EPA-450/3-77-054
September 1977
CHARACTERIZATION
OF THE
WASHINGTON, D.C.
OXIDANT PROBLEM
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
\
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EPA-450/3-77-054
CHARACTERIZATION
OF THE WASHINGTON, D. C.
OXIDANT PROBLEM
Final Report
b)
Frank A. Record, Program Manager
GCA Corporation
GCA/Technology Division
Bedford, Massachusetts
Contract No. 68-02-1376
Task Order No. 27
EPA Project Officer: Warren P. Freas
ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
September 1977
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This report 1s issued by the Environmental Protection Agency to report
technical data of Interest to a limited number of readers. Copies are
available free of charge to Federal employees, current contractors and
grantees, and nonprofit organizations - 1n limited quantities - from
the Library Services Office (MD-35), Research Triangle Park, North
Carolina 27711; or, for a fee, from the National Technical Information
Service, 5285 Port Royal Road, Springfield, Virginia 22161.
This Final Report was furnished to the U.S. Environmental Protection
Agency by GCA Corporation, GCA/Technology Division, Bedford, Massachu-
setts 01730, in fulfillment of Contract No. 68-02-1376, Task Order No.
27. The opinions, findings, and conclusions expressed are those of
the authors and not necessarily those of the Environmental Protection
Agency or of cooperating agencies. Mention of company or product names
is not to be considered as an endorsement by the Environmental
Protection Agency.
11
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FOREWORD
As its first task under Contract No. 68-02-1376, Task Order No. 27, GCA/
Technology Division was to evaluate the adequacy of the data base in the
National Capitol AQCR for developing and testing techniques by which
changes in VMT and/or vehicle emissions could be related to changes in
ambient levels of oxidants and carbon monoxide. The data were to be
drawn from a baseline summertime period in either 1973 or 1974 and the
corresponding period in 1976. If the data base proved to be adequate,
work in developing these techniques was to begin.
At the conclusion of this task it was jointly concluded by the EPA Project
Officer and GCA/Technology Division that fundamental inadequacies in the
existing data bases would prevent carrying out the development and testing
of such techniques at this time. As a result of this decision, a more
general study of the oxidant problem in the Washington, D.C. area was sub-
stituted for this phase of the work. The results of this general study
are presented in this report. Weekly reporting of oxidant levels and
current traffic, visitor, and meteorological statistics that might relate
to these levels was carried out for the Bicentennial summer season as
scheduled in the original scope of work.
Under a CO phase of the program, relationships between traffic, vehicle
emissions, and CO levels within the Washington, D.C. area were analyzed
using revised CO Hot Spot Guideline techniques and supplementary computer
simulation models. The results of this work are provided in a separate
report.
iii
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CONTENTS
Page
Foreword ill
List of Figures vii
List of Tables xi
Acknowledgments xiii
Executive Summary xv
Sections
I Introduction 1
Project Overview 1
Short Term Trend 2
II The Data Base 5
Emission Inventory Data 5
Routine Surface Network Data 6
Meteorological Data 6
Traffic Count Data 6
Special THC, CH,, NMHC, and CO Observations 10
Detailed HC Composition Data 10
Aircraft Observations 11
III Distribution of Precursor Emissions 12
IV Summary and Interpretation of Data From Local
Networks 25
Summary of Ozone Data 25
Influence of Monitor Siting 51
Comparison of Upwind/Downwind Concentrations 54
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CONTENTS (continued)
Sections Page
V Summary of Selected Aircraft Flight Data 59
Overview of Ground-Level Ozone Concentrations and
Associated Meteorological Conditions During Flight
Program 59
VI Summary of Hydrocarbon Field Measurements 86
THC, CH, , NMHC, and CO Data 86
NMHC/NO Ratios 91
X
HC Species Data 91
VII Summary and Conclusions 105
References 108
Appendices
A Air Pollution Alerts Chronological History A-l
B Mixing Heights at Sterling, Virginia B-l
C Area and Point Source Emissions of Hydrocarbons and
Nitrogen Oxides C-l
D Characteristics of Monitor Sites D-l
E Trajectories E-l
F Additional Aerial Survey Data F-l
G Summary Tables of Hydrocarbon and Carbon Monoxide Data G-l
vi
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FIGURES
No. Page
1 Comparison of High Ozone Concentration at Five Virginia
Monitoring Sites During 1973-1976 3
2 Distribution of Monitors Throughout Washington
Metropolitan Area 7
3 Meteorological Network 9
4 Planning Districts for the Washington Metropolitan Region 13
5 Emission Density Map of Total Hydrocarbons for the National
Capitol AQCR 15
6 Emission Density Map of Total Hydrocarbons for Central
Metropolitan Washington Area 16
7 Emission Density of Total Hydrocarbons by Planning District
Within the National Capitol AQCR 17
8 Emission Density of Total Hydrocarbons by Planning District
Within Central Metropolitan Washington Area 18
9 Emission Density Map of Nitrogen Oxides for the National
Capitol AQCR 19
10 Emission Density Map of Nitrogen Oxides for Central
Metropolitan Washington Area 20
11 Emission Density of Nitrogen Oxides by Planning District
Within the National Capitol AQCR 21
12 Emission Density of Nitrogen Oxides by Planning District
Within Central Metropolitan Washington Area 22
13 Emission Rates of Nitrogen Oxides From Grouped Point
Sources 23
14 Average of Maximum Daily 0, Concentrations for Selected
Geographical Areas 36
15 Daily Sequence of Meteorological Parameters and an Index
of Maximum 0, Concentration 37
16 Day-by-Day Variation in Maximum Ozone Concentration Index
for Washington, D.C. (Upper Curve) with Variations in
Traffic Counts (Lower Curves) 40
vii
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FIGURES (continued)
No. Page
17 Diurnal Variation of Pollutants During June, July,
and August 1976 at Massey and Engleside 44
18 Diurnal Variation of Pollutants During June, July, and
August 1976 at the Alexandria Health Department and
Shirlington 45
19 Diurnal Variation of Pollutants During June, July, and
August 1976 at Seven Corners and Lewinsville 46
20 Diurnal Variation of Pollutants During June, July, and
August 1976 at Sterling Park and Gaithersburg 47
21 Diurnal Variation of Pollutants During June, July, and
August 1976 at Bethesda and Silver Spring 48
22 Diurnal Variation of Pollutants During June, July, and
August 1976 at Cheverly and Suitland 49
23 Diurnal Variation of Pollutants During June, July, and
August 1976 at the CAMP Station in Washington, D.C. 50
24 Maximum 1-hour Ozone Concentration as a Function of
Morning Wind Direction at Selected Sites Outside the
Central Metropolitan Area 53
25 Seventy-Five Mile Square Grid for Use in Trajectory
Calculations 55
26 Computer-Calculated Trajectory for Air Parcel Passing
Over Washington, D.C. (Point B) at 1400 EST on
5 June 1976 56
27 Comparison of Average Ozone Concentrations Observed
From 0800 to 1600 EST at Upwind, Downwind, and CAMP
Stations 57
28 Spiral Locations of Aircraft Soundings During Air
Sampling Program 61
29 Daily Values of the Maximum Ozone Concentration Index
(13 Station Average) and Selected Meteorological Parameters
During Aircraft Sampling Program 62
viii
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FIGURES (continued)
No. Page
30 Surface Weather Map for 18 August 1976, 0700 EST 63
31 Surface Weather Map for 22 August 1976, 0700 EST 63
32 Surface Weather Map for 24 August 1976, 0700 EST 65
33 Surface Weather Map for 27 August 1976, 0700 EST 65
34 Surface Weather Map for 29 August 1976, 0700 EST 66
35 Midday (1300 EDT) Temperature Soundings Taken at
Sterling, Virginia During the Period 17-31 August 1976 66
36 Low-Level Trajectories of Air Parcels Passing Through
Washington, D.C. at 1400 EST on 16, 17, 18, and 19
August 1976 69
37 Low-Level Trajectories of Air Parcels Passing Through
Washington, D.C. at 1400 EST on 20, 21, and 22 August
1976 70
38 Sampling Track During Flight No. 1 72
39 Sampling Track During Flight No. 2 73
40 Sampling Track During Flight No. 3 74
41 Ozone Concentrations During Horizontal Sampling,
Flight No. 3 75
42 Temperature and Ozone Profiles, Flight No. 1 76
43 Ozone Profile, Flight No. 3 77
44 Sampling Track During Flights No. 4 and No. 5 79
45 Sampling Track During Flight No. 7 80
46 Sampling Track During Flight No. 8 81
47 Ozone Concentrations During Horizontal Sampling,
Flight No. 5 82
48 Temperature and Ozone Profiles, Flight No. 4 83
ix
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FIGURES (continued)
No. Page
49 Ozone Concentrations During Horizontal Sampling,
Flight No. 8 84
50 July and August 1976 Average NMHC Concentrations
(Solid Lines) and Average CO Concentrations (Dashed
Lines) Normalized to 6 to 9 a.m. Values 90
51 Relationship Between Acetylene and Carbon Monoxide
Concentrations at Four Sites 102
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TABLES
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Temperature and Radiation Indices During Summer
Months, 1973-1976
Summary of Air Quality and Meteorological Data
Available for Analysis
Peak Period Conversion Factors
3
Maximum Daily Ozone Concentrations, ng/m — June,
July, August 1976
Number of Sites Equal to or Above Oxidant Standard
Number of Days Site Recorded Maximum Concentration
Frequency Distributions of Maximum Daily 03 Concentrations
at 18 Monitoring Sites During June, July, and August 1976
Percent of Days When Maximum Observed 03 Concentration Fell
on Indicated Hour
Percent of Days When 03 Concentration Exceeded Standard
on Indicated Hour
Average of the Maximum Ozone Concentration Measured at
15 Individual Monitors by Day of the Week, |-ig/nr
Number of Sites Equal to or Above Oxidant Standard by
Day of Week
Thirteen Monitoring Sites Ordered by Magnitude of
Oxidant Levels
Summary of Aircraft Sampling Program
Mixing Layer Transport Wind
Summary of THC, CH4, NMHC, and CO Data From Six RTI
Sites - July and August 1976
NMHC and NO* Average Concentrations and Corresponding
Ratios at the CAMP Station
NMHC and NOx Average Concentrations and Corresponding
Paj
4
8
14
27
30
31
32
34
35
42
43
52
60
67
87
92
Ratios at Fairfax 93
xi
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TABLES (continued)
No. Page
18 NMHC and NOx Average Concentrations and Corresponding
Ratios at Bethesda and Suitland 94
19 Periods With Detailed Hydrocarbon Analyses at Six Sites 95
20 Average Concentrations of Hydrocarbons and Carbon
Monoxide at Four Monitoring Sites 97
21 Concentrations of Hydrocarbons at Four Monitoring Sites
Ordered by Magnitude 98
22 Comparison of Average Hydrocarbon to Acetylene Ratios
With Ratios Obtained in Tunnel Air 99
23 Common Sources of Hydrocarbons 100
24 Linear Correlation Coefficients Between Carbon Monoxide
and Acetylene and Various Hydrocarbons at Four Monitoring
Sites 101
xii
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ACKNOWLEDGMENTS
We take this opportunity to thank the members of the following local and
state agencies who provided air quality, emissions, and meteorological data
for the analysis, and who answered numerous questions with regard to the
data and siting of the monitors:
• Bureau of Air and Water Quality Control, Environmental Health
Administration, Washington, D.C.
• Metropolitan Washington Council of Governments
• Air Pollution Control, Fairfax County Health Department,
Fairfax, Virginia
• Bureau of Air Quality and Noise Control, Environmental Health
Administration, State of Maryland
• Department of Environmental Protection, Montgomery County,
Maryland
• Alexandria Health Department, Alexandria, Virginia
• State Air Board, Northern Virginia Office
We would also like to thank the Office of Environmental Quality of the
Federal Aviation Administration for providing air quality data collected
during the Concorde Monitoring Program at Dulles International Airport,
and EPA's Environmental Monitoring and Support Laboratory — Las Vegas for
its cooperation in supplying the Aerial Oxidant Survey data.
Special thanks are due Mr. Warren Freas, EPA Project Officer, for his
considerate guidance and assistance throughout the program. Dr. Edwin L.
Meyer, Jr. and Mr. Thomas McCurdy, also of QAQPS, participated in project
discussions, and their interest and advice are warmly acknowledged.
xiii
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It is also a pleasure to acknowledge the assistance of GCA/Technology
Division staff members, particularly that of Dr. Robert M. Patterson, who
was responsible for the trajectory analyses, of Mr. Victor Corbin, who
was responsible for the computer-plots of the aircraft data, and of
Ms. Linda Vincent who assisted in both of these efforts. Dr. Paul F.
Fennelly helped interpret the hydrocarbon data.
xiv
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EXECUTIVE SUMMARY
INTRODUCTION
This report documents the magnitude of the measured oxidant problem in
Washington, D.C. and environs and analyzes data from the summer study con-
ducted by EPA in 1976 to better define the relationship between oxidant
concentrations and precursor emissions. The Washington, D.C. area was
selected for study partly because of its known oxidant problem, and partly
because of the possibility that an influx of summertime visitors during
the Bicentennial Year might result in a clearly definable increase in
oxidant levels which could be associated with a measured increase in
vehicular travel.
