SEPA
United States
Environmental Protection
Agency
Environmental Sciences Research EPA-600/3-78-062
Laboratory July 1978
Research Triangle Park NC 2771 1
Research and Development
Measurement of Light
Hydrocarbons and
Oxidant Transport
Houston Area 1976
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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 ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/3-78-062
July 1978
MEASUREMENT OF LIGHT HYDROCARBONS
AND OXIDANT TRANSPORT
Houston Study 1976
by
H. Westberg, K. Allwine, and E. 'Robinson
Air Pollution Section
Chemical Engineering Department
Washington State University
Pullman, Washington 99164
Contract No. 68-02-2298
Project Officer
Joseph J. Bufalini
Gas Kinetics and Photochemistry Branch
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
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DISCLAIMER
This report has been reviewed by the Environmental Sciences Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. 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.
11
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ABSTRACT
An extensive air pollutant monitoring program, including ground level
and aerial sampling, was carried out in the Houston area during the month
of July 1976. Measurements included ozone, oxides of nitrogen, PAN, methane,
carbon monoxide, individual hydrocarbons (Cp-C-m), halocarbons, condensation
nuclei, and visual distance plus numerous meteorological parameters. Specific
areas of interest included (1) oxidant formation and transport within the
Houston urban plume, (2) relationships between ozone layers aloft and the
vertical temperature profile, (3) composition and effects of refinery and
petrochemical emissions on the local Houston air mass, and (4) identification
and quantisation of individual C2-C,Q hydrocarbons in the Houston atmosphere.
Results of this field program showed that the city of Houston serves as a
strong pollutant source. Ozone concentrations were generally high in down-
wind areas. During the study period, there were no "blanket" areas of ozone
in southern Texas. Therefore, high oxidant levels observed in Houston are
a direct result of the precursors emitted in the Houston area.
m
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CONTENTS
ABSTRACT iii
FIGURES vi
TABLES viii
ACKNOWLEDGEMENTS x
1. Introduction 1
2. Conclusions 3
3. Experimental Procedure 5
Site description 5
Field laboratory . . , 5
Ground instrumentation 7
Meteorological measurements 10
Aircraft description 10
Aircraft measurements 11
Data handling procedures 15
Calibration procedures 16
4. Results and Discussion 19
Meteorology 19
Hydrocarbons 20
Oxidants 41
Secondary pollutant production and transport 60
Oxides of nitrogen 86
Halocarbons 89
Visibility and particles 90
REFERENCES 98
APPENDICES
A. Pollutant and meteorological data 100
B. Aircraft data 126
C. Individual hydrocarbon data 233
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FIGURES
Number Page
1 Map of Houston area 6
2 Diagrams of Cessna aircraft employed in Houston field study. . . 12
3 Total Ion Chromatogram for sample collected in Houston 23
4 FID chromatogram for sample collected between, 6 and 9 am on
July 12 at WSU trailer site (a: Co-Cc analysis; b: Cc-Cm
analysis) . .. 26,27
5 Summary of 6-9 am hydrocarbon data obtained at the three
Houston area ground sampling .sites 34
6 Peak hourly average ozone readings at two Houston area ground
sites 48
7 Diurnal Ozone pattern recorded between July 7 and 12, 1976 ... 50
8 Afternoon flight path on July 5 with ozone concentrations
(ppb) marked along the route (see Appendix B for time,
altitude and other details) 51
9 Afternoon flight path on July 10 with ozone concentrations
(ppb) marked along the route (see Appendix B for time,
altitude and other details) 52
10 Morning (a) and afternoon (b) flight paths on July 8 with
ozone concentrations (ppb) marked along the route
(see Appendix B for time, altitude and other details) 54
11 Morning (a) and afternoon (b) vertical soundings conducted
on July 8, 1976 (see Appendix B for details) 55
12 Relationship between peak hourly ozone and PAN
concentrations in Houston during July, 1976 59
13 Diurnal ozone and PAN patterns in Houston during the period
of July 7-12, 1976 61
14 Surface weather map for the morning of July 12, 1976
(7 am EST) 62
15 Morning flight path on July 12 with ozone concentrations
(ppb) marked along the route (see text and Appendix B for
time, altitude and other details) 64
vi
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Number Page
16 Ozone and temperature vertical profiles at about 9 am
on July 12, 1976 66
17 Nitric oxide and nitrogen dioxide vertical profiles at
about 9 am on July 12, 1976 67
18 Ozone and temperature vertical profiles at about 11 am
on July 12, 1976 68
19 Ozone and temperature vertical profiles at about 3:15 pm
on July 12, 1976 69
20 Ozone and temperature vertical profiles at about 5:15 pm
on July 12, 1976 70
21 Pollutant changes at the WSU trailer site on July 12, 1976. . . 74
22 Afternoon flight path on July 12 with ozone concentrations
(ppb) marked along the route (see text and Appendix B for
time, altitude and other details) 75
23 High ozone region (shaded area) to the west of Houston on the
afternoon of July 8, 1976 (see Appendix B for flight
details) 78
24 Pollutant changes at the WSU trailer site on July 8, 1976 ... 80
25 Ground level 6-9 am hydrocarbon and NOX concentrations
recorded at the WSU trailer site 87
26 Relationship between ozone concentration and bscat values
in plume approximately 90 miles downwind of Houston plume
(Fit #10; July 12, 1976) 93
27 Relationship between ozone concentration and bscat values
in plume approximately 45 miles downwind of Houston
(Fit #10; July 12, 1976) 94
28 Relationship observed between ozone concentration and
t>scat values during vertical sounding in Houston
plume (Fit #10; July 12, 1976) 95
29 Relationship between ozone concentration and b^ra1. values
directly over Houston (Fit #7; July 8, 1976). . 96
30 Sulfate data obtained during the afternoon of July 22, 1976
(Fit #26 - see Appendix B for details) 97
vn
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TABLES
Number Page
1 Meteorlogical Summary for the July 1-25 Period 21
2 Hydrocarbon Levels in 6-9 am WSU Trailer Sample on
July 12, 1976 25
*3
3 Individual Hydrocarbon Concentrations (iug/nr) in Samples
Collected Between 6 and 9 am at the WSU Trailer Site . . . . 28
4 Individual Hydrocarbon Concentrations (ug/m3) in Samples
Collected between 6 and 9 am at the South Site 30
5 Individual Hydrocarbon Concentrations (yg/m3) in Samples
Collected Between 6 and 9 am at the North Site 32
6 Hydrocarbon Compositional Comparison at Two Sites Between
6 and 9 am on July 16, 17, 19 and 20, 1976 36
7 Individual Hydrocarbon Concentrations (pg/m ) in Samples
Collected During the Afternoon Hours at the WSU Trailer
Site 37
8 Average Vehicular Component Based on C2~C5 Hydrocarbons at
at Two Houston Locations 38
9 Average Vehicular Contribution at Three Houston Area
Sampling Sites 39
10 Comparison of Houston Area Hydrocarbon Concentrations 40
11 Individual Hydrocarbon Concentrations (ng/m3) in Samples
Considered to be Representative of Background Air 42
12 Individual Hydrocarbon Concentrations (yg/m3) in Samples
Collected in Air Masses Containing Ozone Levels Greater
than 80 ppb 43
13 Annual Statistics for Ozone in the Houston Area, 1974-1976 . . 45
14 Ozone Hourly Average Concentrations (ppb) at WSU Trailer
Site During the Period July 1-25, 1976 46
15 PAN Hourly Average Concentrations (ppb) at WSU Trailer
Site During the Period July 2-23, 1976 57
16 Winds Measured At the WSU Trailer Site on July 12, 1976. ... 63
vm
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Number Page
17 Surface Ozone Concentrations (ppb) on July 12 71
18 Surface Measurements at WSU Trailer Site on July 12, 1976. . 72
19 Surface Winds Recorded at Houston Area Airports on
July 8, 1976 77
20 Hydrocarbon, Halocarbon and CO Levels in Sample A-l
Collected E of Baytown (30001) at 9:15 am on
July 8, 1976 81
21 Hydrocarbon, Halocarbon and CO Levels in Sample A-2
Collected W of Houston (10001) at 10:10 am on
July 8, 1976 82
22 Hydrocarbon, Halocarbon and CO Levels in Sample A-3
Collected N of Houston (12501) at 4:00 pm on
July 8, 1976 83
23 Hydrocarbon Levels in 6-9 am WSU Trailer Site Sample
on July 8, 1976 84
24 Hydrocarbon - Acetylene Ratios in Morning and Afternoon
Air Masses on July 8, 1976 85
25 Hydrocarbon/N0x Ratios in "High Oxidant" Areas Around
Houston 88
26 Hydrocarbon/N0x Ratios in Various Types of Air Masses. ... 89
27 Halocarbon Concentrations in the Houston Area 91
IX
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ACKNOWLEDGEMENTS
We wish to thank the Environmental Protection Agency, Environmental
Sciences Research Laboratory, Research Triangle Park, NC, for financial sup-
port of this work. The guidance and technical advice provided by Dr. J.
J. Bufalini and W. E. Lonneman was much appreciated.
The assistance provided by the City of Houston and Texas Air Control
Board is greatfully acknowledged.
In addition to the authors, significant contributions to this research
program were made by E. Allwine, D. Skaggs, T. Twilligear and M. Wiggins.
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SECTION 1
INTRODUCTION
Air Pollution problems in the Houston area have received considerable
attention in recent years. Houston is one of the many large U.S. cities
where summertime oxidant levels commonly exceed the National Ambient Air
Quality Standard (NAAQS). Although the sequence of chemical transformations
which gives rise to photochemical oxidants is very complex and not completely
understood, the general mechanism for the formation of ozone and associated
secondary products has been established. Basically, oxides of nitrogen
(NOX) and reactive hydrocarbons .participate in a series of reactions which
are initiated and sustained by natural sunlight. While several chemical
species are produced by this process, ozone is the product most commonly
measured and has been used almost exclusively as an indicator of the degree
of photochemical oxidant pollution.
A hydrocarbon control strategy has been adopted by the United States
Environmental Protection Agency as the optimum means for reducing oxidants.
Appendix J to Title 40, Part 51 of the Code of Federal Regulations (1) has
been used to estimate the degree of reduction in hydrocarbon emissions need-
ed to achieve the primary NAAQS for photochemical oxidants. Appendix J was
derived from envelope curves enclosing points depicting 6-9 am ambient non-
methane hydrocarbon concentrations and corresponding daily maximum ambient
oxidant concentrations measured in several cities in the United States.
The applicability of this type of control strategy in the Houston area
has been questioned since air quality studies seem to indicate that little
correlation exists between ground level 6-9 am hydrocarbon levels and oxi-
dant concentrations recorded later in the day. It is estimated that hydro-
carbon emissions were reduced by about 40% during the 1974 to 1975 period in
Houston (2). However, a similar reduction in oxidant levels has not been
recorded.
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A better understanding of local pollutant dispersion and transport pro-
cesses is especially needed in the Houston area. Compared to other large
metropolitan regions, the Houston vicinity is unique because of its unusually
large industrial complex. Point sources contribute approximately 60% of the
hydrocarbon and NOX emissions, while in other cities the industrial contri-
bution is usually much less than 50%. Three dimensional information concern-
ing pollutant behavior is very important because of the complex nature of
emission patterns from the various sources (e.g. surface emissions, low
stacks, tall stacks, etc.). Stack effluents many times have sufficient plume
rise to become imbedded in stable inversion layers. Processes that control
ozone formation and persistence in these elevated layers often differ from
those near the surface.
Washington State University conducted an air quality study in Houston
during July, 1976. Through the use of both an instrumented aircraft and a
ground laboratory we were able to obtain considerable information concerning
the formation and transport of oxidants. Results from this field program
are described in this report.
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SECTION 2
CONCLUSIONS
Hydrocarbon concentrations (6-9 am) at three ground level sites in the
Houston area generally fell in the range of 200-1000 yg/m . However, there
were occasions when the hydrocarbon total exceeded 2000 yg/m3. The extreme
O
hydrocarbon concentrations (> 2000 yg/nr) were most often observed at the
site in north Houston. On mornings when hydrocarbon concentrations in the
2000-3000 yg/m range were recorded, it was common to find as much as 90%
of the hydrocarbon burden comprised of aromatic species. Afternoon hydro-
carbon levels at the WSU trailer site in northwest Houston averaged about a
factor of three lower than those measured during the 6-9 am period.
o
Background hydrocarbon concentrations averaged about 40 yg/m . Samples
collected in air masses containing elevated ozone exhibited hydrocarbon con-
o
centrations in the 200 yg/nr range and thus were considerably above the back-
ground level. The hydrocarbon content that could be ascribed to automotive
tailpipe emissions between 6 and 9 am at the three sampling sites varied from
25 to 31%. A similar vehicular content (^25%) was determined from hydro-
carbon samples collected by aircraft in the downwind Houston plume.
Ozone concentrations at the WSU trailer site equalled or exceeded the
80 ppb NAAQS on seven of the 25-day sampling period. It was not uncommon
for aircraft measured ozone concentrations to exceed 80 ppb on days when
ground level concentrations were much below the standard. There is little
doubt that ozone concentrations in the region downwind of Houston generally
exceed those monitored at ground level stations in the Houston urban-
industrial complex. Between July 1 and 24, 1976 there were no "blanket"
ozone episodes in southern Texas. Consequently, we believe that oxidants
measured in the Houston area during the July study period resulted from
precursors emitted in the immediate Houston area. There was no evidence
of surface ozone enhancement due to subsiding air masses from aloft.
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The presence of PAN in the Houston atmosphere was primarily limited to
the daylight hours. Elevated PAN concentrations were observed to persist
into the nighttime hours only on two occasions. The highest hourly average
PAN concentration was 11.5 ppb; however, the average of all measurements be-
tween 10 am and 4 pm was only 1.0 ppb. On a daily basis there existed a good
correlation between PAN and ozone. On days when ozone showed high peak val-
ues, PAN concentrations peaked as well.
The Houston plume was detectable for long distances downwind. Aircraft
data collected on July 12, clearly show a pronounced ozone plume as far as
90 miles downwind of Houston. Ozone levels approaching 190 ppb were recorded
at that distance and they remained elevated over a cross-sectional distance
of about 45 miles. A reduction in visual range always coincided with elevat-
ed ozone in the downwind plume.
Hydrocarbon - NOX ratios during the 6-9 am period generally fell in a
range of 7.5 to 18.5 at the northwest Houston ground sampling site. Similar
Hc/N0v ratios were observed in air masses that contained high oxidant levels.
A
On several occasions the ground level, diurnal, pollutant patterns in Houston
were consistent with a photochemical oxidant producing mechanism.
Ambient fluorocarbon-11 concentrations averaged between 400 and 650 ppt
in northwest Houston. This is high when compared to average background con-
centration in upwind areas of about 140 ppt. This difference was used as an
aid for tracing the Houston plume. Ground level carbon tetrachloride con-
centrations averaged about 300 ppt in Houston and showed little diurnal var-
iation.
Samples collected in the Houston vicinity for sulfate analysis exhibited
o
concentrations ranging from near zero to 10.8 yg/m . In general, highest
sulfate levels were recorded in areas downwind of the ship channel industrial
area.
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SECTION 3
EXPERIMENTAL PROCEDURE
SITE DESCRIPTION
The air monitoring study described in this report was conducted mainly
in the Houston area. However, there were a few long-range aircraft flights
that extended into Arkansas and Louisiana. Ground operations centered around
our instrumented field laboratory, which was located at a City of Houston
monitoring site in the northwest section of the city. The laboratory was
situated in a vacant lot at the intersection of Lane and Malibou Streets.
The surrounding area included a fire station, city park and residential
buildings. Under southeasterly wind conditions, this location was approxi-
mately eight miles downwind of the Houston metropolitan area.
Two satellite sites were established for collecting hydrocarbon samples.
One, which will be referred to as the WSU north site, was at a Texas Air Con-
trol Board station near Houston Intercontinental Airport. The other (WSU
south site) was at another City of Houston monitoring site south of Hobby
Airport. In addition to the WSU collection locations, Texas Air Control
Board personnel recorded individual hydrocarbon levels in Pasadena. The net-
work provided by these sites allowed excellent coverage of air masses moving
across the Houston area on the prevailing southeasterly winds (Figure 1).
The aircraft employed in this study was based at Lakeside Airport, which
is about 15 miles west of Houston on Highway 10.
FIELD LABORATORY
A 23-ft. custom-built travel trailer served as our field headquarters.
This laboratory contains 52 ft. of bench and rack space for accommodation of
the monitoring instruments, meteorological sensors and data acquisition and
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Figure 1. Map of Houston area.
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reduction system. Most of this equipment is permanently mounted in the
trailer for easy transport from site to site. The laboratory can be set up
with most instruments fully operational in one day. Constant temperature
within the trailer is maintained by two large air conditioners mounted on
the roof.
Outside air is brought into the trailer through a 4-in. stainless steel
line. The top of the air inlet stack is about 20 ft. above ground level.
This sample line runs the full interior length of the trailer and serves
as a manifold for supplying outside air to the continuously monitoring in-
struments. An air flow rate through the line of approximately 100 cfm is
maintained by a squirrel-cage fan at the exhaust end.
Equipment is laid out within the trailer such that those instruments
monitoring the reactive gases (ozone and nitric oxide) are closest to the in-
let end of the manifold.
GROUND INSTRUMENTATION
A brief description of the instruments included in the field laboratory
is provided below.
Ozone Monitor - A Meloy Model OA350 Ozone Analyzer was used for ozone meas-
urements. Operation of this instrument is based on the gas-phase chem-
iluminescent reaction between ozone and ethylene, which produces light
energy in the 300 to 600 nm region. The light emitted is detected by
a photomultiplier tube and converted to an electrical signal compatible
with recording devices.
NO, N02 and NOX Monitor - We employed a TECO Model 14D for oxides of nitrogen
measurements. This instrument employs the chemiluminescent reaction be-
tween nitric oxide and ozone as the detection technique. The 14D has
dual chambers; one for NO and another for NOX. It is capable of selec-
tive detection of NO, N02 and NOX. It has a lower sensitivity limit
of approximately 5 ppb for NO, NO and NO .
L. X
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Methane, Carbon Monoxide and Total Hydrocarbon Monitor - A Beckman Model 6800
Air Quality Gas Chromatograph was used for these measurements. This
automated gas Chromatograph employs a flame ionization detector for hy-
drocarbon analysis. Carbon Monoxide is reduced to methane prior to en-
tering the detector. This instrument provides a CH4, CO and THC reading
at 5-minute intervals and is interfaced with our computer system for
data reduction.
Halocarbon Monitor - A Hewlett Packard Model 5700A Gas Chromatograph equip-
co
ped with a constant-current ° Ni electron capture detector was used to
monitor ambient levels of fluorocarbon-11, chloroform, fluorocarbon-113,
methyl chloroform, carbon tetrachloride and trichloroethene. Separation
was achieved on a 10-ft. x 1/8-in. stainless-steel column containing 10%
SF-96 on Chromosorb W. The column was maintained at 55°C. With a car-
rier gas (95% argon - 5% methane) flow of 20 ml/min., three analyses
could be run each hour. This instrument was automated by attaching a
1-ml sample loop, a Carle microvalve (#5518), a Carle valve actuator
(#4201) and a Carle valve minder (#4101). A manual technique was used
for injecting aircraft collected samples.
PAN Monitor - Peroxyacetyl nitrate levels were monitored three times per hour
using an Analog Technology Corporation tritiated-scandium electron cap-
ture detector. PAN was separated from other ambient gases on a 51 x
1/8" 10% Carbowax 600 Gas Chrom Z glass column. Both the column and
electron capture detector were maintained at room temperature.
Individual Light Hydrocarbon Measurements - These measurements were made with
Perkin Elmer Model 900 Gas Chromatographs. The standard dual-flame in-
strument was used with the addition of a sub-ambient accessory. The
normal carrier gas flow system was modified to include a freeze-out trap
for concentrating organics in ambient air. The column used to separate
light hydrocarbons was a packed capillary (201 x 1/16") containing
Durapak n-Octane/Porasil C. When operated with a carrier gas (He) flow
of -\;50 ml/ min. and temperature-programmed from -70 to 80° at 24°/min.,
this column provided excellent resolution of the C2~C5 hydrocarbon frac-
tion. This hydrocarbon analysis method was not automated. Analysis for
hydrocarbons in the C5-C-|0 molecular weight range was performed on a
8
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30 meter SE-30 glass capillary column. The same type of cryogenic con-
centration procedure described for the light hydrocarbons was used. The
resolving power of the glass capillary column was enhanced by employing
a sub-ambient temperature programming method.
Mass Spectrometric Analysis - A Hewlett Packard 5930A Mass Spectrometer coup-
led with a Hewlett Packard 5700 Gas Chromatograph was employed for gc-ms
analysis. The mass spectrometer is a standard quadrupole instrument
which has been modified by the addition of a second 4-in. diffusion
pump. The glass capillary columns we use for hydrocarbon analyses re-
quire a low carrier gas flow rate (< 5 ml/min.). This, coupled with the
extra pumping capacity, permits the total gc column effluent to be pass-
ed directly into the mass spectrometer. Thus, the mass spectrometer
serves exactly the same function as the flame ionization detector and a
chromatogram resulting from the flame detector will be nearly identical
to that recorded by monitoring the total ion current in the mass spec-
trometer. This makes it relatively easy to verify peak assignments.
Samples collected and analyzed in the field using the flame ionization
detector were shipped to our mass spec laboratory where they were ana-
lyzed using the same chromatographic conditions as in the field. Hydro-
carbon identities reported in this study are based on retention time
comparisons with standards plus mass spectral fragmentation patterns.
All the ground instruments, with the exception of the Perkin-Elmer 900
gas chromatograph, obtained air samples on a continuous basis from the trail-
er manifold. Samples for hydrocarbon analysis were taken from the trailer
manifold, Teflon bags or metal canisters. These canisters were constructed
of stainless steel with all the inner surfaces polished using the "Summa"
process. The cans were filled with air using a metal bellows pump and seal-
ed by closing two bellows valves. By pressurizing these containers to 10
psig, about 5 liters of air could be obtained for sampling purposes. These
stainless-steel containers provided the means by which ambient air samples
could be returned to our home laboratory in Pullman, WA, for mass spectromet-
ric analysis.
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METEOROLOGICAL MEASUREMENTS
Instrumentation used to measure the various meteorological parameters
included three separate systems:
1) Climet CI-60 Data System - This instrument package contained sen-
sors for measuring wind speed, wind direction, dew point, tempera-
ture and solar radiation. Output from the various sensors was
channeled into a translator which conditions the signals and pro-
vides an output voltage compatible with the data-logging system.
A measure of air turbulence was calculated from time-averaged stan-
dard deviations in wind direction.
2) Aerovironmental Model 300 Monostatic Radar - This acoustic sounder
measured the turbulent fluctuation of atmospheric temperature on
electrosensitive chart paper. A continuous record of the intensity
of echo return as a function of height and time is obtained. The
instrument has a maximum vertical range of 1000 meters.
3) Warren-Knight Model 84 Double Center Theodolite - Pilot balloons
were used in conjunction with this theodolite for monitoring upper-
level wind speed and direction. The balloons were of the 30g type
and the standard rise rate table was used for computations.
AIRCRAFT DESCRIPTION
A twin engine light aircraft was specially instrumented and used for
this study. The aircraft was a Cessna 336 Skymaster owned by Washington
State University. This aircraft has a high wing and fixed gear configuration
with the engines mounted fore and aft on the fuselage. All probes and sens-
ing devices were mounted on the fuselage or under the wings. (See Figure 2).
Our aircraft was equipped to measure ozone, oxides of nitrogen, conden-
sation nuclei, visual range, temperature, humidity and various navigational
parameters. It was also equipped to collect grab samples for subsequent hy-
drocarbon and halocarbon analysis. Sulfate samples were collected on filters
with a TWOMASS sampler developed by Washington University, St. Louis, MO.
10
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A Topaz solid-state inverter was used to convert the 28-VDC alternator
output to 120-VAC for operating the air pollutant analyzers. This inverter
provided about 1500 watts of usable power, which was more than sufficient
for our needs.
Air to be used for analysis was brought into the aircraft through a 4-
inch sampling probe extending approximately 10 inches outboard of the left
side of the fuselage. The probe was connected to a 4-inch, clear plexiglass
manifold inside the aircraft. This manifold was positioned down the left
side of the cabin, across the aft bulkhead, and vented out the right aft cab-
in window. Air sampling equipment was provided air from the manifold through
1/4-inch Teflon tubing. The large size of the sampling probe and manifold
provided us with ample air flow for all equipment. Emissions from the air-
craft's front engine were exhausted on the right side of the plane. Detailed
checks have shown that engine exhaust and "prop wash" do not adversely effect
ambient monitoring (3).
AIRCRAFT MEASUREMENTS
Ozone Monitor - A Bendix Model 8002 Chemiluminescent Analyzer was used to
measure ozone levels aloft. The response time ( < 10 sec for 90% re-
sponse) of this instrument is sufficiently rapid for meaningful aircraft
measurements. Ozone analyzers of the type used in this study respond to
changes in atmospheric pressure. Ground level pressure changes are mi-
nor and need not be of concern. However, when an instrument is car-
ried aloft, pressure factors must be considered. All of our aircraft-
collected ozone data has been corrected for altitude using equations de-
veloped from pressure chamber studies.
Condensation Nuclei - An Environment One Rich 100 Analyzer was used to mea-
sure very small particulate material in the atmosphere. This unit re-
sponds to particles with diameters of 0.0025 micron and larger and it
covers a concentration range of 300 to 10 particles per cubic centi-
meter. Response time for this instrument is 5 sec., which makes it very
suitable for airborne measurements.
11
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MONITORING
EQUIPMENT
VENT
TEMPERATURE AND
RELATIVE HUMIDITY PROBE
•AIR SPEED PROBES
INLET PROBE
Figure 2. Diagrams of Cessna aircraft employed in Houston field study.
12
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Nitrogen Oxides - The Monitor Labs Model 8440 Nitrogen Oxides Analyzer was
used for the measurement of NO and NOV. This instrument employs the
/\
chemiluminescent reaction of nitric oxide and ozone to measure nitric
oxide concentrations. N02 is determined by first converting the N02 to
NO and subsequently measuring the total nitric oxide (NO + N02) by the
chemiluminescent method. The N02 concentration is then determined by
the difference of (NO + N02) and NO. This instrument has a separate
photomultiplier tube for the NO and NOX channels, which is important for
aircraft work where large distances are covered in a short period of
time.
Hydrocarbon and Halocarbon Analysis - Stainless-steel canisters were used for
collecting samples for hydrocarbon and halocarbon analysis. All analy-
ses were performed at the ground laboratory shortly after completion of
the flight.
Temperature, Relative Humidity and Navigational Parameters - A Metrodata M8
Airborne Meteorological- and Navigational System was used to measure tem-
perature, humidity, airspeed, altitude, bearings from two points (VOR)
and distance from one point (DME). The temperature and humidity data
are derived from sensors mounted under the aircraft wing. The airspeed
and altitude systems use potentiometric transducers, which are connected
to the aircraft pitot-static system. VOR/DME data are acquired from
navigational receivers installed in the aircraft.
Visual Range - A MRI Integrating Nephelometer was used to monitor light scat-
tering and visual range. Air was not dried before entering the analyzer
tube so changes in atmospheric humidity must be taken into account when
examining these data. The quantitative output of this instrument is
given in units of scattering coefficient and meteorological range (vis-
ual distance). Sensitivity for scattering coefficient is 0.1 to 100 x
10~^m~' and for local visual distance is °° to 0.3 miles. We used a
flashlamp rate of 16/sec. and an averaging time (time constant) of 0.1
sec.
Sulfate - Samples for sulfate analysis were collected on paliflex filter
tapes using a TWOMASS sampler developed at Washington University,
13
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St. Louis, MO (4). The analysis was accomplished using a flash vapor-
izer coupled to a flame photometric sulfur detector (5). The analytical
procedure followed is summarized below.
1. 0.25 ml aliquots of distilled water were pipetted into two ml press
cap plastic vials. The distilled water contained 0.3 g sulfur
per ml and the vials caused no change in this concentration which
indicates they are essentially inert to contained sulfur concentra-
tions.
2. 0.6 cm diameter circles were punched from the paliflex filter strips
using an ordinary hand punch. These circles represented either
the entire sulfate sample spots or filter strip blanks which were
punched from the clean areas between the sample spots. These cir-
cles were placed in the vials, checked for complete wetting of
the paper, and then the vials capped. Extraction of sulfate was
accomplished by allowing the vials to stand with occasional
shaking for 3 hours or longer.
3. Standard sulfate solutions were prepared from MgSO^ reagent. The
stock solution contained 500 vg sulfur per ml. and dilutions of
the stock solution were made to provide 20, 4 and 0.8 yg sulfur
per ml. standard solutions.
4. The flash vaporizer, Meloy SA-160 sulfur analyzer and HP3380A inte-
grator instrument system was standardized by applying 0.5 and 1.0
yl aliquots of the standards onto the stainless strip of the vap-
orizer, allowing the distilled water to evaporate, and flashing
with a pulse from 0.3 farad charged to 15.3 volts.
5. Similarly, 1.0 and/or 5.0 yl aliquots of the sulfate filter ex-
tracts were applied to the vaporizer strip, dried, and flashed.
A second flash was always performed following samples and standards
to ensure complete vaporization on the first flash (typically 90-
98%) and to keep the vaporizer strip clean.
14
-------
6. The "quantity of sulfur vs. peak area" data for standards were
plotted on log-log graph paper and a "best-fit" straight line was
drawn through the points for quantities of sulfur greater than two
nanograms. A non-linear relationship generally existed for less
than two nanograms sulfur.
7. The quantities of sulfur in the sample aliquots were read from the
calibration curve and multiplied by 50 or 250 for five or one ml
sample aliquots respectively to give the total nanograms of sulfur
in the samples. These values were then multiplied by three and di-
vided by 1000 to convert the results to micrograms of sulfate.
The actual air concentrations measured were calculated by subtract-
ing the blank value from each sample and dividing by the sampled
air volume in cubic meters to obtain results in micrograms of sul-
fate per cubic meter.
DATA HANDLING PROCEDURES
All data collected in the aircraft and from most continuous monitoring
ground instruments was recorded on 4-track magnetic tape using Metrodata Mo-
del DL620A data logging systems. Output from the gas chromatographs was
channeled directly into a Hewlett Packard 3352 data system. This system pro-
vided individual hydrocarbon identification and quantitation information im-
mediately following each gc run.
We have developed the software necessary to allow our HP2100 minicom-
puter (basic component of HP3352 data system) to process 4-track magnetic
tape data in the field (6). This permits field personnel to look at nearly a
complete data set each day, which is very advantageous from the standpoint of
recognizing instrumental manfunctions as well as short term pollutant rela-
tionships that warrant further study. The hardware involved in this opera-
tion includes a Metrodata Model TR625 tape reader, the Hewlett Packard 2100
computer, a Printec 100 high speed printer and a teletype for communicating
with the system. The data processing operation involves converting raw
voltages to scientific units, plus time averaging and tabulating for easy
review.
15
-------
The frequency of data recording in the field was dependent on the sampling
technique. In the aircraft, where considerable distance was covered in a
short time, instrument and sensor responses were recorded five times every
two seconds. Under normal flying conditions, this corresponds to a data
point approximately every 70 ft. On the ground, where pollutant and meteoro-
logical parameters were monitored at a fixed point, data recording times
varied from one minute for ozone, oxides of nitrogen and the meteorological
sensors to twenty minutes for halocarbons and PAN.
Field data collected on 4-track magnetic tape was transferred to 9-track
tape in our home laboratory. This provides a permanent storage mechanism
plus a data format that is compatible with Washington State University's
IBM-360 computer.
CALIBRATION PROCEDURES
A comprehensive data quality control program is an essential part of all
field studies. Instrument calibration and zero checks must be documented so
that any questions concerning data quality can be resolved. We kept daily
records of these events and have used this information in arriving at the
numbers provided in this report. Any data that appeared questionable was not
included. A summary of precautions taken to insure data integrity for the
various measurements is provided below.
Ozone - The ground based and airborne ozone analyzers were calibrated at
least once a week using a McMillan Model 1000 ozone generator. This
ozone source was specially designed to provide outputs in the 20 to
200 ppb range. Absolute calibration of the McMillan generator was based
on the standard KI method plus spectral measurements using a Dasibi Mod-
el 1003-AH ultraviolet ozone photometer.
