United States
Environmental Protection
Agency
Environmental Sciences Research
Laboratory
Research Triangle Park NC 27711
EPA-600 2-80-023
January 1 980
Research and Development
Cross-Country
Urban and Rural
Measurements of
NO. and SO*
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-80-023
January 1980
CROSS-COUNTRY URBAN and RURAL MEASUREMENTS
of NOX and S02
by
Lee Langan
Michael A. Peache
Jean Jacques Garbarz
Environmental Measurements, Inc.
San Francisco, California 94111
and
Ralph E. Baumgardner
Robert K. Stevens
Atmospheric Chemistry and Physics Division
Environmental Sciences Research Laboratory
Research Triangle Park, North Carolina 27711
Contract No. 68-02-2484
Project Officer
Ralph Baumgardner
Atmospheric Chemistry and Physics Division
Environmental Sciences Research Laboratory
Research Triangle Park, North Carolina 27711
ENVIRONMENTAL SCIENCES RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
-------
DISCLAIMER
This report has been reviewed by the Environmental Sciences Research
Laboratory, U.S. Environmental Protection Agency, and approved for pub-
lication. Approval does not signify that the contents necessarily reflect
the views and policies of the U.S. Environmental Protection Agency, nor
does mention of trade names or commercial products constitute endorsement
or recommendation for use.
-------
ABSTRACT
Total sulfur and oxides of nitrogen measurements, gathered
along two long-distance routes across the United States, are
presented in this report. Supportive information describing the
instrumentation, procedures, moving laboratory, and regional
meteorological conditions are provided.
Over 300,000 measurements were made. Points consisting of
ten-measurement averages have been plotted; they are also pre-
sented in a graphic analysis. This analysis consists of fre-
quency distribution plots of segments of the trip, for example,
through rural areas and crossing urban developments. These plots
provide a means of classification of the degree of pollution
present and monitored with this moving laboratory technique.
The data were gathered from Denver, Colorado, to Raleigh,
North Carolina, in August 1576, and from Los Angeles, California,
to Raleigh, North Carolina, in November 1976. In November the
laboratory stopped at six rural locations to record time-
averaged data, which are also presented.
111
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CONTENTS
Abstract iii
Figures and Tables vi
Acknowledgements vii
1. Introduction 1
2. Equipment and Operating Procedures ... 4
Air Quality Moving Laboratory . 4
The MAP System 7
Measurement Instrumentation 7
Calibration 10
Operations 12
3. Data Presentation 16
4. Discussion 45
Moving Results 45
Stationary Measurements 45
5. Analysis 46
Total Sulfur Results 47
Nitrogen Oxides 48
Appendix
A. Ammonia Filter Data 65
v.
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FIGURES
Number Page
1 Routes of travel for both trips 2
2 The AQML at a New Mexico stop site 5
3 The AQML and interior details 6
4 A typical printout of MAP System averages 8
5 The AQML during calibration 11
6 Ground-level temperatures and wind 14
7 Surface wind direction and speed 15
8-26 Moving data plots 17-35
27 Trip 1 Data Summary 36
28 Trip 2 Data Summary 37
29-35 Stopped data plots 38-44
36-50 Data presentations 50-64
TABLES
I Participants in the program vii
2 Stopped data summary 16
3 Ammonia filter data 65
VI
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ACKNOWLEDGEMENTS
Data collection and equipment maintenance during the cross-
country trips were performed by the persons from Environmental
Measurements, Inc. and the U.S. Environmental Protection Agency
listed in the table below.
Table 1
Participants in the Cross-Country Measurement Program
Individual
Ralph Baumgardner Denver-St. Louis
(EPA)
Gary Klauber
(EMI)
Keith Kronmi Her
(EMI)
Lee Langan
(EMI)
GiIbert Newcomb
(EMI)
Richard Paur
(EPA)
Michael Peache
(EMI)
Philip Schug
(EMI)
Robert Stevens
(EPA)
Wi11iam Vaughan
(EMI)
Charles White
(EMI)
Trip I Trip 2
Los Angeles
Dal las-Raleigh
Jackson-Raleigh
Denver-St. Louis
Denver-Kansas City
Denver
St. Louis-Raleigh
St. Lou is-Lexington Phoenix-Jackson
Kansas City-St. Louis
Kansas City-Raleigh Los Angeles-Phoenix
Los Angeles-Dallas
ResponsiblIity
Calibration
Operations
Operations,
Engineering
Software,
Operations
Engineering,
Operations
Calibration
Operations,
Meteorology
Engineering,
Operations
Calibraticn.
Operations
Operations,
Cal ibrations
Software,
Operations
Data reduction and report preparation were accomplished by
Lee Langan, Michael Peache, Jean Jacques Garbarz, Joan Geary,
and Evelyn More.
vii
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SECTION 1
INTRODUCTION
On two occasions in 1976, very sensitive, rapid-response
air quality analyzers were driven across the United States to
seek data background levels and to observe cross-urban effects.
This report presents the results of these trips. The results may
be -of interest to those concerned with air quality in rural re-
gions, with the fate of sulfur or nitrogen oxides, and with the
establishment and monitoring of national standards.
The West-to-East traverses extended from Denver, Colorado,
to Raleigh, North Carolina, in August, and from Los Angeles,
California, to Raleigh in November. Nearly 8,000 kilometers were
driven. The general routes are shown in Figure 1.
The surveys were conducted by Environmental Measurements,
Inc. (EMI) with the support of two U. S. Environmental Protection
Agency (EPA) contracts: Purchase Order DA-6-99-6876A and Contract
68-02-2484. The report was prepared under Purchase Order DA-7-
3954A. The sensors included a total sulfur gas monitor, a dual-
chamber nitrogen oxide and nitrogen dioxide monitor, and a state-
of-the-art ammonia monitor.
Most of the data were gathered while moving, and an effort
was made to stay away from nearby motor vehicles that could in-
fluence results. Of necessity each traverse extended over several
days; the intent was to-cover distances between major urban sites
with continuous data. Generally, the day's operations began and
ended with calibrations ,of all instrumentation. Periodically, on
some days, stopped data were gathered at rural sites for a few
hours.
The equipment and operating procedures are discussed first.
A presentation of the results and the relevant meteorological
conditions follows. The concluding sections (4 and 5) contain
observations, discussion, and analyses.