After a review of existing data it was estimated that the maximum increase
in areawide VMT likely to occur between the summers of 1973 and 1976 was
10 percent. The possibility of detecting the effect of such a small
change in VMT on observed oxidant levels in view of the large variations
that occur from year to year as a result of differences in meteorological
conditions was considered to be extremely small. In addition, the avail-
able traffic data were inadequate to define areawide changes in VMT for
comparison with oxidant levels on a daily basis. As a result, the emphasis
of the work was shifted from an analysis of the effect of changes in VMT
on observed air quality to a characterization of the oxidant problem in
the area.
xv
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DATA ANALYZED
The various summaries and analyses presented in this report are based on
the following sets of data, some of which were obtained from the regularly
operated surface networks and ongoing activities, and some from special
measurement programs.
Emission Inventory Data
HC and NO emission inventory data were provided by the Metropolitan
Washington Council of Governments for the base year 1973. Area source
emissions for HC and NO were furnished for each of the 145 Policy Analysis
Districts in the Washington metropolitan region, and a point source emis-
sion inventory was provided for the major NO sources.
A
Routine Surface Network Data
Local agencies supplied ozone and other gaseous pollutant data of interest
at 18 sites of which 7 were in Washington, D.C., 5 were in Maryland, and
6 were in Virginia. Also, observations made at two stations in the vicinity
of Dulles International Airport during the summer period as part of a
program to monitor operations of the Concorde airplane were made available
by the Federal Aviation Administration. As part of the summer program,
EPA's Environmental Monitoring and Support Laboratory conducted a quality
assurance program of the monitoring networks.
Meteorological Data
The surface meteorological data used in the analysis consisted of cli-
matological data from National and Dulles International Airports, wind
speed and direction from eight local agency sites in Virginia and Maryland,
and solar radiation data from the Alexandria Health Department site. In
addition to the two regular upper air soundings which are made daily at
xvi
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Sterling, Virginia, one additional sounding per day was made during July
and August in support of the summer program.
Traffic Count Data
Daily traffic volume data were supplied by the Washington Department of
Transportation, through the Council of Governments, for the following
three sites: (1) Memorial Bridge, (2) Anacostia Freeway at Howard, and
(3) South Capitol Street Bridge.
Special THC. CH, . NMHC. and CO Observations
Ambient concentrations of total hydrocarbons, methane, nonmethane hydro-
carbons and carbon monoxide were measured at six sites by Research Triangle
Institute. Integrated concentrations over 3-hourly periods from 0600 to
1800 EDT were obtained on a daily basis from July 3, 1976 through
September 1, 1976. The six sites were the West End Library and CAMP
sites in Washington, D.C., the Fairfax and Alexandria sites in Virginia,
and the Bethesda and Suitland sites in Maryland.
Detailed HC Composition Data
Ten percent of the grab samples described above were analyzed routinely
by RTI for the following hydrocarbons:
• ethane and ethylene • 1-butene
• acetylene • isopentane
• propane • cyclopentane
• propylene • n-pentane
• isobutane • toluene
• n-butane
xvii
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Aircraft Observations
Concentrations of CL, NO, NO , S09 and condensation nuclei were measured
•J A, Z,
by the EPA Air Quality Branch of the Environmental Monitoring and Support
Laboratory-Las Vegas during 16 flights from August 17, 1976 through
August 27, 1976. The flight patterns began as approximate circles around
the perimeter of the Washington Tower Control Area, but evolved into
longer flights to Investigate conditions during a stagnation period which
developed during the program. One or more spiral soundings were usually
made during each flight.
DATA ANALYSIS
Summary figures and tables based on data from the 20 monitoring stations
are presented to show the geographical extent and magnitude of the oxidant
problem. Emphasis is placed on the maximum hourly ozone concentration
observed daily at each station, the time of day when this maximum occurred,
and the frequency with which the standard was violated. Other features of
the ozone concentration field that are discussed include its relationship
to meteorological conditions, a comparison of upwind/downwind concentrations
relative to the central Washington, D.C. area where precursor emissions
are heavily concentrated, day of the week comparisons, and major differences
in ozone levels at neighboring stations. Average monthly curves showing
the diurnal behavior of ozone and other pollutants are also presented.
The principal tool used in determining air flow within the area is a
computer-calculated trajectory based on surface wind data. Trajectories
for each day of the study period are given in Appendix E of this report.
Computer plots of the aircraft data were studied in an attempt to identify
the Washington urban plume and the impact of local emissions and transport
effects on ozone levels. Selected plots describing the three-dimensional
ozone field during the buildup of high ozone levels are included in the
discussion.
xviii
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The hydrocarbon measurements made by RTI during the summer program are
summarized by site, by day of the week and by time of day. NMHC/NO
ratios are calculated from NMHC data obtained by RTI using FID instrumen-
tation and NO data reported by the local networks. Hydrocarbon species
X
data are presented and used with results obtained by Lonneman in earlier
studies to estimate the contribution of vehicular sources to NMHC
concentrations.
SUMMARY CONCLUSIONS
The analyses of the foregoing data sets resulted in the following principal
findings:
1. The emission density of both hydrocarbons and nitrogen
oxides decreases rapidly with distance from the city
center. Except along major highways, the emission
densities drop by roughly one order of magnitude in
about 8 kilometers outward from the center of Washington,
and roughly another order of magnitude in an additional
16 kilometers.
2. On all but 10 days during June, July and August of 1976,
the oxidant standard was equalled or exceeded at one or
more monitors within the study area. No evidence was
found for a trend in the number of violations; recent
year-to-year variations in the severity of the oxidant
problem are attributed to differences in meteorological
conditions.
3. Ozone concentrations at all sites almost always behave
in the classical way, with low concentrations at night,
a minimum near 0600 a.m., and the daily maximum shortly
after noon. When the maximum does occur at night, it
rarely exceeds the standard. This suggests domination
by locally generated ozone.
4. Changes in the rate of ozone formation appears to occur
on an areawide scale with concentrations rising and
falling in response to meteorological conditions. Thus
violations usually occur at many locations within the
study area on a high ozone day.
xix
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5. High ozone concentrations are typically associated with
high temperatures, at least a moderate amount of solar
radiation, and a slowly moving or stagnating air mass
that has accumulated a variety of pollutants during
its recent history.
6. Although ozone is an areawide phenomenon, substantial
differences in maximum concentrations occur at nearby
locations as a result of very local influences, such
as strong sources of nitric oxide. The practice of
monitoring ozone near heavily traveled streets and
highways severely limits the usefulness of some of
the data for meso and larger scale field studies.
7. No significant difference in the time of the ozone
maximum was detected between the upwind and downwind
edges of Washington. On the average, however, after-
noon concentrations downwind were nearly 20 percent
higher than concentrations upwind. Because of dif-
ficulty in eliminating the impact of localized site
interferences, this conclusion should be considered
provisional. Also, the main effects of Washington's
emissions downstream could well be occurring outside
the monitoring network.
8. An average value of 9.7 was found for the NMHC/NC^
ratio, using data from the Fairfax, Bethesda, Suitland,
and CAMP sites and NMHC concentrations determined by
flame ionization detection. When data from Fairfax
(a residential/commercial site approximately 20 kilo-
meters west of Washington, D.C.) was removed, the ratio
was 6.7.
9. NMHC concentrations, averaged from six sites over the
0600 to 0900 a.m. period showed Saturday and Sunday concen-
trations to be 77 and 91 percent, respectively, of weekday
concentrations.
10. Application of Lonneman's procedures for estimating the
vehicular contribution to ambient NMHC concentrations was
impaired by the limited number of hydrocarbon species that
were measured by gas chromatographic analysis. The use of
his approach with an estimate of total NMHC obtained by
flame ionization detection, indicated that, on the average,
vehicular emissions accounted for approximately 56, 77, 97,
and 92 percent of the total NMHC measured at the Alexandria,
CAMP, Fairfax, and Bethesda sites, respectively.
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11. Although individual hydrocarbon/acetylene ratios varied
widely at the same site, the average ratios, with the
notable exceptions of ethylene/ethane and toluene, showed
good agreement among sites. Comparison of the average
ratios with the values reported by Lonneman from tunnel
experiments showed ratios at the four study sites from 2.5
to 8 times higher than tunnel ratios for toluene; roughly
2 times higher for n-butane, isopentane, n-pentane, and
isobutane; and slightly lower for propylene. No tunnel
ratio for ethylene/ethane was available for comparison.
The amounts of 1-butene and cyclopentane found were too
small to impact significantly on the total amount of
NMHC, and were less than would have been expected from the
tunnel experiments. Providing measured levels are valid, these
comparisons suggest the presence of major sources of toluene
(and of ethylene/ethane) in addition to motor vehicles, plus
lesser, more uniformly distributed nonvehicular sources of the
other principal hydrocarbon species. The lack of better agree-
ment between the tunnel ratios and the ratios at Bethesda and
Fairfax where NMHC concentrations had been estimated to be
primarily from motor vehicles (see 10, above) is unexplained.
12. Although significant differences in ozone concentration
were encountered in horizontal flight, aircraft sampling
at an altitude of about 670 meters (2200 ft) failed to
show any major increase in ozone that could be directly
related to Washington's emissions. However, flight
restrictions prevented a careful search for the Washing-
ton plume which may not have been located at flight
altitude at the sampling distances employed.
xxi
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SECTION I
INTRODUCTION
PROJECT OVERVIEW
With the discovery that the oxidant problem is widespread, and not centered
primarily in the vicinity of a few major urban areas as originally thought,
it has become generally recognized that revised procedures are needed to
guide the development of oxidant control plans. This report covers one
small part of EFA's continuing effort to collect and analyze observational
data which might prove useful in making these revisions. Washington, D.C.
and its environs was selected for study partly because of its known oxidant
problem, and partly because of the possibility that an influx of summer-
time visitors during the 1976 Bicentennial Year might result in a clearly
definable increase in oxidant levels which could then be associated di-
rectly with a measured increase in vehicular travel.
As stated in the Foreword, a review of the problem and an examination of
data sources at the start of the project showed the impracticality of
attempting to relate changes in vehicle miles traveled directly to changes
in oxidant levels. Estimates indicated that the maximum increase in
VMT likely to occur between the summers of 1973 and 1976 would not exceed
10 percent. The possibility of detecting the effect of such a small
change in VMT on observed oxidant levels was judged to be extremely small
in view of the large variations which frequently occur from year to year
as a result of differences in meteorological conditions. Furthermore,
the available traffic data were inadequate to define areawide changes in
VMT for comparison with oxidant levels on a daily basis. As a result,
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the characterization of the oxidant problem in the area became the prin-
cipal thrust of the work.
To provide background information on the problem, oxidant levels during
the past 4 years are examined briefly in this introduction. Section II
describes the data available for the study, and the remainder of the report
uses these data to describe the magnitude and geographical extent of the
problem and to explore the part played by the transport of ozone and
precursors to the high oxidant concentrations observed with the monitoring
network.
SHORT TERM TREND
Recent (1973 to 1976) ozone data at five Virginia sites were reviewed for
obvious year-to-year changes that might indicate a trend in oxidant levels
or the frequency of violations of the standard. Figure la, taken from
2
the 1976 Annual Report of the Fairfax County Health Department, presents
a year-by-year comparison of the highest 1-hour ozone concentrations ob-
served at four sites during the 1973 to 1976 period. For this 4-year
period, the 1-hour maximums were lowest in 1974 and highest in 1975. A
more broadly based statistic, and hence a more reliable one for determin-
ing trend, is the number of hours above the standard. This number has
been plotted in Figure Ib for the 1973 to 1976 period. Again, 1974 appears
as the best year, that is, the year with the fewest violations. Also,
1976 has fewer violations than 1975. Because only two of the monitors
were operated in 1973, it is not as clear how 1973 violations compare with
those in 1975 and 1976, but 1973 appears to have been quite similar to
1975 and 1976.
Figure Ic shows a different type of year-to-year comparison using an
Alexandria site. Here, the number of hours at or over the standard has
been plotted for each hour of the day. Once again, 1974 is the best year
and no regular trend is evident, although the two most recent years ex-
perienced nearly twice as many violations as the two earlier years.
-------
900
400
510, soo
- 200
i
X
IOO
>-SEVEN CORNERS
0-ENOLESIDE
^-FAIR FAX
A-LEWINSVILLE
1*73
l»74 1975
YEA*
500
o
ec
S 400
u 300
i
< 200
u>
(E
2 100
1976
SEE KEY AT LEFT
1973 1974 1979 1976
YEAN
I"
,0
etc
JUNE,JULY end
AUGUST ONLY
-UTS
-1976 ALEXANDRIA
0« M 10 It 14 M W tO 22 24
HOUR (EST)
Figure 1. Comparison of high ozone concentration at five Virginia
monitoring sites during 1973-1976
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A comparison of the severity of the oxidant problem during each of the
4 years can also be made by comparing the number of Air Pollution Alerts.
A history of Air Pollution Alerts has been prepared by the Metropolitan
Washington Council of Governments and is included as Appendix A of this
report. In summary, during the months of June through August, there were
five alerts called in 1973, one in 1974, three in 1975, and six in 1976.
The total number of alert days in each of the 4 years was: 22 in 1973,
4 in 1974, 14 in 1975, and 20 in 1976.
Taken together, these various measures of the severity of the oxidant
problem suggest that the years 1973, 1975, and 1976 were roughly comparable.
On the other hand, all indices have indicated that the problem was less
severe in 1974 than during the other 3 years. Since there was no known
large decrease in 1974 emissions, the explanation for the lower oxidant
levels presumably lies in differences in meteorological conditions. It
was outside the scope of work of this contract to investigate this pos-
sibility in depth, but the important role played by meteorology in the
formation and transport of oxidants has been well documented by other
3-9
investigations.