A zero check was made once a day on the ground ozone instrument. How-
ever, in the aircraft numerous checks were made during each flight. The
airborne ozone data has been adjusted for zero drift whenever necessary.
EPA Region-VI personnel made two calibration comparisons with our ground
ozone instruments during the study period. The ozone concentrations in-
cluded in this report are based on the EPA calibration. Therefore, our
16
-------
ozone data should be fully consistent with oxidant measurements reported
by EPA Region-VI and the local control agencies (Texas Air Control Board
and City of Houston).
Oxides of Nitrogen - Our span gas for the TECO and Monitor Labs instruments
was a tank containing 1.0 ppm NO. The tank concentration was verified
by gas phase titration in our home laboratory. Comprehensive calibra-
tion checks were performed in our WSU laboratory before and after the
field study. Various nitric oxide concentrations in the .04 to 1.0 ppm
range were generated using a Meloy Model CN020 Nitrogen Oxides/Ozone
Calibrator. Both instruments responded in a linear fashion throughout
this concentration range. While in the field, a span check was made at
least once a week and zero checks were made daily.
Total Hydrocarbon, Methane and Carbon Monoxide - The Beckman 6800 AQGC was
calibrated using a tank containing 7.2 ppm C (THC), 2.19 ppm methane and
3.00 ppm carbon monoxide. The hydrocarbon mixture in the calibration
tank was standardized relative to hexane. Calibration checks were made
about every other day.
Fluorocarbon-11 and Carbon Tetrachloride - The electron capture gas chromato-
graph was calibrated from standards made up in ambient air. At the pre-
sent time, we feel this is the best method since the moisture and oxygen
content of the standard will be nearly the same as in samples collected
during routine analysis periods. The calibration was based on a Freon-11
standard that had been certified by mass spectrometry. Samples from this
standard were run daily throughout the study period in order to monitor
stability of the electron capture detector. Other halocarbon calibra-
tions were carried out in a similar manner.
Individual Light Hydrocarbons - Identification of the light hydrocarbons (C2-
Cc,} was based on retention time comparisons. Resolution of light hydro-
carbons on the Durapak n-Octane/Porasil C column was excellent and re-
tention times were extremely reproducible. Thus, little difficulty ex-
isted in making unambiguous peak identifications. Calibration of the
Perkin Elmer gas chromatographs was achieved by measuring instrument re-
sponse of known concentrations of hexane in air. Three different hexane
sources were used to prepare standards in the ppb range. In the field,
17
-------
an internal standard (neo-Hexane, .209 ppm) was included in each air
analysis in order to insure calibration reliability. Higher hydrocarbon
(Cg-Cig) identities were determined through retention time comparisons
with known standards plus mass spectral analysis. Instrument calibra-
tion was performed in the same manner as mentioned above for the light
hydrocarbons.
Meteorological Parameters - Calibration curves supplied by the manufacturer
were used to convert the Climet CI-60 sensor output signals to the ap-
propriate temperature, wind speed, etc., readings. While in the field,
sensor signals were checked routinely to insure correct operation.
Particulate Measurements - The condensation nuclei counter and nephelometer
were calibrated in our home laboratory prior to going into the field.
No calibration checks were made in the field since their primary func-
tion was not to provide absolute numbers, but rather to determine gross
horizontal and vertical inhomogenities within an air mass. We were
concerned only with relative differences.
PAN - PAN calibrations were performed by W. E. Lonneman (EPA - Research
Triangle Park). Mr. Lonneman provided and installed the PAN instrument
used in this study. The calibration was based on standards prepared in
ESRL laboratory at Research Triangle Park, NC.
18
-------
SECTION 4
RESULTS AND DISCUSSION
A data presentation as well as interpretive discussion follows in this
section. The format consists of a number of subsections dealing with specif-
ic topics of concern in the Houston area. Subjects that will be discussed
include the following:
Meteorology Oxides of Nitrogen
Hydrocarbons Halocarbons
Oxidants Visibility and Particles
Secondary Pollutant Production
and Transport
METEOROLOGY
Rain and cloudiness prevailed in southern Texas during most of July,
1976. Precipitation in Houston was approximately 50% above normal, while
some stations in south-central Texas were as much as 500% above normal.
Brownsville, Corpus Christi and Del Rio, Texas, recorded their wettest July
in history (7). Cooler than normal temperatures accompanied the excessive
cloudiness. In the Houston area, temperatures were approximately 3° below
normal for July, while farther to the west in the Great Bend country they
were about 8° below normal. This unusually wet and cool weather in Texas
was associated with weak, slow westward-moving, 700 mb disturbances similar
to the monsoon lows of southern Asia.
A brief summary of weather conditions on each day of the study is pro-
vided in Table 1. The majority of this information was abstracted from
National Weather Service data collected at Houston's Hobby Airport.
19
-------
HYDROCARBONS
Hydrocarbon measurements included a continuous record of methane and to-
tal hydrocarbon levels at the WSU trailer site, plus numerous individual hy-
drocarbon analyses on samples collected at various locations throughout the
Houston area. Samples for detailed hydrocarbon analysis were routinely col-
lected at several sites:
1) WSU Trailer Site - 6 to 9 am integrated sample and afternoon
grab sample;
2) North Site - 6 to 9 am integrated sample;
3} South Site - 6 to 9 am integrated sample.
These sampling locations are shown in Figure 1. Grab samples for hydro-
carbon analysis were collected at various times during the study period in
downtown Houston, Washburn Tunnel and in the industrial area along the
Houston ship channel. A large number of samples were also collected by air-
craft.
As indicated in the experimental section, individual hydrocarbon identi-
ties were established through a comparison of retention times and mass spec-
trometric fragmentation patterns. Using these procedures, we have been able
to identify about 75 hydrocarbon species. This generally corresponds to
about 90% of the individual hydrocarbon total. Figure 3 shows a total ion
chromatogram obtained from an ambient sample collected in downtown Houston.
The numbered peaks were identified as indicated above.
Once a hydrocarbon pattern has been established using the gc-ms tech-
nique, it can easily be extrapolated to the large number of field samples
since we employ exactly the same column and gas chromatographic conditions
in both the field analysis (flame ionization detector) and laboratory analy-
sis (mass spec detector). For example, Figure 4b shows a chromatogram typ-
ical of those obtained in the field. The pattern provided by peaks 55, 56
and 58 (ethylbenzene, p & m-xylene and o-xylene) is readily distinguishable
in both chromatograms. There are other commonly encountered patterns in the
lower molecular weight ranges as well. Using these marker peaks, the low
concentration peaks recorded in a field chromatogram can usually be identi-
fied.
20
-------
TABLE 1. METEOROLOGICAL SUMMARY FOR THE JULY 1-25 PERIOD.
Date
July
1
2
3
4
5
6
7
8
9
10
11
Cloud
AM
.5
.5
.5
1.0
1.0
.8
1.0
1.0
1.0
1.0
1.0
Cover (a)
PM
.5
.4
1.0
1.0
.8
1.0
1.0
1.0
1.0
1.0
.8
Surface
AM
SW/8
S/12
S/10
S/4
N/10
NE/8
NE/4
E/3
NE/5
NE/8
SE/10
Wind
PM
S/7
S/10
S/15
S/7
NE/7
SE/10
S/10
S/3
E/5
SE/8
SE/8
5000' Wind(b) Precipitation
AM PM AM PM
0 0
0 0
SW/20 .05 2.0
SW/4 0 0
SW/9 T 0
NE/8 E/14 0 0
0 0
SE/6
0 1.38
— .50 .45
— - SE/21 1.91 0
T 0
TOTAL
0
0
2.05
0
T
0
0
1.38
.95
1.91
T
Temperature
10AM
85
89
85
85
75
80
83
84
75
74
85
3PM
91
85
77
88
76
81
85
86
76
88
85
Remarks
PM thunderstorms
East-Southeast
light rain in AM
thunderstorms in
PM
ground fog in AM
high overcast all
day
morning thunder-
storms
visibility 1-5 mi .
in haze & smoke
during AM
high overcast all
day
some breaks in
overcast in AM
thunderstorms in
PM
low clouds-light
rain-fog & haze
all day
low vi sibil ity in
haze & smoke all
day
(continued)
-------
TABLE 1. (continued).
ro->
ro
Date
July
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Cloud Cover(a)
AM PM
1.0
.7
1.0
1.0
1.0
1.0
.9
.5
.5
.8
.5
.8
.3
.2
.9
.8
1.0
1.0
1.0
.8
.8
.6
.3
.8
.6
1.0
1.0
.5
Surface
AM
NE/8
S/7
NE/6
S/8
SW/7
SW/8
S/5
SW/10
S/10
E/6
E/5
calm
NE/10
SW/10
Wind
PM
SSE/9
S/10
S/10
S/5
SW/5
SW/12
S/10
SW/10
SW/8
SW/10
SE/10
SE/10
E/5
SE/8
5000'
AM
E/17
SW/10
S/17
S/24
S/14
SW/12
—
S/15
SE/10
—
___
SE/7
E/9
E/7
Wind(b)
PM
E/14
SE/7
S/20
S/14
SW/16
___
—
SE/10
SE/14
S/5
___
—
—
SE/4
Precipitation
AM PM TOTAL
0
0
1.45
0
0
0
0
0
0
.13
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
T
2.48
0
0
0
1.45
0
0
0
0
0
0
.13
0
T
2.48
0
Temperature
1 0AM 3PM
85
85
76
84
86
84
85
88
86
82
87
86
87
85
84
88
83
87
83
90
91
92
91
88
92
83
92
92
Remarks
early morning
thunderstorms-
low visibility
with haze & smoke
in PM
isolated thunder-
storms in area
all day
evening thunder-
storms (5 PM)
early AM thunder-
storms
tornados and
thunderstorms in
PM
fog, haze and
smoke in AM
heavy rain in PM
reduced visibility
in haze & smoke
all day
(a) 0-1.0 scale
(b) Pibal measurement at WSU trailer
-------
INCREASING TIME AND TEMPERATURE
1. 2 - Methyl 1 butene
2. 2 - Methyl butane
3. Halocarbon
4. 1 - Pentene
5. 3 - Methyl - 1 - butene
6. n - Pentane
7. Isoprene
8. Carbon disulfide
9. t - 2 - Pentene
10. c - 2 - Pentene
11. 2 - Methyl - 2 butene
12. 2,2 - Dimethylbutane
13. Cyclopentene
14. fCyclopentane
V.4 - Methyl - 1 - pentene
15. 2.3 - Dimethyl butane
16. (2 Methylpentane
\t-4- Methyl - 2 pentene
17. c - 4 - Methyl - 2 - pentene
18. 3 - Methylpentanp
19. fZ Methyl .-. 1 pentene
Vl - Hexene
20. n - Hexane
21. t 2 - Hexene
22. fZ - Methyl 2
U - 3 - Methyl
23. c - 2 - Hexene
24. Methylcyclopentane
25. c 3 - Methyl 2 pentene
26. 2,2,3 - Trimethylbutane
27. 1,1,1 Trichloroethane
28. 2,4 - Dimethylpentane
29. Benzene
30. 1 - Methylcyclopentene
31. Cyclohexane
32. 2 - Methylhexane
33. 2,3 - Dimethylpentane
34. 3 - Methylhexane
35. 01 methyl cyclopentane
36. Dimethylcyclopentane
pentene
2 pentene
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
Dimethylcyclopentane
2,2,3 - Trimethylpentane
n - Heptane
Methylcyclohexane
Trlmethylcyclopentane
Ethylcyclopentane
2,5 - Dimethylhexane
2,4 - Dimethylhexane
2,3,4 Trimethylpentane
Toluene
2,3 - Dimethylhexane
2 - Methyl heptane
(3 Ethylhexane
\3 - Methylheptane
C - 9 Alkane
Dimethylcyclohexane
n - Octane
Ethylcyclohexane
C - 9 Alkane
Ethylbenzene
/p • Xylene
\m - Xylene
Styrene
o - Xylene
n Nonane
i Propylbenzene
n - Propylbenzene
3 - Ethyl toluene
2 - Ethyl toluene
1 Ethyl toluene
1,3,5 • Trimethylbenzene
1,2,4 Trimethylbenzene
1,2,3 - Trimethylbenzene
Methylstyrene
1,3 - Diethylbenzene
1,4 - Diethylbenzene
C - 10 Subst'd. benzene
C - 10 Subst'd. benzene
Figure 3. Total gas chromatogram for sample collected in Houston,
23
-------
The results of this procedure are exemplified in Table 2, which lists
individual species and concentrations for a sample collected at the WSU
trailer site on the morning of July 12 (Figure 4 a-b). As shown, the total
of all identified hydrocarbons was 977 yg/m3. The small unidentified peaks
in Figure 4b amounted to an additional 116 yg/m3. Therefore, a total of
1093 vg/m3 individual hydrocarbon species were present in this sample,
90% of which were identified.
This summation of individual hydrocarbons on the morning of July 12
agrees favorably with the total non-methane hydrocarbon value obtained at the
same time with the Beckmann Air Quality Gas Chromatograph. The latter meas-
urement was 1.4 ppmC compared to the 1.6 ppmC (1093 yg/m3) summation of indi-
vidual hydrocarbons.
In presenting detailed hydrocarbon analyses at the various sampling lo-
cations, we have selected the individual species most often present and have
displayed these in Tables 3, 4, and 5. It should be recognized that the to-
tal concentrations shown in these tables don't include all the individual
species identified. Therefore, the total concentration given is somewhat
lower than the actual ambient level. The hydrocarbons included in these
three tables were considered to be representative of the three hydrocarbon
classes (paraffins, olefins and aromatics), and the tables are of convenient
size for discussion purposes. The total NMHC concentration obtained by sum-
ming the individual species for samples listed in Tables 3, 4, and 5 is pro-
vided in Appendix C.
Several features concerning hydrocarbon behavior in the Houston area can
be derived from Tables 3, 4, and 5. The 6 to 9 .am hydrocarbon total for sev-
eral days in July at the three sampling sites is shown in Figure 5. Concen-
o
trations at the site in south Houston varied between 200 and 900 yg/m , while
at the WSU trailer site and in north Houston the ambient concentration ex-
ceeded 2000 yg/m3 on several mornings. These high levels were most frequently
observed at the north site; and consequently, the highest overall average was
recorded at that site. Examination of Table 5 shows that on the dates with
high hydrocarbon concentration at the north site, aromatic species make-up a
majority of the total. For example, Table 6 compares the compositional
breakdown on July 16, 17, 19, and 20. July 17 and 19 were mornings when the
24
-------
TABLE 2. HYDROCARBON LEVELS IN 6-9 AM WSU TRAILER SAMPLE ON JULY 12, 1976,
Hydrocarbon
yg/m;
Hydrocarbon
22.0
20.0
26.0
36.0
21.0
31.5
80.0
6.0
8.0
11.0
114
55.5
4.5
1.0
3.0
5.5
9.0
10.5
39.0
4.5
21.5
4.5
26.0
2.5
4.0
1.
21,
7,
24,
9.0
23.0
23.5
.0
,0
.0
.5
Ethane
Ethylene
Acetylene
Propane
Propene
i-Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
t-2-Pentene
c-2-Pentene
Cyclopentene
Cyclopentane
2,3-Dimethylbutane
2-Methylpentane
c-4-Methyl-2-Pentene
3-Methylpentane
1-Hexene
n-Hexane
t-2-Hexene
2-Methyl-2-Pentene
c-2-Hexene
Methylcyclopentane
2,4-Dimethylpentane
Benzene
Cyclohexane
2,3-Dimethylpentane
3-Methylhexane
8.0 Dimethylcyclopentanes
15.5 2,2,3-Trimethylpentane
12.0 n-Heptane
10.0 Methylcyclohexane
2.0 Ethylcyclopentane
6.0 2,4-Dimethylhexane
1.0 2,3,4-Trimethylpentane
57.0 Toluene
4.0 2,3-Dimethylhexane
10.5 2-Methylheptane
8.0 3-Ethylhexane
7.0 Cg-Alkane
6.5 n-Octane
3.0 Ethylcyclohexane
5.9 C9-Alkane
17.0 Ethyl benzene
40.5 p & m-Xylene
8.0 Styrene
19.5 0-Xylene
6.0 n-Nonane
3.0 i-Propylbenzene
6.5 n-Propylbenzene
16.0 p-Ethyltoluene
m-Ethyltoluene
8.0 o-Ethyltoluene
8.0 1 ,3,5-Trimethylbenzene
18.0 1 ,2,4-Trimethylbenzene
5.0 1 ,2,3-Trimethylbenzene
3.0 Methylstyrene
3.5 1,3-Diethylbenzene
4.0 1,4-Diethylbenzene
2.5 C10-Aromatic
2.5 C10-Aromatic
Total Identified 977
Unknown 116
TOTAL 1093
-- Less than .5ug/m3
25
-------
11
1. Ethane
2. Ethylene
3. Acetylene
4. Propane
5. Propene
6. i-Butane
7. n-Butane
8. 1-Butene
9. i-Butene
10. t-2-Butene
11. i-Pentane
12. n-Pentane
13. Cyclopentane
14. 1-Pentene
INCREASING TIME 8 TEMPERATURE
Figure 4a. FID chromatogram for sample collected between 6 and 9 am on July
12 at WSU trailer sit$(C2-C5 analysis).
26
-------
ro
r
INCREASING TIME a TEMPERATURE
Figure 4b. FID chromatogram for sample collected between 6 and 9 am on July 12 at WSU trailer
site (C5-C-|Q analysis).
-------
TABLE 3. INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/m3) IN SAMPLES COLLECTED BETWEEN 6 AND 9 AM AT
THE WSU TRAILER SITE.
ro
00
Ethane
Ethyl ene
Acetyl ene
Propane
Propene
i -Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2 ,4-Dimethyl pentane
Benzene
Toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 ,3 ,5-Trimethyl benzene
1 , 2, 4-Trimethyl benzene
1 , 2, 3-Trimethyl benzene
TOTAL yg/m3
7/5
14.0
5.5
3.0
31.0
45
13.0
24.5
1.0
2.0
2.0
--
28.5
14.5
1.0
7.5
6.0
6.5
1.5
8.0
13.0
2.5
6.5
3.5
1.5
3.0
1.5
206
7/7
8.0
6.0
12.0
22.0
10.0
12.0
27.0
4.5
4.0
4.5
--
35.0
19.0
2.5
12.0
10.5
8.0
2.0
10.0
20.5
5.0
11.0
6.5
3.0
8.0
2.0
265
7/8
19.0
20.0
20.0
46.0
26.0
51.0
69.0
6.0
8.0
10.0
--
90.0
45.5
6.0
24.5
21.5
16.0
4.0
18.0
35.0
7.5
20.0
11.5
5.0
9.5
3.5
593
7/9
18.0
11.0
16.0
52.0
15.0
28.0
48.0
3.0
4.5
5.5
--
55.5
30.0
2.5
14.0
9.5
11.0
2.5
13.0
28.0
7.0
14.5
6.0
3.0
6.5
2.5
407
7/10
14.0
12.0
7.0
31.0
9.0
16.0
30.5
2.5
3.0
4.5
--
29.0
15.0
1.5
9.5
7.5
9.5
5.0
10.0
23.0
6.0
14.0
5.0
3.5
4.5
2.5
275
7/12
22.0
20.0
26.0
36.0
21.0
31.5
80.0
6.0
8.0
11.0
--
114
55.5
4.5
39.0
21.5
26.0
7.0
24.5
57.0
17.0
40.5
19.5
8.0
18.0
5.0
719
7/13
25.0
17.0
23.0
39.0
16.0
27.5
63.5
4.5
6.5
8.0
--
72.0
36.0
2.5
24.5
15.0
21.0
5.0
17.5
39.0
10.0
27.0
12.0
6.0
12.0
3.5
533
7/14
3.0
5.0
6.0
6.0
5.0
3.0
9.5
1.0
3.0
2.5
--
15.5
8.0
1.0
6.5
4.0
4.0
1.0
6.5
12.5
3.5
8.5
4.5
2.5
5.5
2.0
130
7/15
13.5
10.0
13.5
28.5
12.0
205
846
10.0
8.5
24.0
--
599
296
19.0
125
73.5
48.0
13.5
42.5
61.0
13.0
31.5
15.0
5.0
11.0
3.0
2527
7/16
6.5
6.0
28.0
17.0
15.0
15.5
48.5
3.0
5.0
7.0
--
61.5
32.0
2.0
22.5
15.0
20.0
5.0
18.5
41.5
14.0
33.5
15.5
6.0
18.0
4.0
461
7/17
37.0
12.5
16.0
62.5
16.0
38.0
68.0
4.0
5.0
7.5
75.5
38.0
3.0
21.5
13.0
15.0
4.0
16.0
32.5
11.0
26.0
10.0
4.0
9.0
3.5
549
(continued)
-------
TABLE 3 (continued).
PO
MD
Ethane
Ethyl ene
Acetylene
Propane
Propene
i- Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2 ,4-Dimethyl pentane
Benzene
toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 , 3, 5-Trimethyl benzene
1 , 2, 4-Trimethyl benzene
1 , 2, 3-Trimethyl benzene
TOTAL yg/n3
7/19
15.0
16.0
24.0
30.0
16.0
73.0
313
6.0
7.5
13.5
—
239
122
6.0
52.5
32.5
24.5
7.0
23.0
46.0
14.0
35.0
15.0
6.0
12.5
4.0
1153
7/20
12.5
20.0
23.5
21.5
19.0
16.0
46.0
3.5
6.0
8.0
--
63.0
31.0
2.0
22.0
13.0
U.O
4.5
18.0
40.5
12.5
33.5
14.5
7.0
30.0
6.5
488
7/21
24.5
19.5
22.0
48.0
15.5
28.0
69.0
4.0
6.0
7.5
--
87.0
42.5
2.5
29.0
17.5
17.0
5.5
20.5
49.0
13.0
35.0
15.0
1.5
14.0
2.0
595
7/22
42.0
*
31.5
45.0
26.0
30.0
82.5
1.0
5.0
5.0
--
110
54.5
2.0
29.0
20.0
27.0
5.0
19.0
48.5
16.5
40.0
19.0
11.5
19.5
7.0
697
7/23
68.5
*
19.5
62.5
51.0
36.0
82.0
5.0
6.5
9.5
__
106
51.0
3.5
9.0
33.0
20.0
4.5
19.0
41.5
14.0
31.5
14.0
5.0
12.0
4.5
709
7/24
118
*
13.0
621
82.5
42.0
65.0
3.5
4.0
5.0
--
7A.O
42.5
2.5
26.5
16.0
20.5
14.5
19.0
32.5
7.5
22.0
10.0
4.5
8.0
3.0
1257
AVE
27.0
13.0
18.0
70.5
21.0
39.0
116
4.0
5.5
8.0
—
103
93.5
4.0
28.0
19.5
18.0
5.5
18.0
37.5
10.0
25.5
11.5
5.0
12.0
3.5
723
-- Less than
* Value questionable or no data
-------
TABLE 4. INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/m3) IN SAMPLES COLLECTED BETWEEN 6 AND 9 AM AT
THE SOUTH SITE.
CO
o
Ethane
Ethyl ene
Acetylene
Propane
Propene
i- Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2 ,4-Dimethyl pentane
Benzene
Toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 , 3, 5-Trimethyl benzene
1 , 2, 4-Trimethyl benzene
1 ,2 ,3-Trimethyl benzene
TOTAL yg/m3
7/9
18.0
59.0
32.0
91.0
145.0
148.0
64.5
5.0
8.5
4.0
__
77.0
85.5
2.0
17.0
11.0
18.0
7.0
16.5
31.5
12.0
21.0
7.0
2.5
3.5
2.0
889
7/10
9.0
24.5
2.0
16.5
8.5
8.5
11.5
1.0
1.5
1.0
__
12.0
6.5
__
4.0
3.0
13.0
--
6.5
13.5
2.5
4.0
3.0
2.0
2.0
1.5
158
7/12
10,0
19.5
4.0
21.5
6.5
18.0
24.5
1.0
2.0
1.0
__
23.0
12.5
1.0
6.0
5.0
9.0
*
*
*
*
*
*
*
*
*
—
7/13
73.0
126
26.5
110
13.5
49,5
60.0
4.0
5.0
—
_-
49.0
34.0
2.0
20.0
12.0
16.0
3.0
14.0
29.0
9.0
21.0
10.5
5.0
18.0
3.5
714
7/14
18.0
24.5
15.0
50.0
17.5
46.5
79.0
6.0
6.0
12.0
--
76.5
40,5
4.0
23.0
14.5
21.0
3.5
23.5
39.0
15.0
33.0
14.5
5.5
8.0
5.0
601
7/15
21.0
33.5
7.0
32.5
4.5
15.5
24.0
1.5
2.5
2.0
--
22.0
13.0
1.5
7.0
5.0
5.0
1.5
5.5
15.5
5.5
8.0
4.5
2.0
4.0
— —
244
7/16
7.5
39.5
4.0
14.5
4.0
7.5
14.0
1.0
2.5
1.5
--
14.0
11.0
1.0
5.0
5.0
18.5
--
5.0
12.0
3.5
6.0
3.0
2.0
5.0
1.5
193
(continued)
-------
TABLE 4 (continued).
Ethane
Ethyl ene
Acetylene
Propane
Propene
i -Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2 ,4-Dimethyl pentane
Benzene
Toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 , 3, 5-Trimethyl benzene
1 , 2, 4-Trimethyl benzene
1 , 2, 3-Trimethyl benzene
Total yg/m3
7/17
33.0
10.5
6.0
40.5
5.5
18.0
31.0
1.5
1.5
2.5
__
30.0
17.5
1.0
9.5
6.0
9.0
2.0
7.5
17.5
3.0
10.0
3.0
3.0
4.5
1.5
275
7/19
3,5
7.5
3.5
3.5
3.0
2.5
13.5
1.0
2.0
-~
--
12.5
11.0
--
4.0
3.0
9.5
--
5.5
24.0
36.0
137
80.0
19.0
258
37.0
677
7/20
9.0
13.0
4.5
17.0
5.5
24.5
21.0
1.0
2.5
~-
--
14.0
10.0
--
4.0
3.0
6.5
2.0
7.0
10.0
3.0
4.5
5.0
2.0
8.5
l'.5
179
7/21
10.0
18.0
8.5
10,5
7,0
8.5
18.5
1.5
5.0
7.5
__
25.0
14.0
1.5
11.0
7.0
23,5
*
*
*
*
*
*
*
*
*
--
7/22
5.0
34.0
8.0
80.5
8.5
32.0
57,0
3.0
3.0
7.0
__
55.0
28.5
1.0
7.0
16.0
11.0
3.0
12.5
30.0
10.0
18.0
10.0
5.0
12.5
3.5
461
AVE
18.0
34.0
10. n
40.5
19.0
32.0
34.5
2.5
3.5
3.5
—
37.0
26.0
1.5
10.0
7.5
13.0
2.5
10.5
22.0
10.0
26.5
14.0
5.0
32.5
5.5
421
-- Less than .5 yg/m3
* Value questionable or no data
-------
TABLE 5. INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/m3) IN SAMPLES COLLECTED BETWEEN 6 AND 9 AM AT
THE NORTH SITE.
oo
Ethane
Ethyl ene
Acetylene
Propane
Propene
i -Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2 ,4-Dimethyl pentane
Benzene
Toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 ,3,5-Trimethylbenzene
1 , 2, 4-Trimethyl benzene
1 , 2, 3-THmethyl benzene
TOTAL ug/m3
7/9
17.5
15.0
5.0
34.0
7.0
17.0
30.5
2.0
2.5
2.5
--
30.5
17.5
1.0
8.5
5.5
7.0
2.5
8.0
27.0
4.5
12.5
5.5
3.0
5.0
8.5
280
7/10
18.0
10.0
3.5
58.0
8.5
27.0
39.0
3.0
2.5
3.0
--
28.5
19.0
1.5
8.5
5.5
12.0
2.5
8.0
21.5
5.0
7.0
4.5
3.0
4.0
4.5
308
7/12
8.0
5.0
1.5
10.0
2.0
6.5
12.0
1.0
1.0
1.0
--
9.0
4.5
1.0
3.0
2.0
5.0
—
4.0
51.0
53.0
206
113
74
308
69
951
7/14
6,0
11.5
3.0
- 7.5
2.5
4.0
7.5
1.0
2.0
1.0
__
10.0
6.5
--
3.5
2.0
3.0
.5
4.0
13.0
3.0
12.0
5.0
2.0
7.5
2.0
120
7/15
17.5
9.5
6.5
27.0
6.0
20.5
49.0
2.0
3.0
3.0
--
43.0
21.5
2.0
12.0
8.5
9.5
*
*
*
*
*
*
*
*
*
—
7/16
17.5
14.0
9.0
38.0
9.5
26.0
64.0
3.0
4.0
5.5
- •
65.0
32.0
2.5
19.0
12.0
13.0
4.0
14.0
42.0
3.5
20.5
2.0
4.0
12.0
4.0
440
(continued)
-------
TABLE 5 (continued).
co
co
Ethane
Ethyl ene
Acetylene
Propane
Propene
i -Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2 ,4-Dimethyl pentane
Benzene
Toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 , 3, 5-Trimethyl benzene
1 , 2, 4-Trimethyl benzene
1 , 2, 3-Trimethyl benzene
TOTAL yg/m3
7/17
33.0
10.5
6.0
40.5
6.0
18.0
31.0
1.5
2.5
2.5
—
30.0
18.0
1.0
10.0
6.0
9.0
3.0
14.0
140
158
484
385
199
522
125
2256
7/19
14.5
16.0
9.5
45.0
11.0
31.0
47.0
2.5
4.0
4.0
—
42.0
23.0
2.5
21.0
12.5
25.0
3.0
13.0
173
224
778
161
975
224
31.0
2893
7/20
22.0
19.0
8.0
40.5
9.0
21.0
40.0
2,0
3.5
3.5
—
41.0
22.0
2.0
14.5
13.5
15.0
2.0
11.0
28.0
7.0
23.0
10.5
4.0
12.5
5.0
376
7/21
25.0
23.0
10.0
43.5
13.0
33.0
48.0
3.0
3.5
3.0
—
45.0
27.5
2.5
23.0
14.0
28.0
3.0
14.0
140
158
484
385
199
522
125
2375
AVE
18.0
13.5
6.0
34.5
7.5
20.5
37.0
2.0
3.0
3.0
--
34.5
19.0
1.5
12.5
8.0
12.5
2.5
10.0
70.5
68.5
225
119
163
180
41.5
1110
-- Less than .5yg/m3
* Value questionable or no data
-------
2800
2600
2400
2200
2000
1800
1600
ufl/m3
m 1400
1200
1000
800
600
400
200
0
—
-
KEY
Traitor
-
D=D
North | |
-
-
-
~
-
-
-
-
:
So
uth
9
1
10
•
mm
r"i
•
-
12
f
i
13 4 15
I
16
1
i
r^
-
:
_•
IT 19
•
1
20
-
-
-
-
21 22 Ave.
DATE
Figure 5. Summary of 6-9 am hydrocarbon data obtained at the three Houston
area ground sampling sites.
.34
-------
hydrocarbon concentration was exceptionally high at the north site. It can
be seen seen that about 90% of the hydrocarbon burden was comprised of aro-
matics on these mornings. On the 16th and 20th, when total concentrations
were lower and more comparable between the north site and WSU trailer site,
a more normal distribution of aromatics, paraffins and olefins was observed.
On July 19 the total hydrocarbon level was also quite high at the WSU trailer
site; however, the compositional breakdown is very different when compared
with the north site. At the trailer site, paraffinic species are by far the
most abundant. The complexity of Houston's hydrocarbon sources is exempli-
fied by the fact that two sampling sites approximately 10 miles apart can
exhibit very different compositional patterns.
Afternoon average ambient hydrocarbon levels at the WSU trailer site were
about a factor of three lower than during the 6-9 am period. With the excep-
tion of the most photochemically reactive olefins, the hydrocarbon to acety-
lene ratios didn't vary much between morning and afternoon. Also, the per-
centage of olefins, aromatics and paraffins is comparable during both periods
of the day at the site in northwest Houston. This indicates that the same
emission sources contribute to the morning and afternoon hydrocarbon burden
in this section of Houston. Table 7 provides a summary of hydrocarbon analy-
ses on samples collected during afternoon hours at the WSU trailer site.