This dual set of long-distance, en route measurements has
demonstrated the value of moving environmental monitoring by this
technique. The overview of the geographic distribution on a
broad scale and the long distances of low levels interconnecting
the urban anomalies depict the consistency of the air contamina-
tion. The regional plateaus of higher concentrations show the
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TRIP I
Denver to Raleigh
August 1976
TRIP 2
Los Angeles to Raleigh
November I 976
Figure 1. Routes of travel with each traverse day delineated. Shading indicates peri-
ods of monitoring while dark. Stopped data locations are noted by asterisk.
-------
diffusion and collective gathering of many localized sources un-
der low wind conditions. The background levels provide observa-
tions necessary for the use of regional modeling. The peaks and
urban anomalies allow comparison of separate metropolitan sites
using a rapid and relatively inexpensive reconnaisance method.
Highly sophisticated instruments can be used in the field to
cover large areas, to provide monitoring otherwise prohibitive
in cost if a fixed-base network is established. And, if need be,
anomalous conditions can be traced, at the time of their occur-
rence, by traversing up-wind of the initial contact.
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SECTION 2
EQUIPMENT and OPERATING PROCEDURES
The EMI Air Quality Moving Laboratory (AQML) was an out-
fitted Dodge Maxivan designed for routine regional or local
surveys. Data processing instrumentation was supplied by EMI;
the high sensitivity analyzers and calibration and collection
equipment were supplied by EPA.
The EMI/EPA staff developed operating procedures for the
unique conditions of this continuous long-range measurement pro-
gram. These ranged from the logistics of subsistence and main-
taining a suitable pace to the details of quality assurance.
Most operations became routine, making it apparent that such a
technique of measurement could be maintained without undue stress,
given a protocol and reliable equipment.
Data processing en route was automatic, requiring operator
interaction only about each half hour. After the fact, editing
and plotting were straightforward and included adjusting all tra-
verses to a common coordinate system, reducing all measurements
to common stored engineering units, and plotting the results.
The large data base suggested the use of larger computer
memories. Fortunately, these have evolved with desktop computers
since the project's field work. A Hewlett-Packard Model 9845B
was used for final data analysis.
AIR QUALITY MOVING LABORATORY
The Dodge Maxivan used for the cross-country measurements
is pictured at one of the stationary stop sites in Figure 2.
This vehicle contained a standard support installation: an in-
board 3.5kW Onan generator, an EMI MAP-II navigational and data
system, two automotive air conditioners, desk space with four
below-table racks for analyzers, a glass and Teflon air intake
manifold with pump, a storage closet for operating and cali-
brating gases, and a Hewlett-Packard 9830A programmable calcula-
tor with peripheral printer, plotter, and tape cassette.
To this array were added EPA's analyzers: a Meloy Model 285
flame photometer total sulfur monitor, a Thermo Electron chemi-
luminescent NO/NOX monitor (trip 1) and Aerochem chemiluminescent
-------
Figure 2. The EMI AQML proceeded a short distance off a New
Mexico highway to gather stopped data near Lordsburg
(8 November 76).
NO/NOX ammonia monitor (trip 2), and related calibration equip-
ment and gases. Some chart recorders and test instruments were
also present. Figure 3 shows some of the equipment inside the
van. The AQML proved sufficiently comfortable with two air con-
ditioners, but it was crowded when four people were present,
along with their luggage for the long trip.
-------
The EMI Air Quality Moving
Laboratory
HP9830, MAP-II System, and
plotter inside the moving van
Meloy analyzer (below) and
calibrating apparatus next
to the HP9830 printer
Cross-calibration at EPA-RAMS
Site 108
Figure 3. The Air Quality Moving Laboratory and interior details.
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THE MAP SYSTEM
The EMI MAP II navigational and data system operates under
the control of the HP-9830, which provides all data formating and
printing. Each of the analyzers was connected to an analog-to-
digital channel of MAP; sampling was performed each 20 meters
along the route of travel. Each 200 meters the average measure-
ment was listed, together with the position and time of the last
sample, and plotted in realtime. While the AQML was stopped,
three-second samples stored every 30 seconds were obtained.
These data were stored on tape cassettes for subsequent analysis;
they were also plotted in realtime for review by the operator.
When only two analyzers were in use, switching on the chemilumi-
nescent monitor and scrubbing on the flame photometric monitor
were noted by automatic formating changes in the data listings.
A partial list from trip 1 (shown in Figure 4) is typical of
the visual data. Each 1i.ne contains location, time, digitized
analyzer data, and the difference in seconds and meters since the
preceding line. Each event covered a grouping of consistent data
(between two known points, stopped data, a calibration, and the
like). Because of the limit of the 9830's memory, no event of
200-meter data exceeded 50 kilometers (250 lines of data). En ->
route, this was about an hour of data, referred to as a set of
data. Each cassette could store six sets of data, so more than
two cassettes were rarely used for each day's data.
In addition to the data averaging, the MAP computer derives
the actual position of the vehicle each meter along the route.
By combining this position with the bearing of the vehicle, moni-
tored by the gyrocompass installed in the van, a new Cartesian
(x,y) coordinate is calculated. These north-south and east-west
distances are added to a position defined at the beginning of
each event. Every 200 meters a new position is identified.
A quasi-Universal Transverse Mercator (UTM) system of geo-
graphic locations was attempted because values from this accepted
framework were used at the beginning of each trip. The UTM ref-
erence is not, however, contiguous across the country. Due to
the earth's curvature, several grids intersect. The initial UTM
reference was simply continued for each trip so that the plotted
routes that follow are equal-area projections across the United
States.
MEASUREMENT INSTRUMENTATION
A high resolution total sulfur monitor manufactured by Meloy
Laboratories, Inc. was installed in the AQML. Sensitivities
on the order of one part per'billion (ppb) were obtained.
A chemiluminescent monitor manufactured by the Thermo Electron
Corporation was installed to measure total nitrogen oxides (NOX)
-------
EVENT
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218
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244
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240
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Figure 4. HP-9830 printout of MAP system averages in the dis-
tance mode (every 200 meters) showing the location
(x,y), the time, the total sulfur (TS), the values
for NO or NOX from the TECO readings, the distance
(D) between two averages, and the time (T) between
those averages. ~~~
8
-------
and nitric oxide (NO) in August; a prototype chemiluminescent
monitor produced by Aerochem Research Laboratories was used in
November. Bendix Corporation and Research Triangle Institute
double-dilution calibration systems were used for spanning the
low level concentrations of both systems; a sulfur dioxide per-
meation tube and NO gas cylinder were concentration sources.