Climatological data from National Airport were examined briefly for rela-
tionships between meteorological indices and the severity of the oxidant
problem during these 4 years. Table 1 lists indices, calculated for
June, July, and August, which indicate that the summer period in 1974
was colder, and had less sunshine, than the corresponding periods of
the other 3 years. The small number of Air Pollution Alert days during
1974 suggests that there were also few periods when slowly moving or
stagnating high pressure cells dominated Washington's weather that year*
Table 1. TEMPERATURE AND RADIATION INDICES DURING
SUMMER MONTHS, 1973-1976
Av»rag« temperature (F)
Percent possible sunshine
1973
78.7
64
1974
76.3
58
1975
78.6
65
1976
77.6
70
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SECTION II
THE DATA BASE
The various summaries and analyses presented in this report are based on
the following sets of data, some of which were obtained from the regularly
operated surface networks and ongoing activities, and some from special
measurement programs:
• Emission inventory data
• Routine surface network data
• Meteorological data
• Traffic count data
• Special THC, CH,, NMHC, and CO observations
• Detailed HC composition data
• Aircraft observations
Brief descriptions of these seven data sets follow.
EMISSION INVENTORY DATA
HC and NO emission inventory data were provided by the Metropolitan
X,
Washington Council of Governments for the base year 1973. No projections
to 1976 were available, but is unlikely that many major changes in the
emission pattern have occurred during that 3-year period. Details of the
procedures used to develop the inventory are given in a report available
from COG. Area source emissions for HC and NO were provided GCA for
A
each of the 145 Policy Analysis Districts in the Washington metropolitan
region, and a point source emission inventory was provided for the major
NO sources.
-------
ROUTINE SURFACE NETWORK DATA
The surface networks operated by the local agencies to monitor ozone and
other gaseous pollutants of interest to this program comprise 18 stations.
In addition, measurements were being made during the study period at and
in the vicinity of Dulles International Airport by the Federal Aviation
Admimistration as part of its program to monitor operations of the Concorde
airplane. The locations of these 19 sites are shown in Figure 2, and
a check list of the pollutants measured at each station is given in Table 2.
As might be expected, there was a wide range in the degree of completeness
of the data among the various sites.
METEOROLOGICAL DATA
The surface meteorological data used in the analyses consisted of local
climatological data from the National Weather Service stations at National
and Dulles International Airports, wind speed and direction from eight
local agency sites in Virginia and Maryland, and solar radiation data from
the Alexandria Health Department site. The locations of these meteoro-
logical stations are shown in Figure 3. In addition to the two regular
upper air soundings which are made at Sterling, Virginia, one additional
sounding per day (at approximately 1300 EST) was made during July and August
in support of this program. Mixing heights calculated by EPA from the
soundings made during this 2-month period are listed in Appendix B.
TRAFFIC COUNT DATA
Daily traffic volume data were supplied by the Washington Department of
Transportation, through COG, for the following three sites: 1) Memorial
Bridge, 2) Anacostia Freeway at Howard, and 3) South Capitol Street Bridge.
-------
Figure 2. Distribution of monitors throughout Washington
metropolitan area. Ozone is measured at Sites 1
through 17. Special HC sites are indicated by
the symboll
-------
Table 2. SUMMARY OF AIR QUALITY AND METEOROLOGICAL DATA AVAILABLE FOR
ANALYSIS (EXCLUDING AIRCRAFT MEASUREMENTS)
oo
SeapUai »ite
Map no.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Designation* and location
Dulles International Airport, Sterling, Virginia
Massey Bldg., Fairfax. Virginia
Kngleside. Alexandria. Virginia
Health Dept., Alexandria . Virginia
Shir Unfit on. Arlington. Virginia
Seven Corners* Falls Church. Virginia
Lewinsville, McLean. Virginia
Gaithersburg lab., Gaithersburg. Maryland
Alrmon No. 6, Bethesda. Maryland
Alrmon No. 5, Silver Spring. Maryland
Airmen No. 4, Cheverly. Maryland
Airnon No. 3, Suit land. Maryland
Sharpe Health School. Washington. D.C.
Cleveland Park Library. Washington. D.C.
West Bad Library, Washington, D.C.
CAMP Station, Washington, D.C.
D.C. General Hospital. Washington. D.C.
Tenley-Frlendshlp Library, Washington, D.C.
St. Elizabeth's Hospital. Washington. D.C.
National Airport. Washington, D.C.
Westgate. Alexandria, Virginia
Occoquam Hill. Occoquam. Virginia
Ravensworth. Springfield. Virginia
Benchmark. Fairfax. Virginia
Great Falls. Virginia
County Office Bldg., Rockvllle. Maryland
Pollutant •••••red
Sp^i.^
program
X
X
X
X
X
X
°3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
•°2
X
X
X
X
X
X
X
X
X
X
X
X
X
X
NO
X
X
X
X
X
X
X
X
X
X
X
THC
X
X
CH,
X
X
CO
X
X
X
X
X
x
X
X
X
X
X
X
X
X
X
X
X
X
Meteorological data
Hind speed
and direction
X
x
X
X
X
X
X
X
X
X
Solar
radiation
X
Upper air
sounding
X
Site name used throughout this report is designated by an underline.
bSpecial K, detailed 1C and CO sampling program (KTI).
-------
KCYiO"MMIFAC! WIND SPEED AMD OINECTION
•MftPACE OBSERVATIONS PLUS UPPER AIM SOUMDIM
-SOLAH RADIATION
ROCKVILLE
• 26
< SEVEN
N CORNERS
20«(NATION
ACEXANORIA
493 —
RAVENSWORTH
Figure 3. Meteorological network. Locations of wind monitoring
stations are shown by •'&; solar radiation monitor
by a +, and surface and upper air station by a $
-------
Traffic counts were provided each day for the 0900 to 1600 EDT period as
well as for the 24-hour period. These data were incorporated into the
weekly reports which summarized tourist activity and ozone concentrations
on a current basis.
SPECIAL THC, CH4, NMHC, AND CO OBSERVATIONS
Ambient concentrations of total hydrocarbons (THC), methane (CH,), non-
methane hydrocarbons (NMHC) and carbon monoxide (CO) were measured at six
sites by Research Triangle Institute as part of the overall data collection
program. THC, CH, and CO concentrations were measured in grab samples
using a Beckman 6800 Air Quality Chromatograph. Except for occasional
periods when technical problems were experienced, integrated concentra-
tions over 3-hourly periods from 0600 until 1800 EDT were obtained on a
daily basis from July 3rd through September 1st. The sampling and analysis
protocol for this program, and the raw data, are described in RTI's Final
Data Report. The six sites (Fairfax, Bethesda, Suitland, Alexandria,
West End and CAMP) are distributed both within and around the District of
Columbia, as shown in Figure 2.
DETAILED HC COMPOSITION DATA
Detailed hydrocarbon analyses of 10 percent of the grab samples described
above were analyzed by RTI using a modified Perkin-Elmer Model 900 gas
chromatograph coupled to a Hewlett-Packard 2100A computer programmed for
peak area analysis. Each sample was analyzed routinely for the 11 hydro-
carbons listed below:
1) ethane and ethylene 7) 1-butene
2) acetylene 8) isopentane
3) propane 9) cyclopentane
4) propylene 10) n-pentane
5) isobutane 11) toluene
6) n-butane
10
-------
Procedural details and the raw data are also tabulated in RTI's Final
Data Report.
AIRCRAFT OBSERVATIONS
Concentrations of 0_, NO, NO , S09, and condensation nuclei were measured
J X £»
by the EPA Air Quality Branch of the Environmental Monitoring and Support
Laboratory — Las Vegas during 16 flights beginning on August 17, 1976 and
ending on August 27, 1976. The instrumented B-26 aircraft used during the
study was based at the Baltimore International Airport. The sampling air-
craft was restricted to altitudes greater than 610 meters (2000 feet)
while flying in the vicinity of the Washington Tower Control Area (TCA).
Flight patterns began with circles flown around the perimeter of the
Washington TCA (diameter about 60 kilometers, or 37 miles) at an altitude
of 610 to 670 meters (2000 to 2200 feet). Patterns evolved into longer
flights as the stagnation period which occurred during the sampling period
developed. Typically, one or more spiral soundings were made at preselected
locations during each flight.
11
-------
SECTION III
DISTRIBUTION OF PRECURSOR EMISSIONS
Figure 4 identifies by number the 145 planning districts into which the
Washington metropolitan region is divided. The Metropolitan Washington
Council of Governments supplied the area of each district and an annual
estimate of its total HC and NO emissions for the 6 to 9 a.m. period
«C
based on the conversion factors given in Table 3. This information was
used to calculate emission densities from which the maps shown in
Figures 5 through 12 were prepared. A set of four emission density maps
is presented for each pollutant. Two of these show the whole AQCR, and
two show the 16-kilometer (10-mile) square containing the District of
Columbia in a larger scale. In each case, one map gives the calculated
emission density by planning district, and the second map depicts, in a
less detailed fashion, the geographical differences in emissions by
differences in shading.
In the case of hydrocarbons, emissions are considered as total emissions
from all sources, but in the case of nitrogen oxides, the very signifi-
cant emissions from major point sources have not been included. These
point source emissions have been roughly consolidated in Figure 13, which
shows the approximate location and magnitude of grouped sources. The
three major power plants, Chalk Point, Dickerson, and Possum Point, located
in the outskirts of the region, contribute large quantities of NO to the
«£
regional inventory, as shown by Figure 13. In addition to the point source
emissions included in the totals shown in Figure 13, approximately
1000 kilograms per 3 hours are emitted within the 16 kilometer square,
largely along the Potomac and Anacostia Rivers.
12
-------
POLICY ANALYSIS DISTRICTS
Figure 4. Planning districts for the Washington metropolitan region
-------
Table 3. PEAK PERIOD CONVERSION FACTORS
(Daily to 6-9 a.m.)
Source
Auto
VMT
Trips
Trucks
Aircraft
Petroleum
Storage
Handling
Service stations
Solvents
Dry cleaning
All others
Factor,
18.3
14.5
16.5
13.0
12.5
17.0
17.0
12.5
12.5
12.5
14
-------
Figure 5. Emission density map pf total hydrocarbons for the
National Capitol AQCR. Units are kg/km2/6 to 9 a.m.
Filled circles show locations of ozone monitors
(see Figure 6 for central area)
15
-------
oooo
°o oooo
oooooo
Figure 6. Emission density map of total hydrocarbons for central
metropolitan Washington area. Units are kg/km2/6 to
9 a.m. Filled circles show locations of ozone
monitors
16
-------
Figure 7. Emission density of total hydrocarbons by planning
district within the National Capitol AQCR. Units
are kg/knr/6 to 9 a.m. (see Figure 8 for central
area)
17
-------
N
A
Figure 8. Emission density of total hydrocarbons by planning district
within central metropolitan Washington area. Units are
kg/km2/6 to 9 a.m.
18
-------
Figure 9. Emission density map of nitrogen oxides for the
National Capitol AQCR. Units are kg/km2/6 to
9 a.m. Filled circles show locations of ozone
monitors (see Figure 10 for central area)
19
-------
R
1
o
. 000
o o o o
O O O O O O
o o o o o o
oooooooo
Looooooooo
oooooooooo
oo o o
ooo
oo o o o o oo
000
ooo o ooo
o o o o o o o
oooooooooo
oooooooo oo
0 OOOOOOOOOOOO
O OO OOOOOO O O
ooooooo
ooooo o o o o o
OOOOOO0
oooo oooooooo
O OOOOOOOOOOOO
o ooooo
OOOOOOO
ooooooo
OOOOOO O
O O O O O O
ooooo ooo
ooooooo
o O O O O O
o oooo
o o oo
ooooo
oooooo %
O O O O w'
oooo
ooo
OOOOOOO
oooooo
ooooO
o°o00
>too
Figure 10. Emission density map of nitrogen oxides for central
metropolitan Washington area (area sources only).
Units are kg/km2/6 to 9 a.m. Filled circles show
locations of ozone monitors
20
-------
Figure 11. Emission density of nitrogen oxides by planning
district within the National Capitol AQCR (area
sources only). Units are kg/kmz/6 to 9 a.m.
(see Figure 12 for central area)
21
-------
N
/
Figure 12. Emission density of nitrogen oxides by planning district
within central metropolitan Washington area (area sources
only). Units are kg/km2/6 to 9 a.m.
22
-------
Figure 13. Emission rates of nitrogen oxides from
grouped point sources. Units are kg/
3 hours
23
-------
As would be expected, the emission density of both hydrocarbons and
nitrogen oxides decreases rapidly with distance from the city center.
For example, except along major highways, the emission densities drop by
roughly one order of magnitude in about 8 kilometers (5 miles) outward
from the center of Washington, and by roughly another order of magnitude
in an additional 16 kilometers.
The placement of the 17 ozone monitors with respect to area-source HC and
NO emissions can be seen in Figures 5, 6, 9, and 10.
X
A listing of the area and point source emissions within the AQCR, as
provided by COG, is given in Appendix C.
24
-------
SECTION IV
SUMMARY AND INTERPRETATION OF DATA FROM LOCAL NETWORKS
SUMMARY OF OZONE DATA
General
In preparing the summary tables and figures of ozone concentrations pre-
sented in this section, emphasis was placed on maximum hourly concentra-
tions and the frequency of violations of the standard. Many of these
tables were prepared by hand, which made possible a broadening of the
data base by including certain subjectively selected days with partial
data. For example, on days with partial data, the highest observed con-
centration was considered as the maximum if its inclusion appeared to
add useful information with regard to the frequency of occurrence of high
concentrations. When tabulated, such values are prefixed with a > sign
if they were reported next to a period with missing data. In other cases,
the data base was expanded by including hours for which concentrations
were estimated to be above the standard by modest interpolation or extrap-
olation. Because of the procedures which were employed in preparing the
data summaries, the tables which follow are more appropriate for general
descriptive purposes than for rigorous statistical comparisons. During
the study, questions arose with regard to some of the Washington, D.C.