The average ethylene/acetylene ratios differ between the three hydrocar-
bon.sampling sites. The daily ratio at the WSU trailer was generally less
than one with an average value of .72. The ethylene/acetylene ratios at the
north and south sites were 2.3 and 3.4 respectively. The lower value observ-
ed at the trailer site in northwest Houston indicates a higher automotive
contribution at that site. Grab samples that were collected in downtown
Houston at high density traffic locations consistently exhibited an ethylene/
acetylene ratio less than one.
The identification of hydrocarbon source contributions is important in
the Houston area if proper control strategies are to be devised. Several
research groups have addressed this problem. In 1973, Lonneman and Bufalini
(8) reported the results from a one-day program in which samples were col-
lected at various urban, industrial, tunnel and rural locations in the
Houston vicinity. Estimates of vehicular hydrocarbons at the different
35
-------
TABLE 6. HYDROCARBON COMPOSITION COMPARISON AT TWO SITES BETWEEN 6 AND 9 am
ON JULY 16, 17, 19 and 20, 1976.
North Site WSU Trailer Site
7/16/76
Total yg/m3
% aromatic
% paraffin
% olefin
7/17/76
Total yg/m3
% aromatic
% paraffin
% olefin
7/19/76
Total yg/m3
% aromatic
% paraffin
% olefin
7/20/76
Total yg/m3
% aromatic
% paraffin
% olefin
440
23
69
8
2256
90
9
1
2893
89
10
1
375
27
63
10
461
32
60
8
•
549
20
72
8
1153
13
81
6
488
33
55
12
sites were made by comparing certain hydrocarbon/acetylene ratios with those
obtained in tunnel samples. The latter was assumed to be a valid representa-
tion of pure automobile emissions. A significant contribution from
non-vehicular hydrocarbon sources was observed at most of the sampling sites.
At some of the locations, as little as 10-15% of the hydrocarbon burden could
36
-------
CO
TABLE 7. INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/m3) IN SAMPLES COLLECTED DURING THE AFTERNOON
HOURS AT THE WSU TRAILER SITE.
Ethane
Ethyl ene
Acetylene
Propane
Propene
i -Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2,4-Dimethylpentane
Benzene
Toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 , 3, 5-Tri methyl benzene
1 , 2, 4-Trimethyl benzene
1 , 2, 3-Trimethyl benzene
TOTAL yg/m3
7/6
6-2
5.0
3.0
2.5
9.5
2.0
5.0
10.0
--
1.5
1.0
--
11.0
5.5
--
3.0
2.0
2.5
2.0
5.5
4.0
1.0
3.0
2.0
1.5
6.0
1.0
89.5
7/9
6-4
6.0
--
8.0
14.0
10.5
14.0
34.0
2.0
4.0
—
--
53.0
23.5
2.0
16.0
10.0
9.5
2.0
10.5
24.0
6.5
14.0
6.0
2.5
7.0
1.5
280.5
7/10
6-4
3.5
4.5
11.0
18.5
9.0
14.0
24.5
1.0
2.0
--
3.0
32.0
15.5
--
2.5
3.0
6.5
1.5
10.0
20.0
7.0
11.0
5.5
2.5
6.0
1.5
221.0
7/12
G-4
11.
7.
7.
41.
11.
42.
37.
2.
3.
1.
--
39.
21.
4.
11.
7.
11.
2.
11.
15.
9.
11.
7.
3.
4.
2.
324.
5
5
0
5
5
0
5
0
0
5
0
5
0
5
0
5
0
0
5
0
0
0
0
0
0
0
7/13
6-4
4.0
4.0
3.0
5.5
2.0
4.0
13.0
-_
2.0
1.0
--
15.0
8.0
1.0
4.0
3.0
3.5
1.0
5.5
8.5
3.0
4.0
3.0
2.5
3.0
--
103.5
7/14
6-4
9.0
9.0
9.0
19.0
6.0
17.0
35.5
2.0
2.5
2.0
--
37.0
20.0
2.5
14.0
13.0
24.5
1.5
12.0
18.5
9.0
13.5
6.0
2.5
3.0
2.0
290.0
7/15
G-4
4.0
5.0
9.5
10.0
5.0
9.5
34.5
1.5
2.5
2.5
--
37.5
19.5
1.5
10.5
6.5
8.5
2.5
9.5
20.0
11.0
22.0
8.5
4.0
8.0
2.5
256.0
7/17
6-4
5.0
3.5
2.0
4.5
1.5
2.5
6.0
1.5
--
--
--
8.0
5.5
—
2.5
1.5
4.0
—
4.0
6.0
3.5
4.0
3.0
2.0
3.0
1.0
74.5
7/21
6-4
8.0
14.0
16.5
20.5
24.5
33.5
82.0
4.0
12.0
13.5
--
79.0
44.0
3.0
6.5
28.0
23.0
2.0
9.0
15.5
8.5
21.0
5.5
7.5
20.0
3.0
504.0
AVE
6.0
5.5
7.5
16.0
8.0
15.5
31.0
1.5
3.5
2.5
1.0
31.0
19.5
3.5
8.0
8.0
10.5
1.5
8.5
14.5
6.5
11.5
5.0
3.0
6.5
1.5
238.0
-- Less than .5ug/m3
-------
be attributed to vehicular sources. In their sample considered to be most
representative of vehicular and industrial emissions emanating from the city,
approximately 50% of the total hydrocarbons could be attributed to vehicular
sources.
A more extensive study was conducted in 1975 by Texas Air Control Board
(TACB) personnel (9). They used the Lonneman method of ratioing to arrive at
the automotive contribution at three Houston area sites. The TACB study in-
cluded a larger data base and, in addition, considerable effort was put into
arriving at hydrocarbon/acetylene ratios truly representative of automotive
emissions in the Houston area. As would be expected, they found the vehic-
ular component of the ambient C2-C5 hydrocarbon mixture to always be great-
er in downtown Houston than in the adjacent industrial area. However, they
showed that the majority of the C2-C5 hydrocarbon burden in both areas was
derived from nonvehicular sources. This was even the case during the early
morning traffic rush period. Table 8 summarizes the average vehicular com-
ponent during various periods of the day at two Houston locations. It is
evident from this table that vehicular hydrocarbons usually comprise less
than 40% of the downtown hydrocarbon burden and less than 20% in the indus-
trial region. These findings agree with the earlier work conducted by
Lonneman and Bufalini (8).
TABLE 8. AVERAGE VEHICULAR COMPONENT BASED ON Co-Cc HYDROCARBONS AT
TWO HOUSTON LOCATIONS (9)
Time
0500-0600
0730-0830
1000-1100
1200-1300
1500-1600
1630-1730
Downtown
23%
45%
35%
24%
29%
34%
Jacinto City
15%
34%
11%
12%
15%
12%
38
-------
A third attempt to relate hydrocarbon composition to emission sources in
the Houston area has been reported recently (10). Specific vehicular-
industrial hydrocarbon breakdowns were not reported in this latter study;
however, it was concluded that both automobile and industrial processes are
important to the hydrocarbon problem in Houston. The University of Houston
group further concludes that in the downtown area automobiles do contribute
more to the pollution burden, as the frequency of olefins has been found to
be greater than at sites in the industrial area.
By using the ratioing technique, we have derived source contributions
from data we collected during July 1976. We have used the vehicular hydro-
carbon/acetylene ratios derived in the TACB study. These appear to have been
carefully established from a much better data base than we possess. Table 9
shows the average vehicular percentage based on C^C^ hydrocarbons during the
0600-0900 time period at our three sampling sites. The vehicular component
varies between 25 to 31%. Thus, these results support the contention that
TABLE 9. AVERAGE VEHICULAR CONTRIBUTION AT THREE HOUSTON AREA SAMPLING
SITES.
WSU Trailer North Site South Site
Average Co-Cc
Hydrocarbons (ug/m3) 505 191 252
Average Acetylene
(yg/m3) 18 6 10
C2-C5/Acetylene 28.1 31.8 25.2
C2-C5/Acetylene
from vehicular source t 8.0 8.0 8.0
% Vehicular contribution
to C2-C5 hydrocarbon total 29 25 - 31
t The C2-C5/Acetylene ratio of 8.0 was taken from reference 9. We collected
three samples during the July field program in areas that should be dominated
by automotive emissions. The average C^C^/Acetylene ratio in the three sam-
ples was 8.3.
39
-------
hydrocarbons derived from non-automotive sources are the major constituent
of the Houston atmosphere even during the 0600-0900 peak traffic period.
It should be emphasized that the vehicular percentages derived in Table
9 were based on the C£-Cg hydrocarbons only. This probably results in an
upper limit value at most of the sites. This is especially true at the
north site, where the abnormally high aromatic content implies an even great-
er industrial contribution. In other words, if the entire C2-C-|Q hydrocarbon
spectrum had been considered, the automotive contribution at the north site
would be considerably less than 25%.*
It is obvious from Tables 3, 4 and 5 that the NAAQS for hydrocarbons of
160 yg/m3 (.24 ppmC) was exceeded on nearly every morning at the three sampl-
ing sites. We feel that the hydrocarbon burden measured at the three sites
results primarily from emission sources in the area between Baytown and the
western fringes of Houston. Table 10 provides a comparison of the average
0600 to 0900 ambient hydrocarbon concentrations at the urban sites with the
average concentration obtained from samples collected to the east of the
Baytown industrial area. These latter samples were collected during periods
of easterly or southeasterly winds and are considered to be representative
of background air entering the Houston area at various times throughout the
study period.
TABLE 10. COMPARISON OF HOUSTON AREA HYDROCARBON CONCENTRATIONS
Trailer North South Background Air High Og Air
Average
Hydrocarbon
Concentration ug/m 723 1110 421 41.5 206
* Lonneman obtained a I .. /CoH9 ratio of 4.3 for automobile emissions
aromatics ^ ^
in the 1973 Houston study. If this factor was compared with our average
numbers I .. /CoH? = 878/6 = 146, less than 3% of the average hydro-
aromatics ^ £-
carbon burden at the north site would be due to vehicular sources.
40
-------
It is clear from this table that, on the average, a minimum of a 10 fold
enhancement in hydrocarbon concentrations was recorded in the Houston urban-
industrial area. The category listed as "High 03" in Table 10 was included
to provide an indication of hydrocarbon concentrations in air masses with an
ozone concentration greater than 80 ppb. All of the samples included in the
"High 03" category were collected below 4000' by aircraft. Some of these
were directly over the Houston urban-industrial area, while others were col-
o
lected in the downwind plume. The 206 yg/m average hydrocarbon burden is
less than the ground level 0600-0900 am averages; however, it is signifi-
cantly larger than hydrocarbon concentrations in the background air.
Tables 11 & 12 provide a detailed summary of the samples considered in
the "Background Air" and "High 03" classifications. The A coding above the
date refers to an aircraft collected sample for which the collection location
and times can be found in the Appendix.
It is difficult to group the aircraft hydrocarbon data in distinct cate-
gories for discussion purposes because samples were never collected in the
same location. The two exceptions are the classifications provided in Tables
11 & 12, which represent "background air" and polluted air masses (High 03).
Since the latter class consists entirely of samples collected in the urban
plume, it is interesting to compare the average vehicular content of the air-
borne plume with that observed at ground level. Using a C2~C5/acetylene
ratioing procedure identical to that shown in Table 9, the vehicular content
of the aircraft collected plume samples was 25%. This is about the same as
the 29, 25 and 31% values obtained at the three ground stations.
OXIDANTS
Ozone
A large ozone data base exists for the Southeastern Texas region due to
the monitoring efforts of the Texas Air Control Board and City of Houston.
Ozone trends in the Houston area for the period 1974-76 have been reviewed by
Gise (11). Table 13 shows that ozone levels have exhibited an increasing
trend during the three-year period. This is in spite of the fact that hydro-
carbon emissions were reduced by an estimated 40% during the same period (2).
41
-------
TABLE 11. INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/m3) IN SAMPLES CONSIDERED
TO BE REPRESENTATIVE OF BACKGROUND AIR.
Ethane
Ethyl ene
Acetylene
Propane
Propene
i -Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2 ,4-Dimethyl pentane
Benzene
Toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 , 3, 5-Trimethyl benzene
1 , 2, 4-Trimethyl benzene
1 ,2, 3-Trimethyl benzene
TOTAL yg/m3
A-l
7/7
3.0
—
2.5
1.0
1.0
1.0
--
__
--
--
1.5
1.0
--
4.0
1.5
1.0
--
2.0
5.0
1.5
1.5
1.0
1.0
1.0
1.0
31.5
A-l
7/12
4.5
1.0
—
4.5
1.0
2.0
2.5
--
__
--
--
2.0
2.5
1.0
--
1.5
1.0
--
2.5
2.0
1.0
1.5
2.5
2.0
1.0
36.0
A-l
7/14
3.0
2.0
--
4.0
1.0
2.0
3.5
--
_ _
--
_-
4.0
3.5
--
—
2.0
--
--
2.5
2.5
2.0
1.5
2.0
1.5
3.0
--
40.0
A-l 20
7/20
10.5
3.0
--
9.5
2.0
4.0
4.5
--
_ _
--
--
3.0
2.0
1.0
2.0
1.0
1.0
3.0
8.0
2.0
1.0
1.5
1.0
1.0
--
61.0
Ground Level
mi E of Bay town AVE
7/4/76
2.5
2.0
—
1.5
--
1.0
2.0
--
« _
--
--
2.5
1.0
--
4.0
3.0
3.5
3.0
3.0
1.5
1.0
1.0
1.0
1.0
1.5
1.0
37.0
4.5
2.0
—
4.5
1.0
2.0
2.5
__
__
_-
__
2.5
2.0
—
2.0
2.0
1.5
1.0
2.5
4.0
1.5
1.0
1.5
1.5
1.5
.5
41.5
— Less than .5yg/m3
* Value questionable
42'
-------
TABLE 12. INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/m3) IN SAMPLES COLLECTED IN AIR MASSES CONTAINING
OZONE LEVELS GREATER THAN 80 PPB.
CO
Ethane
Ethyl ene
Acetylene
Propane
Propene
i -Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2 ,4-Dimethyl pentane
Benzene
Toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 , 3, 5-Trimethyl benzene
1 , 2, 4-Trimeth.yl benzene
1 , 2, 3-Trimethyl benzene
TOTAL yg/m3
A-4
7/7
16.0
14.0
9.0
55.0
19.0
50.0
61.0
5.5
3.5
4.0
--
48.0
27.0
2.0
12.0
11.5
16.0
2.0
23.0
22.0
6.0
14.0
6.0
3.0
4.0
--
434
A-3
7/8
8.5
6.5
28.5
3.0
25.0
24.5
1.0
1.5
1.0
__
21.5
13.0
3.0
6.5
5.0
7.0
1.0
10.0
11.5
3.0
4.0
3.0
2.0
1.5
1.0
193
A-l
7/10
11.0
16.5
4.0
19.0
3.5
55.0
13.5
1.5
1.5
--
—
10.5
12.0
1.0
4.5
3.5
9.0
--
6.5
7.0
1.5
2.5
2.5
1.5
1.0
1.0
190
A-2
7/10
13.0
15.0
5.0
26.5
5.0
21.0
27.5
1.5
1.5
--
—
24.5
14.5
1.0
7.5
8.0
7.5
1.0
10.0
13.0
4.0
6.0
4.0
1.5
3.0
1.5
223
A-3
7/12
47.0
15.0
3.0
25.5
8.5
13.5
12.0
1.0
1.5
--
—
9.5
6.0
2.0
3.0
5.0
2.0
--
5.0
3.5
2.0
2.0
1.5
2.0
1.0
1.0
173
A-4
7/12
14.0
5.0
27.0
1.5
20.5
20.0
1.0
2.0
--
—
17.0
10.0
1.5
6.0
4.0
4.5
1.0
8.5
9.0
5.0
8.5
4.0
2.0
4.0
3.0
179
A-2
7/14
13.0
10.0
5.0
22.0
2.5
22.0
21.5
1.0
1.5
--
—
18.5
10.5
1.0
6.0
6.5
6.5
1.0
7.5
7.0
3.0
2.5
2.0
1.5
2.5
--
175
(continued)
-------
TABLE 12 (continued).
Ethane
Ethyl ene
Acetylene
Propane
Propene
i -Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
2-Methylpentane
3-Methylpentane
n-Hexane
2 ,4-Dimethyl pentane
Benzene
Toluene
Ethyl benzene
p & m-Xylene
o-Xylene
1 , 3, 5-Trimethyl benzene
1 , 2, 4-Trimethyl benzene
1 , 2, 3-Trimethyl benzene
TOTAL yg/m3
A-3
7/14
12.0
9.5
9.0
26.5
5.0
22.5
37.5
1.5
2.5
1.0
—
35.5
20.5
--
10.0
10.5
8.5
1.5
11.0
17.5
6.0
9.5
5.0
2.5
2.0
3.0
270
A-l
7/18
11.0
4.0
1.0
18.5
1.0
10.0
15.5
--
1.0
—
--
12.5
7.5
2.5
5.0
2.5
--
2.0
9.5
5.5
2.0
1.5
2.0
1.5
3.0
l.'O
120
A-2
7/20
11.0
7.5
2.5
19.0
2.5
15.5
30.0
1.0
1.5
—
__
25.5
12.5
1.0
5.0
8.0
6.0
1.0
7.5
8.5
3.5
4.0
4.5
2.5
4.5
—
185
A-3
7/20
8.5
5.0
1.0
15.0
2.0
13.0
14.0
--
1.5
__
-_
14.5
10.5
--
4.5
5.5
4.5
—
4.0
4.0
2.0
2.0
3.5
2.0
3.5
—
121
A-6
7/22
34.0
*
1.5
22.0
6.0
17.5
19.0
--
1.5
—
—
13.5
10.0
--
4.0
2.5
3.0
. —
6.0
5.0
2.0
2.0
1.5
2.0
2.5
4.0
160
AVE
16.5
10.5
4.5
25.5
5.0
24.0
24.5
1.5
2.0
.5
--
21.0
13.0
1.5
6.0
6.0
6.0
1.0
9.0
9.5
3.5
5.0
3.5
2.0
2.5
1.5
206
-- Less than .5yg/m3
* Value questionable
-------
Analysis of ambient air quality data in the Houston area indicates that
little relationship exists between ambient hydrocarbon levels and ozone con-
centrations (12). Additional studies have shown that meteorology is an im-
portant factor since most ozone episodes occur when weak pressure gradients
prevail (13). Also, it has been pointed out that a type of "blanket" ozone
effect commonly exists in Texas with many stations in widely distributed
areas exceeding the .08 ppm standard at the same time.
TABLE 13. ANNUAL STATISTICS FOR OZONE IN THE HOUSTON AREA, 1975-1976 (11).
Aldine (North Site)
1974 1975 1975
Houston (TACB Site)
1974 1975 1976
Number of Hours
> .08 ppm
Percent of Hours
> .08 ppm
Percent of Days
> .08 ppm
Number of Hours
> .12 ppm
Number of Hours
> .16 ppm
83
3.4
24.3
13.
3.
251
4.2
25.4
67.
14.
397
7.7
41.5
90.
24.
213
3.0
20.7
55.
8.
202
3.7
22.7
56.
16.
279
4.2
24.4
62.
27.
The relative importance of ozone and/or ozone precursor transport into
the Houston area vs. ozone production from locally emitted precursors has not
been well established. Data collected by WSU during July, 1976, is valuable
from this standpoint since synoptic scale transport was minimal during this
period. Between July 1 and 24, 1976, there were no "blanket" ozone episodes
in southern Texas. We believe that secondary pollutants measured in the
Houston area during July, 1976, resulted from precursors emitted in the im-
mediate Houston area. Thus, one of the unique features of these data is that
they provided a basis for establishing Houston's potential for generating
oxidants.
45
-------
TABLE 14. OZONE HOURLY AVERAGE CONCENTRATIONS (ppb) AT WSU TRAILER SITE DURING THE PERIOD JULY 1-25, 1976,
ov
DATE
TIME
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
1
..
—
—
1
1
4
4
5
15
21
27
38
52
49
32
28
34
21
21
22
4
0
0
0
2
5
9
8
5
6
1
0
1
15
22
19
20
21
31
24
19
19
17
9
4
4
4
6
4
3
7
6
6
5
5
4
11
16
20
21
21
24
24
26
20
12
9
5
0
0
0
0
0
0
4
0
0
0
0
__
0
0
1
3
5
9
12
28
31
36
36
17
19
9
4
0
0
5
0
—
0
0
0
0
0
0
5
__
«_
10
11
11
13
14
__
5
0
0
0
0
6
0
0
0
0
0
0
0
0
2
8
21
39
43
37
38
23
13
10
2
0
0
0
0
0
7
0
0
0
0
0
0
0
31
21
18
32
34
33
44
38
48
44
30
10
5
0
0
0
0
8
0
0
0
0
0
0
0
0
3
16
40
76
108
150
179
136
50
25
0
__
_-
—
--
9
—
—
__
__
_-
_-
_—
__
__
__
_—
_—
—
40
18
2
0
0
0
0
0
0
0
10
0
0
0
0
0
0
0
0
0
0
8
3
14
12
12
11
19
17
16
7
0
0
0
0
11
0
0
0
0
0
0
0
0
0
0
1
5
--
__
--
--
27
25
15
5
3
0
0
0
12
0
0
0
0
0
0
0
11
0
8
33
68
--
81
87
76
62
'41
35
25
5
0
0
0
13
0
0
0
0
0
0
0
0
0
5
10
25
35
30
30
15
5
3
0
0
0
0
0
0
14
0
0
0
0
0
0
0
0
0
0
10
10
15
35
65
80
55
40
10
0
0
0
0
0
15
0
0
0
0
0
0
0
0
0
0
0
5
5
5
15
15
10
5
0
0
0
0
0
0
16
0
0
0
0
0
0
0
0
10
10
13
20
23
11
0
0
--
--
— —
— —
— —
— —
— —
(continued)
-------
TABLE 14 (continued).
TIME
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
17
_.
--
__
--
--
--
_.
--
--
—
--
--
--
--
__
--
--
--
--
6
2
1
0
0
18
3
2
2
3
0
0
1
3
7
10
18
27
43
58
41
46
54
35
15
6
1
1
1
0
19
0
0
0
0
0
0
1
1
4
14
22
26
30
30
27
21
16
11
11
5
2
0
0
0
20
0
0
0
0
0
0
0
1
8
27
--
__
--
--
62
62
58
85
48
30
20
5
5
5
DATE
21
8
8
0
0
0
0
0
0
2
13
58
80
80
100
43
35
40
45
28
28
13
0
0
0
22
0
0
0
0
0
0
0
0
5
43
25
38
50
53
68
73 .
53
35
30
23
13
3
0
0
23
0
0
0
0
0
0
0
3
5
18
28
60
65
48
25
30
--
8
15
8
0
0
0
0
24
0
0
0
0
0
0
0
3
8
13
65
55
73
75
78
88
83
70
50
23
8
0
0
5
25
5
5
3
0
0
0
0
0
5
13
20
38
45
53
102
108
140
138
103
118
95
38
23
18
-------
180
140
03 100
(ppb)
60
20
WSU TRAILER SITE
--TACB SITE (Joeinto City)
i I
10 12 14 16 16 20 22 24 26
DATE
Figure 6. Peak hourly average ozone readings at two Houston area ground sites
48
-------
Hourly average ozone concentrations at the WSU trailer site in NW
Houston equaled or exceeded the 80 ppb NAAQS on seven of the 25-day sampling
period. Table 14 provides a summary of the hourly averages. As shown in
Figure 6, the highest hourly value was 179 ppb recorded during the afternoon
of July 8. In addition to July 8, the standard was equaled or exceeded on
July 12, 14, 20, 21, 24 and 25. Figure 6 also contains a plot of ozone peaks
recorded at the TACB site (Jacinto City) east of the downtown area. The
curves for the two sites are very similar, with the exception that the WSU
site generally showed a slightly higher peak on days when both stations ex-
ceeded 80 ppb. This is not unexpected, since with prevailing southeasterly
winds the site in northwest Houston is farther downwind; and consequently,
the air mass generally had more time to age.
The diurnal ozone pattern at the WSU trailer site was typical of that
observed in other urban areas. Near zero ozone levels were recorded during
nighttime and early morning hours, with peak values recorded during midday.
Figure 7 shows the diurnal changes for the period July 7-12.
It was not uncommon for our airborne ozone monitor to record 03 values
in excess of 80 ppb on days when ground level stations were much below the
standard. Figure 8 and 9 show two such examples. On July 5, the highest
hourly average ozone value at the WSU trailer site was 14 ppb. In east
Houston at the TACB site, the peak value was only 5 ppb higher. Ozone con-
centrations recorded aloft during the afternoon hours on July 5 are shown in
Figure 8. It can be seen that 0^ in excess of 80 ppb existed in a small area
about 15 miles to the west of Houston. A more dramatic example was observed
on July 10 (Figure 9) when ground level ozone never exceeded 30 ppb, yet
concentrations at ^ 1500 ft., 20 miles to the southeast of Houston exceeded
130 ppb. There is little doubt that ozone concentrations in the region down-
wind of Houston generally exceed those monitored at ground stations in the
Houston urban-industrial area.
It was stated earlier that oxidant episode conditions during July in the
Houston area resulted from local emissions. This conclusion was based in
part on aircraft survey flights, which always showed upwind ozone concentra-
tions to be significantly below 80 ppb. The flights conducted on July 8th
provide a good example. Winds were out of the east during the morning hours
49
-------
Ul
o
' V"^^P"^"^»^I
12 16 20 24
TIME Of DAY
03
(ppb) 90
30 -
24 4 8
12 16 20 24
Figure 7. Dirurnal ozone pattern recorded between July 7 and 12, 1976.
-------
TEXAS
Figure 8. Afternoon flight path on July 5 with ozone concentrations (ppb)
marked along the route (see Appendix B for time, altitude and
other details).
51
-------
-A-1
Socrit
9.6mi.
Figure 9. Afternoon flight path on July 10 with ozone concentrations (ppb)
marked along the route (see Appendix B for time, altitude and
other details).
52
-------
with a shift to southerly during the afternoon. As can be seen in Figure
lOa, ozone concentrations throughout the Houston region were generally less
than 40 ppb in the morning hours between 8 and 10 am. The upwind ozone con-
centration didn't increase much during the afternoon hours as shown in Figure
lOb; however, in areas to the north and west of Houston, concentrations well
in excess of 100 ppb were recorded. It should be recalled that a peak hourly
average of 179 ppb was recorded at the WSU trailer site in northwest Houston
on July 8.
During July, 1976, we observed no evidence of surface 03 enhancement due
to subsiding air masses from aloft. One or more vertical profiles were per-
formed on each flight to check for this phenomenon. Figure lla and b, which
show ozone profiles recorded on July 8, are generally typical of the study
period. The morning sounding shows a fairly constant 30 to 40 ppb ozone con-
centration from the surface to 8000'. It is clear from the afternoon profile
that the high ozone band in the lower 3500' was generated at the surface and
not the result of downward mixing from aloft. There was no significant
change in 0^ concentration above 4000' through the day.
Ozone production resulting from photochemical processes involving only
natural precursors has undergone intensive study recently. In a study con-
ducted by Stanford Research Institute (14), strong evidence is presented to
support the hypothesis that no local ozone synthesis occurs at rural loca-
tions. Ozone data from many rural monitoring stations were analyzed with
the finding that at no season of the year did there exist a diurnal variation
in ozone with an afternoon maximum similar to that observed in polluted
atmospheres.
A similar conclusion was reached by Westberg (15) in a review prepared
for the Environmental Protection Agency. In this study, the potential for
ozone production in a rural air mass containing natural terpenic hydrocarbons
was estimated based on reported hydrocarbon levels. Since the sum total of
individual natural hydrocarbons seldom exceeds a few ppb, it is unlikely that
a measurable quantity of ozone can be produced through the photooxidation of
natural hydrocarbons in ambient air. We are aware of the reported high lev-
els of "natural" hydrocarbons at a site north of Houston (16). This work
53
-------
(a)
(b)
Figure 10. Morning (a) and afternoon (b) flight paths on
July 8 with ozone concentrations (ppb) marked
along the route (see Appendix B for time, altitude
and other details.)
54
-------
i I i r
8
7
ALT
(xlC^ftMSL)
(a)
4
3
2
I
0
6
5
ALT
(xlCTftMSL)
(b) 3
52 56 60 64 68
TEMP
_L
j_
j_
10 20 30 40
(ppb)
T
55 61 6*7
79 85 91
25 35 45 55 65 75 85 95 105
(Pf*)
Figure 11. Morning (a) and afternoon (b) vertical
soundings conducted on Ouly 8, 1976
(see Appendix B for details).
55
-------
involved a total hydrocarbon analysis which showed concentrations in the 1-
10 ppm range. Due to the close proximity to Houston's tremendous anthropo-
genic hydrocarbon source, these data must be considered with caution.* At
no time in our 1976 study were terpenic or other natural hydrocarbons ob-
served in samples collected in rural areas around Houston.
PAN
Ambient peroxyacetyl nitrate concentrations were monitored at the WSU
trailer site from July 2 to 23. An automated electron capture gas chromato-
graph was employed which provided a reading every 20 mintues. Table 15 sum-
marizes the hourly average PAN concentrations throughout the sampling period.
It can be seen that the presence of this oxidant was primarily limited to the
daylight hours. On two occasions (July 4 and 23) PAN was observed to persist
into the nighttime hours; however, on both of these evenings the concentra-
tions were below 1 ppb. The absence of PAN during the early morning hours
is noteworthy since this implies that a carry-over of photochemical oxidants
from one day to the next did not occur.
The highest hourly average PAN measurement at the site in northwest
Houston was 11.5 ppb on July 8; however, the average of all measurements
between 10:00 AM and 4:00 PM was only 1.0 ppb. This is lower than recorded
in other major metropolitan areas. Lonneman, Bufalini and Seila (17) report-
ed an average of 18.4 ppb in Los Angeles, 6.3 in St. Louis and 3.7 in Hoboken,
NJ, during the same daytime period. Without additional data, it is difficult
to judge weather the 1.0 ppb average determined July, 1976, is representative
of the Houston area. The overall average may be low due to the unusual mete-
orology during the July study period and the particular site at which PAN was
monitored.
On a daily basis, there existed a good correlation between PAN and ozone.
Figure 12 shows that little or no PAN production was observed on days when
* During recent studies by EPA personnel at the same site, much lower hydro-
carbon concentrations were recorded. The EPA study of January 4-6, 1978
found NMHC levels that varied between 200-500 ppb (18).
56
-------
TABLE 15 . PAN HOURLY AVERAGE CONCENTRATIONS (PPB) AT WSU TRAILER SITE DURING THE PERIOD JULY 2-23, 1976,
en
DATE
TIME
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
2
—
--
--
—
--
—
—
0
0
0
0
—
0
0
0
0
0
0
0
0
0
0
0
3
0
0
0
0
0
0
0
0
0
0
.2
.1
.2
.2
.2
0
0
0
0
0
0
0
0
0
4
0
0
0
0
0
0
0
0
0
0
0
.1
.2
.5
.5
.4
.3
.2
.7
.7
.6
.5
.5
.4
5
.1
0
0
0
0
0
0
0
0
0
0
.2
.2
.3
0
.1
.3
.5
.6
.5
.5
0
0
0
6
0
0
0
0
0
0
0
0
0
0
.4
.3
1.2
.9
1.3
.7
.5
.8
.5
.4
0
0
0
0
7
0
0
0
0
0
0
0
0
0
.3
.6
1.0
1.4
1.7
1.7
2.5
2.0
2.3
.2
0
0
0
0
0
8
0
0
0
0
0
0
0
0
0
0
1.8
3.5
6.5
9.7
11.5
7.0
2.6
2.2
1.1
0
0
0
0
0
9
0
0
0
0
0
0
0
0
0
0
.1
.1
0
0
0
0
.4
.1
0
0
0
0
0
0
10
0
0
0
0
0
0
0
0
0
0
0
.2
.4
.6
.4
.4
.8
.9
.8
.2
0
0
0
0
11
0
0
0
0
0
0
0
0
0
0
0
0
.4
1.5
.9
]9
.5
.2
0
0
0
0
0
0
12
--
--
--
--
--
--
—
--
--
--
5.1
2.5
4.0
4.8
2.7
4.9
1.7
.6
0
.2
0
0
0
13
0
0
0
0
0
0
0
0
0
0
0
.5
.9
.6
.8
.6
.3
0
0
0
0
0
n
0
(continued)
-------
TABLE 15 (continued).
en
00
TIME
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
14
0
0
0
0
0
0
0
0
0
0
0
.1
.6
2.5
3.1
4.3
.5
.3
0
0
0
0
0
0
15
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
--
--
—
--
—
--
__
—
16
__
—
—
__
--
__
__
__
0
.2
.3
.6
.3
0
0
.2
0
0
0
0
0
0
0
17
0
0
0
0
0
0
0
0
0
0
0
.1
.5
.8
.8
.8
.8
.5
.2
0
--
_-
--
__
18
__
__
—
__
—
-_
—
—
0
0
.3
.9
1.1
.5
.5
.5
.5
.1
0
0
0
0
0
19
0
0
0
0
0
0
0
0
0
0
.2
.3
.2
.3
.2
.2
0
0
0
0
0
0
0
20
0
0
0
0
0
0
0
0
0
.5
,Q
1.1
1.7
1.2
1.0
1.0
1.0
.7
.6
.3
0
0
0
0
21
0
0
0
0
0
0
0
0
0
1.1
3.8
3.4
2.9
4.0
.8
.8
1.0
1.3
.4
0
0
0
0
0
22
—
—
—
--
--
—
--
--
--
--
--
.6
1.3
1.5
2.3
1.6
.7
.6
.5
0
0
0
0
23
0
0
0
0
0
0
0
0
.1
.6
i.n
1.8
2.8
1.6
.5
2.0
1.3
1.6
2.8
3.5
1.6
.6
.1
0
-------
180
140
03 100
(ppb)
60
20
18
14
PAN I0
(ppb)
j I
I I I I I I I I I I I I
24 6 8 10 12 14 16 18 20 22 24 26
DATE
10
12 14
DATE
16
18
20 22 24 26
Figure 12. Relationship between peak hourly ozone and PAN concentrations in
Houston during July, 1976.
