Brookings, SD1"
Underhill, VT^
Big Moose, NY
McArthur, OH
Yampa, CO
Start
Date
08/27/78
08/01/80
08/25/78
10/24/81
08/29/78
08/20/78
08/26/78
08/24/78
08/18/78
09/08/78
08/22/78
11/07/81
10/29/81
10/23/81
10/21/81
10/13/81
10/17/81
10/20/81
10/25/81
11/05/81
10/30/81
01/01/81
10/26/81
10/01/81
08/12/82
End Date
07/31/80
—
12/31/80
—
06/30/80
—
—
06/30/80
—
—
12/31/80
—
—
—
—
—
—
—
—
—
—
05/15/84
— — —
Latitude
42°32'00"
42°35'50"
41°34'30"
41°34'30"
38°34'50"
39°59'02"
37°52'50"
35°17'05"
41°02'39"
35°43'43"
37°50'50"
44°56'58"
38°08'10"
35°47'32"
44°37'05"
32°03'18"
32°28'25"
32°21'06"
32°39'58"
39034'10"
44°19'43"
44°31'42"
43°49'03"
39°14'06"
40°10'
Longitude
72°32'08"
72°32'55"
75°59'40"
75°59'40"
75°14'45"
82°01'05"
87°07'47"
86°54'11"
85°19'08"
78040'48"
80°25'00"
84°38'30"
83°27'17"
90°08'03"
68°58'30"
82°28'25"
87°05'03"
90°17'15"
94°25'06"
95°18'17"
96°49'45"
72°52'08"
74°54'08"
82°28'41"
106°55'
Elevation
(m)
73
98
335
335
6
250
131
244
244
128
701
473
235
112
67
64
42
76
81
346
499
442
603
224
2390
a Site 1 was moved from Montague to Turner Falls, MA.
b Co-located sampling conducted-1979. For later years, data are from only one
of the two samplers.
c Site 2 operated through 12/31/80 as Scranton, PA. The same site was reacti-
vated on 10/24/81 and the name was changed to Tunkhannock, PA.
d Site 4 was originally called Duncan Falls, OH.
e Site 7 was originally called Roanoke, IN.
f Co-located sampling being conducted from 10/09/83 for one year.
9 Co-located sampling conducted from 10/17/81 to 01/21/83.
h Co-located sampling being conducted from 10/12/83 for one year.
i Co-located sampling conducted from 11/14/81 to 02/23/83.
L-6
-------
The Multistate Atmospheric Power Production Pollution Study/Research in
Acidity from Industrial Emissions (MAP3S/RAINE) wet deposition monitoring
program began in 1976 with four sites (Whiteface, NY; Ithaca, NY; Penn State,
PA; Charlottesville, Virginia); four additional sites (Champaign, IL;
Brookhaven, NY; Lewes, DE; Oxford, OH) were added in 1978 and Oak Ridge
National Laboratory joined the program in 1981. Precipitation samples are
collected on a modified-event basis, as defined by the operator, and shipped
cooled to a central laboratory where electrical conductivity, pH, S04 , N03~,
NH4 , Cl~, Na , K , Ca , and Mg^ are measured. For additional information on
data availability contact Dr. Tony 01 sen, Battelle Pacific Northwest Labora-
tories, P.O. Box 999, Richland, Washington.
Other forms of wet deposition, such as clouds or fog have not been as
extensively studied and no formal data bases have been developed. However,
individual researchers have useful data for these sources of deposition. For
example, as a part of the Cloud Chemistry Program, Dr. Volker Mohnen, Atmos-
pheric Sciences Research Center, State University of New York at Albany, 1400
Washington Avenue, Albany, New York, has been characterizing the chemicals in
cloud water.. Similiarly, Dr. Michael R. Hoffman, Environmental Engineering
Science, W. M. Keck, Engineering Laboratories, California Institute of Tech-
nology, Pasadena, California, has been studying the composition of fog water.
L-7
-------
-------
APPENDIX M
Supplementary Reports:
General Trends in Dry Deposition
-------
-------
Dry Deposition -- General Trends
Ozone
An indication of the increase in ozone concentration across the U.S. was
given by Logan (1985) in her recent analysis of tropospheric ozone. The
surface concentration has increased 0.006-0.022 ppm (20-100%) since the 1940s
in both rural Europe and the central Eastern United States. An upward trend in
annual mean ozone concentration in Germany is suggested by monitoring data from
two sites in East Germany where increases of 5 to 12 ppb are reported from 1955
to 1975 (Ashmore et _al_., 1985). Seasonal patterns in ozone occurrence at the
surface were discussed by Logan (1985): (1) a broad summer maximum within a
few hundred kilometers of populated and industrialized regions of Europe and
the U.S.; and (2) a minimum in summer or autumn in sparsely populated regions
remote from industrial activity.