Ultra high purified zero air produced by Scott Merrin, Inc. was
used to attain zero levels to monitor potential instrumental
drifts at these low levels. Frequent "zeroes" in the total sul-
fur were also obtained by using a Meloy SO2 scrubber manufactured
by Meloy.
Background gaseous sulfur measurements were made with the
Meloy Model SA-285, which uses the flame photometric detector
as its measurement "principle. The measurement is of the chemi-
luminescense produced when gaseous sulfur compounds are burned in
a hydrogen-rich flame. The reaction emits a broad band of light
with its maximum at 394nm. The intensity of the emission is di-
rectly proportional to the square of the sulfur concentration.
This monitor is designed to have optimum sensitivity and
stability to allow for measurements as low as 1 ppb. Sample air
is drawn continuously through the detector at a controlled flow
rate of 200cc perx minute. Hydrogen is applied to the detector at
a positive flow of 150cm3 per minute. The light emission is mea-
sured with a cooled photomultiplier tube. The current output of
the photomultiplier tube is linearized and connected to a voltage
before display on a meter or recorder. By using selective chemi-
cal scrubbers supplied with the unit, it is possible to remove
hydrogen sulfide (H2S) or sulfur dioxide (S02). By measuring the
total sulfur present, then placing the appropriate scrubber in
line, it is possible, by measuring the difference in signal, to
determine specifically the S02 or H2S.
Measurements of background levels of NO and nitrogen dioxide
(N02l were made during the August trip with a Thermo Electron
Model 12 NO-NOX monitor. This instrument can measure NO and N02
from 0 to 10.00. ppb with a detectable minimum of 2 ppb by using
the gas phase chemiluminescent reaction of nitric oxide and ozone.
A high temperature thermal converter converts NO2 to NO, allowing
for measurement of NOx (N02 + NO) and the determination of N02
present by subtraction (NOx - NO).
Sample air is pulled through the NO detector at a flow rate
of 100.cc per minute where it reacts with ozone at a reduced pres-
sure of 10 torr. A switching valve gives a response for NO; then
the sample is sent through the thermal converter for a NOX (NO +
N02l measurement. A red-sensitive photomultiplier tube with an
optical filter observes the light from the reaction of NO to 03
in the detector and converts it to an electrically amplified sig-
nal. An output signal for both NO and N02 is possible.
-------
Measurement of background levels of NO and NO2 were made
during the November trip with a prototype nitrogen dioxide, nitric
oxide, and ammonia monitor manufactured by Aerochem Research La-
boratories. This monitor also uses the reaction of NO and 03 as
its measurement principle. Using a detector especially designed
by Aerochem to increase the residence time for the NO:03 reaction,
the Aerochem monitor is capable of measuring NO, NO2, and ammonia
(NH3) from 0 to 500 ppb with minimum detectable limit of 1 ppb.
The monitor has two NO:03 detectors, each capable of measuring NO
or NOX by using a thermal converter. The monitor was set up for
the study with one channel having a low temperature (300°C) con-
verter in line to measure NO + NO2 and the other channel having
a high temperature (1000°C) converter to convert NO2 and NH3,
giving a signal for NO, N02, and NH3. The sample air is pulled
into the monitor at a flow of SOOcc per minute, half of the flow
going to each detector. Ozone flow for the reaction is generated,
using a single ozone generator with the flow being split into each
detector.
Using thermal converters with each detector and an ammonia
scrubber with one detector, it was possible to measure background
levels of NH3 by subtracting the difference between the signal
with the scrubber and the signal generated without the scrubber.
These results were monitored only experimentally during the trips.
CALIBRATION
At the beginning of the project, an effort was made to cali-
brate the measuring instruments each morning and evening. This
allows for conversion of response units to convenient and fami-
iar units: parts per billion (ppb). As the program continued,
at least one calibration was made each day (Figure 5).
Two calibration systems were used during the studies. The
first, a Bendix Model 8851 calibration system, has capabilities
for generating known concentrations of NO and NO2 (using the gas
phase titration of NO with 03) and of sulfur compounds and NH3
(using permeation tubes). A cylinder of NO at 49 ppm (standardized
by the National Bureau of Standards' Standard Reference Method) was
diluted to produce concentrations from 0.01 ppm to 0.50 ppm using
the Bendix system, which has dilution flow control up to SOOOcc
per minute. The chemiluminescent NO-NOX monitors were calibrated
for NO by this technique.
The Bendix system also has a permeation tube oven that pro-
vides controlled temperature to within 0.1° at 25°C. Dilution air
passes through the oven housing the permeation tubes of either
S02, H2S, or NH3- Permeation rates for each of these tubes were
determined gravimetrically before the beginning of the study.
10
-------
Figure 5. Calibrations were normally accomplished twice a day,
before and following the travel.
Using the permeation system of the Bendix, calibration concentra-
tions of SC>2, H2S, and NH3 between 0.010 and 0.50 ppm could be
generated.
The second calibration system used in the study was a double
dilution permeation system built by Research Triangle Institute to
deliver known concentrations of gases below 0.010 ppm. Using the
RTI system, known concentrations of SC>2, ^S, and NH3 were gener-
ated between 0.001 and 0.010 ppm. The RTI permeation calibration
system consists of two automatic flow controllers, a temperature-
controlled permeation tube oven, and an automatic digital readout
of flows and temperature. Two mass-flow controllers control air
flow of the permeation oven and dilution flow between 200 and
10,OQOcc per minute. Zero air entering the unit is split, part
going through one flow controller to the permeation oven, providing
flow over the permeation tube, and part going through the second
flow controller, providing dilution flow. A glass capillary allows
IQOcc per minute of air flowing over the permeation tube to be
mixed with the dilution air, giving a double dilution to the ori-
ginal concentration. Temperature within the permeation oven is
controlled to within 0.10°C. The double dilution system was used
11
-------
to achieve very low concentrations for S02 for calibration across
the usual ambient range observed. Careful selection and calibra-
tion of the flows with a bubble tube resulted in three-point
calibrations ranging from 10 to 25 ppb of SO2- The instrument
received at least one three-point calibration every survey day
and one or two span checks at the 25-ppb level to confirm the
stability of instrumental calibration under the vibration and
temperature conditions experienced in the AQML. Although there
was some zero drift observed with occasional high temperatures,
it amounted to fewer than 7 to 8 ppb S02 and was confirmed by
monitoring zero air, as opposed to mere SOX scrubbing. These
drifts have been removed from the data. The stability of the
calibrations was excellent during the course of the study, re-
quiring no changes in calibration factors over a given week of
moving measurements.