59
-------
ambient ozone levels remained below 80 ppb. However, on days when ozone
showed high peak values, PAN concentrations peaked as well. Since PAN is
considered to be a tracer of urban pollution, the perfect correlation between
PAN and ozone episodes supports the earlier statement that high ozone levels
observed in the Houston region during July, 1976, resulted from anthropo-
genic causes and not from stratospheric intrusion. The diurnal ozone and
PAN patterns also coincided closely, as illustrated in Figure 13.
SECONDARY POLLUTANT PRODUCTION AND TRANSPORT
In order to characterize secondary pollutant production in the Houston
area, a detailed discussion of the air chemistry observed on two separate
days is provided. On both days, July 8 and 12, ground level ozone concentra-
tions exceeded the 80 ppb National Ambient Air Quality Standard.
July 12, 1976
Weather patterns around July 12 were influenced by a western extension
of the Bermuda High. High pressure and light winds were generally present
up to the 500 mb level. Figure 14 shows the surface weather map for the
morning of July 12.
Winds were out of the southeast from the surface to 5000' during the
late morning and afternoon hours on July 12. Table 16 lists Houston winds
at 1100 and 1715. With the southeasterly flow, air moving into southern
Texas had previously traveled over the Gulf of Mexico. The onshore flow of
warm, moist air caused numerous thunderstorms and a continual overcast in
southeast Texas. Weather observers in the Houston area reported no less than
80% sky cover during the daylight hours of July 12. Maximum solar radiation
measured at the WSU field laboratory on July 12 was approximately 60% of
that recorded on a clear day.
Even though the skies were mostly overcast during the daylight hours on
July 12, ozone levels in excess of 200 ppb were observed downwind of Houston
in the afternoon hours. Ozone concentrations recorded during a morning
flight in the Houston vicinity showed considerable variation in the zone from
1000 to 1500 ft above the surface. Some values exceeded 100 ppb, but in most
areas the ambient ozone concentration was near or below 50 ppb. Most of the
60
-------
6 PAN
(ppb)
8 12 16 20 24
4 8 12 16 20
TIME OF DAY
24
8
12 16 20 24
Figure 13. Diurnal ozone and PAN patterns in Houston during the period of July 7-12, 1976.
-------
1012
1016
Figure 14. Surface weather map for the morning of July 12, 1976 (7 am EST)
.62
-------
higher readings were observed west of Houston while the upwind area to the
east exhibited the lowest level.
TABLE 16. WINDS MEASURED AT THE WSU TRAILER SITE ON JULY 12, 1976.
HEIGHT
(FEET)
SFC
700
1400
2000
2700
3300
3900
4500
5100
1100
D
140
100
113
119
116
106
108
107
100
S
12
5
5
9
13
16
18
17
17
1715
D
170
122
119
122
116
120
122
120
74
S
9
10
9
8
6
7
8
9
14
D = direction in degrees SFC = surface
S = speed in knots
Figure 15 shows the morning flight path with ozone concentrations marked
at specific points along the route. The flight began at point "a" at 0845.
Following a spiral ascent and descent at point "b" the aircraft headed east
at an altitude of approximately 1000 ft to a point "c" upwind of Baytown.
Ozone concentrations all the way along this leg were below 45 ppb. It can be
seen in Figure 15 that ozone concentrations along the upwind leg from point
"c" to "d" were in the 30 - 40 ppb range. Ozone levels remained below 80 ppb
along flight leg "e" - "f" as well as to the west of Houston along the most
westerly portion of the route covered between points "f" and "g." As the
aircraft approached the Houston downtown area enroute to spiral point "g",
ozone concentrations increased dramatically with a high of 162 ppb recorded
near the Astrodome. The ambient ozone levels remained above 80 ppb along
63
-------
Figure 15. Morning flight path on July 12 with ozone concentrations (ppb) marked
along the route (see text and Appendix B for time, altitude and other
details).
64
-------
most of the remainder of the route. The morning flight ended at Lakeside
Airport, the point of departure, at 1130.
It is clear from the foregoing discussion that ozone levels well in ex-
cess of 100 ppb had developed at the 1000 to 1500 ft level to the west of
Houston's industrial and downtown areas before noon on July 12. In contrast,
air moving into this region from the east during this period contained 30-
40 ppb ozone.
The two aircraft soundings at 0900 and 1100 were useful for establishing
vertical pollutant profiles. Ozone and temperature changes with altitude at
0900 are shown in Figure 16. The ozone profile shows values in the 30 ppb
range with little fluctuation between 500 and 9000 ft. The low ozone levels
below 500 ft are probably the result of scavenging by nitric oxide. This hy-
pothesis is supported by Figure 17 which shows that nitric oxide levels were
highest below 500 ft. Based on this early morning vertical sounding there is
no evidence of a significant carry over of ozone produced the day before.
There does not appear to be any potential for increasing surface ozone levels
by downward mixing of an ozone rich layer aloft.
By the time of the second spiral (^ 1100), ozone had developed rapidly
through the lower 3000 ft. As shown in Figure 18, maximum concentrations
were near 120 ppb at 2000 ft and about 160 ppb in a shallow layer at 2800 ft.
The temperature profile was close to the dry adiabatic lapse rate throughout
the 1000 to 4000 ft region and showed no inversion usually characteristic of
the top of a surface mixing layer.
By 1500, ozone concentrations downwind of Houston had increased to
greater than 150 ppb throughout the lower 2000 ft of the atmosphere. Figure
19 shows ozone and temperature profiles at a point approximately 20 miles
northwest of Houston. It can be seen that the top of the ozone rich layer
extended to at least 4000 ft. Above 4500 ft, ozone levels were in the 40 ppb
range and therefore, had changed little since the morning measurement. A
second vertical profile was flown during the afternoon flight at a point ap-
proximately 45 miles downwind of Houston. Ozone concentrations at this dis-
tance and time (1700) approached 200 ppb at the 2500 ft level and exceeded
100 ppb to over 4000 ft. Figure 20 graphically illustrates this ozone-
altitude relationship. The change in temperature with altitude is also shown
65
-------
8
ALTITUDE
XIO°ft. MSL 5
20
40
52 56 60 64 68 72 76 80 84
\
\
TEMP (»F)
\
\
\
\
\
60
8
9:05 o.m. H
\
\
6
5
4
3
\
\
Figure 16. Ozone and temperature vertical profiles at about 9 am on July
12, 1976.
66
-------
ALTITUDE
8
9
8
lor ten
6
5
3
2
I
Figure 17. Nitric oxide and nitrogen dioxide vertical profiles at about
9 am on July 12, 1976.
67
-------
9
8
7
6
ALTITUDE
(XI03fi. MSL)
4
I
0
60
80
72 74 76 78
TEMP («F)
9
8
ll'-IOp.m.-
5
4
3
2
100
120
140
160
ppb
Fiaure 18 Ozone and temperature vertical profiles at about 11 am on
July 12, 1976.
68
-------
8
7
6
ALTITUDE
(XlOft. MSL) _
0
4
3
2
I
0
50 60 70 80 90 100 110
\
\
TEMP (»F)
\
\
9
8
3.20pm-I
20 40 60 80
OO 120 WO 160 180
PRb 0
Figure 19. Ozone and temperature vertical profiles at about 3:15 pm on
July 12, 1976.
69
-------
9
8
7
6
ALTITUDE
(XK)3ft. MSL)
3
2
100
120
140
78 62 86 90 94 98 102
TEMP (°F)
9
8
5:15 p.m. -
\
160
180
Fiqure 20 Ozone and temperature vertical profiles at about 5:15 pm
on July 12, 1976.
6
5
3
2
I
0
70
-------
in Figure 20. Once again, the lapse rate was near the dry adiabatic, and
there was no indication of an inversion at the top of the mixing layer. Late
in the afternoon the mixing layer in the area northwest of Houston was about
5000 ft deep.
Ozone concentrations recorded at surface stations around the Houston
area on July 12 were much lower than the values observed aloft. Table 17
lists afternoon hourly averages at several different sites. Stations on the
upwind side of Houston, such as Clute, didn't exceed 50 ppb. Monitoring
sites closer in to the city exhibited maxima in the 60 to 70 ppb range;
Fuqua = 60 ppb (south site in Figure 1), Clinton = 77 ppb (near TACB site in
Figure 1), Aldine = 70 ppb (north site in Figure 1). The 87 ppb hourly aver-
age recorded between 1400 and 1500 at the WSU station in northwest Houston
was the highest surface reading.
TABLE 17. SURFACE OZONE CONCENTRATIONS (ppb) ON JULY 12
TIME
1200
1300
1400
1500
1600
1700
CLUTE
38
41
45
44
35
34
CLINTON
50
60
69
77
41
43
FUQUA
53
61
60
53
54
53
ALDINE
__
56
58
70
64
60
WSU
68
—
81
87
76
62
Table 18 lists hourly average pollutant measurements at the Washington
State University laboratory site on July 12. The diurnal ozone, NOX, hydro-
carbon and carbon monoxide patterns are typical of those observed in large
urban areas. Ambient NOX, hydrocarbon and carbon monoxide concentrations
peaked during the 0600-0900 morning period. Ozone levels were low in the
early morning hours. They began to increase about 1000 with a peak value
of 87 ppb recorded during the early afternoon hours. A large increase in
the N02/NO ratio accompanied the ozone change. The photochemical product
71
-------
TABLE 18. SURFACE MEASUREMENTS AT WSU SITE ON JULY 12, 1976
TIME
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
0
0
0
0
0
0
0
0
0
8
33
68
--
81
87
76
62
41
35
25
5
0
0
0
NO
ppb
16
9
4
24
25
48
113
105
61
31
11
6
6
6
6
6
5
6
9
4
9
9
6
8
N02
ppb
17
16
16
14
14
14
22
25
31
49
45
40
29
26
26
21
36
38
34
27
35
34
25
28
NMTHC
ppmC
.4
,3
.3
.5
.8
.8
1.5
1.7
1.1
.6
.7
.8
.7
.8
.6
.3
.5
.5
.4
.5
1.0
.6
.4
.4
CO
ppm
1.5
1.2
1.0
1.1
1.5
2.8
4.7
5.0
3.1
1.9
1.7
1.4
1.4
1.1
1.2
1.1
1.3
1.1
1.5
2.0
1.6
1.7
1.3
1.3
CH4
ppm
2.1
2.2
2.2
2.4
2.7
4.0
3.5
3.6
2.9
2.4
2.2
2.0
2.1
2.0
2.0
1.9
1.9
1.9
1.9
1.9
1.9
2.1
2.0
2.1
CFC13
ppt
433
415
398
731
852
896
2222
1384
1173
1290
504
817
298
275
—
357
314
326
271
269
363
449
313
425
PAN
ppb
0
0
0
0
0
0
0
0
0
0
0
5.5
2.3
3.6
4.6
1.8
4.4
2.0
1.0
.3
0
0
0
0
.72
-------
PAN was present in measurable quantities during the period when ozone levels
were elevated. Figure 21 summarizes these pollutant patterns on July 12.
The aerometric data shown in Figure 21 suggest a photochemical produc-
tion mechanism for the afternoon ozone build-up. Nitric oxide, nitrogen di-
oxide and ozone concentrations throughout the afternoon hours are consistant
with a photochemical stationary state condition.
Non-methane hydrocarbon/NOv ratios during the 0600-0900 pollutant injec-
A
tion period varied between 11 and 13 at the WSU sampling site in northwest
Houston (Table 18). This is not much different from the ratio observed in
other major urban areas in the United States. Smog chamber experiments and
field irradiations of captive air samples have shown that an initial Hc/N0x
ratio of 12-14 is near optimum for oxidant production (19). Afternoon oxi-
dant levels in excess of 200 ppb downwind of Houston verify the high oxidant
forming potential of emissions from the urban area.
Individual analysis of C2-C-JQ hydrocarbons revealed a compositional
breakdown of approximately 10% olefins, 25% aromatics and 65% paraffins in
the 0600-0900 sample collected at the WSU laboratory. An aircraft sample
collected at 1700 near Hempstead in a region of elevated ozone showed nearly
the same percentage of olefins, aromatics and paraffins as recorded in the
early morning sample. However, some of the more reactive olefins were absent
in the afternoon sample. For example, i-butene, 1-butene, c-2-butene and
t-2-butene, which totalled 25 jig/nr in the morning sample, were not present
in the downwind high oxidant region. Also the propene/acetylene ratio had
decreased from about .8 in the morning sample to .3 in the afternoon aircraft
sample. The sum of the individual concentrations in this sample was approxi-
mately 200 yg/rrr which is about five times the average background level
(Table 10).
Data obtained during the afternoon flight on July 12 were very useful
for defining the impact of Houston area emissions on the downwind region.
Figure 22 shows the path flown and ozone concentrations at various points
along the route. The flight began at Lakeside Airport and proceeded in a
northwesterly direction to spiral point "b", approximately 20 miles downwind
of Houston. Ozone levels between this spiral point and point "c", approxi-
mately 45 miles from Houston, seldom dropped below 100 ppb. A high reading
73
-------
03
NO
NO?
(ppb)
8 10 12
TIME Of DAY
14
16
18
20
22
NMTHC
(ppm)
Figure 21. Pollutant changes at the WSU trailer site on July 12, 1976.
-------
Scole \
1.5" = I6mi. \
\
Spiral 2
0
120 ,02
HC
Grab Sample
Spiral I
(300'-*IOOOO')
158
\ Houston
Lakeside ^
Airport
57
Figure 22. Afternoon flight path on July 12 with ozone concentrations (ppb) marked
along the route (see text and Appendix B for time, altitude and other
details).
75
-------
of 258 ppb was recorded south of Hempstead at about 1600. While traveling
between point "c" and "d", the aircraft exited from the Houston plume before
reaching the southwest turn point. Ozone concentrations accordingly dropped
to about 60 ppb. The plume was then picked up again as the aircraft began
the northbound track toward Bryan. Ozone levels increased to nearly 190 ppb
and then dropped off again as the plane approached Bryan. Ozone concentra-
tions around Bryan were down to 60 ppb. On the return leg toward Houston,
ozone levels increased once again as the aircraft entered the plume. A spi-
ral ascent near Hempstead at 1715 showed 100 ppb ozone existed as high as
5000 ft, while some readings nearer the surface approached 200 ppb.
This flight data collected on July 12 clearly shows a pronounced ozone
plume as far as 90 miles downwind of Houston. Ozone readings were as high as
180 ppb at that distance and remained elevated over a cross-sectional dis-
tance of about 45 miles. A very deep mixing layer was present during the
afternoon hours. At approximately 45 miles northwest of Houston, an ozone
concentration of 100 ppb was recorded at 5000 ft.
July 8', 1976
Skies were mostly cloud covered between sunrise and sunset on July 8.
National Weather Service observers at Houston International Airport reported
a total sky cover of 10 tenths or overcast during the daylight hours. Per-
cent of possible sunshine was recorded as 34%. Thunderstorms in the Houston
area resulted in rainfall amounts varying from .46 in. at the Intercontinen-
tal Airport to 1.38 in. at Hobby. In spite of the seemingly unfavorable
conditions for photochemical oxidant production, high ozone levels were re-
corded around Houston on this day. The 179 ppb hourly average monitored at
the WSU trailer site was the highest during the July study period. Very
light easterly winds during the morning hours, followed by a reversal in di-
rection during the afternoon hours, appears to have limited the dispersion
of Houston area emissions. Consequently, secondary pollutants produced
from precursors emitted in the morning remained along the western fringes of
Houston rather than being transported long distances downwind, as was the
case on July 12.
Table 19 lists surface winds at Houston's two major airports. It can be
seen that winds were light and somewhat variable during the morning hours but
76
-------
primarily from the northeasterly quadrant. About mid-afternoon the winds
showed a significant increase in velocity with an accompanying shift to
southwest.
TABLE 19. SURFACE WINDS RECORDED AT HOUSTON AREA AIRPORTS ON JULY 8, 1976
TIME
(CDT)
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
Hobbj
Direction
000
030
050
050
090
200
230
080
080
180
200
220
190
f
Speed(kts)
0
5
6
4
2
3
4
4
5
15
4
6
5
Interconti
Direction
350
020
050
110
000
310
280
050
020
010
200
250
190
nental
Speed(kts)
4
4
6
4
0
2
3
4
4
3
11
9
7
Figure 23 shows that during the late afternoon hours, high ozone levels
covered a region approximately 20 miles wide and at least 40 miles long north
and west of Houston. The limited dispersion accompanied by significant oxi-
dant production makes July 8 an interesting day in which to examine chemical
changes in the Houston atmosphere. As pointed out in an earlier section, air
quality data collected on July 8 suggest anthropogenic precursors emitted in
the Houston urban-industrial complex as the sole source of the elevated oxi-
dant levels. There was no evidence for ozone enhancement due to long range
transport or natural mechanisms on this day.
77
-------
Figure 23. High ozone region to the west of Houston on the afternoon of July
8, 1976 (see Appendix B for flight details).
78
-------
Figure 24 shows the diurnal behavior pattern of various ambient pollu-
tants on July 8. The data used to construct this diagram were gathered at
the WSU trailer site in northwest Houston. All of the diurnal pollutant
changes shown in Figure 24 are consistent with a photochemical oxidant pro-
ducing mechanism. Following the N0-N02 cross-over time (^ 9 am), ozone lev-
els developed rapidly, reaching a peak hourly average at 3 pm CDT and then
dropping off to less than 50 ppb by 5 pm. PAN production correlated closely
with ozone formation after an initial lag of about one hour. Non-methane
hydrocarbon and nitric oxide concentrations decreased throughout the morning
hours. The morning Hc/NOY ratio was about 8 at the ground level monitoring
/\
site. This is in the range favorable for oxidant production.
The one inconsistency in the ground data is the Og-NC^/NO relationship
during the afternoon hours when ozone concentrations were at their maximum.
The N02/N0 ratio was about 6, which is at least a factor of 2 below what it
should be based on photochemical stationary state conditions. This is one
feature that we observed quite often in air masses that contained ozone lev-
els greater than 100 ppb. We suspect that our nitrogen oxide monitors pos-
sess insufficient accuracy when NO levels are less than 5 ppb. For example,
afternoon N02 levels on July 8 varied between 20 and 26 ppb, while concurrent
NO concentrations averaged 4 ppb. If the NO concentration was actually 2 ppb
or less, the N02/N0 ratio would have been compatible with the 150 to 180 ppb
ambient ozone concentration.
Individual hydrocarbon concentrations measured at various times and lo-
cations on July 8 are summarized in Tables 20, 21, 22 and 23. The two air-
craft samples collected during the morning hours (Tables 20 and 21) are con-
sistent with an east to west air movement during the morning hours. The
o
53.5 yg/rrr of hydrocarbons in sample A-l collected east of Baytown at about
9:15 is in the range normally representative of background air. Carbon mon-
oxide, fl uorocarbon-11 and carbon tetrachloride concentrations were also typ-
ical of those encountered in background air. By contrast, the sample col-
o
lected to the west of Houston (A-2, Table 21) contained a total of 404 yg/m
of hydrocarbons. The anthropogenic tracers, carbon monoxide, F-ll and
were 3 to 6 times more concentrated in this sample.
79
-------
00
o
03
NO
(ppb)
8
10 12 14
TIME Of DAY
16
18
20
22
NMTHC
PAN
4(ppbxK»
H .2
Figure 24. Pollutant changes at the WSU trailer site on July 8, 1976.
-------
TABLE 20. HYDROCARBON, HALOCARBON AND CO LEVELS IN SAMPLE A-l COLLECTED E,
OF BAYTOWN (30001) AT 9:15 AM ON JULY 8, 1976.
yg/m3
Hydrocarbon
yg/m3
Hydrocarbon
2.5
1.0
4.0
1.0
2.0
2.0
1.0
1.5
1.0
1.0
1.0
1.5
1.0
1.0
1.0
5.0
.5
Ethane
Ethylene
Acetylene
Propane
Propene
i-Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
t-2-Pentene
c-2-Pentene
Cyclopentene
Cyclopentane
2,3-Dimethylbutane
2-Methylpentane
c-4-Methyl-2-Pentene
3-Methylpentane
1-Hexene
n-Hexane
t-2-Hexene
c-2-Hexene
Methylcyclopentane
2,4-Dimethylpentane
Benzene
Cyclohexane
1.5
2.5
9.0
2.0
2.0
2.5
1.0
1.5
i.n
.5
1.0
1.0
1.0
1.0
1.0
1.0
2,3-Dimethylpentane
3-Methylhexane
2,2,3-Trimethylpentane
n-Heptane
Methylcyclohexane
2,4-Dimethylhexane
2,3,4-Trimethylpentane
Toluene
2,3-Dimethylhexane
2-Methylheptane
3-Ethylhexane
n-Octane
Ethylcyclohexane
Ethyl benzene
p & m-Xylene
Styrene
o-Xylene
n-Nonane
i-Propylbenzene
n-Propylbenzene
p-Ethyltoluene
m-Ethyltoluene
o-Ethyltoluene
1 ,3,5-Trimethylbenzene
1 ,2,4-Trimethylbenzene
1 ,2,3-Trimethylbenzene
Methylstyrene
1 ,3-Diethyl benzene
1 ,4-Diethylbenzene
Total Individual
Hydrocarbons
l Olefin
z Aromatic
E Paraffin
TOTAL
53.5
8
45
47
CH4(ppm) 2.0
CO(ppm) .5
CFCl3(ppt) 149
CClJppt) 198
-- Less than .5ug/m3
81
-------
TABLE 21 . HYDROCARBON, HALOCARBON AND CO LEVELS IN SAMPLE A-2 COLLECTED W.
OF HOUSTON (10001) AT 10:10 AM ON JULY 8, 1976.
yg/m3 Hydrocarbon
14.5 Ethane
19.5 Ethyl ene
8.5 Acetylene
26.0 Propane
14.0 Propene
34.5 i -Butane
31.0 n-Butane
3.5 1-Butene
3.5 i-Butene
t-2-Butene
c-2-Butene
35.0 i-Pentane
18.0 n-Pentane
5.5 1-Pentene
1.5 t-2-Pentene
3.0 c-2-Pentene
3.5 Cyclopentene
2.5 Cyclopentane
2.5 2, 3-Dimethyl butane
10.5 2-Methylpentane
2.5 c-4-Methyl-2-Pentene
11.5 3-Methyl pentane
2.5 1-Hexene
11.0 n-Hexane
1.0 t-2-Hexene
c-2-Hexene
5.5 Methyl cyclopentane
2.0 2, 4-Dimethyl pentane
13.5 Benzene
9.5 Cyclohexane
Total Individual
Hydrocarbons yg/m3 %
T. Olefin 60 15
z Aromatic 89 22
E Paraffin 255 63
TOTAL 404
yg/m3
8.0
in.o
5.0
3.5
--
1.5
1.0
27.0
1.0
3.5
2.0
2.5
1.0
4.5
13.0
2.0
6.0
2.0
1.5
1.5
4.5
—
2.0
3.0
5.5
2.0
.5
1.5
1.0
Hydrocarbon
2 , 3-Dimethyl pentane
3-Methyl hexane
2 ,2 ,3-Trimethyl pentane
n-Heptane
Methyl cycl ohexane
2, 4-Dimethyl hexane
2 ,3 ,4-Trimethyl pentane
Toluene
2, 3-Dimethyl hexane
2-Methyl heptane
3-Ethyl hexane
n-Octane
Ethyl cycl ohexane
. Ethyl benzene
~p & m-Xylene
Styrene
o-Xylene
n-Nonane
i-Propyl benzene
n-Propyl benzene
p-Ethyl toluene
m-Ethyl toluene
o-Ethyl toluene
1 , 3, 5-Trimethyl benzene
1 , 2, 4-Trimethyl benzene
1 , 2, 3-Trimethyl benzene
Methyl styrene
1 ,3-Di ethyl benzene
1 ,4-Diethyl benzene
CH^ppm) 2.1
CO(ppm) 1.6
CFCl3(ppt) 556
CCMppt) 1218
— Less than .5yg/m3
82
-------
TABLE 22 . HYDROCARBON, HALOCARBON AND CO LEVELS IN SAMPLE A-3 COLLECTED N,
OF HOUSTON (12501) AT 4:00 PM ON JULY 8, 1976.
ug/m3
Hydrocarbon
8.5 Ethane
Ethylene
6.5 Acetylene
28.5 Propane
3.0 Propene
25.0 i-Butane
24.5 n-Butane
1.0 1-Butene
1.5 i-Butene
1.0 t-2-Butene
c-2-Butene
21.5 i-Pentane
13.0 n-Pentane
3.0 1-Pentene
t-2-Pentene
1.5 c-2-Pentene
2.0 Cyclopentene
1.5 Cyclopentane
1.0 2,3-Dimethylbutane
6.5 2-Methylpentane
1.5 c-4-Methyl-2-Pentene
5.0 3-Methylpentane
1-Hexene
7.0 n-Hexane
t-2-Hexene
c-2-Hexene
2.5 Methylcyclopentane
1.0 2,4-Dimethylpentane
10.0 Benzene
7.5 Cyclohexane
yg/m3
Hydrocarbon
3.0 2,3-Dimethylpentane
7.0 3-Methylhexane
2.0 2,2,3-Trimethylpentane
2.0 n-Heptane
1.5 Methylcyclohexane
1.0 2,4-Dimethylhexane
2,3,4-Trimethylpentane
11.5 Toluene
1.0 2,3-Dimethylhexane
4.0 2-Methyl heptane
2.5 3-Ethylhexane
1.0 n-Octane
Ethylcyclohexane
3.0 Ethyl benzene
4.0 p & m-Xylene
1.0 Styrene
3.0 o-Xylene
1.0 n-Nonane
i-Propylbenzene
1.0 n-Propylbenzene
2.0 p-Ethyltoluene
m-Ethyltoluene
1.0 o-Ethyltoluene
2.0 1,3,5-Trimethylbenzene
1.5 1,2,4-Trimethylbenzene
1.0 1,2,3-Trimethylbenzene
1.0 Methylstyrene
1,3-Diethyl benzene
1.5 1,4-Di ethyl benzene
Total Individual
Hydrocarbons
E Olefin
I Aromatic
E Paraffin
TOTAL
pg/m3
14.5
43.5
179
237
%
6
18
76
CHjppm)
CO ( ppm )
CFCl3(ppt)
CClJppt)
2.2
.9
290
597
-- Less than .5yg/m3
* Value questionable
83
-------
TABLE 23. HYDROCARBON LEVELS IN 6-9 AM WSU TRAILER SAMPLE ON JULY 8, 1976,
yg/m3
Hydrocarbon
pg/m;
Hydrocarbon
19.0
20.0
20.0
46.0
26.0
51.0
69.0
6.0
8.0
10.0
90.0
45.5
6.0
4.5
6.5
7.0
24.0
6.0
21.5
4.0
16.0
2.0
11.0
4.0
18.0
11.0
Ethane
Ethylene
Acetylene
Propane
Propene
i-Butane
n-Butane
1-Butene
i-Butene
t-2-Butene
c-2-Butene
i-Pentane
n-Pentane
1-Pentene
t-2-Pentene
c-2-Pentene
Cyclopentene
Cyclopentane
2,3-Dimethylbutane
2-Methylpentane
c-4-Methyl-2-Pentene
3-Methylpentane
1-Hexene
n-Hexane
t-2-Hexene
c-2-Hexene
Methylcyclopentane
2,4-Dimethylpentane
Benzene
Cyclohexane
14.5 2,3-Dimethylpentane
14.0 3-Methylhexane
8.5 2,2,3-Trimethylpentane
8.5 n-Heptane
7.5 Methylcyclohexane
3.0 2,4-Dimethylhexane
2,3,4-Trimethylpentane
35.0 Toluene
1.5 2,3-Dimethylhexane
6.0 2-Methyl heptane
5.0 3-Ethylhexane
3.5 n-Octane
3.5 Ethylcyclohexane
7.5 Ethyl benzene
20.0 p & m-Xylene
4.5 Styrene
11.5 o-Xylene
3.5 n-Nonane
1.5 i-Propylbenzene
3.5 n-Propylbenzene
9.0 p-Ethyltoluene
m-Ethyltoluene
4.0 o-Ethyltoluene
5.0 1 ,3,5-Trimethylbenzene
9.5 1,2,4-Trimethylbenzene
3.5 1,2,3-Trimethylbenzene
1.5 Methylstyrene
1.0 1,3-Di ethyl benzene
2.0 1,4-Di ethyl benzene
Total Individual
Hydrocarbons
X Olefin
x Aromatic
E Paraffin
TOTAL
92.5
137
500.5
730
13
19
68
CH^Cppm)
CO(ppm)
CFCl3(ppt)
CClJppt)
— Less than .5yg/m3
..84
-------
Hydrocarbon changes from morning to afternoon are supportive of photo-
chemical oxidant production on July 8. Table 24 lists various hydrocarbon/
acetylene ratios in the morning air mass west of Houston and in the more aged
air mass found in the same area during the afternoon hours. The ratios all
show a decrease in the aged air mass, as would be expected. Benzene shows
the least change, which is in agreement with smog chamber experiments that
have shown it to be unreactive in atmospheric photochemical simulation exper-
iments. Olefins with a 69% decrease in ratio showed the largest change, fol-
lowed by aromatics at 36% and paraffins with an 8% loss. The relative order
of change for these three hydrocarbon classes is consistent with that pre-
dicted from chamber experiments.
Very little aerometric data have been published with which we can com-
pare the data in Table 24. This is especially true of cases in which the
same air mass was followed throughout the diurnal period. Calvert (20) has
provided an indepth analysis of LARPP data collected in Los Angeles on
November 5, 1973. He established a fractional removal rate for propene of
about 8% hr. based on aircraft data collected between 8 am and 2 pm. Based
on the data in Table 24, propene disappeared at a rate of about 11% hr.
in Houston between 10 am and 4 pm on July 8, 1976, The two numbers agree
fairly well considering the differences in meteorology, light intensity, etc.,
that certainly existed.
TABLE 24. HYDROCARBON-ACETYLENE RATIOS IN MORNING AND AFTERNOON AIR MASSES
ON JULY 8, 1976.
propene/ acetylene
2-methyl pentane/acetyl ene
benzene/acetyl ene
to! uene/acetyl ene
£ol ef i ns/acetyl ene
Earomati c/acetyl ene
Eparaf f i ns/acetyl ene
AM
1.6
1.2
1.6
3.2
7.0
10.5
30.0
PM
.5
1.0
1.5
1.7
2.2
6.7
27.5
% Change
-68
-17
- 6
-47
-69
-36
- 8
-------
OXIDES OF NITROGEN
The nitric oxide record at the northwest Houston sampling site resembled
the diurnal pattern generally observed in urban areas. The highest hourly
average was normally observed during the 6 to 9 am rush traffic period. Peak
levels that often approached 100 ppb during the morning injection period de-
creased rapidly to the 25 ppb range or less by early afternoon. On after-
noons when high oxidant levels were recorded at the northwest sampling site,
nitric oxide levels were below 5 ppb.