Agency data for Stations 13, 14, 15, and 17 which had been provided on
encoding sheets early in the program. Since these questions centered
principally on the hour of entry of the observations and were never fully
resolved, summaries in this report which are based on time of day do not
include these four stations.
25
-------
Table 4 lists the maximum 1-hour ozone concentrations measured each day
during the 3-month period by station. The two locations in the vicinity
of Dulles International Airport where measurements were made by the FAA
have been designated 1A and IB in Table 4. The so-called neighborhood
site, 1A, is located at Sterling Park approximately 3-1/2 miles to the
north-northeast of the main airport ramp, and Site IB is located at the
south edge of the main ramp, where it is presumably subject to NO scav-
enging because of its proximity to aircraft exhaust. It is of interest
to note that in all but 5 of the 66 days with observations at both loca-
tions during this period, the ozone concentration was less at Station IB
than at Station LA, with an average difference of about 13 percent.
Perhaps the most prominent feature of Table 4, and one which is consistent
with general experience, is a tendency for uniform ozone concentrations to
occur within the 30-mile by 30-mile study area. For example, June was
characterized by concentrations below or near the standard throughout the
network during the first 4 days of the month. This period with relatively
low concentrations was followed by a period of about 8 days when the
standard was substantially exceeded at most sites. These 8 days experi-
enced high temperatures and low resultant wind speeds. Then, with the
exception of June 15th, concentrations again were low until the 26th,
when maximum concentrations exceeded the standard at 13 of the 17 sites
with observations. Measurable precipitation occurred on six of these
days having below average concentration, and steady southerly winds pre-
vailed. Widespread high concentrations continued from the 26th through
the 29th, a period with generally fair weather, midday temperatures in
the upper 80's, and more variable winds. These areawide fluctuations
are perhaps more easily seen in Table 5 which gives the number of sites
with the maximum concentration equal to or greater than the standard
(160 ug/m or 0.08 ppm). An overall impression gained from Tables 4 and 5
is that the oxidant problem is an areawide phenomenon with concentrations
fluctuating in response to changes in the meteorological conditions of
the prevailing air mass. On the other hand, examination of Table 4 shows
Chat extreme differences in maximum concentration are sometimes recorded
26
-------
Table 4. IfcXIMUM DAILY OZONE CONCENTRATIONS, Lig/m - JUNE 1976
10
Date
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Bay of
week
Tu«s.
Wed.
Tlturs.
Frl.
Sac.
Sun.
Hon.
Tues.
Wed.
Thurs.
Frl.
Sat.
Sun.
Hon.
Tues .
Wed.
Thurs.
Fri.
Sat.
Sun.
Hon.
Tues.
Wed.
Thurs.
Frl.
Sat.
Sun.
Hon.
Tues.
Wed.
Station identification
Virginia
DULLES
1A
_
_
_
-
-
-
-
-
-
-
_
-
-
-
144
106
122
180
206*
226
160*
144
IB
86
38
96
84
90
84
70
80
200*
200
200*
150
80
110
144
54
102
116
80
-
50
98
100
82
102
162
168
186
126
106
FAIR
2
113
54
127
162*
221*
181
191
201
230
284
-
-
-
-
-
-
_
-
-
-
_
127
196
230*
265
196
137
ESG
3
103
54
74
78
167*
176
201
265
>348
260
265
240
74
74
167*
74
34
49
44
49
25
34
64
69
103
245
245*
289
167
108
ALEX
4
160
60
14 0
140
270*
180
210*
280
360
280
250
290
120
110
220*
90
130
>liO
150
130
70
IOC
130
110
120
240
290
SHIR
5
130
44
70
60
120
164
190
230*
220
200*
330
324
110
50
>110
40
44
50
60
50
36
50
90
76
100
130
190
390 >220
270 i 200
60
124
SCOR
6
191*
93
162*
172*
265
196
206
260*
255
314*
274
250
118
113
225*
98
122
132
122
122
54
113
142
137
123
206*
245*
343
260
152
McL
7
118
54
123
142
201
157
176
196*
211
230*
221*
201
88
69
176*
54
83
88
88
78
34
93
118
93
98
142
176*
191
-
Maryland
GAIT
8
120
60
180*
240*
200
180*
220*
200
160
220*
>240
240
140
100
200*
100
120
120
140
120
80
120
140
80
100
140
200*
200
80
40
BETH
9
160*
40
140
140
200
140
180
>180
220
340
>180
_
—
>180*
80
180*
140
120
100
-
-
160*
140
100
160
280
140
SSPR
10
100
40
80
120
200
140
200
>200
380
100
240
200*
80
60
-
-
60
40
40
40
-
-
—
60
80
180
200
160*
100
CSEV
11
IOC
200*
80
80
180
160*
220
>180
380
>260*
260
240*
80
60
100
-
100
60
40
60
-
-
_
60
160*
200
220
260*
100
son
12
120
40
80
ICO
ISO
140
180
>200
360
240*
>260
200*
100
SC-
-
60
100
120
30
-
-
-
-
_
>180
320
220*
120
Washington, D.C.
MSHS
13
10
10
20
70
60
70
90
100
170
380*
310
250*
120
150
276*
110
180*
170*
150
150
70
130
200
190
140
200
310*
380
620*
390*
CLEV
14
-
-
-
90
40
160*
130
110
90
150
100
90
60
40
30
10
20
90
80
90
110
90
HEL
15
110
180
50
180
100
130
140
130
280*
200*
210*
170*
220*
120
80
80
130
120
180
160*
60
110
50
40
70
170*
150
140
330*
140
CAMP
16
120
60
90
110
130
150
170*
190*
210*
190*
210*
200*
95
64
140
50
80
90
90
90
40
74
90
70
90
170*
200*
270*
180*
90
DCC
17
_
-
-
-
_
-
-
-
50
70
90
90
50
-
-
-
-
Notes: 1A = Sterling Park; IB - South Ravp
*
indicates concentration > standard
-------
Table 4 (continued). MAXIMUM MILY OZONE CONCENTRATIONS, ng/m - JULY 1976
ro
oo
Date
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Day of
week
Thurs.
Fri.
Sat.
Sun.
Mon.
Tues.
Ved.
Thurs.
Fri.
Sat.
Sun.
Mon.
Tues.
Wed.
Thurs .
Fri.
Sat.
Sun.
Mon.
Tues.
Ued.
Thurs.
Fri.
Sat.
Sun.
Mon.
Tues.
Wed.
Thurs .
Fri.
Sat.
Station identification
DULLES
1A
106
138
166*
128
170
230*
104
144
128
128
124
108
128
106
168*
100
106
116
140
142
160
142
110
158
96
122
130
112
132
112
114
IB
104
124
146
126
164*
182*
-
—
106
106
108
86
82
84
126
80
82
90
136
112
142
154
84
122
82
114
150
110
122
124
122
FAIR
2
118
167*
196*
176*
216*
225*
118
186*
186*
181
98
118
147
127
172*
132
142
152
>167*
181*
196
>225*
113
196*
137
176*
191
221*
>225*
157
172*
Virginia
BK
3
122
142
186
181*
333*
>122
93
113
191*
181
93
127
157
137
>206
>108
137
152
142
152
172
127
64
152
113
147
>172
216
157
137
-
4
130
130
260
210*
350
280*
150
190
200*
270*
180*
150
130
130
360
160*
150
190*
230*
2iO*
260
-
-
230*
140
220*
200
>300
>170*
_
170*
SHIR
5
104
120
160
140
200*
76
>50
80
130
176*
80
104
100
110
220
136
110
140
150
>124
160
64
64
210*
116
150
180
280*
180*
120
170*
SCO»
6
132
137
206
181*
274
245*
127
>157
186*
196
132
132
132
142
221
132
147
157
181*
250
206
186
>98
191*
137
201*
201
299
216*
167*
216*
MeL
7
-
132
191
157
240*
216*
113
127
167*
162
74
108
152
118
186
108
127
132
176*
157
157
78
> 54
147
59
98
118
186
196*
123
142
Maryland
GAIT
8
_
120
80
60
140
140
—
_
100
120
100
60
120
120
180
100
100
120
-
-
60
100
40
40
20
40
60
100
-
20
120
BETH
9
_
-
-
-
160
220*
60
180
-
160
_
-
120
100
160
_
_
_
180*
-
140
-
100
140
100
>160*
140
220
>200
120
160*
ssra
10
180*
140
180*
160
160
100
20
100
140
180
_
_
160*
120
200
_
460*
_
180*
120
180
-
-
160*
100
140
180
260
180
140
180
CHOT
11
160*
160*
200*
160
200*
100
60
100
160*
220*
-
>160*
4«0*
180*
—
200*
160*
_
180*
180*
260*
60
40
240*
140
160*
260
500*
240
-
180*
SUIT
12
140
160*
220*
160
240
200*
80
160*
160*
200*
-
-
140
140
>160*
_
120
_
>200*
-
-
-
-
180*
100
180*
200
340
240
180*
200*
Washington, D.C.
MSHS
13
400*
220*
190
200
290
250*
330*
330*
170*
270
230*
280*
-
-
—
_
_
_
-
60
40
40
10
10
10
10
50
140
230
140
140
CLEV
14
90
150
130
190
140
80
140
180*
180*
160
160*
250*
200*
160*
70
150
160*
150
130
90
50
30
30
30
40
160*
250
200
-
50
70
WEL
15
30
24
12
12
18
30
48
—
-
-
-
-
12
54
84
48
36
36
-
120
60
24
24
30
-
-
60
66
24
6
6
CAMP
16
_
-
—
-
-
140
60
80
120
130
130
110
124
100
*
220
110
90
140
180*
150
*
190
100
74
184
110
174
*
190
290
100
140
140
DCG
17
120
120
170*
170*
160*
20
-
—
170
70
90
130
90
200
200*
120
110
120
110
150
120
80
140
160*
140
220
210
>320
250*
160
Notes: LA - Sterling Park; 18 * South
indicates concentration > standard
-------
Table 4 (continued). MAXIMUM DAILY OZONE CONCENTRATIONS, ng/m -AUGUST 1976
to
VO
tat*
1
2
3
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Day of
week
Sun.
Hon.
Tues.
Wed.
Thurs.
Fri.
Sat.
Sun.
Hon.
Tues.
Wed.
Thurs.
Fri.
Sat.
Sun.
Mon.
Tues .
Wed.
Thurs.
Fri.
Sat.
Sun.
Mon.
Tues.
Wed.
Thurs.
Fri.
Sat.
Sun.
Mon.
Tues.
Station identification
Virginia
DULLES
1A
92
_
160*
172*
166*
108
76
80
128
130
194*
198*
208*
136
118
102
126
160*
270*
208
182*
182*
260
260*
204*
102
110
142
94
138
IB
74
80
148
136
128
146
84
58
68
124
114
162*
160*
170*
114
106
94
124
152
260*
180
158
168*
224
196*
146
94
102
124
96
118
FAIR
2
108
93
201*
225
186*
250*
108
98
103
157
>162
245*
260*
225*
147
137
93
152
191*
284*
304
260*
230*
>314
230*
152
98
137
142
103
176*
KNG
3
-
98
113
225*
176*
152
103
54
83
152
225*
>147
137
88
103
98
147
108
147
245
216*
225
216
103
137
137
88
147
98
^127
ALEC
4
80
60
130
240*
210*
180*
110
80
_
120
240
240
260
220*
140
90
70
>150
180*
210*
310
250*
240
>240
240
220*
140
130
130
60
160*
SHIR
5
90
70
80
160
120
50
40
36
160*
170
220
200
160
90
90
90
96
90
110
310
-
176
84
170
150
90
70
110
64
110
SCOR
6
127
118
206*
270
260*
289*
103
113
103
167
225*
245
206
225
152
113
98
157
191*
235*
314
225*
>196
314
265
201*
113
137
142
88
181*
McL
7
98
98
167*
201
181*
196*
59
88
78
137
181
196
206
196*
127
113
>83
147
176*
250*
230
172*
176
274
196
152
78
>137
127
> 93
157
Maryland
GAIT
8
40
_
j
-
-
80
80
140
180
160
180
120
100
80
120
120
260*
200
180*
>200
220
>160
120
60
140
80
60
80
BETH
9
80
80
160*
>200*
>280*
80
60
60
>160*
160*
>200
>200
280
180*
100
80
260*
280
24 C*
220
260
XJ20
_
_
220*
160*
80
*
180
SSFR
10
80
80
160*
120
180*
40
60
_
160*
80
200
120
80
100
80
120
80
-
200
160*
>180
180
60
_
_
1.1
-
80
120
CHEV
11
100
60
60
200*
160*
>220*
80
40
60
140
200*
140
260
160*
80
120
100
100
100
120
400
220*
250
UO
16C*
100
_
-
-
-
120
SUIT
12
80
600*
260*
>220*
>180*
100
60
60
140
120
80
60
_
-
100
80
140
>240
140
160
160*
140
120
100
80
80
40
100
Washington, D.C.