Periodically an SOX scrubber was inserted into the sample
line to confirm that the principal signal was SC>2 • Generally,
SOX scrubbing brought the instrument response to within 2-3 ppb
of zero air readings, indicating that the majority of sulfur was
coming from SOX and not H2S. The only place an appreciable (10
ppb) H2S signal was observed with the SOX filter in place was in
Eastern Texas and Western Louisiana.
OPERATIONS
After the morning calibration the AQML was driven along the
least-travelled route to the next major urban area. Individuals
shared the load of driving and monitoring the data gathering.
Periodic interaction was required with the automated system,
route planning, and usual observations. The intent was to tra-
verse interurban regions in a continuous survey. A conscious
attempt was made to stay away from traffic or, when this proved
difficult, to stay away from any truck or automobile by either
passing or dropping back. The measured effect of an adjacent
vehicle's pollution is obvious in the data plots. Data spikes
are common but of short duration. They have not been removed
from the data. Diesel trucks created larger anamolies in nitro-
gen and sulfur oxides than did gasoline-powered automobiles.
Seven times during the second trip the AQML was stopped to
make stationary measurements in conjunction with filter samples
taken at the same time and analyzed for NH3 by the Air Monitoring
Center of Rockwell International, as described in Appendix A.
The sites chosen to make the stationary measurements were several
kilometers off the highway in rural areas. Stationary and filter
data were collected near Lordsburg, New Mexico; Shreveport,
Louisiana; Jackson, Mississippi; Ragland, Alabama; Commerce,
Georgia; and Silver City, North Carolina. In addition, one set
of stationary data only was collected near Superior, Arizona.
12
-------
Included in Appendix A is a letter from Willard Richards of
Rockwell International describing the filter analysis, along with
a table of the results.
Summary maps of meteorological conditions are plotted in
Figures 6 and 7. The conditions were noted during the traverses,
but the overview was derived from the U.S. Weather Bureau's daily
maps representing the 0700 EST status. The data plotted are taken
from these publications and display the condition most represen-
tative and nearest the moving laboratory as it proceeded across
the country. The 0700 wet and dry bulb temperatures and the 24-
hour variation for the day are plotted in Figure 6 for each of
the 18 survey days; upper-level wind speeds and directions com-
plement these. In Figure 7 ground winds and the movement of re-
gional highs are plotted to reflect forces on the pollution move-
ments .
13
-------
TRIP I
Denver to Raleigh
August 1976
TRIP 2
Los Angeles tc Raleigh
November 1976
24.5 - 26.5 MPS
TRIP I
Denver to Raleigh
August 1976
-»-Dry Bulb
Wet Bulb
Minimum
TRIP 2
Los Angeles to Raleigh
November 1976
Figure 6. Ground-level temperatures and 500 mb wind direction
and speed plotted for 0700 EST each day.
14
-------
TRIP I
Denver to Raleigh
August 1976
TRIP 2
Los Angeles to Raleigh
November 1976
Figure 7. Surface wind direction and speed and daily movement
of major high pressure centers influencing measurements.
15
-------
SECTION 3
DATA PRESENTATION
Most of the data are presented in a two-figure format, one
per sampling day. Total sulfur is on each top graph and nitro-
gen oxides on the one below. On both, the road has been plotted
above the data. Locations of cities and times are indicated
along the roads. On those occasions when the distance covered
during the day of sampling exceeded the maximum allowed by the
plotting frame (440km), the remainder of the data was placed in
the right hand top corner of each graph. The figures, 8 through
26, conclude this section in chronological order. Figures 27
and 28 are the trip summaries from preliminary reports.
Scrubbing of SOX is apparent on the data plot when sharp
vertical lines fall to 3ppb or less of total sulfur. Data during
stopped measurement periods of the second trip are listed in
Table 2 below. In each case, these are rural sites several kilo-
meters off the highway (refer to Figure 2 on page 5), and they
are composed of sets of 30-second averages (3-second samples)
over an approximately two-hour mid-afternoon period. About 30%
of the time the S02 was scrubbed, which provided a total sulfur
result and an SO2 result. The stopped data are spatially indi-
cated on the road and are plotted as a function of time in Figures
29 through 35, which follow the moving data. The total sulfur is
above the nitrogen oxides; scrubbing and NOX-NO switching are
shown in the data.
TABLE 2. STOPPED DATA SUMMARY
DATE
7 Nov 76
8 Nov 76
15 Nov 76
17 Nov 76
Nov 76
19 Nov 76
20 Nov 76
1
S ITE
(near)
Superior, AZ
Lordsburg, NM
Shreveport, LA
Pelahatchie, MS
Ragland, AL
Commerce, GA
Si Iver City, NC
TOTAL
SULFUR
(ppb)
S02 MEASUREMENT
(TS-scrubber) PERIOD
(ppb) (minutes)
22.24
63.
180.
122.
127.
120.
126.
161.