With the exception of a few periods during the last-week of the study,
nitrogen dioxide concentrations seldom exceeded 50 ppb at the WSU trailer
site. Daily N02 peak concentrations were commonly observed during the mid-
afternoon hours. Hourly average N02 and NO readings at the northwest Houston
site are tabulated on a daily basis in Appendix A.
Oxides of nitrogen measurements are important because of the integral
part NO and N02 play in atmospheric photochemical processes. The amount of
ozone produced is significantly affected by the hydrocarbon to NOX ratio.
In NOX rich atmospheres (Hc/N0x <5) oxidant production is retarded, however,
when the hydrocarbon and NOX mixture exists in proportions of about 10 to 1
conditions are optimum for secondary pollutant production. Figure 25 shows
a plot of the 6 to 9 am hydrocarbon and NOX concentrations recorded at ground
level in northwest Houston. In most instances the Hc/N0x ratio fell in the
range of 7.5 to 18.5 with the average being about 11.5. How representative
this value is of the Houston area in general is difficult to assess. We did
not operate continuous NOX monitors at the north and south Houston hydrocar-
bon sampling sites. However, a NOX reading was made on the Teflon bag sam-
ples collected for hydrocarbon analysis at these two sites. Based on about
10 samples from each location the Hc/N0x ratio in south Houston averaged 30,
while that at the north site averaged 83. We feel that a higher Hc/N0x ratio
should be observed at these two sites, because they are closer to the ship
channel chemical complex; however, the absolute magnitude should be consid-
ered with caution because of the bag sampling method utilized may have re-
sulted in some loss of NOX on the walls.
The real time NOX monitor carried aboard the aircraft provided a means
of acquiring information concerning hydrocarbon/NOx ratios at various loca-
86
-------
.20
.18
.16
.14
NOX .12
(ppm)
.10
.08
.06
.04
.02
0
= 18.5
.5
1.0 1.5 2.0 2.5
NMTHC(ppm)
J
30
Figure 25. Ground level 6-9 am hydrocarbon and NOX concentrations
recorded at the WSU trailer site.
87
-------
tions and altitudes over Houston. Table 25 provides a summary of the ratio
observed in air masses exhibiting photochemical activity. It can be seen
that the average Hc/N0x ratio recorded in these "high ozone" areas is essen-
tially the same as the average determined at ground level in NW Houston
between 6 and 9 am. There is some indication that as the air mass ages the
ratio increases since the highest ratios in Table 25 were recorded late in
the day.
TABLE 25. HYDROCARBON/NOX RATIOS IN "HIGH OXIDANT" AREAS AROUND HOUSTON
Sample Code
and Date
A-3
A-l
A/2
A-3
A-4
A -2
A-3
A-2
A-3
7/8
7/10
7/10
7/12
7/12
7/14
7/14
7/20
7/20
Collection
Time
1555
1525
1536
1115
1705
1415
1428
1815
1825
He
(ppm)
.45
.44
.52
.40
.41
.41
.63
.43
.28
NOX
(ppm)
.053
.035
.041
.048
.030
.042
.078
.035
.018
Hc/N0x
8.4
12.6
12.7
8.3
12.4
8.5
8.1
12.3
15.5
Remarks
03 =
°3 =
o3 =
°3 =
o3 =
°3 =
o3 =
°3 =
°3 =
200 ppb
125
no
110
186
120
100
140
no
AVERAGE Hc/N0x =10.9
Several other categories of interest as far as hydrocarbon/NOx ratios
are concerned are listed in Table 26. These data were collected on aircraft
flights throughout the study period. The background and petrochemical cate-
gories exhibit higher hydrocarbon/NOx ratios (28 and 24) than the ratio (12)
in samples collected over or downwind of the Houston urban area during the
early morning hours. It should be noted that the number of samples in each
of the three classifications is small and consequently more data would be
required for highly reliable averages.
-------
TABLE 26. HYDROCARBON/NOX RATIOS IN VARIOUS TYPES OF AIR MASSES.
Background Air
Urban Plume
(Low Ozone)
Ref i nery PI ume
AVERAGE HC/NOV RATIO
28
12
24
No. of Samples
2
4
4
HALOCARBONS
Fluorocarbon-11 , methyl chloroform (1,1 ,1-trichloroethane), carbon tet-
rachloride, fluorocarbon-113, chlorofonm and trichloroethylene concentrations
were monitored continuously at the sampling site in northwest Houston. The
ambient concentrations of these halocarbon species were also determined in
aircraft collected samples and some ground level grab samples. Table 27 pro-
r
vides a summary of various halocarbon data sets. The individual measurements
used to arrive at the averages in Table 27 are tabulated in Appendix A.
Ambient fluorocarbon-11 concentrations at the ground level trailer site
were generally highest during the early morning hours. We calculated an av-
erage concentration of 649 ppt for the period from 0100 to 0800. This com-
pares to 405 ppt during the midday period and 509 ppt during the evening
hours. This range of about 400 to 650 ppt for F-ll is similar to that meas-
ured in the Los Angeles atmosphere. For example, Simmonds, et al., (21) re-
ported an average F-ll concentration of 650 ppt during a three day sampling
program conducted at various sites in the Los Angeles Basin.
The average ambient F-ll concentrations at ground level in Houston gener-
ally exceeded the tropospheric background level -\, 140 ppt by at least a fac-
tor of three. This difference provides a basis for using F-ll as a tracer of
man's activities. The 258 ppt average F-ll concentration in air masses con-
taining elevated ozone (Table 27) is well above the background level. Fur-
thermore, all of the samples included in the high ozone category of Table 27
89
-------
exhibited F-ll concentrations greater than 190 ppt with several approaching
300 ppt. These data support the earlier stated contention that anthropogenic
precursors were the primary source of oxidants measured in and around Houston
during July, 1976. F-ll emissions in the Houston area appear to differ some-
what on weekdays and weekends. As can be seen in Table 27, weekend averages
were approximately 15% lower than those recorded during the week.
The ambient CC14 concentrations measured in the Houston vicinity are
higher than the levels recorded in Los Angeles. An average concentration
of 220 ppt was reported in the Los Angeles Basin study referred to previously
(21). Table 27 shows that ground level CC14 exhibited little diurnal vari-
ation. When all sampling days are considered, there is less than 25 ppt dif-
ference between the early morning, midday and evening averaging periods.
This diurnal behavior seems to imply that an increase in CCl^ emissions occurs
durring normal working hours. It can be seen in Table 27 that the highest
average was recorded during the 9 am to 4 pm period on weekdays.
If the diurnal emission rate was relatively constant, a decrease in con-
centration would be expected during midday when atmospheric mixing is at a
maximum.
VISIBILITY AND PARTICLES
The relationship between visibility and ozone concentration in the
Houston atmosphere has been reported to vary considerably. On some occasions,
reduced visibility will coincide with elevated ozone levels. However, at
other times, episode ozone conditions will exist and yet visibility will be
good. The opposite also appears to be true, since there are times when visi-
bility is restricted and ozone levels are low. These findings have provided
a basis for the argument that chemical transformations in the Houston atmos-
phere differ from those in the Los Angeles Basin (22).
Our airborne data indicates that a positive correlation always existed
between enhanced ozone levels and decreased visibility in the plume downwind
of Houston. Figure 26 shows data recorded during a pass across the plume at
a distance of about 90 miles from Houston on the afternoon of July 12 (see
darkened line in Figure 22). Maxima and minima in the bscat and ozone curves
90
-------
TABLE 27. HALOCARBON CONCENTRATIONS IN THE HOUSTON AREA.
CFC13 CH3CC13 CCli,
ALL DAYS AT TRAILER SITE
0100 - 0800 649 964 369
0900 - 1600 405 680 349
1700 - 2400 509 910 345
WEEKDAYS AT TRAILER SITE
0100 - 0800 683 1214 365
0900 - 1600 432 908 385
1700 - 2400 526 1230 354
WEEKENDS AT TRAILER SITE
0100 - 0800 565 495 375
• 0900 - 1600 336 253 282
1700 - 2400 468 312 327
AIRCRAFT SAMPLES COLLECTED IN "BACKGROUND" AIR
176 — 218
AIRCRAFT SAMPLES COLLECTED IN HIGH OZONE
258 — 502
91
-------
are coincidental. Figure 27 provides a second example of this type of
visibility-ozone correlation. Data in this graph were collected on the same
flight about 45 miles from Houston. Measurements in the main section of the
plume show both high ozone and high scattering coefficient. This relation-
ship persists in the vertical plume profile as well. Figure 28 shows that
ozone and bscat values are highest in the 3000 feet immediately above the
surface and then both decrease in the region from 3000 to 5000 feet.
In air masses directly over Houston, there were occasions when the cor-
relation between high ozone and elevated bscat readings was not as good.
Figure 29 shows a case where the greatest degradation in visibility was dis-
placed somewhat from the region of highest ozone. The reason for this appears
to be that the section of the plume with highest bscat values also contained
high NOX levels which scavenged a significant portion of the ozone. This be-
havior is not entirely unexpected in the region close to ship channel emission
sources, since the air mass has not had time to become completely mixed.
Filter tapes for sulfate analysis were collected during five aircraft
flights. Several seven minute integrated samples were obtained on each of
the five flights. Sulfate concentrations were found to vary from less than
0.1 to 10.8 yg/m3. Since the samples were collected over distances of about
15 miles, it is difficult to relate high sulfate readings to specific sources,
however, it does seem that the highest sulfate levels were recorded in areas
downwind of the ship channel industrial area. Figure 30 shows the location
of sulfate samples collected during the afternoon flight on July 22. Winds
on that afternoon were from the southeast (110-130°). Sample #3 which was
collected to the southeast of Baytown (upwind) contained the least sulfate
(< 0.1 yg/m3) while samples 2, 4 and 5, which were obtained in the region
influenced to the greatest extent by the industrial plume, contained up to
10 yg/m3 of sulfate. The two samples collected further to the west (#1 and
#6) contained less than 1 yg/m3 sulfate. These latter two samples probably
represent emissions emanating more from the downtown Houston area.
Sulfate data collected on other days differed very little from that just
described for July 22. Concentrations never exceeded 11 yg/m3 and for the
o
most part, ranged from 0.5 to 6.0 yg/m.
92
-------
co
scat z-
(10" V)
1680
1628 1632
RJOHT TIME
1636
1640
(ppb)
Figure 26. Relationship between ozone concentration and
b values in plume approximately 90 miles
downwind Houston (Fit. #10; July 12, 1976).
-------
scot
1544
i
1548 1552 1556
FUSHT T1«€
1604
(ppb)
Figure 27. Relationship between ozone concentration and
b . values in plume approximately 45 miles
downwind Houston (Fit. #10; July 12, 1976).
-------
cn
DSCdt
(idV)
6 -
5 -
4 -
3 -
— o
— b
scot
KXX)
2000
3000
(FT.)
L- 2OO
>- ISO
03
-160(ppb)
- 140
- 120
- 100
4000
5000
Figure 28. Relationship observed between ozone concentration
and b . values during vertical sounding in Houston
plume (Fit. #10; July 12, 1976.
-------
10
8
6 -
bscat
(KTV) *
4 -
1546
1550
I6O6
TtltC
Figure 29. Relationship between ozone concentration and
b values directly over Houston (Fit. #7;
July 8, 1976).
-------
TEXAS
Sulfate #1
Sulfate #2
Sulfate #3
|a II.SffM.
M/ro
0.2
1.7
Sulfate #4
Sulfate #5
Sulfate #6
2.0
10.1
0.7
Figure 30. Sulfate data obtained during the afternoon of July 22, 1976
(Fit #26 - see Appendix B for details).
-------
REFERENCES
1. Requirements for Preparation, Adoption, and Submittal of Implementation
Plans. Title 40, Code of Federal Regulations: Part 51. (1971).
2. Tannahill, G. K. The Hydrocarbon/Ozone Relationship in Texas. In:
Proceedings Ozone/Oxidants Interactions with the Total Environment
Speciality Conference - Air Pollution Control Association. Dallas, TX.,
March, 1976.
3. Adams, D. F. and R. K. Koppe. Instrumenting Light Aircraft for Air
Pollution Research. J. Air Poll. Control Assoc., 19(6): 410-415, 1969.
4. Macias, E. S., R. B. Husar and J. C. Husar. Monitoring of Atmospheric
Aerosol Mass and Sulfur Concentration. In: Proceedings of the
International Conference on Environmental Sensing and Assessment, Las
Vegas, Nevada, 1975.
5. Far-well, S. 0. and D. F- Adams. Sulfur Analysis by Capacitive Dis-
charge - Flash Vaporization. Manuscript in preparation.
6. Farwell, S. 0., H. H. Westberg, K. J. Allwine, and N. K. Shrauger. Mini-
Computer Data Processing System for Air Monitoring Studies. Analytical
Chemistry, 49(3): A357-A368, 1977.
7. Wagner, A. J. Weather and Circulation of July 1976. Monthly Weather
Review, 104(10): 1333, 1976.
8. Lonneman, W. A. and J. J. Bufalini. Hydrocarbon Analysis of Houston
Atmosphere. U.S. Environmental Protection Agency Memorandum, September,
1973.
9. McMurry, J. R., R. Flannery, L. H. Fowler, and D. J. Johnson. Ambient
Sampling for Stationary and Mobile Source Hydrocarbons in Houston, TX.
In: Proceedings of Annual Air Pollution Control Association Meeting,
Boston MA., June, 1975.
10. Siddiqi, A. A. and F. L. Worley. Urban and Industrial Air Pollution in
Houston, Texas - I. Hydrocarbons. Atmospheric Environment, 11: 131-143,
1977.
11. Gise, J. P. Recent Ozone Trends in Texas. In: Proceedings of American
Institute of Chemical Engineers 83rd National Meeting, Houston, TX.,
March, 1977.
98
-------
12. MacKenzie, K. A Review of the Relationship Between Ambient Total Non-
Methane Hydrocarbon Concentrations and Ambient Ozone Levels in Houston.
In: Proceedings Ozone/Oxidants Interactions with the Total Environment
Speciality Conference - Air Pollution Control Association. Dallas, TX.,
March, 1976.
13. Price, J. H. A Study of Factors Associated with High Urban Ozone
Concentrations in Texas. In: Proceedings Ozone/Oxidants Interactions
with the Total Environment Speciality Conference - Air Pollution Control
Association. Dallas, TX., March, 1976.
14. Singh, H. B., F- L. Ludwig and W. B. Johnson. Ozone in Clean Remote
Atmospheres: Concentrations and Variabilities. Stanford Research
Institute Final Report Prepared for The Coordinating Research Council,
Inc., June, 1977.
15. Westberg, H. The Issue of Natural Organic Emissions - Review and Analy-
sis. EPA-600/3-77-116, U.S. Environmental Protection Agency, Research
Triangle Park, NC, 1977.
16. Whitehead, L. and R. K. Severs. Background Hydrocarbon Levels in East
Texas. In: Proceedings of American Institute of Chemical Engineers
83rd National Meeting, Houston, TX., March, 1977-
17. Lonneman, W. A., J. J. Bufalini and R. L. Seila. PAN and Oxidant
Measurement in Ambient Atmospheres. Environmental Science and Techno-
logy, 10(4): 374-380, 1976.
18. Bufalini, J. J. Private Communication. 1978.
19. Dimitriades, B. Effect of Hydrocarbon and Nitrogen Oxides on Photo-
chemical Smog Formation. Environmental Science and Technology, 6: 253,
1972.
20. Calvert, J. G. Hydrocarbon Involvement in Photochemical Smog Formation
in Los Angeles Atmosphere. Environmental Science and Technology, 10(3):
256-262, 1976.
21. Simmonds, P. G., S. L. Kerrin, J. E. Lovelock and F. H. Shair. Distri-
bution of Atmospheric Halocarbons in the Air over the Los Angeles Basin.
Atmospheric Environment, 8: 209-216, 1974.
22. Program Description of the Houston Area Oxidants Study. Houston Chamber
of Commerce. Houston, Texas. June, 1976.
99
-------
TABLE A2 . SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 2, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
ppb
5
9
8
5
6
1
0
1
15
22
19
20
21
31
24
19
19
17
9
4
4
4
6
4
NO
ppb
6
5
5
7
6
16
67
59
25
10
10
10
10
19
14
12
16
14
12
11
9
8
7
6
N02
ppb
5
2
3
5
3
11
18
23
14
6
3
3
3
7
8
4
7
4
7
9
9
9
8
9
GAS DATA
NMTHC CO
ppmC ppm
.8 .9
.7 .7
.7 .6
.7 .5
.8 .6
.7 .7
.7 1.2
1.2 2.8
1.1 2.3
1.1 1.1
.6 1.0
.2 .8
.3 .9
.3 .9
.4 .9
.4 1.1
.4 1.2
.5 1.1
__ — _
__ --
_ _ .._
«*. .. _
__ -_
.7 .9
CH4 CFCI3
ppm ppt
2.5 -
2.7 --
2.7 --
2.8 --
2.9 —
2.9 --
3.0 —
3.5 —
3.4 —
2.1 —
2.0 —
2.0 -
1.9 ~
1.9 —
1.8 170
1.8 236
1.8 219
1.8 153
265
214
203
208
285
2.9 198
cci4
ppt
1— Ml
--
__
--
--
--
--
--
165
163
159
151
168
—
—
128
86
151
CH CCI3
ppt
_ _
--
—
—
—
-_
--
—
--
__
—
--
--
__
227
546
700
261
225
--
—
204
533
137
MET. DATA
WS WD O^ TMP
knt deg deg °F
6 200
7 200
4 190
5 190
4 180
5 190
4 190
8 200
12 190
15 190
12 190
14 200
13 200
13 200
15 190
15 190
14 190
12 200
8 180
9 180
7 190
7 190
7 180
5 170
25 78
25 78
27 77
25 76
18 75
18 74
20 77
20 82
29 87
23 90
29 90
27 92
27 91
26 92
30 90
29 91
26 90
30 90
32 82
27 80
28 79
32 79
30 78
30 78
DP RAD
°F mLy
70 0
71 0
71 0
71 0
70 0
69 0
70 157
71 348
71 645
70 1009
70 1231
70 958
71 1422
69 1398
70 756
69 1006
69 969
70 778
69 92
71 0
71 0
71 0
71 0
71 0
BARO
"Hg
29.99
29.98
29.99
30.00
30.00
30.02
30.03
30.04
30.04
30.04
30.04
30.04
30.03
30.01
30.01
30.00
30.00
30.00
29.99
29.99
29.99
30.02
30.03
30 04
102
-------
TABLE Al. SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 1, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
°3
ppb
— _
--
—
1
1
4
4
5
15
21
27
38
52
49
32
28
34
21
21
22
4
0
0
2400 0
NO
ppb
— — m
—
—
15
12
20
37
54
20
10
10
9
9
8
13
12
18
13
11
10
13
15
13
9
N02
Ppb
B «•
14
12
30
37
40
19
6
3
2
4
5
6
4
8
8
9
13
13
13
12
10
GAS DATA
NMTHC CO
ppmC ppm
-
--
--
— __
—
—
--
--
--
__
—
--
--
--
—
—
.6 1.2
.6 1.1
.5 1.1
.7 1.4
—
1.2 1.4
.8 1.3
.8 1.1
CH4 CFCI3 CCI4 CH3CCI3
ppm ppt ppt ppt
--
— — — _ __ __
™™ —— — — «_
-- -- _- __
—
--
--
— — — — __ — _
—
— — — — — — -_
--
— — — _ __ __
— — — —
—
— — — — — — __
2.1
2.1
2.1
2.4
—
3.0
3.0
MET.
WS
knt
4
4
6
10
7
6
5
7
9
11
8
5
8
10
11
15
11
8
10
7
7
7
8
3.2 — — -- 9
WD
deg
190
190
190
70
120
190
190
190
220
220
240
210
200
200
190
190
190
190
190
190
190
190
190
190
o^
deg
12
14
10
10
8
23
23
25
22
12
13
21
18
21
23
27
26
26
28
27
24
27
29
32
DATA
TMP
°F
76
75 .
74
74
74
76
76
81
85
87
91
93
94
95
93
93
92
91
89
85
82
80
79
78
DP RAD
°F mLy
0
0
0
0
0
0
— 103
-- 389
-- 696
— 805
— 985
68 1360
67 1348
67 1391
67 873
67 761
66 769
66 494
66 298
66 97
69 0
69 0
70 0
70 0
BARO
"Hg
29.99
30.00
30.00
30.02
30.01
30.01
30.02
30.02
30.02
30.03
30.03
30.01
29.99
29.98
29.99
29.99
29.98
29.98
29.97
29.99
30.02
30.02
30.01
30.00
101
-------
APPENDIX A
Ozone, nitric oxide, nitrogen dioxide, non-methane total hydrocarbon,
carbon monoxide, methane, fluorocarbon-11, carbon tetrachloride and methyl
chlorofrom concentrations recorded at the WSU trailer site are listed in
this section. Meteorological parameters including wind speed, wind di-
rection, temperature, dew point, relative humidity, Solar radiation and
barometric pressure are also tabulated. The data are compiled on a
daily basis and recorded as hourly averages. Time is Central Daylight
Time.
100
-------
TABLE A3 . SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 3, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
7
6
6
5
5
4
11
16
20
21
21
24
24
26
20
12
9
5
0
0
0
0
0
0
GAS DATA MET. DATA
NO N02 NMTHC CO CH4 CFC13 CCI4 CH3CCI3 WS WD Q^ TMP DP RAD BARO
ppb ppb ppmC ppm ppm ppt ppt ppt knl deg deg °F °F mLy "Hg
57 .6 .8 2.0 201 156 651 7 170 28 /8 71 0 30.03
56 .6 .7 1.9 183 154 411 5 170 25 77 7] 0 30.03
55 .6 .6 1.9 251 159 164 4 160 20 77 72 Q 30.02
57 .5 .6 1.9 217 172 741 4 180 22 76 72 o 30 02
66 .5 .7 2.0 219 170 561 5 180 24 76 72 0 30.03
9 10 .9 .8 2.0 216 166 753 6 190 23 79 72 157 30.03
11 9 .9 .9 2.0 300 242 117 7 190 33 84 73 434 30.06
11 7 1.1 1.1 2.0 266 398 213 8 190 26 86 73 626 30.06
11 4 I.I 1.0 2.1 208 272 130 8 190 29 87 73 753 30.07
10 3 .8 .9 2.1 174 -465 247 15 190 31 89 73 879 30.06
94 .6 .8 2.2 201 255 107 10 200 22 89 73 942 30.06
84 .6 .8 2.1 199 291 91 15 190 27 90 73 681 30.05
84 .3 .8 2.0 205 181 126 14 190 8 91 73 1250 30.04
83 .3 .9 2.0 221 236 209 23 190 18 93 72 1005 30.03
10 5 .4 1.1 2.0 222 167 112 13 190 31 90 74 768 30.00
94 .3 1.0 2.0 232 175 90 17 230 23 79 74 334 30.04
16 8 .3 1.1 2.0 241 230 201 calm 27 85 75 693 30.01
15 9 1.3 1.4 2.2 250 505 449 10 190 19 82 74 200 29.99
23 12 1.1 I./ 2.2 297 403 367 8 190 22 82 75 127 30.00
13 8 .8 1.7 2.2 313 167 115 5 190 26 82 74 43 30.01
12 8 .9 1.4 2.2 329 180 190 8 190 27 81 73 0 30.00
10 5 1.2 1.3 2.1 999 174 153 5 190 23 80 73 0 30 02
16 8 .2 1.2 2.2 443 231 108 6 190 27 80 73 0 30 02
12 8 .2 1.1 1.8 354 245 115 7 190 30 80 73 0 3002
103
-------
TABLE A4 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 4, 1976
Time 0,
hr ppb
0100 0
0200 0
0300 0
0400 0
0500
0600 0
0700 0
0800 1
0900 3
1000 5
1100 9
1200 12
1300 28
1400 31
1500 36
1600 36
1700
1800 17
1900 19
2000 9
2100
2200 4
2300 0
2400 0
NO
ppb
13
12
7
4
__
10
26
13
8
7
6
7
9
5
6
7
—
8
8
11
--
16
15
15
N02
ppb
13
10
6
4
__
5
7
6
2
1
1
1
3
3
2
3
--
7
13
22
--
19
21
21
GAS DATA MET. DATA
NMTHC CO CH4 CFCIj CCI4 CH3CCI3 WS WD Q^ TMP DP RAD BARO
ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy "Hg
.3 1.1 1.9 301 380 271 5 190 26 79 73 0 30.02
.2 1.0 2.0 400 339 138 6 180 22 78 73 0 30.02
.3 .8 2.2 275 267 128 6 190 24 78 73 0 30.01
.4 .6 2.4 298 246 225 4 190 21 77 73 0 30.01
.5 .5 2.4 286 232 170 4 180 30.01
.6 .7 2.6 335 241 191 calm 9 75 72 10 30.03
.8 1.6 2.9 439 226 1022 4 160 8 76 73 108 30.03
.6 1.1 3.0 515 846 418 3 210 21 82 74 378 30.05
.5 .9 2.9 291 183 100 5 190 25 85 74 461 30.05
.4 .8 2.9 320 182 80 7 190 27 86 77 580 30.05
.2 .6 2.3 286 189 223 8 170 29 87 72 692 30.05
.2 .7 2.1 236 173 148 7 200 24 90 72 1146 30.05
.2 .8 2.0 211 182 174 6 190 24 91 71 915 30.02
.2 .7 2.0 303 177 165 10 190 21 92 69 898 30.01
.2 .7 2.0 222 209 287 9 190 - 21 93 69 1017 29.99
.2 .7 2.0 199 267 272 8 190 17 94 70 895 29.98
.2 .7 2.0 197 361 169 10 190 — — — — 29.98
.3 1.1 2.1 311 225 299 7 190 32 87 71 171 29.98
.4 1.2 2.2 364 255 306 7 190 22 84 71 67 29.98
.4 1.2 2.2 325 274 179 5 190 22 82 69 28 29.98
.4 1.1 2.2 1196 237 187 4 180 29.98
.4 1.6 2.2 458 215 148 3 180 14 77 69 0 30.00
.5 1.4 2.2 290 212 118 calm 12 76 68 0 30.00
.6 1.4 2.2 341 215 226 calm 17 76 68 0 30.00
104
-------
TABLE A5- SURVACE DATA COLLECTED AT HOUSTON, TX, ON JULY 5, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
0
.»
0
0
0
0
0
0
5
_ _
_ _
10
11
11
13
14
~ -.
_ H
5
0
0
0
0
NO
ppb
25
_ _
38
34
31
30
28
27
19
_ _
_ «
_ _
10
12
14
14
15
__
_ _
21
38
52
48
38
GAS DATA MET. DATA
N02 NMTHC CO CH4 CFCI3 CCI4 CH^Clj WS WD (TQ TMP DP RAD BARO
ppb ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy "Hg
21 .6 1.6 2.2 603 213 259 3 190 13 76 69 0 29.99
..6 2.1 2.2 684 332 353 4 250 -- -- — - 29.98
11 .8 2.0 2.2 753 575 608 4 190 8 76 71 0 29.97
15 .8 1.9 2.2 701 368 917 calm 14 76 71 0 29.96
14 .7 1.7 2.2 786 312 598 calm 10 75 70 0 29.97
14 .7 1.5 2.2 589 283 310 calm 11 76 70 0 29.98
10 .7 1.4 2.2 366 264 363 4 350 15 76 70 62 30.00
7 .7 1.3 2.2 324 301 395 10 360 14 78 71 231 30.01
5 .6 1.0 2.2 299 445 379 4 330 14 81 72 432 30.00
.4 .6 2.0 191 232 408 6 50 -- -- -- - 30.01
.4 .6 2.0 187 220 131 8 220 -- -- -- — 30.03
.4 .8 1.9 400 277 214 4 50 -- -- -- — 30.02
13 .3 .8 1.9 358 242 273 7 360 18 73 68 200 30.01
10 .3 .7 1.9 211 221 137 10 20 -- -- -- — 30.02
7 .2 .8 2.0 272 223 162 7 50 18 74 70 440 30.00
10 .3 1.0 2.0 326 208 182 7 40 25 76 70 591 29.98
17 .3 1.3 2.2 450 225 240 6 60 25 77 70 377 29.97
.3 1.4 2.1 334 238 354 8 140 -- -- -- ~ 29.98
.5 1.5 2.2 377 263 238 10 90 -- -- -- ~ 29.98
34 .7 1.9 2.2 1771 323 261 8 150 18 78 68 116 29.97
41 .8 2.4 2.2 555 1056 250 5 60 18 74 68 55 29.97
30 .9 .25 2.4 1100 545 314 4 180 16 74 69 0 29.97
23 .9 2.5 2.5 772 1438 2041 calm 16 73 69 0 29.99
24 .9 2.5 2.6 664 1303 561 calm 13 73 69 0 29.99
105
-------
TABLE A6. SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 6, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
0
0
0
0
0
0
0
0
2
8
21
39
43
37
38
23
13
10
2
0
0
0
0
0
NO
ppb
27
15
19
15
15
18
55
55
28
15
10
10
7
6
8
13
20
21
27
22
19
25
38
34
GAS DATA MET. DATA
N02 NMTHC CO CH4 CFCI3 CCI4 CH CCI3 WS WD Q^ TMP DP RAD BARO
ppb ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy "Hg
20 .7 2.2 2.6 829 595 247 calm 11 73 69 0 29'.99
17 .7 1.7 2.6 479 394 243 calm 12 73 70 0 29.99
15 .7 1.6 2.6 691 397 229 4 30 9 73 70 0 29.97
14 7 1.3 2.6 790 391 228 4 30 9 73 69 0 29.96
10 .7 1.1 2.6 335 365 178 5 30 12 73 69 0 29.96
9 .6 1.1 2.5 218 322 153 4 50 14 73 69 0 29.99
12 .6 2.2 2.5 366 366 138 7 40 14 73 69 80 29.99
13 .7 2.6 2.5 445 386 159 8 40 16 74 70 194 29.99
11 .3 1.8 2.3 396 606 191 10 60 16 77 71 673 30.01
8 .3 1.4 2.2 365 448 153 10 50 18 81 71 974 30.01
8 .3 1.1 2.0 606 416 221 9 90 19 82 71 914 30.01
8 .5 .9 2.0 237 237 231 9 120 20 82 70 973 30.00
10 .3 1.1 2.0 318 234 191 7 160 23 85 70 801 30.00
7 .4 .9 1.9 463 230 209 7 90 23 86 70 854 29.99
9 .4 1.1 1.9 236 534 388 9 70 26 85 69 832 29.97
18 .6 1.2 1.9 301 347 262 8 70 22 82 69 873 29.96
25 .4 1.6 2.0 313 395 311 11 130 22 83 69 526 29.95
33 .4 2.0 2.0 425 265 264 8 100 20 82 68 329 29.96
37 .6 2.1 2.1 594 286 283 8 170 21 80 70 150 29.98
36 .6 2.0 2.1 401 423 443 4 190 22 79 69 42 29.99
26 .6 1.9 2.1 348 915 412 4 190 23 77 69 0 29.99
24 .6 1.7 2.1 399 542 455 3 100 18 76 68 0 30.00
24 .6 2.1 2.2 591 242 491 6 40 13 76 69 0 30.00
24 .6 2.0 2.2 653 436 391 4 40 14 75 70 0 29.99
106
-------
TABLE A7. SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 7, 1976
Time
hr
0100
\J I \J\J
0200
\Jt— \j\J
0300
\J w W
0400
v/~ w
0500
\j\j \J\J
0600
0700
\J I W
0800
\j\j\j \j
0900
1000
1100
i i \j \j
1200
I t. \J\J
1300
1 w W.