From hourly monitoring data, ozone has been characterized in the U.S. and
Europe by a mean concentration over a selected time period (e.g., 7-hr, daily,
weekly, monthly, annually). The most available example of this type character-
ization of the level of ozone across the U.S. is given by the estimation of the
7-hr seasonal mean (9 a.m.-4 p.m.; May-September) by kriging techniques using
the SAROAD databases from 1978-1980 (Reagan, 1983). The ozone concentration is
reported for one-half degree grid squares across the U.S.; an example of such a
map is given in Figure M-l for 1982. The mean seasonal ozone concentration is
0.035-0.056 ppm for the Eastern U.S. and this range is fairly characteristic
for a large portion of the rest of the nation. Only few regions display
concentrations higher than 56 ppb. These estimations were made without
distinguishing among types of monitoring sites, but did not include sites
within 10 km of large metropolitan centers. Investigating ozone air quality at
remote sites located within National Forests ranging across the U.S. (Figure
M-2), Evans
-------
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M-2
-------
Figure M-2. Remote monitoring sites in National Forest areas of the U S
Evans (1985). ' '
M-3
From
-------
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M-4
-------
equal to or greater than 0.10 ppm (Table M-l). If the air quality recorded at
the site is actually representative of the air quality in the nearby national
forest then this information is an indication of the ozone concentration for at
least one if not all years during the period of 1978-1983, since not all sites
are characterized for all years. The authors caution that before specific
statements of risk are made, additional ozone monitoring is required at sites
within the national forest and the distribution characterized.
Sulfur Dioxide
Over the past 10 to 15 years in the United States, SOg levels in urban
areas and near many point sources have been markedly reduced by control
programs (USEPA, 1982). The decreasing trend in urban concentration is shown
in Figure M-4 with both annual means and values at the 90th percentile. The,
spatial and temporal trend in S02 concentration is best shown with range of
maximums and values at the 90th percentile. These values are given in Figure
M-4 for annual trends and also in Table M-2 for S0£ concentrations by regions
in the U.S. Regional differences are not striking, although the more indus-
trialized and populated Regions I-V had annual mean concentration of 10 to 20
ppb, somewhat higher than the concentration range from the less industrialized,
less populated Regions VI-X (3-15 ppb). These data also may reflect the
location of the monitors, with some sited for population-oriented monitoring
and others for point-source monitoring. The concentration of S02 is affected
by meteorological variables influencing transport, dispersion, and removal, as
well as by topography and location of source. As a result, the monitoring of
S02 is obviously highly influenced by the site location. A better indication
of regional differences in S02.concentrations may be differences in sulfur
emission patterns (USEPA, 1982). Non-urban monitoring of S02 is more limited
than urban monitoring. Annual mean concentrations of about 1 ppb are seen,
with most values near the detectability level. Altshuller (1984), reviewing
historical S02 concentrations, reported no apparent trend in non-urban monitor-
ing from 1965 to 1977. An indication of seasonality of S02 occurrence in
non-urban sites is given in the quarterly averaged S02 concentrations from six
sites in the late '60s and early '70s shown in Table M-3. An annual average of
about 5 ppb is observed with concentration highest in the first and fourth
quarters. Rural sites in Kentucky, Ohio, and Indiana displayed a seasonality
to S02 concentrations with means less than'5 ppb during summer and 15 to 20 ppb
during winter. The annual mean concentrations in Europe are close to those
observed in the U.S.; concentrations range from 10 ppb in rural areas of the
United Kingdom, the Netherlands, and Federal Republic of Germany to 1 ppb or
less in remote areas of northern and western Europe (Altshuller, 1984).
Related to this observation, the emission rates in West Germany have remained
at approximately 3.5 million metric tons/year between 1966 and 1978 (Guderian,
1985). In a study identifying monitoring sites that could be used to charac-
terize air quality for potential impact on national forests, Lefohn et al.
(1985) identified only 8 monitoring sites out of 33 possible that experienced
S02 concentrations equal to or greater than 0.10 ppm more than 50 times over a
12-month period (Table M-4). On.ly one of these -sites was in a national forest,
the others were within 60 miles.
M-5
-------
Table M-l. National Forests east of the 95th meridian potentially experiencing
hourly ozone concentrations equal to or greater than the 0.10 ppm
over the 7-month period April-October (1979-1983). From Lefohn et j
(1985).