16
-------
PPB
U5/H1
400
50-
200
•IBB
JUL
H0 KM
OISTHNCE;: i 1 HB KM
Figure 8. August 18 - 1600-2300 MDT - Colorado
17
-------
PPB
B/H3
M0B
3BB
-2BB
•IBB
O
O
o
o o
SB
IBB
=f=
0
o
0
01
BISTRNCE:
H0 KM
PPB
IEBB-
IZ0B-
U1
U
e>
NITRDBEN DXI
ID
i
HB0-
B-
BBB-
H00-
V •
a-
IU Z UI < <
^ o -J u x
_J H -I UJ K
• l l O *^ Z ^
> Z > UJ X
UJ « (fl I/I <
d S 5 5
•K 5 S
^ „, i, Jl ^ i. 1 '
_ _, _ , -H , • ^
g | <0 ZS" M
."3 U. " I
1 HM
1- ~ Z
« S "> jl
J 1 1
1 — u^Y^-^n L^^n_jpjH_r|jn_^kj-t rkJ-J. rT^w^'U-J
DI5TRNCE: 1-
Figure 9. August 19 - 1QOO-2400 MDT - Colorado-Kansas
18
-------
PPB
IS0-
-300
100-
o: --2BB
SB-
H00
-100
1
1
DISTRNCE:
HB KM
Figure 10. August 20 - 0000-0100, 1300-1800 CDT - Kansas-Missouri
19
-------
PPB
ISO-
SB-
•HH e
-300
•ZHH
-I 1 h-
BISTRNCE:
HB KM
PPB
IEB0--
1200
HBB-
z
o
z
-I 1-
H 1 1 (_
HB KM
Figure 11. August 24 - 2000-2300 CDT - Missouri-Illinois
20
-------
Figure 12. August 25 -
1100- 230Q CDT - Illinois-Indiana-Kentucky
21
-------
PPB
UB/H'
ISH-
•30H
I Eta-
HBB
•ZBB
•IBB
DISTRNCC:
40 KM
Figure 13. August 26 - 1000-1900 EOT - Kentucky-Virginia
22
-------
Figure 14. August 27 - 1000-1600 EOT - Virginia-North Carolina
23
-------
PPB
IS0
JE/H3
H0B
100
•200
•IBB
H
DI5TRNCD
H0 KM
PPBl
H004
H
-I H0 KM
Figure 15. November 3 - 1900-2100 PST - Los Angeles
24
-------
Figure 16. November 4 - 1300 PST to 0200 MST - California-Arizona
25
-------
Figure 17. November 7 - 1100-2000 MST - Arizona
26
-------
PPB
UB/H3
I5H-
100-
300
H00
-100
DISTHNCt:
H0 KM
Figure 18. November 8 - 1300-2200 MST - Arizona-New Mexico
27
-------
PPB
[EBB-
I2BB-
H00-
o
<
DISTRNCE: i 1 HH KM
Figure 19. November 9 - 1500-2200 MST - New Mexico-Texas
28
-------
PPB
I EBB- •
I2B0--
H00--
B0B-
HBB-
D:
o
too.—Mlfv_rv
D iSTRIKE: i~
M0 KM
Figure 20. November 10 - ILOQ MST to 2400 CST - Texas
29
-------
PPB
UG/HJ
ISB-
•HB0
SB-
•Z0H
•IBB
DISTRNCE:
-I 40 KM
Figure 21. November 14 - 1200-2000 GST - Texas-Louisiana
30
-------
PPB
150-
UB/M3
00
200
-t-
DISTHNCE:
H0 KM
Figure 22. November 15 - 1400-2400 CST - Louisiana-Mississippi
31
-------
Figure 23. November 17 - 1000-1900 CST - Mississippi-Alabama
32
-------
DI5THNCE: i ! '10 KM
Figure 24. November 18 - 1000 CST to 2100 EST - Alabama-Georgia
33
-------
Figure 25. November 19 -
1000-2100 EST - Georgia-North Carolina
34
-------
PPB
I Se-
H0B
30B
•200
-100
DI5TRNCE:
H0 KM
PPB
RTF
DISTRNCE::
H0 KM
Figure 26. November 20 - 1000-1800 EST - North Carolina
35
-------
ROUTE OF TRAVEL (1 CR = 60 KM)
HEAVY INTERSTATE TRAFFIC
Figure 27. Trip 1 data summary - Denver to Raleigh - August 18-27, 1976
-------
fUTRQGEH OXIDES
lM^JL-^J«Jl(l^^
d|.. HI1ROSBI OXIDES
WfllL-~.-t.
Figure 28. Trip 2 data summary - Los Angeles to Raleigh
November 4-20, 1976 (before data adjustments)
37
-------
57.
HJ.
a *•
^"-»
•t]
a a.
SB-
am.
IB-
Figure 29. Stop site east of Phoenix (Superior, AZ) - November 1;
stationery data only (no filter samples)
38
-------
SI.
HI.
31-
21-
II •
su-
it-
Figure 30. Stop site #1 - November 8 - Lordsburg, NM
39
-------
01
MB
3 38
/-\
•o
B a
•w
IB
saa
IBS-
Figure 31. Stop site #2 - November 15 - Shreveport, LA
40
-------
a
HI
3 »
IBB
Figure 32. Stop site #3 - November 17 - Pelahatchie, MS
. 41
-------
HH.
3 38-
tan
g
ZBB
I0B
Figure 33. Stop site #4 - November 18 - Ragland, AL
42
-------
38.
..
II.
jl
D)
Figure 34. Stop site #5 - November 19 - Commerce, GA
43
-------
a
sail
sun
3SB
IBB
Figure 35. Stop site #6 - November 20 - Silver City, NC
44
-------
SECTION 4
DISCUSSION
MOVING RESULTS
These results clearly show long distances of consistant
quasi-uniform data between urban islands of higher content.
Rural levels differed regionally; between some cities the levels
were very low, while higher backgrounds existed between others.
Low levels of total sulfur, below one part per billion, were
experienced; plumes of over a hundred ppb were crossed; tens of
ppb were common in urban measurements. Higher rural backgrounds
were present from the Mississippi River east.
In the nitrogen oxides' plot the switching to NO measurements
during the August trip clearly results in troughs, which demon-
strates that NOX mainly consists of NO2. During the November trip
only NOx was recorded.
There was a purposeful intent to travel on and off the Inter-
state Highway System along the route. The Interstate segments of
travel resulted in much higher NOX levels due to the traffic. The
effect in the total sulfur results was less obvious and more
closely related to individual vehicles. Diesel vehicles were very
sulfurotis. Travel in and for some distance east of Los Angeles
reflected the content of air breathed by many automobile commuters.
NOX levels were normally in excess of 300-400 ppb.
Low levels of NOX were observed to a few ppb in the western
deserts. In the South, levels rose to tens of ppb; in urban areas
and on highways levels exceeded hundreds of ppb frequently. Off
heavily travelled streets, upwind of concentrated traffic, levels
of several tens of ppb remained in urban locations.
STATIONARY MEASUREMENTS
At the seven stop sites the levels of sulfur were less than
10 ppb except at the last site, where levels of 50 ppb were
reached. The NOX measurements showed background levels of less
than 25 ppb at all sites except Stop Site #6, which was near a
dairy feed lot in a heavily agricultural region. The NOX signal,
which was often above 50 ppb during this final test, was almost
entirely removed by the NHs denuder.
. 45
-------
SECTION 5
ANALYSIS
After the cross-country trips, it was possible to reduce the
data to a calibrated form and to plot them as a function of dis-
tance. A variety of plots were reviewed, and the preliminary
analysis of the data, resulting from an overview of these plots,
was presented in preliminary reports. Plots of this nature are
found in Section 3. It was obvious that anomalies of pollution
occurred in the vicinity of cities that were crossed during the
trips and that these were separated by broad regions of consid-
erably less pollution. A method of displaying an overview of
these data in some uniform fashion was sought.