1400
1 ~v/ w
1500
1 w W
1600
1700
1 / W
1800
1900
1 ./ W W
2000
u-W W
2100
2200
2300
2400
°3
ppb
0
o
0
0
0
0
o
31
21
18
32
34
33
44
38
48
44
30
10
5
0
0
0
0
NO
ppb
8
14
11
6
10
27
57
45
21
9
7
7
5
4
5
8
13
12
11
12
19
30
51
55
GAS DATA MET. DATA
N02 NMTHC CO CH4 CFCI3 CCI4 CH3CCI3 WS WD O^ TMP DP RAD BARO
ppb ppmC ppm ppm ppt ppt ppt knt deg deg °F °F ml_y "Hg
15 .5 1.5 2.2 964 278 323 4 20 15 74 69 0 29.98
14 .4 1.2 2.2 395 237 218 calm 13 73 69 0 29.97
12 410 2.2 516 247 326 calm 18 73 69 0 29.98
12 '4 822 440 264 256 calm 11 73 69 0 29.99
12 '4 .8 2.2 378 274 218 calm 12 72 69 0 30.00
12 4 1.0 2.2 283 288 226 5 40 12 72 68 0 30.02
15 '5 2.1 2.2 593 296 321 5 30 16 73 69 85 30.03
17 6 2.8 2.2 402 337 296 8 60 17 76 70 284 30.05
15 42420 -- — '-- 8 50 20 79 70 483 30.06
a '4 l'l 2 0 — -- — 4 60 21 83 70 931 30.05
9 '4 '9 2*0 -- - -- 3 90 18 85 70 912 30.06
8 '4 '9 2 1 — -- — 4 50 23 85 69 880 30.05
8 '4 l!o 2'.1 328 268 546 6 140 22 87 68 701 30.04
17 '3 1.1 2.1 358 279 712 8 180 17 80 70 242 30.03
22 '314 2.2 464 284 632 7 130 13 81 73 276 30.03
30 *3 1.9 2.2 561 313 2110 13 180 20 85 72 559 30.02
28 *4 1 7 2.0 302 292 372 11 190 27 87 69 493 30.03
33 '4 1 9 2.1 318 407 364 12 190 25 83 69 296 30.03
15 '4 1.6 2.1 365 195 328 7 190 33 79 69 120 30.03
17 4 1.4 2.1 319 281 348 calm 30 76 68 32 30.03
20 3 1.5 2.2 471 233 998 3 190 24 75 69 0 30.03
20 .4 1.9 2.2 516 280 7032 calm 11 74 69 0 30.04
20 6 2.1 2.2 790 293 2718 calm 8 74 69 0 30.04
20 7 2.3 2.4 717 270 1062 calm 10 74 69 0 30.04
107
-------
TABLE A8. SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 8, 1976
Time 0-,
hr ppb
0100 0
0200 0
0300 0
0400 0
0500 0
0600 0
0700 0
0800 0
0900 3
1000 16
1100 40
1200 76
1300 108
1400 150
1500 179
1600 136
1700 50
1800 25
1900 0
2000
2100
2200
2300
2400
NO
ppb
52
58
66
70
70
98
124
94
36
17
10
6
4
4
4
4
4
10
14
— —
__
—
GAS DATA MET. DATA
N02 NMTHC CO CH4 CFCIj CCI4 CH3CCI3 WS WD O^ TMP DP RAD BARO
ppb ppmC ppm ppm ppt ppt ppt knt deg deg °F °F ml_y Hg
18 .8 2.5 2.6 808 235 958 calm 5 73 69 0 30.04
18 .7 2.5 2.8 1056 256 785 calm 7 72 69 0 30.04
18 .8 2.7 2.7 1016 387 905 calm 8 72 68 0 30.03
14 .9 2.7 2.7 1167 354 957 calm 5 71 68 0 30.04
17 .8 2.7 2.7 983 333 797 4 50 7 72 68 0 30.06
20 9 2 9 2.7 734 351 697 calm 9 72 68 16 30.06
28 l'l 4*7 2.7 726 530 503 5 30 10 73 69 74 30.07
30 9 4.3 2.5 1025 1034 390 6 50 10 75 70 254 30.08
33 s 25 2 2 1147 716 256 4 50 14 79 71 402 30.08
37 6 ^0 2.2 671 820 234 2 190 18 81 72 489 30.08
30 .6 17 2.2 506 510 1014 3 200 14 85 73 814 30.08
24 415 2.2 436 417 2989 4 230 17 89 71 1160 30.07
24 \l 1.5 2.2 443 464 2303 4 80 14 89 70 780 30.06
26 .5 1.7 2.2 505 497 1803 5 80 21 89 70 805 30.03
20 517 2.2 443 464 1085 15 180 17 90 70 791 30.05
22 *3 1 7 2.0 336 383 481 4 200 "20 88 69 257 30.04
16 A }\l 20 323 271 270 6 220 12 73 69 53 30.06
27 .4 2.5 2.0 254 237 4336 5 190 17 73 69 53 30.07
26 .7 2.1 2.0 352 203 1336 calm 18 76 70 47 30.07
.6 2.0 2.0 406 186 2528 calm — — ~ " 30.07
.7 2.1 2.2 536 314 1430 calm -- 30.08
.7 2.1 2.4 1219 223 583 5 50 -- 30.09
.8 2.3 2.4 751 219 443 4 40 -- ~ -- -- 30.08
7 2.2 2.4 744 210 609 5 50 -- — ~ — 30.06J
108
-------
TABLE A9- SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 9, 1976
Time
hr
moo
0?00
0^00
0500
OfiOO
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3 N0
ppb ppb
— 24
— 26
-- 18
- 17
-- 37
— 36
40 34
18 34
2 20
0 40
0 39
0 37
0 43
0 18
0 21
0 16
N02
ppb
__
4
3
5
8
7
8
13
25
28
30
25
22
22
17
15
15
GAS
NMTHC
ppmC
.8
.7
.8
.8
.7
.6
.5
.6
.8
.9
.6
.7
.5
.8
.5
.5
DATA
CO
ppm
2.0
1.7
1.5
1.5
1.2
1.2
1.8
2.1
1.9
1.4
1.3
1.6
2.1
2.3
2.2
1.7
CH4
ppm
2.4
2.5
2.6
2.7
2.6
2.6
2.6
2.5
2.4
2.2
2.4
2.1
2.1
2.1
2.6
2.6
CFCI3 CCI4
PPt ppt
657 221
763 311
612 292
602 306
467 282
315 256
484 222
801 203
312 205
283 210
538 206
263 255
547 280
404 325
575 261
581 227
520 725
435 250
488 296
694 302
1038 210
1365 201
926 221
1067 242
CHLCCL
o o
ppt
542
417
619
624
442
224
169
145
117
389
195
369
417
865
590
483
872
284
194
199
166
229
278
244
MET
WS WD (
knt deg
2 30
2 20
3 40
3 40
6 50
5 40
5 50
5 350
6 30
17 180
4 70
5 180
5 190
10 160
8 60
5 50
9 130
6 120
6 90
5 50
7 50
8 70
4 70
4 50
DATA
3^ TMP
deg °F
—
— —
—
__
__
— —
__
21
19 --
21 —
19 --
13 --
14 --
18 --
18 --
18 --
20 --
15 --
12 --
16 --
16 --
16 --
12 --
DP RAD
°F mLy
__
— —
— —
— —
-- —
— — — —
— - —
71 126
72 132
73 322
68 221
69 139
71 237
73 310
71 325
71 273
71 215
71 105
72 27
72 0
72 0
72 0
72 0
BARO
"Hg
30.05
30.04
30.05
30.06
30.07
30.08
30.09
30.11
30.11
30.12
30.14
30.14
30.13
30.11
30.08
30.06
30.05
30. OJ
30.05
30. Qi
30.05
30.07
30.07
30.0!
109
-------
TABLE Ala SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 10, 1976
Time 0^
hr ppb
0100 0
0200 0
0300 0
0400 0
0500 0
0600 0
0700 0
0800 0
0900 0
1000 0
1100 8
1200 3
1300 14
1400 12
1500 12
1600 11
1700 19
1800 17
1900 16
2000 7
2100 0
2200 0
2300 0
2400 0
NO
ppb
15
13
10
11
12
11
14
13
16
15
19
20
14
15
10
15
11
10
6
14
35
41
29
28
GAS DATA MET. DATA
N02 NMTHC CO CH4 CFCI3 CCI4 CH^Clj WS WD O^ TMP DP RAD BARO
ppb ppmC ppm ppm ppt ppt ppt kni deg deg °F °F mLy "Hg
16 .6 1.6 2.6 771 447 209 calm 14 - 72 0 30.06
18 .6 1.6 2.6 804 440 293 5 50 13 -- 72 0 30.03
15 .6 1.4 2.6 633 429 251 5 50 16 -- 72 0 30.03
IK 61428 479 415 454 calm 14 — 72 0 30.04
3 1 14 28 813 462 447 4 50 8 -- 72 0 30.06
'.6 '.4 2.1 ll 489 692 5 130 16 - 72 0 3007
15 .6 1.3 2.7 308 791 2233 7 50 16 - 7 21 30.08
12 51427 432 519 235 calm 17 — 71 40 30.12
7 * I 2:5 342 239 322 14 20 16 - 71 34 30 2
19 51525 450 725 1729 3 30 18 -- -- 56 30.14
8 I K6 d 658 372 205 8 40 21 - - 221 3013
21 .7 1.6 2.5 635 443 233 8 50 19 - -- 451 30.2
19 617 2.2 569 417 237 7 50 21 — - 552 30.10
21 .6 .7 22 553 372 213 9 50 20 - -- 590 30.08
14 6 16 2.2 612 232 208 11 110 20 - - 528 3007
15 51421 576 243 152 14 140 18 -- -- 628 30.06
2i "5 1*3 2*0 454 458 175 12 140 21 — -- 577 30.06
?! 4 14 21 717 417 159 12 150 18 -- -- 163 30.06
22 '.5 1^8 2'.1 470 302 195 10 150 16 ~ -- 90 30.06
28 .6 2.0 2.2 572 624 208 8 150 17 - -- 28 30.07
27 .6 2.0 2.3 471 252 275 8 130 19 -- -- 8 30.07
24 .8 1.9 2.3 388 239 450 7 150 20 -- -- 0 30.08
20 .8 1.8 2.4 465 230 238 5 60 21 - -- 0 30.08
19 8 1.8 2.5 564 -240 297 5 160 15 -- -- 0 30.07
no
-------
TABLE All SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 11, 1976
Time 0-,
hr ppb
0100 0
0200 0
0300 0
0400 0
0500 0
0600 0
0700 0
0800 0
0900 0
1000 0
1100 1
1200 5
1300
1400
1500
1600
1700 27
1800 25
1900 15
2000 5
2100 3
2200 0
2300 0
2400 0
NO
ppb
36
12
12
18
8
10
14
24
18
8
9
8
8
8
8
17
18
8
9
18
24
29
29
22
N02
ppb
15
17
15
10
8
7
8
13
12
5
8
8
11
17
11
18
16
12
18
26
24
21
21
18
GAS DATA
NMTHC CO CH4
ppmC ppm ppm
.8 1.5 2.6
.6 1.5 2.6
.6 1.1 2.6
.6 1.4 2.7
.6 1.5 2.8
.6 1.1 3.2
.6 1.2 3.1
.7 1.3 3.1
.6 1.5 3.0
.5 1.1 2.6
.4 1.0 2.4
.5 1.0 2.2
_ _ —
_ _ —
.2 1.0 1.7
.2 .9 1.7
.2 1.1 1.7
.3 1.2 1.8
.3 1.3 1.8
.3 1.3 1.8
.4 1.7 1.9
.6 1.6 1.9
.4 1.9 2.2
.5 1.7 2.2
CFCI,
O
ppt
706
278
326
492
609
462
543
509
452
244
224
276
280
368
234
232
224
215
315
338
324
409
410
476
cci4
ppt
286
241
281
273
265
254
292
413
282
250
209
200
199
350
237
259
230
258
228
264
321
485
256
480
MET. DATA
CH CCI3 WS WD O^ TMP DP RAD BARO
ppt knt deg deg °F °F mLy "Hg
283 5 170 14 - - 0 30.06
379 5 180 15 - - 0 30.05
337 4 110 13 - 0 30.05
226 5 110 9 - 0 30.05
194 5 180 9 - 0 30.05
322 5 180 11 - - 0 30.08
381 7 180 11 - 16 30.08
306 7 190 10 - 87 30.10
393 8 190 24 - - 606 30.10
161 9 170 23 - - 456 30.10
130 7 130 25 - - 585 30.10
252 12 160 26 - - 761 30.10
133 12 160 28 - 692 30.08
200 11 130 25 - - 637 30.07
145 14 140 22 - - 721 30.06
188 12 170 22 - - 658 30.05
128 11 150 23 - - 596 30.03
174 8 170 23 - - 447 30.02
637 5 110 22 - - 197 30.03
322 4 190 18 90 73 47 30.04
548 4 200 18 86 73 0 30.06
309 4 190 12 86 73 0 30.07
782 4 190 9 85 73 0 30.06
544 5 180 12 83 73 0 30.05
111
-------
TABLE AT2. SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 12, 1976
Time 0-z
hr ppb
0100 0
0200 0
0300 0
0400 0
0500 0
0600 0
0700 0
0800 1 1
0900 0
1000 8
1100 33
1200 68
1300
1400 81
1500 87
1600 76
1700 62
1800 41
1900 35
2000 25
2100 5
2200 0
2300 0
2400 0
NO
ppb
16
9
4
24
25
48
113
105
61
31
11
6
6
6
6
6
5
6
9
4
9
9
6
8
ppb
17
16
16
14
14
14
22
25
31
49
45
40
29
26
26
21
36
38
34
27
35
34
25
28
GAS
NMTHC
ppmC
.4
.3
.3
.5
.8
.8
1.5
1.7
1.1
.6
.7
.8
.7
.8
.6
.3
.5
.5
.4
.5
1.0
.6
.4
.4
DATA MET. DATA
CO CH4 CFCI3 CCI4 CH3CCI3 WS WD O^ TMP DP RAD BARO
ppm ppm ppt ppt ppt knt cleg deg °F °F m!_y "Hg
1.5 2.1 433 353 797 4 190 10 83 73 0 30.04
1.2 2.2 4T5 483 325 calm calm 9 81 73 0 30.03
1.0 2.2 398 308 923 calm calm 8 80 73 0 30.01
1.1 2.4 731 262 1653 calm calm 7 80 73 0 30.01
1.5 2.7 852 233 1401 calm calm 4 79 73 0 30.02
2.8 4.0 896 283 851 5 50 7 80 73 0 30.03
4.7 3.5 2222 315 1071 4 60 9 80 72 36 30.04
5.0 3.6 1384 365 758 3 60 12 81 73 150 30.05
3.1 2.9 1173 1063 604 5 50 22 87 73 537 30.06
1.9 2.4 1290 893 1173 8 70 21 88 73 541 30.05
1.7 2.2 504 926 652 12 140 26 91 72 783 30.05
1.4 2.0 817 664 336 10 140 22 94 70 899 30.04
1.4 2.1 298 707 446 8 70 23 93 71 737 30.02
1.1 2.0 275 776 493 7 40 27 97 71 890 29.99
1.2 2.0 - - - 10 60 27 101 70 829 29.99
1.1 1.9 357 368 365 9 170 25 101 68 839 29.97
1.3 1.9 314 767 358 9 170 24 100 67 616 29.96
1.1 1.9 326 503 310 8 190 22 99 69 547 29.95
1.5 1.9 271 271 263 5 190 25 97 69 197 29.96
2.0 1.9 269 251 198 5 200 25 93 70 42 29.96
1.6 1.9 363 226 2583 5 190 19 90 70 0 29.97
1.7 2.1 449 236 6652 :alm calm 13 89 71 0 29.98
1.3 2.0 313 268 492 4 120 12 89 72 0 29.99
1.3 2.1 425 316 702 5 170 11 89 72 0 29.98
112
-------
TABLE Ala SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 13, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100-
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
0
0
0
0
0
0
0
0
0
5
10
. 25
35
30
30
15
5
5
0
0
0
0
0
0
NO
ppb
9
35
22
25
26
35
89
110
61
17
7
8
8
7
5
10
12
17
15
18
32
43
17
24
N02
ppb
30
25
21
17
16
14
19
26
25
17
11
11
11
9
7
10
9
19
12
13
19
9
14
14
GAS
NMTHC
ppmC
.5
.5
.5
.5
.5
.7
1.3
1.4
.8
.5
<.l
.2
.2
.1
.1
.1
.1
.2
.2
.2
.4
.8
.5
.4
DATA MET. DATA
CO CH4 CFCI3 CC!4 CH3CCI3 WS WD Q^ TMP DP RAD BARO
ppm ppm ppt ppt ppt kni deg deg °F °F ml_y "Hg
1.3 2.3 655 289 757 calm calm 10 88 72 0 29.97
1.3 2.5 583 217 2635 calm calm 6 88 72 0 29.95
1.3 2.7 902 320 3499 4 190 4 87 72 0 29.95
1.3 3.0 813 251 5042 calm calm 0 87 72 0 29.95
1.2 3.0 933 244 2541 calm calm 4 86 72 0 29.97
1.5 3,0 984 234 1289 calm calm 1 86 72 0 29.97
3.2 3.0 756 234 2731 calm calm 14 87 72 56 29.98
5.8 3.5 1037 224 1074 6 200 12 90 73 172 29.99
3.5 2.8 674 333 6396 6 200 18 95 74 561 29.99
1.6 2.1 411 226 2919 7 200 28 98 73 733 29.99
.9 1.9 295 223 273 8 190 25 101 73 910 29.99
.9 1.9 269 250 245 7 170 26 103 72 1061 29.98
1.2 1.9 308 238 1201 9 190 26 103 70 907 29.97
.9 1.9 329 407 1550 5 200 26 103 69 1162 29.96
.8 1.9 264 371 543 10 200 23 104 68 1237 29.95
.8 1.9 285 232 232 10 190 25 100 70 506 29.95
.9 1.9 217 276 445 13 200 27 101 70 802 29.94
.9 1.9 216 210 1058 11 190 31 100 69 716 29.94
.9 1.9 236 200 462 7 200 31 96 68 343 29.94
1.4 2.0 269 212 240 6 190 30 91 68 69 29.95
1.8 2.0 369 198 3454 7 190 25 86 68 0 29.96
2.0 1.9 453 200 3009 6 190 17 85 69 0 29.98
1.5 2.1 327 231 1023 6 190 14 84 70 0 29.99
1.1 2.2 326 665 470 5 150 15 84 71 0 29.98
113
-------
TABLE A14 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 14, 1976
Time 0-,
hr ppb
0100 0
0200 0
0300 0
0400 0
0500 0
0600 0
0700 0
0800 0
0900 0
1000 10
1100 10
1200 15
1300 35
1400 65
1500 80
1600 55
1700 40
1800 10
1900 0
2000 0
2100 0
2200 0
2300 0
2400 0
NO
Ppb
17
30
15
12
8
3
15
27
31
17
28
17
11
7
6
7
12
21
28
29
34
39
45
22
ppb
15
14
14
12
10
4
8
23
20
17
21
21
20
35
41
36
47
35
20
19
15
20
17
14
GAS
NMTHC
ppmC
.4
.4
.4
.4
.3
<.l
.2
.2
.2
.3
.2
.4
.5
.6
.6
.6
.7
.6
.6
.6
.6
.6
.5
.3
DATA MET. DATA
CO CH4 CFCI3 CCI4 CH3CCI3 WS WD O~Q TMP DP PAD BARO
ppm ppm ppt ppt ppt knt deg deg °F °F mi_y "Hg
1.0 2.2 446 209 1281 4 190 13 83 71 0 29.97
1.3 2.3 556 263 694 4 190 7 82 71 0 29.97
1.1 2.3 444 2111 749 4 110 13 82 71 0 29.96
.7 2.3 381 605 1091 5 190 11 82 72 0 29.96
.7 2.3 322 1025 316 13 240 15 81 71 0 30.02
.5 1.9 228 222 152 10 280 18 77 67 0 30.04
1.1 1.9 313 204 167 8 320 14 82 67 8 30.03
1.4 1.9 442 207 568 7 30 16 84 67 26 30.04
1.4 1.9 309 206 150 6 40 19 86 68 123 30.03
1.4 2.3 578 198 398 6 60 20 88 69 248 30.04
1.5 2.2 553 205 403 5 60 19 92 70 500 30.05
1.5 2.1 647 211 878 5 120 22 95 71 736 30.04
1.5 2.1 400 238 283 10 190 26 100 71 833 30.03
1.5 2.1 415 643 588 10 180 23 102 72 590 30.03
1.5 2.1 441 1986 682 10 150 19 101 72 365 30.01
1.6 2.0 427 256 608 8 60 24 103 72 366 30.00
1.9 2.0 353 284 646 7 190 21 102 73 302 29.99
2.1 2.0 386 257 383 8 190 22 99 74 191 29.99
1.9 2.0 458 204 1409 7 190 26 96 74 115 30.00
2.0 2.0 367 1928 678 7 190 17 92 74 21 30.00
1.8 2.0 370 222 949 8 190 12 90 75 0 30.02
2.4 2.0 745 259 697 4 190 12 90 75 0 30.04
2.0 2.1 624 251 756 5 190 10 88 75 0 30.05
1.3 2.2 391 218 1024 6 190 15 89 75 0 30.06
114
-------
TABLE A15 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 15, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
0
0
0
0
0
0
0
0
0
0
0
5
5
5
15
15
10
5
0
0
0
0
0
0
NO
ppb
5
4
4
5
3
12
50
80
65
35
34
16
16
13
12
13
19
20
15
19
37
20
25
26
ppb
10
10
11
12
8
13
18
23
25
23
23
15
15
13
9
9
13
15
15
17
18
18
17
16
GAS DATA MET. DATA
NMTHC CO CH, CFCU CCL CI-LCCl, WS WD (T; TMP DP RAD BARO
*r O H 3 3 "
ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy " Hg
•2 .8 2.1 275 314 234 calm calm 23 89 75 0 30.05
.1 .6 2.1 273 369 233 5 190 16 89 74 0 30.05
.1 .5 2.2 277 351 915 5 190 16 89 74 0 30.05
.1 .5 2.3 224 359 864 6 190 16 88 74 0 30.04
.1 .5 2.2 255 222 2972 4 190 25 87 74 0 30.06
.4 1.1 2.2 262 223 10377 4 130 22 86 73 0 30.06
.3 2.0 2.3 330 276 1418 5 180 15 86 73 26 30.06
1.7 3.3 2.3 467 293 756 8 190 17 87 73 82 30.08
1.5 3.3 2.3 594 453 1796 11 190 16 88 73 121 30.08
.8 2.1 2.3 458 278 1363 12 200 18 88 73 121 30.09
1.3 2.0 2.2 585 277 5739 8 200 23 90 74 214 30.10
.5 1.4 2.1 339 209 2113 9 190 28 92 73 283 30.10
.6 1.2 2.0 369 237 5396 14 200 28 93 73 354 30.10
.4 1.1 -2.0 368 218 1698 14 190 26 93 73 342 30.07
.3 1.0 1.9 - 14 190 26 95 73 677 30.07
.1 .9 1.9 177 182 375 11 190 27 97 73 819 30.06
.3 1.4 1.9 205 183 907 10 190 28 95 73 445 30.06
.4 1.7 1.9 230 176 603 10 190 27 92 73 282 30.05
•5 1.5 1.9 226 178 2205 7 190 26 90 72 71 30.05
• 6 1.4 1.9 247 190 760 5 190 24 88 73 26 30.06
.6 1.9 2.0 322 262 419 5 190 22 87 73 0 30.08
.5 1.8 2.1 299 356 352 4 180 16 87 73 0 30.08
.4 1.2 2.2 303 172 2608 5 190 16 86 73 0 30.10
.2 1.3 2.3 288 341 582 6 190 19 86 74 0 30.10
-------
TABLE A16 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 16, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
°3
ppb
0
0
0
0
0
0
0
0
10
10
13
20
23
11
0
0
_
_
_
_
_
_
_
2400
NO
ppb
13
7
5
4
5
40
91
112
59
_
9
7
7
41
35
29
_
_
_
_
_
_
.
-
N02
ppb
13
12
9
9
10
15
21
25
21
_
11
12
15
55
33
21
-
_
-
_
_
_
_
-
GAS DATA MET. DATA
NMTHC CO CH4 CFCI3 CCI4 CHJCClj WS WD O^ TMP DP RAD BARO
ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy "Hg
.1 1.1 2.2 317 241 330 5 190 20 87 74 0 30.10
.2 .7 2.2 319 181 2220 calm calm 23 86 74 0 30.10
.2 .6 2.3 299 184 262 4 190 21 86 75 0 30.10
.2 .6 2.3 238 242 4353 4 190 14 86 75 0 30.10
.2 .6 2.4 246 1695 2091 3 190 8 85 75 0 30.11
.5 2.1 2.5 318 1227 1341 calm calm 5 85 75 0 30.11
1.0 4.0 2.5 500 867 3270 calm calm 11 86 75 35 30.12
1.6 5.2 2.5 1002 764 1819 6 200 14 87 76 119 30.13
.3 2.9 2.4 678 360 3954 7 200 28 90 77 287 30.13
.5 1.5 2.0 448 311 330 8 200 - 30.13
.2 .9 1.9 482 285 256 5 200 20 96 76 683 30.12
.1 .9 1.9 1265 200 434 14 190 22 101 76 1072 30.10
.2 1.1 1.9 231 272 2169 10 190 19 101 75 953 30.09
.5 1.8 2.0 589 500 1397 7 190 23 92 75 280 30.09
.4 1.8 2.1 343 3260 1448 7 200 17 88 74 57 30.08
.4 2.0 2.2 592 184 251 6 200 21 85 73 29 30.08
.3 2.2 2.1 460 244 194 7 200 - - - 30.06
.9 3.1 2.1 622 224 291 5 200 - 30.08
1.3 4.3 2.3 991 227 1841 calm calm - 30.08
1.0 3.6 2.2 667 267 337 5 40 30.08
.8 2.4 2.2 1345 272 439 5 30 30.10
.7 2.4 2.5 2366 301 253 4 60 30.11
.7 2.3 2.3 573 272 292 5 170 - - - - 30.11
.8 3.0 2.4 615 253 360 6 180 - 30.09
116
-------
TABLE A17 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 17, 1976
Time
hr
0100
0200
0300
0400
0500
OfiOO
0700
0800
0900
1000
1100
1?00
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
03 NO
ppb ppb
__
—
—
6 14
2 13
1 13
0 16
0 13
N02
ppb
—
--
—
_ «
16
13
12
16
13
GAS
NMTHC
ppmC
.9
1.2
1.3
1.3
1.4
1.2
1.1
1.2
1.5
1.2
.7
.2
.1
.1
.1
.1
.1
.1
.1
.1
.3
.2
.3
.3
DATA
CO CH4
ppm ppm
2.8 2.6
2.7 2.9
2.5 3.1
2.4 3.9
2.4 4.0
2.5 3.8
2.3 3.3
2.3 3.8
2.5 4.8
3.1 4.2
1.7 2.5
.7 1.9
.7 1.9
.7 1.9
.7 1.9
.7 1.9
.7 2.0
.7 2.0
.9 2.0
1.1 2.0
1.4 2.0
1.3 2.0
1.0 2.1
1.0 2.1
CFCI3 CCI4
ppt ppt
776 258
615 938
1004 1178
815 925
1273 1047
794 1668
677 681
735 453
697 516
1100 1938
322 202
218 180
260 194
252 195
222 189
255 197
207 198
280 189
328 177
348 185
377 183
327 199
252 374
310 212
CH3CC|3
ppt
477
1039
821
753
581
523
514
615
591
2185
420
120
115
146
138
133
129
115
138
173
178
369
326
149
MET
WS WD (
knt deg
4 180
:alm
4 80
:alm
:alm
:alm
:alm
:alm
6 210
8 210
10 220
8 230
8 200
7 200
8 210
12 200
12 200
10 200
8 200
7 200
6 180
5 180
7 200
7 200
DATA
deg °F
__
__
__
--
—
—
28 94
27 91
23 89
17 88
23 87
DP
°F
__
--
—
—
—
—
70
73
73
72
72
RAD
mLy
« _
— —
— —
--
— —
85
0
0
0
0
BARO
" Hg
30.07
30.06
30.06
30.07
30.08
30.10
30.11
30.12
30.10
30.10
30.10
30.10
30.08
30.07
30.05
30.03
30.03
30.03
30.03
30.04
30.07
30.07
30.05
30.03
117
-------
TABLE A.18 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 18, 1976
Time
hr
0100
V 1 W
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1 1 W
1200
1300'
1 w W V
1400
1500
1600
1 WW W
1700
1800
1900
1 •/ W
2000
2100
2200
2300
2400
°3
ppb
3
w
2
2
3
0
0
1
3
7
10
18
27
43
i v
58
41
46
54
35
15
6
1
1
1
0
NO
ppb
5
5
4
3
8
20
18
19
9
11
6
3
4
4
4
5
4
5
8
11
19
14
11
21
GAS DATA MET. DATA
N02 NMTHC CO CH4 CFCI^ CCI4 CHJSC^ WS WD Q^ TMP DP RAD BARO
ppb ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy "Hg
8 .1 .6 2.0 229 195 177 8 210 27 87 72 0 30.02
10 .1 .6 2.1 217 254 149 5 220 22 86 72 0 30.02
9 2 6 2.1 208 268 184 calm 24 84 72 0 30.02
8 '.3 .6 2.1 208 248 181 calm 16 83 72 0 30.04
9 2 6 2.2 273 239 252 calm 6 82 72 0 30.07
11 '2 1.0 2.3 391 227 1073 calm 9 82 72 0 30.08
11 '.5 1.1 2.6 410 214 1072 5 170 7 82 72 48 30.10
11 4 1.1 2.6 496 288 531 6 70 15 86 73 247 30.11
11 *2 7 2.2 251 385 541 5 190 22 89 74 351 30.12
11 '3 .9 2.1 334 251 497 4 190 17 93 75 531 30.12
5 2 8 2.0 212 183 130 5 190 21 99 75 934 30.12
5 '2 '.5 2.0 235 189 120 4 200 15 102 75 1040 30.11
7 2 7 2.0 242 195 149 10 200 20 104 74 1313 30.10
7 '2 7 2 0 242 194 96 8 190 17 105 72 1174 30.08
7 1_ „ — 242 189 106 10 190 22 106 72 1269 30.06
8 _ 217 194 135 10 200 27 103 72 839 30.05
Q _ 223 427 323 9 190 29 102 72 793 30.05
1? - - — 221 442 224 8 200 29 98 72 407 30.05
15 ._ - - 238 279 428 6 190 25 95 71 127 30.06
14 ._ _- - 287 214 172 5 200 31 92 71 60 30.06
17 „ - — 304 202 183 6 200 27 89 71 0 30.07
16 2 1.1 1.8 411 470 453 5 190 24 87 70 0 30.10
14 .2 1.2 1.8 406 230 287 4 170 22 85 70 0 30.10
16 .2 1.1 1.8 371 553 487 4 70 10 83 71 0 30.11
118
-------
TABLE A19 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 19, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400.