Number of Occurrences > 0.10 ppm
< 50 Occurrences 50-100 Occurrences 100-200 Occurrences
> 200 Occurrences
Tombigee (MS) Chattahoochee (GA) Talladega (AL)
Apalachicola (FL) Oconee (GA) William B. Bankhead (AL)
Ocala (FL) Nantahala (NC) Ouachita (AR)
Shawnee (IL) Cherokee (TN) Uwharrie (NC)
Daniel Boone (KY) New Jersey Pine Barrens
Redbird (KY) (Camden, NJ)
Kisatchie (LA)
Hiawatha (MI)
Manistee (MI)
Superior (MN)
Mark Twain (MO)
Pisgah (NC)
Croatan (NC)
White Mountain (NH)
Francis Marion (SO
Sumter (SC)
George Washington (VA)
Jefferson,(VA)
Green Mountain (VT)
Monongahela (WV)
Chequamegon (WI)
Nicolet (WI)
Hoosier (KY)
' M-6
-------
56
48
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1973
1974 1975 1976 1977
YEAR
Figure M-4. Nationwide trends in annual average sulfur dioxide concentrations
t* a? 197?n-^1977 are sjown' for. 1233 sampling sites (ug m-3 x
(3.82 x 10 *) =^m S
2). From EPA (1982).
M-7
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Table M-3. Sulfur dioxide concentrations at non-urban sites in the eastern
United States (in ug.m~J x (3.82 x 10~4) = ppm SO?) (adapted from
NASN data bank). From Altshuller (1984). .
First
Site Quarter
Acadia National Park, ME
1968 8
1969 12
1970 15
1971 19
1972 6
1973 9
Coos County, NH
1970 NO
1971 12
1972 7
1973 13
Calvert County, MD
1970 ND
1971 20
1972 5
1973 12
Shenandoah National Park,
1968 20
1969 16
1970 16
1971 15
1972 10
1973 18
Jefferson County, NY
1970 ND
1971 8
1973 3
1973 8
Monroe County, IND
1967 19
1968 13
1969 19
1970 13
1971 11
1972 15
1973 30
Second
Quarter
7
9
7
11
6
-NOa
NO
10
6
ND
ND
15
6
9
VA
5
7
6
8.
5
8
ND
5
5
19
5
7
10
8
8
10
11
Third
Quarter
5
8
8
7
6
ND
12
7
4
ND
10
8
6
ND
6
9
11
7
5
6
16
6
5
ND
6
7
8
16
7
7
10
Fourth
Quarter
9
8
15
9
7
ND
8
9
9
ND
18
9
9
8
11
11
8
10
19
7
ND
7
9
25
33
12
18
10
14
15
10
Annual
Average
10
9
*j
11
X X
13
J. 'J
7
9
9
13
X O
7
10
X W
11
X X
11
11
9
~s
9
7
6
\J
11
10
X \J
14
12
11
X X
1 1
X J.
15
a ND = not detectable.
M-9
-------
Table M-4 National Forests east of the 95th meridian potentially experiencing
hourly SO? concentrations equal to or greater than 0.10 ppm over
the 7-month period April-October (1978-1983). From Lefohn et al..
(1985).
Number of Hourly Occurrences _> 0.10 ppm
50-100
> 100
Pensacola (FL)
Jefferson Co. (KY)
Tarpon Springs (FL)
Rockport (IN)
Muhlenberg Co. (KY)
Rumford.(ME)
Iron Co. (MO)
Manchester (NH)
M-10
-------
Nitrogen Dioxide
Nitrogen dioxide has been characterized by the EPA as annually averaged
concentrations (USEPA, 1985). The EPA has used these levels, measured at 177
sites, to observe trends from 1975 to 1983. Like the other gaseous pollutant
monitoring databases, long-term historical monitoring data for nitrogen dioxide
(N02) and nitric oxide (NO) are generally not available for non-urban sites,
but are available from a limited number of urban sites (Altshuller, 1984). The
level of N02 in cities averaged about. 0.026 ppm in 1983, essentially unchanged
since 1975. Mean and maximum concentrations of N02 and NO for a number of
rural sites are given in Table M-5. The mean N02 concentration ranged from 2.1
to 7.5 ppb and tended to exceed the mean concentrations of NO, although the NO
maxima often exceed N02 maxima, suggesting localized intrusions of NO sources
at many rural areas. Remote site monitoring reported even lower mean concen-
trations (Table M-6). Monitoring at Whiteface Mountain in 1983 reported
averages of 1 ppb with excursions to 3 ppb (R. Bradow, personal communication).