Initial attempts were to prepare plots of correlation vs the
separation of data points. The initial assumption was that, over
broad regions, adjacent and even widely separated data points
ould be similar for rural areas^and dissimilar for urban areas.
Therefore, one could provide an analysis to separate the charac-
ter of the region traversed. This approach did not proceed well,
primarily because most of the data points were near the noise
level of the gaseous concentration being measured. One part per
billion does not correlate very well with two parts per billion,
and such threshold values were not uncommon in the western states.
Another way was sought, j
While preparing these materials, Environmental Measurements
was visited by an associate from France, Dominique Rust from the
Commissariat de Energie Atomique (CEA). He described a technique
suggested by Dr. Pierre Zettwoog to provide a common format for
similar long-distance traverses conducted by CEA. The technique
is to provide a frequency distribution for the occurrence of a
given concentration in a given set of data. Once this is calcu-
lated, a cumulative frequency distribution provides an integrated
value that is distinctive for similar sets of data points. This
method proved useful, as follows:
In the data that were accumulated for the two transcontinen-
tal trips, common dimensions have been used in Figures .36 through
50. The concentration for both nitrogen oxide and total sulfur
is plotted as the log of concentration from one part per billion
to one thousand parts per million on the abscissa. On the ordi-
nate, the left edge is from 5-20% of the frequency occurrence of
46
-------
the concentrations, which are plotted as dots. The right ordi-
nate is 100% of the cumulative frequency distribution (integral
curve), plotted as a solid line. If the cumulative plot is steep,
the data tend to be contained within a narrow region. To the left
they are of lower concentrations, and to the right they represent
more significant pollution. A more gradual slope represents a
broader distribution of the occurrence of the contaminants.
The presentations are ordered by showing the total sulfur
data first and then the results from the nitrogen oxide measure-
ments. In each case the results of the first trip are presented
and followed by those of the second trip. Throughout both trips,
while the data were gathered at 200-meter increments, each data
point represents an average of ten samples. Thus, for example,
the 19,026 points represented in the second trip's total sulfur
presentation actually represents 190,260 samplings of the analy-
zers.
In each graph a location is identified, together with the
number of data points used for the presentation. For each trip
and for each gas the results of the entire trip are presented on
a single page. The variation in the number of points used for
each gas is a result of minor periods when one or another instru-
ment may have been off during the course of the trip. The "En-
tire Trip" results are followed by subsets in urban areas tra-
versed by the trip and by subsets in regional rural traverses
between cities. Each takes a distinctive form. No attempt was
made to modify the data that were recorded on the trip other than
to reduce them to engineering units. The spikes that occur as a
result of traffic are thus intermixed with the results of tran-
secting the touchdown of plumes or the general air throughout the
cities on the route. Periodic daily calibrations and spans are
also not excised from the data, but they represent a relatively
small portion of the total data points and should not bias the
results in any significant fashion. To a first order approxima-
tion, these summary data represent the air breathed by the occu-
pants of the vehicle as it traversed across the United States.
TOTAL SULFUR RESULTS
An overview of Trip 1 versus Trip 2 would indicate that the
results of both trips are similar with 90% of the measurements
made falling beneath approximately 11 ppb total sulfur.
Selected urban sites show quite distinct differences, how-
ever. In Trip 1, for example, 90% of the total sulfur results in
Denver fall below 8 ppb; yet in Louisville, this cut-off is ap-
proximately 100 ppb. This same higher level represents Birming-
ham, Alabama, from the second trip. The results from Phoenix and
Los Angeles show somewhat nore sulfur than do those from Denver
47
-------
(90% below 12 ppb); these appear to be related to automotive
traffic.
Rural results are also rather similar. The Great Plains
trip between Denver and Kansas City is comparable to the desert
trip between Phoenix and El Paso, with very little presence of
total sulfur. The trip across the Allegeny Mountains from Lex-
ington to Raleigh shows distinctly more total sulfur presence;
the trip from Dallas to Birmingham across the southern Mississ-
ippi River valley shows a higher level and distinctly more pre-
sence of total sulfur. The time of the Lexington-Raleigh tra-
verse was August 26-27, 1976, during the occurrence of a persis-
tent elevated pollution episode, as defined by later analysis of
regional data.
One must keep in mind that these data are presented as a
preliminary analysis of the total results in an effort to present
a means by which the regional data can be quantatively compared.
They represent results as. they occurred over randomly chosen
times of travel; thus they may be assumed to be good approxima-
tions of what one may find at any time.
NITROGEN OXIDES
The results of the nitrogen oxide measurements are more
difficult to evaluate because they were measured on each trip
with different instruments and because on the first trip there
was a periodic switching between the measurement of total nitro-
gen oxides and NO. The second trip measured only total nitrogen
oxide measurements. Whereas it would be highly desirous to sepa-
rate these data, this has not been done because the data were not
gathered in a fashion to make this analysis convenient. The
results of Trip 1 represent lower concentrations because of the
values obtained when measuring NO only.
On Trip 2 one of the instruments that was used had a range
position, which, when the measurements exceeded this range,
rested at a limit. The fact that this was not monitored at all
times is obvious in the results of the data shown in the entire
trip. The large peak of over 3% occurrence at about 90 ppb
represent this limit; these data should be spread to higher con-
centrations.
It must be remembered that frequent routes on both these
trips are on Interstate highways and that there are frequent
occurrences of automobiles' and other vehicles' proceeding just
in front of the measuring vehicle. Spikes of measurements occur
throughout the trips, but these spikes have little correlation.
They were left in the data, again to represent the air that the
operators and drivers were breathing.
48
-------
With these limitations in mind, the summary representations
still retain an intriguing overview of these cross-country trips.
As in the total sulfur data, the NOX data for both entire
trips are rather similar, with 90% of the results occuring in less
than 200 ppb. The results from the urban measurements in Denver,
Louisville, and Phoenix were all rather similar, with 90% of the
occurrences falling less than approximately 300 ppb. Los Angeles
met expectations with the higher occurrence of NOX, and Birmingham,
while notable in total sulfur content, was low in the presence of
NOX- In the rural results each selected regional traverse had
relatively little traffic. The trip between Denver and Kansas City
was on a little-travelled U.S. highway, and the peaks and troughs
of the frequency occurrence resulted from the switching from the
NO to NOX. Levels of less than approximately 40 ppb NOX were
present for 90% of that trip. This compares favorably with the
relatively untravelled route between Dallas and Birmingham. Re-
sults between Lexington and Raleigh represent a more heavily tra-
velled route and slower transit times through the mountains.