MSHS
13
50
40
70
70
60
40
10
10
70
140
>220*
380
240
210
110
100
80
150
170*
220*
380
200*
210
140
80
180*
140
10
10
90
170*
CLKV
14
110
90
160*
210*
-
-
-
_
—
>240
240
250
140
90
> 80
140
150
150
190
90
60
40
20
40
10
10
10
80
180*
WKL
15
10
10
-
-
-
-
-
60
>250
200
230
100
60
50
60
150
250
160*
150
130
80
30
_
_
-
-
90
CAMP
16
80
74
100
174*
190*
140
90
60
60
110
180*
200
210
180
_
90
90
110
110
140
180
240*
200*
190*
17 o'
94
80
160*
80
174*
DCG
17
40
70
130
190*
190*
170*
100
40
30
110
280*
280
320
300
280*
200*
160*
140
180*
220
250
400
*
180
210'
260*
250*
200*
150
150
150
1:0*
Notes: 1A - Sterling Park; IB - South Ramp
*
indicates concentra t ion > star.d.ird
-------
Table 5. NUMBER OF SITES EQUAL TO OR ABOVE OXIMNT STANDARD
Day
June 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Sites
considered
All
3
2
2
4
10
7
12
12
15
14
14
12
1
1
7
0
2
1
1
1
0
0
2
1
1
13
11
15
12
1
Q
Selected
3
1
2
3
10
7
11
11
12
11
11
9
0
0
6
0
1
0
0
0
0
0
1
0
1
10
9
13
9
0
Day
July 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Sites
considered
All
3
4
12
10
14
9
1
6
9
12
3
3
3
2
13
3
3
1
9
4
9
2
0
8
1
8
11
13
11
3
9
Selected8
2
3
10
7
12
8
0
4
7
10
o 1
1
2
1
11
2
2
1
8
4
8
2
0
7
0
6
8
10
9
2
8
Day
Aug. 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Sites
considered
All
0
1
6
13
10
10
0
0
0
2
12
14
16
15
2
1
1
0
7
10
18
13
16
13
12
6
1
1
2
0
8
o
Selected
0
1
5
10
8
9
0
0
0
2
9
9
11
10
1
0
0
0
5
8
13
10
13
11
10
3
0
1
1
0
8
Sites 1 through 12 plus Site 16.
30
-------
for the same day at neighboring stations. A more complete presentation
of meteorological conditions during the June to August period is given
on pages 37 and 38 of this report.
A second piece of potentially useful information that can be drawn from
Table 4 is the number of days each site recorded the daily maximum con-
centration within the study area. This information is provided in Table 6.
Table 6. NUMBER OF DAYS SITE RECORDED MAXIMUM CONCENTRATION
Slt«
identification
No.
of
d.y*
All
• ItM
S«l«oMd
tltM*
Virginia
DULUU
1A
1
J
IB
0
0
FAIR
2
9
13
INC
3
1
1
ALBK
It
17
16
SHU
5
2
2
aeon
6
17
19
McL
7
0
0
Maryland
GAIT
8
4
7
BETH
9
4
>
SSPR
10
2
3
CHEV
11
15
16
SUIT
12
4
4
Washington, D.C.
MSHS
13
18
CUV
14
2
WBL
15
4
CAMP
16
1
1
DCG
17
7
*Sit«» 1 through 12 plus Sit* 16.
It is immediately clear from Table 6 that the apparent severity of the
oxidant problem within an area such as this can depend significantly upon
the placement of the monitors. Siting characteristics of some of the
monitor locations are described later in this section.
Table 7 gives a frequency distribution of the maximum daily ozone concen-
tration for each of the regular monitoring sites, plus separate distribu-
tions for the two Dulles monitors. Again, large differences exist between
sites, but no clear-cut geographical pattern is evident. The percent of
days on which the standard is equalled or exceeded ranges from 18 percent
at the South Ramp site at Dulles International Airport to 59 percent at
Fairfax, Virginia and at Bethesda, Maryland. It should be borne in mind
that the observation days upon which these percentages and Table 6 are
based are not identical from site to site.
31
-------
lable 7. FREQUENCY DISTRIBUTIONS OF MAXIMUM DAILY 0. CONCENTRATIONS AT 18 MONITORING
SITES DURING JUNE, JULY, AND AUGUST 1976
Site
Location
Virginia
Dulles
Dulles
Fairfax
Engleside
Alexandria
Shirlington
Seven Corners
McLean
AVERAGE
Maryland
Gaithersburg
Bethesda
Silver Spring
Cheverly
Suitland
AVERAGE
Washington, D.C.
Sharpe Health School
Cleveland Park
West End
CAMP
D.C. General
AVERAGE
Iden.
no.
1A
IB
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
No.
of
days
68
89
78
88
88
91
92
89
79
68
73
79
71
85
73
71
85
64
Concentration, pig/nr*
<160
66
82
41
67
43
68
43
62
56
71
41
56
44
52
53
55
73
77
66
50
64
160 -
179
180 -
199
200 -
219
220 -
239
Percent
13
8
11
8
6
12
4
11
9
4
18
11
15
10
12
6
9
6
8
14
9
7
5
18
5
7
4
12
14
10
7
13
17
8
10
11
5
7
4
14
6
7
6
3
4
6
7
6
12
7
7
9
7
11
9
10
9
7
4
4
8
9
6
3
1
14
3
7
6
7
3
6
4
7
0
6
4
4
6
0
3
1
3
3
240 -
259
260 -
279
280 -
299
300 -
319
>320
of days
0
0
3
5
11
0
7
2
4
4
2
2
4
6
4
4
7
3
1
5
4
5
1
4
3
7
0
9
1
4
1
3
1
9
3
3
2
0
0
1
2
1
0
0
3
1
6
1
2
0
2
0
6
0
0
0
1
2
0
2
1
4
2
0
0
2
0
2
1
3
0
1
0
0
0
0
0
0
2
0
0
0
2
1
0
0
0
2
4
2
1
0
1
0
3
2
5
5
3
11
0
1
0
5
3
to
Ni
-------
A feature of oxidant behavior that may contribute to an understanding of
the relative significance of local precursor emissions, transport, and day-
to-day carryover is the diurnal variation in concentration at the various
sampling sites. Tables 8 and 9 summarize this variation in an approximate
fashion by focusing on the time of occurrence of the maximum daily concen-
tration and the hours of the day when the standard was equalled or exceeded.
It is clear from these tables that with few exceptions, concentrations
in excess of the standard were confined to the daytime hours between 0900
and 1900 EST, and that maximum concentrations occurred most frequently in
the early afternoon. This implies that concentrations at all of the sites
are dominated by locally produced ozone, but does not rule out longer range
transport of precursors.
Oxidant Levels and Meteorological Conditions
Meteorological indices from local airports are typically considered repre-
sentative of neighboring urban areas. In an attempt to obtain a similarly
broad based index for oxidant levels to facilitate comparisons with mete-
orological conditions, and also to compare levels in different parts of the
study area, the values listed in Table 4 were averaged by geographical
area. The results are plotted in Figure 14.
The particular areas represented by each curve can be determined by ref-
erence to Figure 2. Although differences among the curves do occur, many
features are easily identified from one curve to another. Because of
these common features, it seemed appropriate to prepare an average curve.
To calculate this average curve, maximum values at all sites except the
two most outlying sites, Dulles International Airport (No. 1) and
Gaithersburg (No. 8) were used. The resulting curve appears at the top
of Figure 15. In Figures 14 and 15, vertical dashed lines have been used
to set off individual weeks and to identify weekends.
Daily meteorological conditions have also been plotted in Figure 15 so that
obvious associations between wind, radiation, temperature and humidity and
33
-------
Table 8. PERCENT OF DAYS WHEN MAXIMUM OBSERVED 03 CONCENTRATION FELL ON INDICATED HOUR
u>
Hour, start time
(EST)
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Number of days
with observations
Site identification number
1A
2
3
4
5
6
7
8
9
10
11
12
16
Frequency of occurrence, percent of days
1
4
4
21
16
16
12
15
12
6
1
1
68
2
1
1
1
1
4
13
11
20
33
30
16
14
1
1
79
1
2
2
1
1
2
6
18
32
23
21
14
3
1
1
1
1
2
87
2
1
4
12
26
34
24
17
15
1
1
1
89
3
1
4
2
3
3
1
2
12
26
20
24
17
15
6
1
1
89
1
1
3
17
17
26
26
18
17
4
1
2
90
3
2
1
12
21
20
25
26
12
7
1
1
87
8
5
5
5
5
3
3
1
1
3
8
8
18
29
37
40
44
29
15
4
1
1
1
1
78
2
2
2
2
2
3
2
6
18
36
45
42
34
26
8
2
3
2
62
3
5
3
3
3
1
1
3
8
15
19
29
44
37
26
19
29
1
73
1
1
1
1
1
1
1
3
15
27
41
44
34
24
20
8
1
3
3
3
1
1
79
1
3
8
25
45
49
48
31
23
11
4
3
1
1
3
71
1
4
2
1
1
1
1
1
2
7
24
38
34
16
15
5
2
1
1
85
-------
Table 9. PERCENT OF DAYS WHEN 03 CONCENTRATION EXCEEDED STANDARD ON INDICATED HOUR
UJ
ui
Hour, start time
(EST)
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Number of days
with observations
Site identification number
1A
2
3
4
5
6
7
8
9
10
11
12
16
Frequency of occurrence, percent of days
1
3
7
15
22
22
26
19
19
16
10
6
3
68
1
9
25
39
40
47
49
47
43
34
18
1
79
1
8
13
22
26
25
22
22
17
13
3
87
4
2
2
4
29
43
48
51
49
42
43
30
16
8
7
3
2
2
89
1
1
1
2
10
15
20
16
16
12
12
9
4
89
1
1
1
1
1
1
1
7
17
29
43
47
54
49
43
39
28
16
6
1
89
5
12
26
28
28
29
24
15
9
1
87
1
1
1
6
10
15
19
23
21
19
19
13
1
1
1
1
1
78
3
19
24
43
46
40
33
32
16
2
2
63
1
4
8
14
16
29
27
25
19
15
12
3
73
3
10
22
23
39
39
37
33
23
16
8
79
3
7
18
30
38
41
38
32
30
18
8
4
1
71
1
1
1
1
1
1
1
0
0
2
11
15
26
27
25
14
8
5
1
85
-------
MM I*, «
Figure 14. Average of maximum daily O-j concentrations
for selected geographical areas
36
-------
*V€*Mf HMIttUU O] COHCfHTK4riOH US SITfSI \
.__ ^ l ! . I „ I I
KtiULTtNT WIND SPCtO/*Vt*»ee WINB SfCfO |
Figure 15. Daily sequence of meteorological parameters and
an index of maximum 0- concentration
37
-------
maximum ozone levels may be detected visually. Four measures of wind
speed and direction have been plotted: (1) the average speed during the
day, (2) the resultant speed, (3) the resultant direction, and (4) the
ratio of the resultant speed to the average speed, which is a measure of
the steadiness of the wind direction during the 24-hour period. Two
symbols have been used in plotting the resultant wind direction. A filled
circle indicates a day when the ratio of resultant to average speed was
^ 0.80, and thus a day when the wind direction was fairly steady, and an
open circle, in contrast, indicates a ratio < 0.80 and hence a day with
variable wind direction. Two measures of solar radiation are shown. One
is the integrated amount of radiation from sunrise to 1300 EST and the
other is the percent possible sunshine during the day as reported on the
NOAA local climatological data sheet. The temperature and relative
humidity at 1300 EST have been used as indices of temperature and moisture,
and the amount of rainfall during the 24-hour period as the measure of pre-
cipitation. The meteorological data were obtained from National Airport,
with the exception of the solar radiation data which were provided by the
Alexandria Health Department.
As expected, in a qualitative sense, periods of high ozone concentration
tend to be associated with lower than average wind speeds, average or
greater than average amounts of radiation, and higher than average temper-
atures. Other researchers have identified these same meteorological con-
3-9
ditions as being associated with high ozone levels. The longest period
with maximum concentrations averaging below the standard occurred from the
16th to the 25th of June when steady winds of above average speed pre-
vailed from the south, and precipitation occurred on 6 of the 10 days.
Traffic Volume Versus Oxidant Level
The only readily available daily traffic count data consisted of that ob-
tained from the three counters mentioned in Section II. The traffic coun-
ters at Memorial Bridge operated satisfactorily throughout the 3-month
period, but difficulties were experienced at the other two locations.
38
-------
Daily counts for the period from 0900 to 1600 EDT have been plotted for
the Memorial Bridge in Figure 16(a). Counts at the other two locations
have been added successively to the Memorial Bridge data ii. Figure 16(b)
and Figure 16(c) on days when the reported counts were not questioned.
The dominating feature of the traffic count data is the weekly cycle. Al-
though the extent of the weekend minimum varies substantially at the
Memorial Bridge, the cycle becomes more regular with the addition of
traffic at the other two locations.
The limited data plotted in Figure I6(c) show that traffic volume is quite
constant during the week from Tuesday through Thursday, peaks on Friday,
and has a minimum on Sunday. The averages show 78 percent of the midweek
traffic volume on Sunday, 95 percent on Monday, 107 percent on Friday, and
88 percent on Saturday. Comparing this weekly cycle of traffic with the
observed variation in the average maximum ozone concentration at 15 sites
(Figure 15, upper curve), or that within the District (Figure 16, upper
curve) shows only occasional agreement, more suggestive of chance than of
a causal relationship. Thus, the major changes in ozone levels appear to
be related to meteorological effects of synoptic scale rather than to day-
to-day changes in emissions.