Particulate
The character of particulate matter is dictated to some degree by size of
the particle, ranging from 5 x 10-9 m to 10-4 m_ j^e mass Of suspended par-
ticles is usually estimated by filtration of known volumes of air and the dry
weight determined. The accuracy and precision of particulate monitoring is
limited by three considerations: (1) sampling methods; (2) sampling frequency;
and (3) monitor location. These limitations are discussed in detail in the
sulfur oxides criteria document (USEPA, 1982). From a general point of view
however, the sampling method has limited determination of particulate chem-
istry, e.g., SOx and NOx concentration. The frequency of sampling removed the
temporal element needed for characterization of this component for air quality
as related to vegetational impacts. The location of the monitors obviously
affects the concentrations reported and thus consideration of particular
regions and potential impacts.
Only the sulfur and nitrogen components of particulate matter have been
suggested to have any apparent influence on forest growth; however, it should
be pointed out that very few studies have addressed this impact directly.
Sulfate, along with ammonium ions, organics, carbon and combustion-associated
metals, is a major component of fine particulate matter. Only a few studies of
aerosol composition have actually conducted material balance or size fraction-
ation. The spatial distribution of sulfate concentration east of the
Mississippi, excluding the Northeast and South Atlantic states is shown in
Figure M-5. The figure also indicates the seasonality of sulfate deposition
with the area increasing during the summer months. Meteorological factors,
influencing transport and conversion beyond the source, can expand the influ-
ence of S02 emissions. At non-urban sites in the Northeast and Midwest,
sulfate concentrations during the summer increased during the 1960s, peaked in
the early 1970s, and subsequently decreased (Altshuller, 1984). The seasonal-
ity of sulfate occurrence, specifically in rural sites, ranged from 1 ppb in
the winter months to 4.6-5.7 ppb in summer (Altshuller, 1984). Diurnal
patterns in concentration have been observed in studies of two rural sites
(Kentucky and Virginia) during the summer of 1976 (Altshuller, 1984). Two
types of patterns were observed, depending on the meteorological conditions.
M-ll
-------
Table M-5. Measurements of concentrations of nitrogen oxides at suburban and
rural sites (ug m~3 x (5.32 x 10"4) = ppm N02; x (8.15 x 10~4) =
ppm NO). From Altshuller (1984).
Nitrogen
Nitric Oxide
Site (Type)
Montague, MA (R)a
Ipswich, MA (R)
Scranton, PA (S)
DuBois, PA (R)
Bradford, PA (R)
McHenry, MD (R)
Indian River, DE (S)
Lewisburg, WV (R)
Shenandoah, VA (R)
Research Triangle
Park, NC (S)
Research Triangle Park,
NC (S)
Green Knob, NC (R)
Appalachian Mt.
Florida, southeast
Period of
Measurement
(Method)
Aug. -Dec. 1977
(chemilumin.)
Dec. 54-Jan. 55)
(colorimetric)
Aug. -Dec. 1977
(chemilumin.)
June-Aug. 1974
(chemilumin.)
July-Sep. 1975
(chemilumin.)
June-Aug. 1974
(chemilumin.)
Aug. -Dec. 1977
(chemilumin.)
Aug. -Dec. 1977
(chemilumin.)
July-Aug. 1980
(chemilumin.)
Nov. 65-Jan. 66
Sep.66-Jan. 67
(colorimetric)
Aug. -Dec. 1977
(chemilumin.)
Sep. 1965
(colorimetric)
July-Aug. 1954
(ug
Mean
3
ND
3
ND
2.4
ND
3
1
1
2.3
NA
10
2.7
ND
m-3)
Max.
78
ND
70
ND
34
ND
114
33
NA
NA
NA
249
NA
ND .
Dioxide
(ug
Mean
7
2.6
11
19
5.1
11
5
4
4
10.6
14.3
13
6.4
1.8
m-3)
Max.
73
3.8
64
70
68
60
48
28
NA
NA
NA
145
NA
3.7
coast
(chemilumin.)
M-12
-------
Table M-5 (continued)
Site (Type)
DiR-idder, LA (R)
Wilmington, OH (S)
McConnelsville, OH (R)
Wooster, OH (S)
New Carlisle, OH (R)
Ashland Co., OH (R)
Franklin Co., IN (R)
Union Co., KY (R)
Giles Co., TN (R)
Creston, . IA (R)
Wolf Point, MT (R)
Pierre, SD (R), site
40 km WNW of Pierre
Jetmore, KY (R)
Period of
Measurement
(Method)
June-Oct. 1975
(chemilumin.)