These compare with the data gathered between Phoenix and El Paso;
yet it must be observed that there were very few vehicles on the
western route, and the results may represent a more regional pre-
sence of NOX.
One is reminded that the entire purpose of both of these
trips was to present an experimental means of gathering regional
data that might be representative. In that same light, the results
here are presented to suggest a convenient form for evaluation.
. 49
-------
ckJ
100
Figure 36.
z
o
o
-10/
a:
H-
10
t—i
o
21
U
=i
O
U
DL
U.
TOTRL SULFUR
TRIP NO 1
ENTIRE TRIP
11700 POINTS
50-
—i
CQ
t-i
Ct
in
I—i
Q
b
Ld
D
O
LJ
U.
LJ
M
-------
100
5
o
n
h
OL
I-
Ul
TOTflL SULFUR
TRIP NO 1
DENVER
977 POINTS
D
CO
M
o:
i-
tn
Hi
O
(J
LJ
O
U
LJ
o
u
LL
LJ
IH
cr
r
u
10 100
LOG CONCENTRHTION (Ppfl)
10130
100
SULFUR
NO 1
^LOUISVILLE
564 POINTS
m
»-i
a.
in
H-*
P
LJ
O
LJ
a.
u.
10
50-
o;
01
u
o
LJ
a:
u
a:
d
u
10 100
LOG CONCENTRHTION (PPB)
1000
Figure 37.
-51
-------
100
5
- I .; . 5
TOTflL SULFUR
TRIP NO t
DENVER KRNSRS CITY
3184 POINTS
50-
m
M
o:
en
M
n
u
LJ
O
LJ
a.
LL.
LJ
O
u
UL
LJ.
(T
D
U
10 100
LOG CONCENTRRTION CPPB)
1000
100
I..'
Z
UJ
u
LL
L.
TOTHL SULFUR
TRIP NO 1
LEXINGTON RRLEIGH
2951 POINTS
O
M
t-
tn
a
50-
u
LJ
O
LJ
a:
u.
Ld
n
o
.10 100
LOG CONCENTRRTION (PPB)
1000
Figure 38.
52
-------
10
CO
M
ft:
h-
tn
M
P
u
D
O
U
ct:
u.
-5
100
TOTRL SULFUR
TRIP NO 2
ENTIRE TRIP
1
26 POINTS
50-
O
n
oa
h-
01
M
Q
y
21
U
ID
O
U
Q:
>
M
I-
o:
ZD
O
X*
> ..i.
10 100
LOG CONCENTRRTION CF'F'B)
1000
Figure 39
-53
-------
Hi
100
LJ
Cl
L
TOTflL SULFUR
TRIP NO 2
LOS flNGELES
1000 POINTS
58-
10 1B0
LOG CONCENTRHTION CPPB)
1 0
R
Ul
u.
100
TOTHL SULFUR
TRIP NO 2
PHOENIX
651 POINTS
50
10 100
LOG CONCENTRflTION (PPB)
1000
Figure 40
54
-------
Hi)
100
Z
o
u
o
u
a:
TOTRL SULFUR
TRIP NO 2
BIRMINGHflM
449 POINTS
10 100
LOG CONCENTRflTION (PPB)
50-
tn
U)
u
u
o
u
a:
L.
u
1300
Figure 41,
55
-------
100
O
M
i
TOTHL SULFUR
TRIP NO 3
PHOENIX EL PflSO
1544 POINTS
>-
u
50-
o
B
Ul
10 100
LOG C'ONCENTRRTION (PPB)
1000
10
-5
U
2
Ul
D
O
UJ
tt
U-
100
TOTHL SULFUR
TRIP NO 2
DRLLRS BIRMINGHRM
3696 POINTS
50-
10
LOG
100
CONCENTRRTION (PPB)
1000
Figure 42.
56
-------
0
M
K
CQ
M
Q:
t-
LO
M
P
U
LJ
D
O
U
QL
L_
-2.5
NITROGEN OXIDES
TRIP/ NO 1
ENJ/1RE TRIP
1L689 POINTS
. '"^^liiiik
50-
OQ
M
Of
I-
UTi
M
Q
U
Z
U
O
LJ
L_
U
M
H
cc
_J
D
U
X
10 100
LOG CONCENTRRTION (PPB)
1Q00
Figure 43
.57
-------
100
NITROGEN OXIDES
i
50-
o
»
M
o:
in
M
a
>-
o
u
o
Ul
o:
u
u
^
a:
D
O
IB 100 1000
LOG CONCENTRRTION
NITROGEN/OXIDES
TRIP
LOUISVILLE
601 POINTS
2.5
50
o
(0
01
>-
U
§
o
Ul
a:
u.
LJ
I
o
10 100
LOG CONCENTRRTION (PPB)
1380
Figure 44
58
-------
t-
*
-2.5
u
o
u
a.
100
NITROGEN OXIDES
TRIP NO 1
DENVER KflNSRS CITY
3163 POINTS
'''•;>i,vi-tv.i ti i
10 108
LOG CONCENTRRTION CPPB)
50-
o
w
M
Lt
in
o
u
a:
L.
U
U
1000
U-
ul
U
O
NITROGEJhl OXIDES
TRIP NO 1
LEXINGTON RRLE1GH
2951 POINTS
100
50
o
t-
M
Q
O
u
u.
u
r
u
;•?
10 100
LOG CONCENTRRTION (PPB)
1000
Figure 45,
. 59
-------
10
m
i— i
a:
h-
<_0
i— i
P
u
z
LJ
_i
O
u
o:
L_
1-5
NITROGEN OXIDES
TR'IP NO 2
ENTIRE TRIP
.8682 POINTS
T '•''*-•-.