Day of the Week Comparisons
Because of a weekly cycle in precursor emissions and in the areal distri-
bution of these emissions, an analysis of weekday-weekend differences in
ambient concentrations of oxidants and precursors is a logical approach
to furthering a basic understanding of the oxidant problem and the likely
effects of some control strategies. However, since a major study is under-
way which addresses this question using east coast data, only a cursory
comparison of ozone levels was carried out during this present study. Two
indices of ozone concentration were used. One was the number of sites
equal to or above the standard, taken from Table 5, and the second was
the average of the maximum concentrations measured at 15 of the monitoring
39
-------
400rNOS. 13,14,19,16,17
I | I I I ' '
(b) MEMORIAL and SOUTH CAPITOL STREET BRIDGES
tor, I I I I I I I > >
1 (c) MEMORIAL BRIDGE, ANACOSTIO FREEWAY and HOWARD and SOUTH CAPITOL ST BRIDGES
•0
70
•0
SO
I
I
I
I -,
I _
§'20 *'I7
•'.9
DATE
Figure 16. Day-by-day variation in maximum ozone concentration
index for Washington, D.C. (upper curve) with vari-
ations in traffic counts (lower curves)
40
-------
sites, used In plotting the top curve in Figure 15. Tabulations of these
indices by day of the week are given in Tables 10 and 11. Both indices
indicate that the highest average oxidant level occurred o-. Saturday, and
the lowest on Sunday. Of all comparisons made, the only difference that
was significant at the 5 percent level was between the number of sites
equal to or above the standard on Saturday and on Sunday.
Diurnal Variation of Pollutant Concentrations
The average diurnal variation of ozone for the months of June, July, and
August has been plotted for 13 monitoring sites in Figures 17 through 23.
When sufficient data are available, diurnal curves are also presented for
nitrogen oxides and hydrocarbons in these figures. The diurnal variation
of carbon monoxide has been included at six of the sites as a measure of
the variation in vehicular emissions. Breaks in the plotted curves indi-
cate hours with less than 10 observations during the month.
Major differences in the magnitude of the average monthly concentrations
occur from site to site. Also, even though the diurnal patterns of the
pollutants are typical of urban areas and conform to general experience,
significant differences do occur among the sites. Some of the more obvious
features of the ozone curves are noted below.
The ozone curves, as expected, show maximum concentrations either at
1200 EST or shortly thereafter, and a minimum near 0600 EST at the time
of day when convective mixing is being established at low levels and when
the morning maximum of NO occurs. Of particular interest are differences
in the behavior of average concentrations at different sites. For example,
it would seem that a basic understanding of the behavior of oxidants in
the Washington, D.C. area must account for such major differences in
average peak concentrations as those which occur among the five sites to
the southwest of Washington, D.C. (see Figures 17, 18 and 19). At these
five sites, peak values are quite consistently high at Massey, Seven
Corners, and the Alexandria Health Department, but substantially lower at
41
-------
Table 10. AVERAGE OF THE MAXIMUM OZONE CONCENTRATION
MEASURED AT 15 INDIVIDUAL MONITORS BY DAY
OF THE WEEK, ug/m3
N
Ave.
a
Day of week
Sunday
153
104
93
212
161
125
136
104
81
62
127
210
114
13
129
45.4
Monday
181
92
50
257
213
148
170
151
109
68
108
194
85
13
140
61.4
Tuesday
118
201
164
83
248
154
156
149
174
131
135
89
193
148
14
153
43.5
Wednesday
71
279
77
107
135
104
122
159
249
199
194
126
168
13
153
63.4
Thursday
95
252
99
88
144
153
189
96
191
174
224
139
146
13
153
51.7
Friday
120
251
101
102
139
166
135
63
133
184
225
188
109
13
147
53.3
Saturday
176
221
97
179
185
190
151
149
150
79
198
272
98
13
165
53.4
Period of record: June 1 through August 31, 1976.
42
-------
Table 11. NUMBER OF SITES EQUAL TO OR ABOVE OXIDANT
STANDARD BY DAY OF WEEK
N
Ave.
a
Day of week
Sunday
7
1
1
11
10
3
1
1
0
0
2
13
2
13
4.0
4.58
Monday
12
1
0
15
14
3
9
8
1
0
1
16
0
13
6.2
6.36
Tuesday
3
12
7
0
12
9
3
4
11
6
2
1
13
8
14
6.5
4.43
Wednesday
2
15
0
2
1
1
2
9
13
13
12
0
12
13
6.3
5.98
Thursday
2
14
2
1
3
6
13
2
11
10
14
7
6
13
7.0
4.90
Friday
4
14
1
1
4
9
3
0
3
10
16
10
1
13
5.8
5.34
Saturday
10
12
1
13
12
12
3
8
9
0
15
18
1
13
8.8
5.82
Period of record: June 1 through August 31, 1976.
43
-------
M4SXY
(*>*)
fNGLCSIOf (NO 3)
tt
Figure 17. Diurnal variation of pollutants during June, July,
and August 1976 at Massey and Engleside
44
-------
(NO. 8)
II 20 22
K> 12
HOUR
NOTE' METHOD Of ANALTIIS CHMMCO
CALODlMtTHIC TO CHIMILUMINIKINCf
OH JULY tltt
Figure 18. Diurnal variation of pollutants during June, July,
and August 1976 at the Alexandria Health Depart-
ment and Shirlington
45
-------
SEVEN COKHfKS
(MO. t)
LEWINSVILLE
(NOT)
MOUft
HOUR
Figure 19. Diurnal variation of pollutants during June, July,
and August 1976 at Seven Corners and Levinsvilie
46
-------
STftLIHO PAKK {HO. I A)
(NO 9)
It 201*
•
£
CH4
--..-.-^
NMHC
I 1
j
— JULY ' |
! . i . .
: i
i i
i i
— JULY |
k-.-_ 1 _.J-'-
r
i i
II 14 It It M tt
HOUR
Figure 20. Diurnal variation of pollutants during June, July,
and August 1976 at Sterling Park and Gaithersburg
47
-------
(MO ft
SH.VC* SP*IN6 (HO lot
0 t 4 • • « • M M • tO II
M II M M M M U
Figure 21. Diurnal variation of pollutants during June, July,
and August 1976 at Bethesda and Silver Spring
48
-------
Figure 22. Diurnal variation of pollutants during June, July,
and August 1976 at Cheverly and Suitland
49
-------
IM
IM
CAM* (HO.M)
tt
Figure 23. Diurnal variation of pollutants during June, July,
and August 1976 at the CAMP station in
Washington, D.C.
50
-------
Shirlington and Engleside. A probable cause for these differences is dis-
cussed below under "Influence of Monitor Siting." Another feature of
the curves which might hold some clue to oxidant behavior is the variation
from month to month at stations to the north and east of Washington (see
Figures 20, 21, and 22).
Peak concentrations taken from the average monthly curves shown in
Figures 17 through 23 are given in Table 12 where they are used to order
the various sites according to the magnitude of the oxidant levels. This
ranking can be compared with the frequency of violations data obtained
from Table 7 and included as the last column in Table 12.
INFLUENCE OF MONITOR SITING
As pointed out earlier in this section, major differences in ozone concen-
trations are observed at neighboring stations within the monitoring network.
One of the possible explanations for these differences is in the amount
of ozone scavenging brought about by nearby vehicular emissions of NO.
This explanation is strongly supported by a review of the monitor locations.
*
Specifically, the last sites in Table 12, where the sites were ranked ac-
cording to the severity of the oxidant problem, are near major traffic
sources. Details of monitor location and traffic flow have been provided
by the local agencies and/or by site visits by GCA personnel. Written
communications from the agencies are included as Appendix D. Briefly,
the Silver Spring probe is about 10 to 15 meters due north of Route 495;
the Gaithersburg monitor is near a busy intersection where carbon monoxide
concentration rises and falls with the traffic; the Shirlington monitor
is near 1-95; the Engleside monitor is about 24 meters northwest of Route 1;
and the CAMP station is in downtown Washington near a parking garage.
Figure 24 was originally prepared to see if the maximum 1-hour ozone con-
centration at stations outside of Washington was higher than normal when
the morning wind direction was from downtown Washington. Unfortunately,
51
-------
Table 12. THIRTEEN MONITORING SITES ORDERED BY MAGNITUDE
OF OXIDANT LEVELS
Site
OCA no.
6
4
2
9
12
11
7
3
1
16
j
8
10
Designation
Seven Corners
Alex. Health Dept.
Massey
Bethesda
Suitland
Cheverly
Lewinsville
Engleside
Sterling Park
CAMP
Shirlington
Gaithersburg
Silver Spring
Peak cone, taken from ave. 3
monthly diurnal curves,3 ug/m
June
164
169
165
141
137
114
119
121
—
112
104
128
94
July
171
177
153
141
161
169
128
140
120
122
120
69
124
Aug.
164
147
163
161
110
118
143
128
133
124
92
108
84
Ave.
166
164
160
148
136
134
130
130
(126)
119
105
102
101
% days
when cone .
> standard
57
57
59
59
48
55
38
33
34
35
32
29
44
Figures 17 to 23, Pages 44 to 51.
52
-------
30O
200
too
°c
300
Kl
o>
§ 100
X
z
lu
§ I0°
w
5
8
°c
300
200
100
O
" ENSLeStOf (3) • *
300
f • •
+ +
•B • 200
• \ +• •"
* H%^B • B 4^100
*" *""!
' i i i i _...j j o
* FAIRFAX (g)
; i ^. ;
• • •*• B ••+ a
""^r^r^y*
'• *y
i i i i i i j
> 50 100 ISO 200 250 300 380 "0 SO 100 ISO 200 2SO SOO 350
"DULLES (IA)
\ 300
_ + * +
* ^ *+ 200
+ ^__B „,_* ?
- " "*f-V .- vx
* • yif 100
*
1 1 1 1 1 1,. ., .J Q
' SAITHERSBURG (8)
- : j
-+ . . . ^*.
* + ++ *
••B* • -fB
+ 4- +••+ • CO OD B
-0 B «3» • B Of
• a B -t-a
Q • D B +
B B
1 1 1 1 1 L i
3 SO 100 ISO 200 2SO 300 3SO "0 SO 100 ISO 200 250 300 350
"BETHESDA (9)
T 300
- * +
a •+
• -H-B + 200
• 0+ B • + • • •
M Q B--HM — -fO
• • • •• BB •
• B Q
•a • act 100
X m 4> >^HV
~ f* T ^f*
o -H-
i 1 . 1 J 1 1 1 .1 0
W
SUITLANOda
0 + 0
• a+
B Q Q Q* •
• « Q D ••
KB-f B B- •»•-«—
•*• -t- B QfJbi
+ • • • 0 +
-+ • ••+ + B
r. • ** +f
WIND DIRECTION, degrMi
Figure 24. Maximum 1-hour ozone concentration as a function of
morning wind direction at selected sites outside the
central metropolitan area. (Months are indicated by
the symbols: • = June; o = July; and + = August.)
Arrows indicate direction when site is downwind
from downtown Washington
53
-------
as can be seen from the plots, the winds rarely blew from the city toward
five of the monitors, so the figure does not fulfill its intended purpose.
It does, however, show at least one example of depressed oxidant levels
when the monitor is downwind from a highway, the most striking example
of this being at Engleside where southeast winds are associated with low
concentrations, and northwesterly winds are associated with high concen-
trations .
COMPARISON OF UPWIND/DOWNWIND CONCENTRATIONS
It was hoped that some additional insight into the mechanism of oxidant
formation in the region might be gained by comparing concentrations and
the time of the occurrence of the daily maximum at upwind and downwind
sites of the densely emitting Washington area. To determine the upwind
and downwind sites, flow within the AQCR was defined by the use of daily
trajectories based on surface wind data from National and Dulles Inter-
national Airports and the local agencies (see Figure 3).
The trajectory calculations were carried out using the trajectory sub-
routine of the DIFKIN model, adapted to calculate trajectories within the
75-mile square grid shown in Figure 25. (Note that the x and y scales of
the grid are not identical.) Figure 26 shows the computer plot of a tra-
jectory for 5 June 1976 as an example. Hourly positions are indicated
by the sequence of letters from A to L. The trajectory Itself is hand
drawn to the letters. The calculation was performed so that the trajectory
would pass over a central point in Washington, D.C., arbitrarily chosen
to be at the intersection of 16th and U Streets, N.W., at 1400 EST. Simi-
lar trajectories for each day of the 3-month period are provided in
Appendix E.
The results of these upwind/downwind comparisons are shown in Figure 27.
In preparing Figure 27a all days which had a well-defined flow of air,
as shown by the trajectories, were selected, and the upwind and downwind
sites identified. The average concentration at each hour of the day
54
-------
7S. >'IOO *
60.0000 •
4^.0000 +
IC.onOO «
lb.0000 «
+ 4 +
« « »
t »
+ *
I « + «
]
I + * +
I
< + +
0.0 +1-
iO.OOui)
US.OOOCl
KC.OOOO
7S.OOOO
Figure 25. Seventy-five mile square grid for use in trajectory calculations.
Numbered locations are ozone monitoring stations (see Table 2)
-------
7S.OOOO «
60.0000
05.0000
JO.noon
IS.0000
0.0
0.0
IS.0000
10.0000
US.0000
60.0000
Figure 26. Computer-calculated trajectory for air parcel passing over Washington,
(Point B) at 1400 EST on 5 June 1976
7S.OOOO
D.C.