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
0
0
0
0
0
0
1
1
4
14
22
26
30
30
27
21
16
11
11
5
2
0
0
0
NO
ppb
22
32
34
25
23
22
117
85
34
26
10
14
8
8
5
11
18
23
15
14
19
26
22
20
GAS DATA MET. DATA
N02 NMTHC CO CH4 CFCI3 CCI4 CH3CCI3 WS WD O^ TMP DP RAD BARO
ppb ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy "Hg
13 .3 .9 2.1 322 510 957 4 150 4 83 71 0 30.12
16 .4 1.4 2.3 634 257 512 5 190 11 82 72 0 30.12
14 .6 1.3 2.7 1289 233 463 8 190 5 81 71 0 30.11
14 .6 1.1 2.4 1698 220 2304 calm 10 81 72 0 30.11
12 .4 1.1 2.6 838 300 1646 3 180 9 81 72 0 30.12
15 .6 1.7 2.5 620 191 1224 calm 9 81 72 0 30.12
22 1.3 5.3 2.9 745 220 1172 5 180 13 82 72 68 30.14
16 1.3 3.7 2.3 763 305 7013 5 190 18 85 74 242 30.16
18 1.1 1.7 1.9 313 304 4151 6 200 26 92 74 576 30.16
11 .4 .9 1.8 281 334 406 10 200 30 96 74 886 30.16
10 .4 1.0 1.9 237 396 241 10 190 25 99 73 1052 30.16
8 .3 .7 1.7 271 424 347 11 200 22 101 73 1162 30.16
6 .1 .7 1.7 183 251 164 11 200 24 103 72 1379 30.15
6 .1 .7 1.6 215 229 327 13 200 27 103 72 1125 30.14
7 .2 .9 1.6 366 289 367 11 200 28 95 73 579 30.14
11 .3 1.1 1.6 351 225 541 10 200 22 95 71 290 30.13
15 .4 1.6 1.6 329 212 1221 10 190 23 96 72 446 30.12
11 .4 1.9 1.6 250 187 589 9 200 33 97 71 586 30.11
10 .4 1.3 1.6 219 222 556 7 200 30 94 71 307 30.12
15 .4 1.4 1.7 247 183 1741 6 190 26 90 72 34 30.13
14 .7 1.5 1.8 349 182 1832 7 190 27 87 72 0 30.14
12 .6 1.6 1.8 334 224 11291 8 190 25 85 72 0 30.14
10 .3 1.2 1.9 335 209 10586 6 190 23 84 72 0 30.15
8 .3 1.0 2.2 436 179 2501 4 200 21 82 72 0 30.14
119
-------
TABLE A2Q SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 20, 1976
Time 0,
hr ppb
0100 0
0200 0
0300 0
0400 0
0500 0
0600 0
0700 0
0800 1
0900 8
1000 27
1100
1200
1300
1400
1500 62
1600 62
1700 58
1800 85
1900 48
2000 30
2100 20
2200 5
2300 5
2400 5
NO
ppb
16
12
8
13
31
75
140
103
39
24
7
6
4
6
7
7
10
11
6
8
9
11
11
9
N02
ppb
9
10
8
8
6
6
5
15
24
28
13
10
10
10
11
12
16
14
15
24
25
34
33
33
GAS
NMTHC
ppmC
.2
.3
.4
.6
.5
.7
1.2
1.2
.6
.6
.2
.1
.1
.2
.2
.2
.3
.4
.4
.5
.5
.7
.6
.5
DATA
CO CH4
ppm ppm
.8 2.2
.7 2.1
.7 2.1
.6 2.2
1.1 2.3
1.8 2.4
4.1 3.0
5.8 3.5
2.9 2.1
2.1 2.2
.9 1.7
.9 1.8
.8 1.8
.8 1.8
.8 1.8
.9 1.8
1.5 1.8
1.3 1.8
1.2 1.8
1.2 1.8
1.8 1.8
1.9 2.2
2.1 2.6
1.6 2.7
CFCI3
ppt
525
504
443
468
608
904
1343
721
1438
404
340
228
233
209
315
210
212
190
220
236
349
532
488
595
cci4
ppt
184
199
192
196
198
215
245
239
313
278
226
207
233
231
231
251
229
460
374
259
228
230
231
229
CH3CCI3
ppt
312
392
426
439
820
1506
1003
1024
2318
1069
809
315
251
230
182
232
811
203
590
543
963
1223
776
1920
MET
WS WD (
knt deg
4 200
calm
calm
calm
calm
calm
calm
calm
8 190
9 190
8 180
10 150
10 150
10 160
10 170
10 160
8 160
9 150
7 150
5 150
6 170
6 180
5 170
5 180
DATA
TQ TMP
deg °F
15 81
13 81
11 80
3 79
4 79
17 78
8 79
21 84
20 92
29 93
26 97
29 99
29 100
29 104
27 103
32 103
29 100
24 98
24 93
26 89
29 86
23 84
18 82
14 81
DP RAD
°F mLy
72 0
72 0
72 0
71 0
70 0
70 0
71 68
74 334
75 656
73 713
72 1118
71 1109
71 1236
72 1457
70 1379
70 1244
69 954
68 608
67 247
68 33
68 0
69 0
70 0
70 0
BARO
" Hg
30.14
30.13
30.13
30.13
30.15
30.16
30.18
30.19
30.19
30.18
30.18
30.18
30.17
30.15
30.14
30.12
30.11
30.11
30.11
30.12
30.12
30.13
30.13
30.12
120
-------
TABLE A2J SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 21, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
8
8
0
0
0
0
0
0
2
13
58
80
80
100
43
35
40
45
28
28
13
0
0
0
NO
ppb
5
5
11
51
31
81
143
122
85
27
13
7
4
6
4
10
13
12
13
8
15
32
29
36
N02
ppb
29
24
20
20
21
24
23
29
47
70
79
35
24
19
18
22
28
28
26
34
42
46
41
36
GAS DATA MET. DATA
NMTHC CO CH4 CFCI3 CCI4 CH3CCI3 WS WD Q^ TMP DP RAD BARO
ppmC ppm ppm ppt ppt ppt knt deg deg °F °F ml_y "Hg
.4 .8 2.1 527 246 290 calm 13 81 70 0 30.11
.3 .7 2.1 648 245 372 3 210 2 79 70 0 30.10
.3 .7 2.2 798 248 872 3 20 4 78 70 0 30.10
.5 .6 2.3 790 245 1413 calm 7 78 69 0 30.11
.6 1.1 2.3 863 274 5720 3 20 12 78 69 0 30.11
.7 1.8 2.4 684 253 1938 calm 9 78 69 0 30.13
1.2 4.1 3.0 912 278 1252 7 130 11 77 69 23 30.14
1.3 5.8 3.5 1393 308 870 7 90 14 80 71 132 30.16
.6 2.9 2.1 1204 301 1900 9 100 19 83 72 256 30.17
.6 2.1 2.2 831 1290 1012 8 120 23 86 72 395 30.16
.2 .9 1.7 524 404 1832 6 100 25 91 72 783 30.15
.1 .9 1.8 322 293 1057 3 80 25 97 71 1432 30.13
.1 .8 1.8 296 228 678 8 180 23 97 71 1069 30.12
.2 .8 1.8 216 247 337 7 150 25 99 69 1150 30.10
.2 .8 1.8 259 228 231 9 170 25 92 70 279 30.08
.2 .9 1.8 292 212 347 8 160 26 92 71 497 30.05
.4 1.4 1.8 235 316 2226 9 130 29 93 72 764 30.05
.4 1.3 1.8 224 274 235 14 110 25 92 70 439 30.05
.3 1.2 1.8 210 261 246 9 130 25 90 68 221 30.07
.5 1.2 1.8 265 491 346 7 170 23 89 69 15 30.08
.6 1.9 1.8 480 219 1274 6 180 15 81 71 0 30.08
.7 1.9 2.2 531 347 2721 4 130 14 80 73 0 30.08
.6 2.1 2.6 450 926 4684 4 140 11 80 72 0 30.08
.5 1.6 2.7 1138 ~- 1527 4 160 6 79 71 0 30.08
121
-------
TABLE A22 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 22, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
0
0
0
0
0
0
0
0
5
43
25
38
50
53
68
73
53
35
30
23
13
3
0
0
NO
ppb
46
66
69
53
63
106
*
*
26
12
8
7
8
4
6
4
9
9
11
4
11
11
13
19
N02
ppb
36
34
37
31
30
37
*
*
125
83
49
39
40
30
26
40
26
47
45
39
48
51
59
63
GAS DATA MET. DATA
NMTHC CO CH4 CFCI3 CCI4 CH3CCI3 WS WD Q^ TMP DP RAD BARO
ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy "Hg
1.3 2.8 2.6 609 1302 625 4 140 0 78 71 0 30.08
1.1 2.3 2.8 1044 807 1611 calm 3 78 71 0 30.08
.9 2.0 3.0 995 650 1688 4 230 1 77 71 0 30.08
1.1 1.9 3.2 1307 503 4153 calm 4 78 71 0 30.08
1.0 1.7 3.1 1230 390 2819 calm 4 77 71 0 30.10
1.3 2.5 3.2 1561 318 2242 calm 7 77 71 0 30.12
1.9 6.4 3.4 1045 276 1639 calm 9 78 71 57 30.13
1.7 6.1 3.5 1467 327 702 calm 14 81 73 271 30.14
.7 2.5 2.5 560 412 2137 10 130 22 88 74 490 30.15
.3 1.5 1.9 380 452 823 5 90 23 93 74 843 30.15
.1 1.0 1.7 258 279 389 6 150 22 96 72 1247 30.14
.1 .9 1.7 234 268 400 10 100 18 99 70 1293 30.14
.2 .9 1.7 239 222 702 7 100 23 99 69 1183 30.12
.1 .8 1.7 197 215 222 5 140 20 100 68 1159 30.11
.1 .9 1.7 190 203 803 9 140 21 101 68 1153 30.10
.2 1.0 1.7 297 242 937 14 120 28 100 69 1045 30.09
.2 1.1 1.7 212 244 358 12 120 29 98 70 842 30.08
.3 1.2 1.7 235 269 308 8 150 30 97 69 645 30.08
.4 1.3 1.7 241 199 1206 9 150 30 93 69 282 30.08
.4 1.2 1.7 234 217 284 8 150 27 90 69 66 30.09
.5 1.2 1.7 287 197 609 5 150 27 86 69 0 30.10
.3 1.3 1.7 355 198 958 4 170 29 84 70 0 30.13
.4 1.5 1.8 371 212 5106 4 180 25 82 70 0 30.13
.6 1.5 2.1 582 210 3660 calm 14 80 71 0 30.14
*NOV > 200 ppb
/\
'122
-------
TABLE A23 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 23, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400.
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
0
0
0
0
0
0
0
3
5
18
28
60
65
48
25
30
__
8
15
8
0
0
0
0
NO
ppb
20
26
40
39
39
55
*
60
25
9
11
10
11
7
6
21
__
26
21
28
52
91
78
88
GAS DATA
N02 NMTHC CO
ppb ppmC ppm
62 .6 1.3
66 .6 1.4
84 .6 1.8
87 1.1 1.9
93 1.6 1.9
124 1.5 2.8
* 1.9 5.1
143 1.1 3.1
71 .2 2.1
58 .2 1.1
63 .3 1.4
40 .3 1.3
61 .3 1.1
39 .3 1.2
56 .3 1.2
104 .5 2.5
.9 2.8
65 1.0 3.1
89 1.2 3.8
107 2.0 4.6
90 1.6 5.6
72 2.4 6.9
51 1.2 5.3
38 .9 4.3
CH4
ppm
2.1
2.1
2.3
2.7
3.1
3.6
3.3
3.2
2.8
1.9
1.8
1.8
1.8
1.8
1.8
1.9
1.9
1.9
2.0
2.1
2.2
2.4
2.6
2.7
CFCI3
PPt
707
771
891
1039
965
885
768
663
495
401
394
357
366
331
368
796
575
1405
718
923
1274
1453
990
1129
cci4
ppt
215
192
199
265
242
259
415
522
659
332
289
300
364
234
256
357
343
657
1139
985
800
694
533
484
CHJXI,
o o
ppt
4300
1770
2152
2008
1433
750
767
538
443
538
1003
355
249
378
419
1192
369
889
1821
1393
1152
1180
1684
780
MET.
WS WD O^
knt deg deg
calm 6
calm 2
calm 3
calm 6
calm 8
calm 10
4 360 1 2
calm 13
calm 18
calm 15
6 80 17
9 40 20
8 180 14
8 140 13
8 10 21
10 120 17
6 140 —
3 180 17
3 140 18
3 150 18
4 130 7
4 120 3
5 280 1 1
calm 9
DATA
TMP
°F
79
78
77
77
77
77
77
82
89
91
90
91
81
83
86
86
—
86
86
84
81
79
79
78
DP RAD
°F mLy
71 0
71 0
70 0
70 0
70 0
70 0
70 65
72 325
74 681
74 681
73 534
75 748
67 310
69 313
71 225
72 255
__
73 209
73 169
73 53
73 0
73 0
73 0
72 0
BARO
"Hg
30.13
30.13
30.12
30.13
30.13
30.14
30.16
30.17
30.18
30.18
30.18
30.18
30.17
30.18
30.18
30.17
30.15
30.13
30.14
30.14
30.14
30.15
30.16
30.16
123
-------
TABLE A2.4 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 24, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
0
0
0
0
0
0
0
3
8
13
65
55
73
75
78
88
83
70
50
23
8
0
0
5
NO
ppb
116
80
75
85
76
82
77
63
12
13
7
8
3
4
2
3
2
4
2
5
6
14
20
8
GAS DATA MET. DATA
N02 NMTHC CO CH4 CFCI3 CCI4 CH3CCI3 WS WD Q^ TMP DP RAD BARO
ppb ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy Hg
26 1.6 4.2 2.7 1101 408 658 calm 7 77 71 0 30.15
20 1.4 2.6 2.9 739 297 308 5 300 10 77 71 0 30.15
15 1.6 2.4 3.0 740 308 321 calm 3 76 70 0 30.14
13 2.1 2.6 3.0 715 298 379 calm 7 76 70 0 30.14
11 2.6 2.0 3.0 978 290 374 calm 10 75 70 0 30.14
14 2.9 2.5 3.0 913 279 262 5 320 11 75 70 0 30.15
14 1.8 2.6 2.9 612 273 262 6 350 18 75 70 35 30.16
22 1.6 2.5 2.9 468 302 245 8 320 15 77 71 205 30.17
28 1.0 2.6 2.5 412 310 284 9 350 15 81 73 480 30.17
25 .5 1.0 2.2 220 230 132 8 30 20 89 74 931 30.16
17 .2 .9 1.9 209 269 149 10 40 23 92 74 1147 30.15
7 .2 .6 1.8 231 245 101 4 50 17 95 73 1065 30.15
15 .2 1.9 1.8 221 277 96 5 80 21 97 72 890 30.13
16 .2 .8 1.8 387 278 137 5 90 24 98 71 1200 30.09
15 .3 .8 1.8 190 257 113 5 120 16 99 70 1199 30.07
12 .3 .9 1.8 226 263 129 10 240 13 99 70 748 30.05
15 .4 1.1 1.8 402 271 174 9 230 17 95 71 607 30.04
15 .5 1.1 1.8 260 234 364 13 330 14 89 69 152 30.06
13 .3 .8 1.8 532 228 167 3 260 14 76 68 26 30.08
28 .7 1.5 1.8 668 244 634 3 320 17 76 70 0 30.08
37 .9 2.1 1.9 1007 272 628 calm 13 76 70 0 30.09
41 1.1 2.3 1.9 857 265 548 4 230 8 76 70 0 30.08
39 1.2 3.0 2.1 1981 257 858 4 120 13 76 71 0 30.08
26 .5 1.3 2.0 670 225 274 calm 13 76 71 0 30.06
124
-------
TABLE A25 SURFACE DATA COLLECTED AT HOUSTON, TX, ON JULY 25, 1976
Time
hr
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
°3
ppb
5
5
3
0
0
0
0
0
5
13
20
38
45
43
102
108
140
138
103
118
95
38
23
18
NO
ppb
6
5
4
10
8
9
10
18
10
9
7
5
4
2
2
2
3
3
3
3
3
4
4
6
GAS DATA MET. DATA
N02 NMTHC CO CH4 CFCI3 CCI4 CH3CCI3 WS WD O^ TMP DP RAD BARO
ppb ppmC ppm ppm ppt ppt ppt knt deg deg °F °F mLy "Hg
20 .7 1.1 2.0 442 211 229 4 270 23 76 70 0 30.05
14 .7 .9 2.1 332 219 742 3 360 19 75 70 0 30.05
11 .7 08 2.1 324 210 2434 4 340 16 74 68 0 30.05
12 08 .9 2.4 259 229 456 3 20 9 74 68 0 30.05
12 .7 .9 2.3 362 228 222 4 350 13 74 68 0 30.05
11 ,8 .9 2o4 464 233 287 3 30 15 74 68 0 30.05
8 1.0 1.2 2.8 775 228 454 calm 14 74 68 0 30.06
9 1.3 1.6 3.0 352 229 1982 calm 11 73 68 0 30.08
10 ,,7 08 2.5 213 222 248 calm 21 78 72 431 30.08
12 05 .7 2.2 197 217 149 5 230 24 84 72 777 30.08
11 A 06 2.1 206 219 496 3 270 18 90 73 1057 30.08
11 .3 09 1.9 278 240 129 7 200 12 94 72 1273 30.06
8 .4 1.0 1.8 240 237 279 4 230 -- — — ~ 30.04
8 .3 .9 1.9 280 253 358 4 200 25 96 72 944 30.03
8 .5 .7 1.8 301 255 153 4 20 19 97 72 1100 30.01
9 .4 .8 1.8 305 268 173 8 160 19 97 73 760 29.99
14 .6 1.2 1.9 388 314 234 6 130 19 97 72 254 29.97
20 .8 1.2 2.0 315 367 234 8 160 23 95 71 373 29.96
24 1.0 1.7 2,0 357 354 195 8 170 29 91 71 191 29.97
24 1.1 1.8 2,0 429 738 371 4 180 23 87 71 27 29.99
32 1.3 2.7 2.1 558 1070 833 3 160 19 84 72 0 30.01
40 1.5 3,2 2.1 768 853 591 6 150 9 82 72 0 30.05
37 1.3 2,5 2.2 804 693 495 6 170 7 82 72 0 30.05
24 1.3 2.1 2.2 786 634 485 3 200 10 81 72 0 30.04
125
-------
APPENDIX B
Three types of aircraft flight information are contained in this
section.
1) A map for each flight showing the route followed, ozone
concentrations (ppb) at selected points along the route,
vertical sounding locations, and bag and can sample collection
points.
2) Plot of ozone concentration and temperature vs. altitude for
all aircraft vertical soundings.
3) Composite plots showing changes in altitude, CN counts, relative
humidity, nitric oxide, nitrogen dioxide and ozone concen-
tration vs. time (and distance) along the flight path.
The data are arranged by flight with flights numbered consecutively
beginning on July 2, 1976. All times refer to Central Daylight
Time.
126
-------
TEXAS
Brenham
Hem
= I6mi.
Figure Bl. Flight #1 on July 2, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 11:20 AM to 12:20 PM
Leg ab: 11:20 - 11:26 at -ulBOO" MSL
b: 11:27 - 12:00 spiral ascent to 12,000' and
descent to 8000'
ba: 12:01 - 12:20 slant descent to landing
(inverter failure)
WIND: 150/11
WEATHER: Partly cloudy and warm
127
-------
ALT
(x!03ftMSL)
12
II
10
9
T
40«v42 44 46 48 50
TEMP
30
40
50
60
70
(ppb)
Figure B2. Vertical ozone and temperature profiles NW of Houston
(fit. fl: point b) at 11:54 PM on July 2, 1976.
128
-------
TEXAS
Scale
l" = I6mi.
Figure B3. Flight #2 on July 2, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME:
6:00 to 7:50 PM
Leg
WIND:
WEATHER:
ab: 6:00 - 6:12 at ^1500' MSL
b: 6:13 - 6:42 spiral ascent
descent to 300'
be: 6:43 - 7:11 at ^1500'
cd: 7:12 7:29 at ^1500'
da: 7:30 - 7:50 slant descent
150/10 to 18
Partly cloudy, 88° F
to 12,000' and
to landing
129
-------
ALT
8
7
6
5
4
3
2
I I
I
56 60 64 68 72 76 80
TEMP
I
I
10 20 30 40 50 60
03
(ppb)
Figure B4. Vertical ozone and temperature profiles NW of Houston
(fit. #2: point b) at 6:20 PM on July 2, 1976.
130
-------
NO
N02
CN
ALTITUDE
(xlO3 ft MSL)
RELATIVE
HUMIDITY
1820 1840 1900 1920
FLIGHT TIME
1940
Figure B5. Plot of aircraft data recorded during flight #2 on
July 2, 1976.
131
-------
Figure B6. Flight #3 on July 4, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 11:30 AM to 1:25 PM
Leg ab: 11:30 - 11:37 at ^1500' MSL
b: 11:38 - 12:23 spiral ascent to 11,000' and
descent to 500'
be: 12:24 - 12:43 at 'v/IOOO1
ca: 12:44 - 1:24 at -x/1000'
WIND: IAH,190/6 HUB,050/6
WEATHER: Mostly cloudy - scattered rain - warm
132
-------
ALT
(x!03ftMSL)
9
8
7
6
5
4
3
2 h
54 58 62 66 70 74 78
TEMP
I
I
I
10 20 30 40 50 60
(ppb)
Figure B7 Vertical ozone and temperature profiles SW of Houston
(fit. #3: point b) at 12:10 PM on July 4, 1976.
133
-------
NO
NO,
CN
ALTITUDE 6
MSL)
4
100
90
RELATIVE
80 HUMIDITY
1200 1220 1240 1300 1320
FLIGHT TIME
Figure B8. Plot of aircraft data recorded during flight #3 on July 4, 1976,
134
-------
Figure B9. Flight #4 on July 5, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME:
5:40 to 8:15 PM
- 6:02 slant climb to 10,000' MSL
- 6:20 spiral descent to 200'
- 6:37 at ^800'
- 6:43 at ^900'
- 6:49 at ^900,'
- 7:11 at ^900'
- 7:24 at MOOO'
- 8:10 at ^900'
HUB,040/7
High broken to overcast clouds, 77°F
Leg
WIND:
WEATHER:
ab: 5:40
b: 6:03
be: 6:21
cd: 6:38
de: 6:44
ef: 6:50
fg: 7:12
ga: 7:25
I AH, 120/7
High brok
135
-------
NO
(ppb)
N02
(ppb)
(ppb)
ALT
(xlO3 ftMSL)
20
10 CN
0 (x!03ppml)
90
80
70
1800 1820 1840 1900 1920 1940 2000
FLIGHT TIME
Figure BIT. Plot of aircraft data recorded during Flight #4
on July 5, 1976.
136
-------
9
8
7
6
ALT
(x!03ftMSL) 5
T I I I
3 -
2 -
8 52 56 60 64 68 72 76
TEMP
I
I
I
10 20 30 40 50 60
03
(ppb)
Figure B1Q Vertical ozone and temperature profiles NW of Houston
(fit. #4: point b) at 6:05 PM on July 5, 1976.
137
-------
Figure B12 Flight #5 on July 7, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 7:40 to 10:40 AM
Leg ab: 7:40 - 8:04 slant climb to 10,000' MSL
b: 8:05 - 8:25 spiral descent to 100'
be: 8:26 - 8:39 at ^900'
cd: 8:40 - 9:02 slant climb to 2000' and slant
descent to cruise at ^900'
d: 9:03-9:14 spiral ascent to 4000' and descent
to 1000'
de: 9:15 - 9:26 between 900' and 1300'
ef: 9:27 - 9:49 at ^900'
fg: 9:50 - 10:06 at ^1000'
gh: 10:07 - 10:19 at ^900'
h: 10:20 - 10:26 spiral ascent to 3000' and descent
to 1000'
ha: 10:27 - 10:33 at ^800'
WIND: IAH,040/7 HUB,040/5
WEATHER: Partly cloudy - ground fog on eastern parts of flight -
70°F
138
-------
ALT
8
7
6
5
4
1 1
I
I
I
I
,50 54 58 62 66 70 74
TEMP
I
10 20 30 40 50 60
03
(ppb)
Figure B13 Vertical ozone and temperature profiles W of Houston
(fit. #5: point b) at 8:15 AM'on July 7, 1976.
139
-------
ALT
(x!03ftMSL)
4
3
0
30
66 68 70 72 74 76 78
TEMP
40
(ppb)
Figure B14. Vertical ozone and temperature profiles East of Houston
(Flight #5: point d) at 9:09 am on July 7, 1976.
140
-------
ALT
(x!03ft MSL)
4
3
2
0
68 72 76 80 84
TEMP
20
30
40
(ppb)
Figure B15. Vertical ozone and temperature profiles NW of Houston
(Flight #5: point h) at 10:23 am on July 7, 1976.
141
-------
03
(ppb)
CN
(x!03ppml)
RH
(%)
ALT 6
(xlO ftMSL) 4
NO
(ppb)
0800 0820 0840 0900 0920 0940 1000 1020
FLIGHT TIME
Figure B16. Plot of aircraft data recorded during Flight #5
on July.7, 1976.
142
-------
CO
(ppb)
80
70
60
50
40
30
20
10
0820 0840 0900 0920 0940
FLIGHT TIME
1000
1020
Figure B16. Continued
-------
Figure B17 Flight #6 on July 8, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 8:10 to 10:10 AM
Leg ab: 8:10 - 8:29 slant and spiral climb to 9000'
8:50 spiral descent to 100'
9:14 at ^1000'
9:19 at -uSOOO1
9:25 at ^2500'
9:43 at %2500'
9:53 at -vlOOO1
9:59 between 400' and 800'
10:00-10:10 slant ascent to 3000' and slant
descent to landing.
WIND: IAH,350/4 HUB,030/6
WEATHER: Clear, 71°F
ab:
b:
be:
cd:
de:
ef:
fg:
gh:
ha:
8:10
8:30
8:51
9:15
9:20
9:26
9:44
9:54
10:0
144
-------
8
7
6
ALT
(x!03ftMSL)
4
3
2
I
I
Gap
I
I
10 20 30 40
(ppb)
52 56 60 64 68
TEMP
Gap
Figure B 18 Vertical ozone and temperature profiles W of Houston
(fit. #6: point b) at 8:40 AM on July 8, 1976.
145
-------
NO
(ppb)
N02
(ppb)
03
(ppb)
ALT
(xi03f!MSL)
0830 0850 0910 0930 0950 1010
FLIGHT TIME
Figure B 19. Plot of aircraft data recorded during
Flight #6 on July 8, 1976.
146
-------
Figure B20 Flight #7 on July 8, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 2:50 to 5:50 PM
Leg ab: 2:50 - 3:04 slant climb to 8000' MSL
b: 3:05 - 3:29 spiral descent to 400' and spiral
ascent to 3000'
be: 3:30 - 3:45 between 2500' and 3000'
cd: 3:46 - 4:04 at ^1000'
de: 4:05 - 4:28 at -\,1200'
ef: 4:29 - 5:08 at VI200'
fg: 5:09-5:50 slant climb to 2000' and descend
to landing
WIND: HUB,080/4
WEATHER: Overcast - isolated thunderstorms - landing was made at
Hobby due to poor visibility and rain at Lakeside
147
-------
8
7
6
ALT
f tMSL)
4
3
2
I I I I I I I
55 61 67 73 79 85 SiT
TEMP
25 35 45 55 65 75 85 95 105
°3
(ppb)
Figure B2 1 Vertical ozone and temperature profiles SW of Houston
(fit. #7: point b) at 3:10 PM on July 8, 1976.
148
-------
N02
(ppb)
NO
(ppb)
(ppb)
RH
ALT
(xlC^ftMSL)
1500
1520 1540 1600 1620 1640 1700 1720
FLIGHT TIME
Figure B 22 Plot of aircraft data recorded during flight #7 on July 8, 1976.
149
-------
Figure B23 Flight #8 on July 10, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 2:45 - 4:30 PM
Leg ab: 2:45-3:00 slant and spiral climb to 9000' MSL
b: 3:01 - 3:16 spiral descent to 200'
be: 3:17 - 3:35 at 1000'
c: 3:36 - 3:43 spiral ascent to 2500' and spiral
descent to 1000'
cd:1 3:44 - 3:51 at ^1000'
de: 3:52 - 4:02 at 0,1000'
ef: 4:03 - 4:21 at ^1000'
fa: 4:22 - 4:30 at MOOO'
WIND: IAH,050/2 HUB ,050/7
WEATHER: Overcast at 8000' - 4 to 5 miles visibility in haze
and smoke - 70 F
150
-------
ALT
(xl03ftMSL)
9
8
7
6
5
4
3
2
I
0
T
T
T
I
I
I
I
56 60 64 68 72 76 80
TEMP
F)
I
I
I
10 20 30 40 50 60 70 80
(ppb)
Figure B24 Vertical ozone and temperature profiles W of Houston
(fit. #8: point b) at 3:10 PM on July 10, 1976.
151
-------
ALT
(x!03ftMSL)
0
I—
75
80 85
TEMP (F°)
20
60
100
140
03
(ppb)
Figure B25. Vertical ozone and temperature profiles SW of Houston
(Flight 18: point c) at 3:39 pm on Ouly 10, 1976.
152
-------
(ppb)
CN
(x!03ppml)
RH
ALT
(xlO^tMSL)
1500 1520 1540 1600 1620
FLIGHT TIME
Figure B 26 Plot of aircraft data recorded during flight #8
on July 10, 1976.
153
-------
N02
(ppb)
NO
(ppb)
50
40
30
20
10
30
20
T
1500 1520 1540 1600
FLIGHT TIME
1620
Figure B26 Plot of aircraft data recorded during flight
#8 on July 10, 1976.
154
-------
Figure B27 Flight #9 on July 12, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 8:45 to 11:25 AM
Leg ab: 8:45 - 9:03 slant and spiral climb to 9000'
b: 9:04-9:25 spiral descent to 100'
be: 9:26 - 9:49 at^!500'
cd: 9:50 - 9:59 at* 1500'
de: 10:00 - 10:08 between 1000' and 1500'
ef: 10:09 - 10:35 between 1000' and 1500'
fg: 10:36 - 11:03 at^lOOO'
g: 11:04 - 11:17 spiral ascent to 4000' and spiral
descent to 1000'
ga: 11:18 - 11:25 at^SOO1
WIND: IAH,100/4 HUB,06b/6 WEATHER: Overcast at 8000' - 77°F
155
-------
ALT
(x!03ftMSL)
9
8
7
6
5
4
3
2
I
0
10
20
30
03
(ppb)
I
48 56 64 72. 80 88
TEMP(F°)
40
50
Figure B28. Vertical ozone and temperature profiles West of
Houston (Flight #9: point b) at 9:04 am on July
12, 1976.
156
-------
ALT
(x!03ftMSL)4
3
2
I
0
75
I
_L
I
I
I
I
50 60 70 80 90 100 110 120
80
TEMP
85
(ppb)
Figure B 29 Vertical ozone and temperature profiles NW of Houston
(fit. 19: point g) at 11:05 AM on July 12, 1976.
157
-------
NO
(ppb)
N02
(ppb)
RH
03
(ppb)
ALT
(xlO3 ftMSL)
0900 0920 0940 1000 1020 1040 1100 1120
FLIGHT TIME
Figure B30. Plot of aircraft data recorded during Flight #9
on July 12, 1976.
158
-------
Figure B3l Flight #10 on July 12, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME:
Leg
WIND:
WEATHER:
3:00 to 5:50 PM
ab: 3:00 - 3:19 slant and spiral climb to 10,000' MSL
b: 3:20 - 3:40 spiral descent to 100'
be: 3:41 - 4:03 at ^1200'
cd: 4:04 - 4:39 at ^1200'
de: 4:40 - 5:06 at VI200'
e: 5:07 - 5:20 spiral ascent to 5000' and spiral
descent to 700'
ea: 5:21 - 5:50 at -x/12001
IAH,100/10 HUB,070/8
Broken clouds at 10,000', overcast at 25,000' - hot,
86 - 101°F
159
-------
8
7
ALT
(xlO^tMSL)
I
70 80 90 100
TEMP(F°)
i r i I I i I
i
l
40 60 80 100 120 140 160 180
03
(ppb)
Figure B32. Vertical ozone and temperature profiles NW of Houston
(Flight #10: point b) at 3:20 pm on July 12, 1976.
160
-------
5
4
ALT
(x!03ftMSL)
1 I I
84 84 88 92 96 100 104
TEMP (F°)
100
120
140
160
180
200
(ppb)
Figure B3 3.
Vertical ozone and temperature profiles SW of
Hempstead, TX. (Flight #10: point e) at 5:10 pm
on July 12, 1976.
161
-------
NO
(ppb)
0
N02
20 (ppb)
1520 1540 1600 1620 1640 1700
FLIGHT TIME
1720
CN
0 (xlO ppml)
Figure B34. Plot of aircraft data recorded during Flight
on July 12, 1976.
162
-------
Figure 635.
Flight #10 on July 13, 1976, with, ozone concentrations (ppb) marked
at points along the route.
TIME:
WIND:
WEATHER:
9:18 - 9:35
HUB, 190/6
Broken clouds
153
-------
ALT
(xK)3ftMSL)
9
8
7
6
5
4
3
2
I
0
I I
5Q 54 58 62 66 70 74 78
TEMP
15 25 35 45
(ppb)
Figure B36 Vertical ozone and temperature profiles W of Houston
(fit. #11: point ) at 9:20 AM on July 13, 1976.
164
-------
NO
(ppb)
CN
ppml)
RH
(%)
03
(ppb)
ALT
(x!03ftMSL)
(ppb)
0910 0930
FLIGHT TIME
e.\j
10
/
0910 0930
Figure B37 Plot of aircraft data recorded during flight #11 on
July 13, 1976.