10 100
LOG CONCENTRflTION (PPB)
50-
CCl
M
or
i-
LO
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Figure 47
. 61
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NITROGEN 0%
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64
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APPENDIX A
AMMONIA FILTER DATA by ROCKWELL INTERNATIONAL
Air Monitoring Center
International
In reply refer to AMC76-9S5
14 December 1976
Mr. R. K. Stevens
Environmental Sciences Research Laboratory
Hall Drop 47
Environmental Protection Agency
Research Triangle Park. North Carolina Z7711
Dear Bob:
We have analyzed the filters which were returned to us from EMI, Project
148, and summarized tn» results in the attached table. The right hand
column gives the observed concentration of ammonia in the ambient air from
each of the two determinations and, below the line, the average of the two
results. The first four columns give the information provided by EMI, Inc.
on the time, location, and circumstances of the collection of each sample.
As described on pages 21 through 23 of the first Monthly Report under
contract 68-02-2463, "Los Angeles Field Modeling and Measurement Study"
(LAFMMS), the AHC still has this method under development. Therefore, im-
provements in the laboratory procedures are still being devised. One evi-
dence of this is that the field blanks in the data reported here had an
average of more than 30 times as much ammonium on them as the field blanks
front the October LAFMMS sampling. The analysis of two laboratory blanks,
which were filters held out of the groups of filters sent to the field,
shows that the high blank readings were caused by the laboratory procedure
for preparing the filters and not by the shipping and field handling pro-
cedures. Me are now developing procedures for preparing filters in larger
quantities with uniformly low blank ammonium contents.
In three cases, the exposed filters contained less ammonium than the blank,
Indicating some variability in the blank values. This variability contri-
butes to the scatter in the data. The general range of the results appears
reasonable.
We would be very Interested to learn how these data compare with those from
the chemi luminescent instrument. Should you desire to publish any of these
data, we very much hope that their source will be clearly acr.nowledgeJ.
Sincerely yours,
Hillard Richards
Project Manager
Enclosure
65
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TABLE 3. AMMONIA FILTER DATA
Slop
51 le *
1
2
3
4
$
6
Laborat
Sample
Date/
Time
11-8-76
1611-1812
11-15-76
1524-1724
11-17-76
1135-1335
11-18-76
1425 EST
1525
11-19-76
1342 EST
1542
11-20-76
1410 EST
1610
cry blanks
Sample
Location
Rt. 81, 4 mi
So. of 1-10
(vicinity of
Lordsburg, NM)
Rt. 157, 2 Km
No. of junet,
LA. * 10 Km
No. of 1-20.
Comment
Holder #3 not
used.
Low stratus.
East of Shreveport,
LA.
Miss. 49, 8 Km
No. Pel aha tehee,
MS. 30 Km East
of Jackson, MS.
9 Km S.Ragland,
AL. » 60 Km
ENE Birmingham.
Refuge Church
Yard.
12 Km NW
Conmerce, GA
(near a creek)
btw. Homer i
Maysville on
Rt. 98, GA.
25 Km WSW
Chapel Hill,
NC. 18 Km ME
Silver City,
NC.
^
Used filter batch.
1608, received
Jackson, MS.
Pine forest area.
Mg NHj/F1lter
1 2 3
blank
1.67 2.13 -
2.07 1.58 1.54
1.23 0.98 1.41
Filter batch 1508, . ,, , qc , ,7
low wind speed. °'41 l'^ l'4/
Clear 8, warm (70°F)
Filter batch 1499
(received
Birmingham, ALO
Filter batch 1499
Near dairy farm/
feedlot, heavy
agricultural
region. Hay odor.
0.45 1.23 1.13
0.53 2.80 1.69
NH3 denuder removes
much of NOx signal.
Also in SOx plume.
.
0.54
1.81
Ammonia
Concentration*
/jq/m3
0.5
-0.6 .
-0.6
-0.6
-0.3
+0.3
0.0
1.8
1.3
1.5
0.9
0.8
0.8
2.6
1.3
1.9
•The ammonia concentration from each filter and the mean is given.
The technique uses oxalic acid coated on a
glass fiber filter. Ambient air is drawn
through a 1 ym fluoropore filter to remove
all particulates, then through the glass
fiber filter coated with oxalic acid. The
ammonia gas passes through the first filter
and is collected on the second. The filters
are subsequently analyzed.
66
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TECHNICAL REPORT DATA
(Please read Inunctions on the reverse before com,
r REPORT NO. ~~~ fa"
EPA-600/2-80-023
4 TITLE AND SUBTITLE
'CROSS-COUNTRY URBAN AND RURAL MEASUREMENTS OF NO
AND so2 x
7. AUTHOR.(S) j j ,
L. Langan, M.A. Peache, and J.J. Garbarz,
R.E. Baumgardner, and R.K. Stevens
9, PERFORMING ORGANIZATION NAME AND ADPRESS
Environmental Measurements. Inc.1
San Francisco, California 94111
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Sciences Research Laboratory -- RTP, NC
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, N.C. 27711
iletingj
3. RECIPIENT'S ACCESSIOf*NO.
5. REPORT DATE j
January 1980 1
6. PERFORMING ORGANIZATION CODE I
8. PERFORMING ORGANIZATION REPORT NO. I
10. PROGRAM ELEMENT NO. I
1AA601 CA-32 (FY-77)
11. CONTRACT/GRANT NO. 1
68-02-2484
13. TYPE OF REPORT AND PERIOD COVERED I
Final
14. SPONSORING AGENCY CODE I
EPA/600/09 I
15. SUPPLEMENTARY NOTES I
16 ABSTRACT
Total sulfur and oxides of nitrogen measurements, gathered along two long-
distance routes across the United States, are presented. Supportive information
describing the instrumentation, procedures, moving laboratory, and regional meteoro-
logical conditions are provided.
Over 300,000 measurements were made. Points consisting of ten-measurement
averages have been plotted; they are also presented in a graphic analysis. This
analysis consists of frequency distribution plots of segments of the trip, for
example, through rural areas and crossing urban developments. These plots provide a
means of classification of the degree of pollution present and monitored with this
moving laboratory technique.
The data were gathered from Denver, Colorado, to Raleigh, North Carolina, in
August 1976, and from Los Angeles, California, to Raleigh, .North Carolina, in November
1976. In November the laboratory stopped at six rural locations to record time-
averaged data, which are also presented.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b,IDENTIFIERS/OPEN ENDED TERMS
c. COSATi Field/Group
*Air pollution
*Sulfur
*Sulfur dioxide
*Nitrogen oxides
*Measurement
*Rural areas
*Urban Areas
United States
13B
07B
05J
8. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (Tl
UNCLASSIFIED
75
20. SECURITY CLASS (TMspage/
UNCLASSIFIED
22. PRICE
Form 2220-1 (9-73)
67
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