-------
10
•
a.
u
o
u
ICO
140
120
100
80
60
40
20
0
DOWNWIND
08 09 10 II 12 13 14 15
HOUR
(a) ALL DIRECTIONS
16
O
U
m
O
160
140
120
100
BO
60
40
20
JUNE 17, 18,19, 20
JULY r.6,19
DOWNWIND (*9)
UPWIND(*3)
08 09 10 II 12 13 14
HOUR
(b) SOUTHERLY FLOW
15 16
160
140
4. 120
I 100
I
m
o
40
20
0
DOWN WIND-
•5."
08 09 10 II 12 13 14 19 16
HOUR
(e ) ALL DIRECTIONS, SELECTED MONITORS
Figure 27. Comparison of average ozone concentrations observed from
0800 to 1600 EST at upwind, downwind, and CAMP stations
57
-------
from 0800 until 1600 EST was then calculated and plotted. Similar aver-
ages were calculated for the CAMP station. For the 27 days with a well-
defined wind field, downwind concentrations during the middle of the day
3
averaged about 10 (ig/m or 10 percent higher than the upwind concentrations.
In Figure 27b, concentrations on seven of these days when Station No. 3
(Engleside) was upwind and Station Nos. 9 and 10 (Bethesda and Silver
Spring) were downwind were treated similarly. The results appear to
reflect local influences rather than differences due to location relative
to the central city. Recall that Silver Spring is just north of Route 495,
and Engleside is northwest of Route 1.
In Figure 27c, the same 27 days used in preparing Figure 27a were used
again but the data from the last six sites in Table 9, judged to be the
most influenced by local traffic or other local sources, were eliminated.
The resulting curves show downwind concentrations from noon on that are
3
about 20 to 25 ng/m , or nearly 20 percent, higher than upwind
concentrations.
One should not rule out the possibility that these differences are a for-
tuitous result of the particular combination of sites used. This cautionary
note is suggested because a comparison of the highest upwind 1-hour con-
centration to the highest downwind 1-hour concentration observed on the
same day showed higher upwind concentrations on 10 of the 27 days inves-
tigated.
58
-------
SECTION V
SUMMARY OF SELECTED AIRCRAFT FLIGHT DATA
This section provides a brief description of the three-dimensional field
of ozone in and about Washington, D.C. on selected days during the latter
half of August 1976. The descriptions are based on the aircraft measure-
ments made by the EPA Air Quality Branch of EMSL-Las Vegas. Table 13
summarizes the 14 flights made during the aircraft sampling program, and
Figure 28 shows the "spiral" locations where vertical soundings were made.
Data from these flights were provided GCA on tapes, and computer plots of
the ozone and NO/NO data, as available, were prepared. These plots were
A
used in conjunction with the ground-level observations made by the local
agencies to select the data to be presented in this report. It was hoped
that the Washington urban plume might be identified, and that perhaps
local and transport influences could be distinguished.
OVERVIEW OF GROUND-LEVEL OZONE CONCENTRATIONS AND ASSOCIATED METEOROLOGICAL
CONDITIONS DURING FLIGHT PROGRAM
Figure 29a shows the rapid buildup and decline of ozone levels within the
Washington area during the study period. The ozone concentration plotted
in Figure 29a is the average of the daily maximum 1-hour values reported
at 13 monitoring stations operated by the local agencies. As indicated
in the figure, a cold front, with precipitation, passed Washington, D.C.
late on the 15th. From the 16th through the 21st, a large high pressure
cell, building eastward from the Great Lakes, controlled the weather along
the eastern seaboard. The winds at Washington during this period veered
from the northwest to the east. The weather map for 0700 EST on August 18th
is shown in Figure 30. The pressure pattern became ill-defined on the 22nd
59
-------
Table 13. SUMMARY OF AIRCRAFT SAMPLING PROGRAM
Flight
number
1
2
3
4
5
6
7
8
9
10
13
14
15
17
Date
8/17/76
8/18/76
8/18/76
8/19/76
8/19/76
8/20/76
8/20/76
8/21/76
8/23/76
8/23/76
8/25/76
8/26/76
8/26/76
8/27/76
Time, EDI
Start
0958
0853
1610
0922
1556
0612
1604
1147
0612
1611
1501
0300
1101
0855
End
1142
1051
1851
1134
1757
0843
1803
1356
0930
1640
1644
0650
1558
1140
Duration,
hr:min
1:44
1:58
2:41
2:12
2:01
2:31
1:59
2:09
3:18
0:29
1:43
3:50
4:01
2:45
Number
of
spirals
. 1
4
5
4
4
5
4
5
1
1
0
1
0
0
Spiral
locations
1
1,2.3,4
1,2,4,5,6
7,8,9,10
7,8,9,10
7,7,8,9,4
7,8,9,4
1,7,11,12,
13
2,7
7
—
7
—
—
Approx.
flight
altitude,
m
670
670
670
660
660
1100
680; 875
670
720; 340
—
1660; 2000
610 to 1510
700 to 2060
1630 to 2330
Flight plan
Twice around Wash. D.C.
Once around Wash. D.C.
Once around Wash. D.C. and
box S. of Wash. D.C.
Once around Wash. D.C. and
box N.K. of Bait.
it
it
ti
Box with Wash. D.C. in N.W.
corner
Wide area N. of Bait., E. to
S.E. of Bait, over ocean
Aborted flight N. of Wash.
D.C.
Wide area box with Wash. D.C.
and Bait, in N.E. corner
Wide area box with Wash. D.C.
and Bait, on S. side
Up Atlantic coast to Nantucket
and return
South to Raleigh /Durham and
return
-------
km. mf.
193 r-120
161
-100
129
-80
97
64
-60
-40
-20
©
20
Omi.
32
•4
129
161 km.
Figure 28. Spiral locations of aircraft soundings
during air sampling program
61
-------
900
,o 260
• E
g
200
ISO
10
o (00
50
HIGH
SHOWERS
and
COLO FRONT
FLIGHT
- NO i
tfttt tt
z, «,
3 »
I I
U '*• IT
19
I I I
14 16 18 20 22 24 26 26 30
(a) AVERAGE MAXIMUM OZONE CONCENTRATION
30.30r
30.20
«
if 90.10
| 90.00
0)
u
* 29.90
29. W
'14 16 18 20 22 24 26 28 30
(b) STATION PRESSURE
100
Is
20
I
95
90
.86
80
14 16 18 20 22 24 26 28 30
(c) INSOLATION
*I4 "16 18 20 22 24 26 28
(d) MAXIMUM TEMPERATURE
. "0 mph
14 16 18 20 22 24 26 28
(•) RESULTANT SURFACE WIND
30
Figure 29. Daily values of the maximum ozone concentration index
(13 station average) and selected meteorological
parameters during aircraft sampling program
62
-------
yv \xv
''/" .' .4 . *• K
Figure 30. Surface weather map for 18 August 1976, 0700 EST
Figure 31. Surface weather map for 22 August 1976, 0700 EST
63
-------
under the influence of a coastal low of tropical origin and the approach
of a very weak cold front which passed Washington late on the 23rd. This
weakening frontal zone was followed by a high pressure cell and ridge line
which gradually moved off the coast. Figure 31 shows the weak pressure
gradient over the eastern part of the country at 0700 EST on the 22nd, and
Figure 32 shows conditions on the 24th. The map for 0200 EST on August 27th
(Figure 33) shows the ridge line off the coast and a cold front approaching
the Great Lakes. This sharp frontal system, shown in Figure 34, passed
Washington on the 29th.
Figure 29 shows the day-to-day changes in several meteorological parameters
during the period. Daily average values of the station pressure and the
daily maximum temperature at National Airport are shown in Figure 29b and
Figure 29d, respectively. Two measures of insolation are plotted in
Figure 29c: (1) the percent possible sunshine at National Airport, and
(2) the amount of solar radiation received at the Health Department in
Alexandria from sunrise to 1400 EDT. The 24-hour resultant wind at
National Airport has been indicated by barbs in Figure 29e. The transport
wind through the mixing layer, as estimated from the Sterling, Virginia
soundings, is given in Table 14, and the midday temperature soundings at
Sterling have been plotted at 48-hour intervals in Figure 35.
Examination of the meteorological data shows that the buildup of ozone con-
centrations is associated with the easterly moving high from the vicinity
of the Great Lakes and the development of a strong subsidence inversion
over the Washington area.
From the 17th of August to the 21st, the base of the deep, stable layer
(see Figure 35) lowered from about 825 to 900 millibars, thus decreas-
ing the depth of the mixing layer by roughly one-half. Also associated
with the slowly-moving high pressure cell was a general reduction in
wind speeds to near calm conditions, as shown by Figure 29e, and Table 14.
Because of the resulting low ventilation rate, pollutants accumulated
64
-------
Figure 32. Surface weather map for 24 August 1976, 0700 EST
I
Figure 33. Surface weather map for 27 August 1976, 0700 EST
65
-------
Figure 34. Surface weather map for 29 August 1976, 0700 EST
(•)
Figure 35. Midday (1300 EDT) temperature soundings taken at
Sterling, Virginia during the period 17-31
August 1976. Soundings are plotted on adlabatic
charts at 48-hour intervals
66
-------
Table 14. MIXING LAYER TRANSPORT WIND
Date
8/16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Nighttime,
0700 EDT
Direction,
deg
330
360
30
20
20
240
340
10
210
200
340
320
260
340
20
Speed,
kts
6
8
6
2
2
1
5
8
6
3
3
2
1
20
3
Daytime,
1300 EDT
Direction,
deg
325
360
30
50
90
90
340
320
20
210
190
360
220
300
340
270
Speed,
kts
14
11
16
10
6
2
6
6
5
6
5
5
4
16
14
6
Estimated from the Sterling, Virginia soundings.
67
-------
within the general air mass, and, as shown by Figure 29c, were subject to
strong solar radiation throughout the daylight periods. With the movement
of the second high pressure cell of the period off the coast on the 25th,
cloudiness increased, and the winds became southwesterly, then northwesterly,
but remained quite light until the passage of the major cold front on the
29th.
Figures 36 and 37 present the low-level trajectories which were calculated
for the 18 through 22 August 1976 period. These trajectories show the
transport of surface air from the northeast, down from the Baltimore-
Philadelphia area, at the start of the period, and the slow, ill-defined
but westward drift beginning early in the afternbon of the 20th and con-
tinuing through the 21st.
. Flight data obtained during the period of ozone buildup was selected as
being of most interest, and a series of figures has been included in the
text to illustrate the major changes that occurred during this period.
Additional figures prepared from the flight data are provided in
Appendix F.
Three types of figures are used to describe the concentration fields:
1. A flight track, superimposed on a map of the area, with ozone
concentrations and sampling time marked at selected points
along the track. For the most part, concentrations plotted
along these tracks are the averages of five readings reported
at 15-second intervals. The transport wind, as estimated from
the Sterling radiosonde data, is shown on the map. Also, a
scale to convert the transport wind to travel distance is in-
cluded on the wind arrow. The locations where vertical
profiles were measured are marked as "spirals."
2. A computer plot of individual 15-second data points versus
elapsed time in minutes. The points along the flight track
at which concentration was plotted in the preceding type
figure are keyed to the computer plot by letters of the
alphabet. If a letter appears with subscripts, the ap-
proximate location was sampled more than once, and the
sampling sequence is indicated by the subscripts.
68
-------
75
cr>
vo
60
45
CO
kl
30
15
8/16
15
30
45
60
75
MILES
Figure 36. Low-level trajectories of air parcels passing through Washington, D.C.
at 1400 EST on 16, 17, 18, and 19 August 1976. Ticks indicate 1-hour
transport
-------
to
Ul
MILES
Figure 37. Low-level trajectories of air parcels passing through Washington, D.C.
at 1400 EST on 20, 21, and 22 August 1976. Ticks indicate 1-hour
transport
-------
3. Computer-plotted profiles of temperature, ozone, and NO/NO .
Individual 15-second data points are plotted as a function
of height.
Conditions Prior to the Ozone Buildup (17 to 18 August 1976)
Figures 38, 39, and 40 show the flight tracks on the 17th and 18th of
August. All three of these flights were made at an altitude of approximately
670 meters, or 2200 feet. On the mornings of the 17th and 18th, ozone con-
centrations were about 40 ppb, but increased slightly during the sampling
period. On the afternoon of the 18th a longer flight was made that in-
cluded a box south of Washington as well as the flight path around
Washington which had been used on Flights 1 and 2. During this flight,
concentrations at the selected points ranged from 75 ppb (Point B) west
of Washington to 110 ppb (Point N) measured just prior to landing in
Baltimore. Again, the flight altitude was 670 meters. Concentrations
increased somewhat with time, and perhaps from west to east, although
there was no clear-cut geographical pattern. Figure 41 shows the computer
plot of ozone concentration versus elapsed time. This plot shows consid-
erable structure to the ozone distribution, but it is not obvious how this
structure relates to ground-level emission patterns. Note that concentra-
tions were near or above the standard during most of this flight. Figure 42
shows the vertical profiles of temperature and ozone measured at spiral
location No. 1 during Flight No. 1, and Figure 43 shows the ozone profile
at the same location on the afternoon of the 18th. By the afternoon of
the 18th the inversion was based slightly below 2 kilometers. The concen-
tration within the stable layer remained at about 0.04 ppm, but between
flight level and the base of the inversion the concentration had increased
to more than twice that amount. Maximum surface ozone concentrations
measured within the study area on the 18th were close to, but did not
exceed, the 0.08 ppm standard.