"165
-------
Figure B38 Flight #12 on July 13, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME:
Leg
WIND:
WEATHER:
5:33 - 8:05 PM
ab: 5:33 - 5:51 slant and spiral climb to 9000' MSL
b: 5:52 - 6:12 spiral descent to 100'
be: 6:13 - 6:37 at ^1500'
cd: 6:38 - 7:04 at ^1500'
de: 7:05 - 7:33 at ^1500' (slant descent to 900' over
Baycliff Power Plant)
ea: 7:34 - 8:05 slant climb to 5500' and slant descent
to landing at Lakeside
IAH,090/13 HUB,100/10
Broken clouds at 5000' - 71°F
166
-------
9
8
7
6
ALT
(xlO^ftMSL)
3
2
I I I I
I I
52 56 60 64 68 72 76 80
TEMP
20 30 40 50 60
(ppb)
Figure B 39 Vertical ozone and temperature profiles W of Houston
(fit. #12: point b) at 6:00 PM on July 13, 1976.
167
-------
03
(ppb)
CN
(x!03ppml)
RH
ALT
(x!03ftMSL)
60
50
40
30
20
10
20
10
90
80
70
60
8
6
4
2
A
\
\
V
1750 1810 1830 1850 1910
FLIGHT TIME
1930
1950
Figure B 40 Plot of aircraft data recorded during flight #12 on
July 13, 1976.
168
-------
N02
(ppb)
NO
(ppb)
20
10
1750 1810
1830 1850 1910
FLIGHT TIME
1930 1950
Figure B4(TPlot of aircraft data recorded during flight #12 on July 13, 1976.
169
-------
Figure B41 Flight #13 on July 14, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME:
Leg
11 :40 AM - 2:35 PM
ab: 11:40 - 11:57 slant and spiral slimb to 9000'
b: 11:58 - 12:15 spiral descent to 100'
be: 12:16 - 12:37 at *80Q'
cd: 12:38 - 1:01 at ^800'
de: 1:02 - 1:22 at ^800'
ef: 1:23 - 1:45 at ^800'
fg: 1:46 - 2:01 at ^800'
gh: 2:02 - 2:25 at ^800'
ha: 2:26 - 2:35 at ^800'
MSL
WIND:
IAH,080/6 HUB,060/8
170
WEATHER: Broken clouds at 2500'-
visibility 2-5 miles in haze and smoke-
750F
-------
9
8
7
ALT
(xlC^ftMSL) 5
I I
I
50 54 58 62 66 70 74 74
TEMP
I
20 30 40
(ppb)
Figure B 42 Vertical ozone and temperature profiles W of Houston
(fit. #13: point b) at 12:05 PM on July 14, 1976.
171
-------
100
RH 80
(%) 60
CN
(xlO3 ppml) 20
80
NOj, 60
(ppb)
40
NO
(ppb)
03
(ppb)
ALT
(xlO3 ftMSL)
20
0
160
140
120
100
80
60
40
20
0
8
6
1150 1240 1230 1250 1310 1330 1350 WIO 1430
FLIGHT TIME
Figure B43 Plot of aircraft data recorded during Flight #13
on July 14, 1976.
172
-------
Figure B 44 Flight #14 on July 14, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 4:20 to 5:40 PM
Leg ab: 4:20-4:30 slant and spiral climb to 6000' MSL
b; 4:31 - 4:42 spiral descent to 200'
be: 4:43 - 4:54 at ^2000'
cd: 4:55 - 5:16 at ^2000'
da: 5:17 - 5:40 at -vlOOO1
WIND: IAH,110/9 HUB,180/10
WEATHER: Broken clouds at 4000'0- high overcast - 6 miles visibility
in haze and smoke - 89 F
173
-------
ALT
6
5
4
3
2
62 66 70 74 78 82
TEMP
30 50 70 90 110 130
(ppb)
Figure B 45 Vertical ozone and temperature profiles NW of Houston
(fit. #14: point b) at 4:35 PM on July 14, 1976.
174
-------
(ppb)
NO
(ppb)
RH
ALT
(xl03f»MSL)
1630 1650 1710
FLIGHT TIME
1730
N02
(ppb)
CN
Figure B46 Plot of aircraft data recorded during flight #14
on July 14, 1976.
175
-------
TEXARKANA
i
SEE INSET
Figure B 47 Flight #15 on July 15, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 11:27 AM - 2:07 PM
Leg
WIND:
WEATHER:
ab:
b:
be:
cd:
de:
ef:
IAH
11
11
1
1
1
1
1
2
2
;
:27
:35
:42
:03
:28
31
,130/7
Broken
:
_
_
~
- 2
1
1
1
1
1
;
HUB
clouds
1:
1:
2:
2:
34 slant climb to 4000' MSL
41 spiral descent to 3000'
02 slant descent to 1500'
27 between
:30 between
07
,1
at
at 1
80/13
000'
TKK
^5000' -
1500'
1500'
,050/1
84°F
and 4000'
and 3000'
0
176
-------
ALT
(xlO3 ftMSL)
72 74 76 78 80 82 84
TEMP
20 30 40 50 60
03
(ppb)
Figure B 48 Vertical ozone and temperature profiles NW of Houston
(fit. #15: point b) at 11:35 AM on July 15, 1976.
177
-------
N02
(ppb)
(ppb)
NO
(ppb)
CN
(xK^ppml)
RH
60
50
40
30
20
10
70
60
50
40
30
20
10
30
20
10
90
80
70
ALT
(x!03ftMSL) 2
NO
—1>
\J
7
c
\
GAE
\
GAP
,GAP
GAP"\
SAP
e.
A-l
1130 1150 1210 1230 1250 1310 1330 1350 1410
FLIGHT TIME
Figure B49 Plot of aircraft data recorded during flight #15 on July 15,
1976.
178
-------
TEXARKANA
SET INSET
36 38
Co! lege
Station
Figure B50 Flight #16 on July 15, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 3:35 to 6:10 PM
Leg ab: 3:35 - 3:58 at 1500' MSL
be: 3:59 - 4:40 at 1500'
cd: 4:41 - 5:40 between 1500' and 3000'
de: 5:41 - 6:01 at 1500'
ef: 6:02 - 6:10 at 1000'
WIND: TKK,210/15
WEATHER: Broken clouds at ^5000' - isolated thunderstorms along
route
179
-------
20
NO 10
(ppb)
CN 5
(xlO^jpml)
30
N02 20
(ppb) _
80
70
60
03
(ppb) 50
40
90
RH
(%) 80
ALT
(x!03ftMSL)
1550 1610 1630 1650 1710 1730 1750 1810
A-2 A-3 A-4 FLIGHT TIME
FigureB5l Plot of aircraft data recorded during flight #16 on July 15,
1976.
180
-------
Figure B52 Flight #17 on July 15, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME:
Leg
7:40 - 8:40 PM
ab: 7:40 - 8:05 at 1500' MSL
be: 8:06 - 8:13 at 1500'
cd: 8:14 - 8:20 at 1500'
d: 8:21-8:29 spiral ascent to 5000'
de: 8:30 - 8:40 slant descent to Lakeside
WIND:
WEATHER: Overcast at ^5000' - isolated thunderstorms enroute
181-
-------
ALT
(xlO3 ftMSL)
4
3
2
80 82 84 86 88 90 92
TEMP
10
15
20 25 30
(ppb)
Figure B5 3 Vertical ozone and temperature profiles W of Houston
(fit. #17: point d) at 8:25 PM on July 15, 1976.
182
-------
N02
(ppb)
NO
(ppb)
°3
(ppb)
RH
CN
(xlO^pml)
ALT
(xKPft MSL)
10
20
10
30
20
80
.
Neva- Above 2
c d—d
1950 2010 2030
FLIGHT TIME
Figure B5 4 Plot of aircraft data recorded during
flight #17 on July 15, 1976.
183
-------
TEXAS
LOUISIANA
•College Station
Baton
Rouge
Scale
l" = 58mi.
Figure B55 Flight #18 on July 18, 1976, with ozone concentrations (ppb) marked
at points along the route. ,
TIME: 8:57 to 10:35 AM
Leg
WIND:
ab:
be:
cd:
de:
Calm
8:57 - 9:24 spiral ascent to 6000' MSL and spiral
descent to 1000'
9:25 - 9:41 at ^1500'
9:42 - 9:58 between 1000' and 1500'
9:59 - 10:13 slant climb to 3300' and slant descent
to 1000'
10:14 - 10:35 at 'x
WEATHER: Broken clouds at 8000' - 77UF
1G4
-------
ALT
(x!03ftMSL)
6
5
4
3
2
68 70 72 74 76 78 80
TEMP
I
15
20 25 30 35
(ppb)
Figure B 56 Vertical ozone and temperature profiles SW of Houston
(fit. #18: point a) at 9:10 AM on July 18, 1976
-------
30
20
NO
30
20
10
CN
30
20
10
10
RH 90
ALT
MSL)
\
920 940 1000 1020 1040
FLIGHT TIME
Figure B 57 Plot of aircraft data recorded during flight #18 on July 18,
1976.
186
-------
\ Lake
Beaumont '. Charles
Figure B 58 Flight #19 on July 18, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME:
Leg
WIND:
11:25 AM to 1:15 PM
ab: 11:25 11:37 slant climb to 4000' MSL
b: 11:38 - 11:44 spiral descent to 1000'
be: 11:45 - 12:33 at MOOO1
cd: 12:34 - 1:15 at -v.10001 (climb to 2500' over Baton
Rouge then descend to 1000')
Calm
WEATHER: Clear and warm
187
-------
ALT
(xlO^ftMSL)
3
2
10
72 74 76 78 80 82
TEMP
20
30
40
(ppb)
Figure B 59 Vertical ozone and temperature profiles near Lake
Charles, LA, (fit. #19: point b) at 11:40 AM on
July 18, 1976.
188
-------
N02
(ppb)
NO
(ppb)
(ppb)
RH
ALT
(xl03f1MSL)
20
10
20
10
90
80
70
60
50
40
30
90
80
\
V
\
1140 1200 1220 1240
FLIGHT TIME
1300
Figure B60 Plot of aircraft data recorded during flight #19 on
July 18, 1976.
189
-------
Figure B6l Flight #20 on July 18, 1976, with ozone concentrations Cppb) marked
at points along the route. !
TIME: 2:53 to 4:25 PM
Leg ab: 2:53 - 3:14 slant climb to 2500' and slant descent to
1000' MSL
be: 3:15 - 3:51 at 'vlOOO1
cd: 3:52 - 4:20 at -ulOOO1
WIND: Northerly at 5 to 10 mph
WEATHER: Clear and hot
190
-------
N02
(ppb)
NO
(ppb)
_
03
RH
(%)
CN
(x
ALT
(xlf/ftMSL)
1500 1520 1540 1600
FLIGHT TIME
1620
Figure B62 Plot of aircraft data recorded during flight
#20 on July 18, 1976.
191
-------
TEXAS
LOUISIANA
^College
Station
Baton
Rouge
Scale
|"= 58mi.
Figure B63 Flight #21 on July 18, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 5:00 to 6:40 PM
Leg ab: 5:00 - 5:09 slant and spiral climb to 7000' MSL
b: 5:10 - 5:26 spiral descent to 1000'
be: 5:27 - 6:10 at VI000'
cd: 6:11 - 6:35 at VI000'
WIND: Light and variable
WEATHER: Clear and warm
192
-------
7
6
ALT 5
(x!03ftMSL)
4
3
2
25
I I
62TO 80~
TEMP (F°)
88
Figure B64.
35 45 55 65
03
(ppb)
Vertical ozone and temperature profiles South of
Lk. Charles, LA. (Flight #21: point b) at 5:10 pm
on July 18, 1976.
193
-------
N02
(ppb)
NO
(ppb)
(ppb)
RH
CN
(x!03ppml)
ALT
(x!03ft MSL)
1710 1730 1750 1810
FLIGHT TIME
1830
Figure B65 Plot of aircraft data recorded during flight #21
on July 18, 1976.
194
-------
Figure B66 Flight #22 on July 20, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 9:03 to 11:10 AM
Leg ab: 9:03 - 9:21 slant and spiral climb to 10,000' MSL
b: 9:22 - 9:43 spiral descent to 150'
be: 9:44 - 10:04 at ^800'
cd: 10:05 - 10:22 at ^800'
de: 10:23 - 10:45 at ^800'
ea: 10:46 - 11:10 at ^800'
WIND: IAH,050/3 HUB,120/3
WEATHER: Clear - 6 miles visibility in haze and smoke - 81°F
195
-------
10
9
8
7
6
ALT
(x!03ftMSL)
4
3
2
I
0
20
30
40
50
60
70
T
(ppb)
Figure B67 Vertical ozone and temperature profiles SW of Houston
(fit. #22: point b) at 9:30 AM on July 20, 1976.
196
-------
30
N02
(ppb)
NO
(ppb)
RH
CN
(x!03ppml)
ALT
(x!03ftMSL)
0910 0930 0950 1010 1030 1050 1110
FLIGHT TIME
Figure B 68 Plot of aircraft data recorded during flight #22 on July
20, 1976.
197
-------
03
(ppb)
0910 0930 0950 1010
IFLIGHT
1030
TIME
1050
illO
Figure B68 Plot of aircraft data recorded during flight #22 on July 20,
1976.
198
-------
Figure B"69 Flight #23 on July 20, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 5:12 to 7:15 PM
Leg ab: 5:12 - 5:39 slant and spiral climb to 12,000' MSL
b: 5:40 - 6:07 spiral descent to 200' and climb to
1400'
be: 6:08 - 6:18 at -x.14001
cd: 6:19 - 6:29 at ^1400'
de: 6:30 - 6:39 at M4001
e: 6:40 - 6:50 2 mile, 520° arc of refinery at
^1400'
ea: 6:51 - 7:10 at ^1400'
WIND: IAH,170/9 HUB,160/14
WEATHER: A few scattered clouds - good visibility - 97°F
199
-------
10
9
8
7
ALT
(xl^ftMSL) 6
5
4
3
2
I i
T
50 60 70 80 90 100
TEMP
25 30 35 40 45 50 55 60 65 70 75 80
(ppb)
Figure B70 Vertical ozone and temperature profiles W of Houston
(fit. #23: point b) at 5:40 PM on July 20, 1976.
200
-------
N02
(ppb)
NO
(ppb)
RH
CN
(x!03ppml)
ALT
(x!03ft MSL) 6
8
1740 1800 1820 1840 1900
FLIGHT TIME
Figure B7 1 Plot of aircraft data recorded during flight #23 on
July 20, 1976.
201
-------
(ppb)
20
10
1740 1800 1820 1840
FLIGHT TIME
1900
FigureB71 Plot of aircraft data recorded during flight #23
on July 20, 1976.
202
-------
Figure B72 Flight #24 on July 21, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME:
Leg
7:55 to 9:15 AM
WIND:
WEATHER;
8:07 slant and spiral climb to 7000' MSL
8:26 spiral descent to 200' and climb to
8:42 at 1000'
8:49 at 1000'
9:01 at 'x/IOOO'
9:15 at •v.lOOO'
IAH,calm HUB,030/4
High broken clouds - 4 miles visibility in fog, haze and
smoke - isolated thunderstorms - 71°F
ab:
b:
be:
cd:
de:
ea:
7:55
8:08
1000'
8:27
8:43
8:50
9:02
203
-------
7
6
ALT
(x!03ftMSL) 5
4
3
2
58 62 66 70 74 78
TEMP
50
60
°3
(ppb)
70
Figure B73 Vertical ozone and temperature profiles W of Houston
(fit. #24: point b) at 8:15 AM on July 21, 1976.
204
-------
N0?
(ppbT
NO
(ppb)
03
(ppb)
CN
(xlO^pml)
ALTITUDE
(x!03ft MSL)
40
30
20
10
70
60
50
40
30
20
10
60
50
40
30
90
80
70
0
6
A
c d
A-l
RELATIVE
HUMIDITY
0800 0820 0840 0900
FLIGHT TIME
Figure B74 Plot of aircraft data recorded during
flight #24 on July 21, 1976.
205
-------
42 40 4l 37
Figure B75" Flight #25 on July 22, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 8:45 to 10:50 AM
Leg ab: 8:45-8:59 slant and spiral climb to 8000.' MSL
b: 9:00 - 9:18 spiral descent to 200'
be: 9:19 - 9:36 at 1000'
c: 9:37 - 10:18 Exxon refinery plume investigation,
altitude between 500' and 3000'
c: 10:08 - 10:16 spiral ascent to 3000' and descent to
200'
cd: 10:19 - 10:28 at •x.lOOO1
de: 10:29 - 10:39 at ^1500'
ea: 10:40 - 10:50 at ^1500'
WIND: IAH,060/5 HUB,030/3
WEATHER: Broken clouds at 10,000' - visibility 4 miles in fog
and smoke - 79°F
206
-------
Figure B75 Flight #25 on July 22, 1976, continued.
IIIIIIIII Probable refinery plume and area of highest ozone
207
-------
7
6
ALT
(x!03ftMSL) 5
4
3
2
70 80 84 88 92
TEMP
25 30 35 40 45
03
(ppb)
FigureB76 Vertical ozone and temperature profiles W of Houston
(fit. #25: point b) at 9:05 AM on July 22, 1976.
208
-------
88 90 92 94 96 98 100
TEMP
ALT
(x!03ftMSL)
4
3
2
I
%•
60
80
100
(ppb)
FigureB 77 Vertical ozone and temperature profiles 7.5 miles
downwind of Exxon's Baytown Refinery at 10:10 AM
on July 22, 1976.
209
-------
N02
(ppb)
CN
(xlO3 ppml)
RH
ALT
(x!03ftMSL)
0900 0920 0940 1000 1020
FLIGHT TIME
1040
Figure B78 Plot of aircraft data recorded during Flight #25
on July 25, 1976.
210
-------
157 160 \I73 I79J70/I33
FigureB79 Flight #26 on July 22, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 12:50 to 3:15 PM
Leg ab: 12:50 - 1:09 slant and spiral climb to 9000' MSL
b: 1:10 - 1:28 spiral descent to 200'
be: 1 :29 1:50 at MOOO1
c: 1:51 - 2:41 Refinery investigation and sample
collections, 'x/IOOO'
cd: 2:42 - 2:49 at 'vlOOO'
de: 2:50 - 3:02 at ^1000'
ea: 3:03 - 3:15 at ^1000'
WIND: IAH,110/6 HUB,150/6
WEATHER: Some scattered clouds - visibility 6 to 7 miles in
haze and smoke - 90°F
211
-------
A-6
Scale
FigureB79 Flight #26 on July 22, 1976, continued,
212
-------
ALT
(x!03ftMSL)
60 70 80 90 100 HO
TEMP
40 44 48 52
(ppb)
Figure B80 Vertical ozone and temperature profiles W of Houston
(fit. #26: point b) at 1:15 PM on July 22, 1976.
213
-------
NO,
(ppb)
NO
(ppb)
CN
(x(03ppml)
RH
ALT
(x!03ftMSL)
1310 1330 1350 1410 1430
FLIGHT TIME
1450 1510
Figure B81 Plot of aircraft data recorded during Flight #26
on July 22, 1976.
214
-------
(ppb)
1310 1330 1350 1410 1430
FLIGHT TIME
1450
1510
Figure B 8 1 Continued
215
-------
TEXAS
44 6866JLJ2
67
40^40 59 7 54
Figure B82 Flight #27 on July 23, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 9:00 to 11:15 AM
Leg ab: 9:00 - 9:17 slant and spiral climb to 9000' MSL
b: 9:18 - 9:37 spiral descent to 200'
be: 9:38 - 9:54 at MOOO1
c: 9:55-10:59 refinery investigation, at ^1000',
see next page
ca: 11:00 - 11:15 at -^1000'
WIND: IAH,030/5 HUB,360/4
WEATHER: Scattered clouds -visibility 5 to 6 miles in haze and
smoke - 81°F
216
-------
Figure B 82 Flight #27, July 23, 1976 continued,
Area c: 9:55 - 10:59 AM
217
-------
9
8
7
6
ALT
(xlC^ftMSL) 5
4
3
2
54 58 62 66 70 74 78 82
TEMP
I
I
25 30
35 40 45
03
(ppb)
50 55
Figure B 83 Vertical ozone and temperature profiles W of Houston
(fit. #27: point b) at 9:25 AM on July 23, 1976.
218
-------
N02
(ppb)
NO
(ppb)
CN
(x!03ppml)
RH
ALT
(xlO3 ftMSL)
0910 0930 0950 1010 1030 1050 1110
FLIGHT TIME
Figure B84 Plot of aircraft data recorded during flight #27 on July
23, 1976.
219
-------
03
(ppb)
0910 0930 0950 1010 1030 1050
FLIGHT TIME
Figure B84 Plot of aircraft data recorded during flight #27 on July
23, 1976.
220
-------
Figure B 85 Flight #28 on July 24, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME:
Leg
WIND:
WEATHER:
10:15 - 11:55 AM
ab:
b:
be:
cd:
de:
ef:
fa:
10:15
10:22
10:35
10:50
11:11
11:34
11:37
- 10:21 si,
- 10:34 sp
- 10:49 at
- 11:10 at
- 11:33 at
- 11 :36 at
- 11:55 at
int and spiral climb to 6500' MSL
:ral descent to 1000'
1000'
VI000'
VI000'
*1000'
0,1000'
HUB ,320/8
Clear - 85°F
221
-------
Figure B85 Flight #28 on July 24, 1976, continued,
222
-------
ALT
62 66 70 74 78 82 86
TEMP
25 35 45 55 65 75
(ppb)
Figure B 86 Vertical ozone and temperature profiles W of Houston
(fit. #28: point b) at 10:30 AM on July 24, 1976.
223
-------
(ppb)
N02
(ppb)
NO
(ppb)
CN
Ul03ppml)
RH
ALT
(x!03ftMSL)
EOUIPMCNT
M \LFUNCTION
1020
1040 1100 1120
FLIGHT TIME
140
Figure $87 Plot of aircraft data recorded during flight #28
on July 24, 1976.
224
-------
Figure B 8« Flight #29 on July 24, 1976, with ozone concentrations (ppt>) marked
at points along the route.
TIME:
2:33 - 4:25 PM
Leg
WIND:
WEATHER:
ab: 2:33
b: 2:51
be: 3:14
cd: 3:31
de: 3:56
ea: 4:09
HUB, 170/5
Broken cl<
2:50 slant and spiral climb to 10,000' MSL
3:13 spiral descent to 200'
3:30 at 1500'
3:55 at ^1500'
4:08 at 1500'
4:25 at 1500'
Broken clouds at 3000' - reduced visibility in haze -
90°F
225 '
-------
FigureB 88 Flight #29 on July 24, 1976, continued,
-226
-------
ALT
(x!03ftMSL)
56 62 66 70 74 78 82 86 90
TEMP
50 60 70 80 90 100
03
(ppb)
Figure B89 Vertical ozone and temperature profiles W of Houston
(fit. #29: point b) at 3:00 PM on July 24, 1976.
227
-------
ALT
(x!03ftMSL)
72 74 76 78 80 82 84
TEMP
40
50
60
70
80
90
(ppb)
Figure B93 Vertical ozone and temperature profiles SW of Houston
(fit. #30: point f) at 10:30 AM on July 25, 1976.
228
-------
N02
(ppb)
NO
(Ppb)
CN
(xlC^ppml)
RH
ALT
(x!03ft MSL)
1450 1510 1530 1550
FLIGHT TIME
1610
(ppb)
GAP IN DATA
Figure,B90 Plot of aircraft data recorded during flight #29
on July 24, 1976.
229'
-------
FigureB'£l Flight #30 on July 25, 1976, with ozone concentrations (ppb) marked
at points along the route.
TIME: 8:35 to 10:45 AM
Leg
fa:
8:44 slant and spiral climb to 7000' MSL
8:59 spiral descent to 200'
9:21 at 1000'
9:49 at 1000'
10:17 at 1000'
10:22 slant descent to 200'
10:32 spiral ascent to 4000' and spiral
descent to 1300'
10:33 - 10:45 at 1300'
ab:
b:
be:
cd:
de:
ef:
f:
8:35 - i
8:45 - 1
9:00 - !
9:22 - '
9:50 -
10:18 -
10:23 -
WIND:
WEATHER:
IAH,270/2 HUB,calm
High scattered clouds - poor visibility in fog and
haze - 75°F
230
-------
7
6
ALT
(xK^ftMSU 5
45 55 65 75 85
(ppb)
60 64 68 72 76 80 84
TEMP
Figure B'9 2 Vertical ozone and temperature profiles W of Houston
(fit. #30: point b) at 8:50 AM on July 25, 1976.
231
-------
NO
(ppb)
N02
(ppb)
(ppb)
CN
(xlC^ppml)
RH
ALT
(xlC^ftMSL)
0820
Figure B94 Plot
1976
0840 0900 0920 0940 1000 1020 1040
FLIGHT TIME
of aircraft data recorded during flight #30 on July 25,
232
-------
APPENDIX C
The summation of all individual hydrocarbon peaks for samples listed
in Tables 3, 4, 5, 7, 11 and 12 are tabulated in this section.
233
-------
TABLE C-l. SUMMATION OF INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/m3) IN
SAMPLES COLLECTED BETWEEN 6 AND 9 AM AT THE WSU TRAILER SITE.
DATE
7/5
7/7
7/8
7/9
7/10
7/12
7/13
7/14
7/15
7/16
7/17
7/19
7/20
7/21
7/22
7/23
7/24
TOTAL IDENTIFIED
IN TABLE 3
206
265
593
407
275
719
533
130
2527
461
549
1153
488
595
697
709
1257
TOTAL OF OTHER HYDROCARBON
SPECIES NOT INCLUDED
IN TABLE 3
(IDENTIFIED AND UNIDENTIFIED)
93
143
267
179
126
378
268
123
1662
350
293
464
436
373
647
392
258
TOTAL NMHC BY
SUMMING INDIVIDUAL
SPECIES
299
408
860
586
401
1097
801
253
4189
811
842
1617
924
968
1344
1101
1515
234
-------
TABLE C-2. SUMMATION OF INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/m3) IN
SAMPLES COLLECTED BETWEEN 7 AND 9 AM AT THE SOUTH SITE.
TOTAL OF OTHER HYDROCARBON
SPECIES NOT INCLUDED TOTAL NMHC BY
TOTAL IDENTIFIED IN TABLE 4 SUMMING INDIVIDUAL
DATE IN TABLE 4 (IDENTIFIED AND UNIDENTIFIED) SPECIES
7/9
7/10
7/13
7/14
7/15
7/16
7/17
7/19
7/20
7/22
889
158
714
601
244
193
275
677
179
461
165
79
332
360
127
129
167
2051
158
301
1054
237
1046
961
371
322
442
2728
337
762
235
-------
TABLE C-3. SUMMATION OF INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/tn3) IN
SAMPLES COLLECTED BETWEEN 6 AND 9 AM AT THE NORTH SITE.
TOTAL OF OTHER HYDROCARBON
SPECIES NOT INCLUDED TOTAL NMHC BY
TOTAL IDENTIFIED IN TABLE 5 SUMMING INDIVIDUAL
DATE IN TABLE 5 (IDENTIFIED AND UNIDENTIFIED) SPECIES
7/9
7/10
7/12
7/14
7/16
7/17
7/19
7/20
7/21
280
308
951
120
440
2256
2893
376
2375
280
245
1590
138
363
4450
8005
380
4696
560
553
2541
258
803
6706
10898
756
7071
236
-------
TABLE C-4. SUMMATION OF INDIVIDUAL HYDROCARBON CONCENTRATIONS (yg/m3) IN
SAMPLES COLLECTED DURING THE AFTERNOON HOURS AT THE WSU
TRAILER SITE.
TOTAL OF OTHER HYDROCARBON
SPECIES NOT INCLUDED TOTAL NMHC BY
TOTAL IDENTIFIED IN TABLE 7 SUMMING INDIVIDUAL
DATE IN TABLE 7 (IDENTIFIED AND UNIDENTIFIED) SPECIES
7/6
7/9
7/10
7/12
7/13
7/14
7/15
7/17
7/21
90
281
221
324
104
290
256
75
504
91
162
133
167
78
169
178
67
252
181
443
354
491
182
459
434
142
756
237
-------
TABLE C-5. SUMMATION OF INDIVIDUAL HYDROCARBON CONCENTRATIONS (ug/m3) IN
SAMPLES CONSIDERED TO BE REPRESENTATIVE OF BACKGROUND AIR.
TOTAL OF OTHER HYDROCARBON
SPECIES NOT INCLUDED TOTAL NMHC BY
TOTAL IDENTIFIED IN TABLE 11 SUMMING INDIVIDUAL
DATE IN TABLE 11 (IDENTIFIED AND UNIDENTIFIED) SPECIES
7/4
7/7
7/12
7/14
7/20
37.0
31.5
36.0
40.0
61.0
36.0
33.5
30.0
37.5
81.0
73.0
65.0
66.0
77.5
142.0
238
-------
TABLE C-6. SUMMATION OF INDIVIDUAL HYDROCARBON CONCENTRATIONS Ug/m3) IN
SAMPLES COLLECTED IN AIR MASSES CONTAINING OZONE LEVELS GREATER
THAN 80 PPB.
TOTAL OF OTHER HYDROCARBON
SPECIES NOT INCLUDED TOTAL NMHC BY
TOTAL IDENTIFIED IN TABLE 12 SUMMING INDIVIDUAL
DATE IN TABLE 12 (IDENTIFIED AND UNIDENTIFIED) SPECIES
7/7
7/8
7/10 (A-l)
7/10 (A-2)
7/12 (A-3)
7/12 (A-4)
7/14 (A-2)
7/14 (A-3)
7/18
7/20 (A-2)
7/20 (A-3)
7/22
434
193
190
223
173
179
175
270
120
185
121
160
146
69
40
82
39
121
64
108
46
79
47
54
580
262
230
305
212
300
239
378
166
264
168
214
239
-------
M REPORT NO.
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
\ EPA--600/3-78-062
2.
3. RECIPIENT'S ACCESSION-NO.
\-i. TITLE AND SUBTITLE 5. REPORT DATE
MEASUREMENT OF LIGHT HYDROCARBONS AND OXIDANT TRANSPORT JulV 1978
i Houston Area 1976
6. PERFORMING ORGANIZATION CODE
|7. AUTHOR(S)
; H. Westberg, K. Allwine, and E. Robinson
8. PERFORMING ORGANIZATION REPORT NO.
PERFORMING ORGANIZATION NAME AND ADDRESS
Air Resources Section
Chemical Engineering Department
Washington State University
Pullman., Washington 99164
10. PROGRAM ELEMENT NO.
1AA603 AJ-05 (FY-76)
11. CONTRACT/GRANT NO.
68-02-2298
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Sciences Research Laboratory-RTF, NC
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/09
15. SUPPLEMENTARY NOTES
16. ABSTRACT
An extensive air pollutant monitoring program, including ground level and aerial
saniuling, was carried out in the Houston area during the month of July 1976. Measure
rnents included ozone, oxides of nitrogen, PAN, methane, carbon monoxide, individual
hydrocarbons (Cp-C-m), halocarbons, condensation nuclei, and visual distance plus
numerous meteorological parameters. Specific areas of interest included (1) oxidant
formation and transport within the Houston urban plume, (2) relationships between
czone layers aloft and the vertical temperature profile, (3) composition and effects
of refinery and petrochemical emissions on the local Houston air mass, and (4)
identification and quantisation of individual Co~^in hydrocarbons in the Houston
atmosphere. Results of this field program showed that the city of Houston serves
as a strong pollutant source. Ozone concentrations were generally high in down-
wind areas. During the study period, there were no "blanket" areas of ozone in
southern Texas. Therefore, high oxidant levels observed in Houston are a direct
the precursors emitted in the Houston area.
result of
(-17. KEY WORDS AND DOCUMENT ANALYSIS
ja. DESCRIPTORS
t ,
,1 2rAir pollution
: * Ozone
: ^Transport properties
Chemical analysis
*Field tests
* Aliphatic hydrocarbons
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
b.lDENTIFIERS/OPEN ENDED TERMS
Houston
19. SECURITY CLASS (This Report)
UNCLASSIFIED
20. SECURITY CLASS (This page)
UNCLASSIFIED
c. COS AT I Field/Group
13B
07B
07D
14B
07C
21. NO. OF PAGES
250
22. PRICE
EPA Form 2220-1 (9-73)
240
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