June-Aug. 1974
(chemilumin.)
June-Aug. 1974
(chemilumin.)
June-Aug. 1974
(chemilumin.)
June-Aug. 1974
(chemilumin.)
May-Dec. 1980
(colorimetric)
May-Dec. 1980
(chemilumin.)
May-Dec. 1980
(chemilumin.)
Aug. -Dec. 1977
(chemilumin.)
June-Sep. 1975
(chemilumin.)
June-Sep. 1975
(chemilumin.)
July-Sep. 1978
(chemilumin.)
Apr. -May 1978
(chemilumin.)
Nitric Oxide
(ug nr3)
Mean
1.9
ND
ND
ND
6.0
4.3
3.0
2.5
5
4.7
<1.0
<0.25
1.2
Max.
17
ND
ND
ND
64
NA
NA
NA
96
28
NA
NA
NA
Nitrogen
Dioxide
(ug nr3)
Mean
4.9
13
12
13
27
15.6
14.3
12.3
11
4.3
1.5
2.3
7.5
• Max.
43
90
70
90
NA
NA
NA
NA
55
25
NA
NA
NA
a R = rural. S = Suburban. ND = not determined. NA = not available.
M-13
-------
Table M-6. Concentrations of nitrogen oxides measured at remote locations
(ug m"3 x (5.32 x 10'4) = ppm N02; x (8.15 x 1CT4) = ppm NO. From
Altshuller (1984).
Site
Colorado, USA
Niwot Ridge
Measurement
Period
(Method)
Jan. and April
1979 (chemilumin.)
Concentrations
NO
0.02-
0.06
N02
NA
in ug nr3
NOX
0.4-
0.5
Remarks
Colorado, USA
Niwot Ridge
Colorado, USA
Fritz Peak
Dec. 1980 to Jan. NA
1981 (chemilumin.)
Fall 1974; Summer NA
Spring 1975-76
(absorption
NA < 0.1
< 0.02 NA
Island of Hawaii
Mauna Kea
Laramie, WY
Ireland, Adrigole
Co. Cork
Ireland, Loop Head
Ireland, Loop Head
spectroscopy) Dec.
1977 (chemilumin.)
Nov. 1954
(colorimetric)
Summer 1975
(chemilumin.)
Aug. -Sept. 1974
(chemilumin.)
April 1979 (Ciff. '
opt. abs. uv)
June 1979
(chemilumin.)
NA
ND
0.01-
0.06
< 0.02
ND
< 0.01
0.2-
NA 0.5
2 ND
NA 0.2-
0.8
0.8 NA
0.3 , ND
0.16 NA
Maritime
air
Maritime
air
Maritime
air
NA = Not available.
ND = Not determined.
M-14
-------
Figure M-5. Contour maps of sulfate concentrations for 1984 are shown: (a)
annual average; (b) winter average; (c) summer average. From
National Research Council (USEPA, 1984).
M-15
-------
In one the peak concentration occurred in mid-afternoon, about the same time
as ozone peaked. The other pattern was characterized by peaks between 2000 and
0400 hours. This pattern was most pronounced on clear nights when ground fog
developed. Neither pattern was observed after passage of a cold front when
concentrations were very low.
Characterization of sulfate aerosol exposure is needed to define temporal
and spatial distributions of concentrations for understanding and developing
exposure regimes.
Nitrate is the other component of particulates of interest in discussing
the ambient air quality as it relates to studies of dry deposition impact on
forests. Most nitrates in the atmosphere are formed in gas-to-aerosol
reactions, principally involving nitrogen dioxide and nitric oxide. These
reactions may form HNOs (gas or aerosol), ammonium nitrate, sodium nitrate, and
lesser compounds. Measurements of these components are subject to many errors.
Sampling techniques have led to errors in determination of concentration levels
(USEPA 1982), consequently much of the data is not usable for exposure charac-
terization. The air quality data regarding nitrate content are just not avail-
able for understanding the dynamics of occurrence over the year or even short-
term temporal variations. At this time, developing sampling techniques and
analysis should be the major effort to increase the understanding_of nitrate
aerosol, HNOs, and other nitrogen components of particulate deposition.
The problems of dry particulate monitoring are not unique to nitrate
aerosols. Anyone wishing a more complete understanding, as well as the current
knowledge of particulate air quality, is referred to USEPA (1982); Altshuller
(1984); Stensland (1984).
M-16
-------
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