71
-------
FLICHT NO. I
IT AU0U3T 1976
ALT.~«70m
BALTIMORE
Figure 38. Sampling track during Flight No. 1. Ozone concentration in
ppb is shown at selected points, followed by time in paren-
- theses. Transport wind at flight altitude is shown by
dashed arrow
72
-------
FLIGHT NO. 2
16 AUGUST 1976 08:93-10=51 EOT
ALT.~670m
BALTIMORE
Figure 39. Sampling track during Flight No. 2. Ozone concentration in
ppb is shown at selected points, followed by time in paren-
theses. Transport wind at flight altitude is shown by
dashed arrow
73
-------
FLUM4T NO. 3
It AUtUST I9T« I6'IO-I8'5I EOT
ALT.
79 (l«:2S)
88 (I6'52) E
89 061
89 (18'
7? (I7t32)
Figure 40. Sampling track during Flight No. 3. Ozone concentration in
ppb is shown at selected points, followed by time in paren-
theses. Transport wind at flight altitude is shown by
dashed arrow
74
-------
58UT*
im.M»-Mie»T
Ol
fr
•
B«
e
>':
•*
««
• SPIRAL
MO.Z
SPIML
XOC
U/BE
r
SCCMT
BEG.NS
0
V
»
•
e
SMWU.
"Q4
SPIRAL
A «V * i g* • J r
--$*J* ^ J~*J[- -•'
#--[
i u u u n j s,
iy2
t i
^i
16'04 EOT
-28 5T
ELR'SED TINE ININI
-sT
"?3 iiJ §3"
Tto T?o flo ito~
Figure 41. Ozone concentrations during horizontal sampling, Flight No. 3
-------
TI9T6 0958-1142 EOT
SPIRAL * I, LOCATION* I
I
»-
'—r- e - —
TEMPERATURE C
8.
2* 53
FLIGHT NO. 1
17 AUGUST 19*6 0958-1142 EOT
SPIRAL *l, LOCATION*!
-'
n
X
W.TITUOE
a
* Oe°e ° ce
^ * "* «« "*""
8Js'B
°*.? .
°* 8 •
02 ' O.'OS ' O.*04 ' O.'OS 0.06
03 (PPM)
Figure 42. Temperature and ozone profiles, Flight No. 1
76
-------
H0.3
«K>-05icoT
*Z.UOCATIflN ft
*
eO.
••_ 2
' 0703 0.04 0.05 0.06 O.Q7 0.06 0.09 0710
03 ippm
Figure 43. Ozone profile, Fligjit No. 3
-------
Conditions During the Period of Ozone Buildup
Figures 44, 45, and 46 show the flight tracks and ozone concentrations at
selected points for aircraft flights on the 19th, 20th, and 21st, respec-
tively. During this period, surface concentrations increased, reaching
peak levels on the 21st, as shown in Figure 29a. On the 19th, morning
and afternoon flights were made over the same flight path at an elevation
of about 660 meters. During the morning, concentrations along the
Philadelphia-Washington corridor averaged about 40 ppb except to the south
and east of Washington where the average was about 50 ppb. This increase
fits in well with the daily pattern, but may also reflect spatial variations,
By the afternoon ozone concentrations at flight altitude had increased
substantially, exceeding 100 ppb both to the north-northeast and southwest
of Washington. Although Washington's emissions may be contributing to the
high ozone concentrations at flight level southwest of the city, they can-
not be blamed for the equally high levels to the north-northeast. The
ozone field does have considerable structure, as shown in Figure 47 , but
much of this structure appears to be the result of inputs received by the
air mass before reaching the Washington area. Figure 48 shows the vertical
distribution of ozone and temperature on the morning of the 19th at a
location where the aircraft could descend to low altitudes. Judging from
this sounding relatively high concentrations remained throughout the night
at a height of 1 kilometer, largely unaffected by the decreases occurring
in the surface layer.
The flight tracks and concentrations for the 20th and 21st given in
Figures 45 and 46 show much the same patchy ozone structure observed
in previous flights. However, in addition, concentrations measured to the
southeast and east of Washington and along the Chesapeake Bay are generally
lower than those measured somewhat earlier farther inland to the west. Al-
though winds were light during this period, the general drift of air was
from east to west. Figure 49 shows the large variations on ozone concen-
tration that were observed while flying northward along the coast on the
afternoon of the 21st.
78
-------
PENNSYLVAN
PLIOHT 4
It MiaUST 1976 0942-M'54
ALT«*>660 in
fl.lt NT 5
It AUGUST 1976 I5'S6-I7'67
ALT." 660 m
41 (IO-04J
41
94 (I6-32T"
85 (16-45)
(IO'35I)
42 I K}i48) (
102 (I6<58){
lOt
41.4(10*59))
46.1 (HMD (
108.3(17121) (
II0.4(I7>33) I
aW
-------
PENNSYLVANIA
FLIGHT NO. 7
20 AUGUST 1976 16:04-18:03 EOT
ALT. ~ 680 ; 879 m
93 (17'Jfl
65 117:41)
\\ 92 (17:14)
\Vv33 (17:28)
i«dj
»Jf —
A
121 (IS:)*)
155 (»:«) ,5 (1W)(|,
Figure 45. Sampling track during Flight No. 7. Ozone concentration in
ppb is shown at selected points, followed by time in paren-
theses. Transport wind at flight altitude is shown by
dashed arrow
80
-------
21 AOOU5T l»r« IK47-IS'S« EOT
\
Figure 46. Sampling track during Flight No. 8. Ozone concentration in
ppb is shown at selected points, followed by time in paren-
theses. Transport wind at flight altitude is shown by
dashed arrow
81
-------
oo
to
raftUGUST (976,1556-1757 EOT
ALTITUDE-660 m
CM
O
o
d
O
o
(0
o
in
o
a.
a.
«u o
z .
o o
M
O
#
090
O
SPIRAL
NO.l
SPIRAL
SPIRAL
NO. 3
6
6
J>
SPIRAL
N0.4
I t
A B
-15=53 EOT
f(J 2$ 30*"
EtRPSEO TIME (NIN)
t t t
t t t
F e H
11
eft
9$ nJo ito Flo
Figure 47. Ozone concentrations during horizontal sampling, Flight No. 5
-------
FLKJHT NO. 4
19 AUGUST 1976,0922-1194 EOT
•PIMM. 02, LOCATION*9
SB—r—r—
TEHFERflTlfflE C
" I
-73 2t 21 2? SO
FLMHT NO. 4
fMUOUST 1976.0912-1134 EOT
9MftM. *Z. LOCATION*9
.%* '
9f
08,
-»- —+_
02 0.03
03 (PPNI
0.04
0. OS
0.06
0.07
0.38
Figure 48. Temperature and ozone profiles, Flight No. 4
83
-------
H4T-IW COT
e
a a
« •
ee
•SPIRAL » "S «S^ SPIRAL^ S\ SPIRAL &t* a SFIWU. «f SPIRAL
NOt oft a/ NQ2 NQ5 a " NQ4 a * ** *
CW3 Q A
••<
e
• • a
a a •
* I. '%
._ . t__f _ ,_*_!_ _ _fJ1_f t IJ_ t t
«ST *i •» •*•»«! etocrn «j H i T-
n 36 COT
dt>' T8 58 5U rt s« §» ?fl i« 5» iflo ^16 i*o il* ilo
ELAPSEO TIME (MINI a •
Figure 49. Ozone concentrations during horizontal
sampling, Flight No. 8
84
-------
Summary
During the period of aircraft sampling, ozone levels at a flight altitude
of about 670 meters varied significantly about what might be described as
the air mass mean. These variations were distributed along the flight
path without any obvious relationship to the Washington D.C. emission
field. This is not surprising if one places Washington's emission field
in perspective with other emissions along the heavily populated and indus-
trialized corridor to the northeast. A sampling program adequate to relate
these variations in concentration to emission density maps with confidence
would require a better definition of the wind field plus horizontal tra-
verses between ground level and 670 meters.
The buildup of ozone concentrations during the sampling period was associated
with a high pressure cell which moved slowly eastward from the Great Lakes,
and the development of a strong subsidence inversion over the Washington
area. This permitted the accumulation of pollutants and continuing chem-
ical reactions during which even the less reactive organic compounds might
play a role.
85
-------
SECTION VI
SUMMARY OF HYDROCARBON FIELD MEASUREMENTS
This section summarizes the data collected by RTI during the hydrocarbon
sampling program, and the results obtained from the detailed analysis
program in which 10 percent of the samples were analyzed for hydrocarbon
components. Concentrations of nonmethane hydrocarbon (NMHC) and nitrogen
oxides are used by local and state agencies to calculate NMHC/NO
X
ratios for use in the isopleth method currently being developed for con-
12
trol purposes. Hydrocarbon species data can be used to help identify
major contributing sources.
THC, CH^, NMHC, AND CO DATA
The ambient concentrations of THC, CH, , NMHC, and CO measured by RTI using
11
a Beckman 6800 Chromatograph and tabulated in their Final Data Report
were averaged by site, sampling period, and day of the week. In addition,
averages of the following ratios were calculated for the same data sets:
NMHC/THC, NMHC/CO, and THC/CO. Summary tables showing the results of
these calculations are provided in Appendix G.
The individual averages tabulated in Appendix G have been regrouped and
combined in Table 15. Concentrations and ratios shown in Table 15a were
obtained by averaging the values for the four sampling periods. Averages
are given for weekdays, for Saturdays, for Sundays, and for all days.
Finally, the averages for the six sites were averaged to provide general
Sites are identified in Figure 2 of Section II.
86
-------
Table 15. SUMMARY OF THC, CH4, NMHC, AND CO DATA FROM
SIX RTI SITES - JULY AND AUGUST 1976
(a) Combined average for four sampling periods:
12 a.m., 12 to 3 p.m., 3 to 6 p.m.
6 to 9 a.m., 9 to
Site and
identifi-
cation
CAMP
(16)
WEST END
(15)
ALEXAN-
DRIA
(4)
FAIRFAX
(2)
SUITLAND
(12)
BETHESDA
(9)
All sites
Day of
week
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Average
concentration, ppm
THC
2.18
2.00
1.86
2.12
2.53
2.90
2.48
2.56
2.45
2.55
2.36
2.46
1.90
1.81
1.84
1.88
2.01
2.14
2.08
2.04
1.78
1.80
1.78
1.78
2.14
2.20
2.07
2.14
CH4
2.02
1.58
1.52
1.57
1.56
1.74
1.58
1.58
1.58
1.64
1.59
1.59
1.58
1.58
1.57
1.57
1.62
1.68
1.62
1.63
1.55
1.58
1.56
1.55
1.65
1.63
1.57
1.58
NMHC
0.61
0.42
0.33
0.55
0.97
1.16
0.90
0.98
0.87
0.90
0.82
0.87
0.33
0.24
0.27
0.30
0.38
0.46
0.45
0.41
0.23
0.22
0.23
0.22
0.56
0.57
0.50
0.56
CO
2.79
1.71
1.10
2.42
2.37
1.89
1.04
2.19
1.65
1.32
1.12
1.54
0.80
0.56
0.52
0.72
0.96
0.94
0.76
0.92
0.90
0.85
0.72
0.88
1.58
1.21
0.88
1.44
Average ratio
NMHC/THC
0.26
0.20
0.15
0.24
0.37
0.37
0.35
0.36
0.33
0.34
0.34
0.34
0.15
0.12
0.12
0.14
0.18
0.19
0.19
0.18
0.11
0.10
0.10
0.11
0.23
0.22
0.21
0.23
NMHC /CO
0.25
0.36
0.38
0.28
0.49
0.64
0.88
0.55
0.65
1.16
1.14
0.77
0.56
1.28
1.08
0.74
0.54
1.08
0.78
0.66
0.42
0.86
0.98
0.53
0.48
0.90
0.87
0.59
THC /CO
1.00
1.60
2.40
1.28
1.31
1.60
2.46
1.46
1.87
2.93
2.98
2.15
3.68
6.35
7.30
4.58
3.14
4.37
3.92
3.46
2.90
4.71
4.64
3.32
2.32
3.76
3.95
2.71
87
-------
Table 15 (continued).
SUMMARY OF THC, CH4, NMHC, AND CO DATA FROM
SIX RTI SITES - JULY AND AUGUST 1976
(b) Average for 6 to 9 a.m. period only
Site and
identifi-
cation
CAMP
(16)
WEST END
(15)
ALEXAN-
DRIA
(4)
FAIRFAX
(2)
SUITLAND
(12)
BETHESDA
(9)
All sites
Day of
week
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Weekdays
Saturday
Sunday
All days
Average
concentration, ppm
THC
2.33
2.07
1.96
2.25
2.70
2.93
2.80
2.73
2.71
2.45
2.50
2.65
2.01
1.86
2.15
2.01
2.15
2.30
2.26
2.19
1.92
2.04
2.10
1.95
2.30
2.28
2.30
2.30
CH4
1.65
1.59
1.71
1.65
1.63
1.90
1.67
1.66
1.65
1.75
1.75
1.67
1.61
1.65
1.65
1.62
1.68
1.99
1.66
1.72
1.64
1.73
1.70
1.66
1.64
1.77
1.69
1.66
NMHC
0.67
0.49
0.24
0.59
1.07
1.03
1.13
1.07
1.06
0.70
0.75
0.97
0.40
0.21
0.50
0.39
0.46
0.31
0.60
0.47
0.28
0.31
0.40
0.30
0.66
0.51
0.60
0.63
CO
3.00
1.87
1.31
2.64
3.07
2.13
1.07
2.78
2.22
1.75
1.20
2.03
1.01
0.65
0.65
0.90
1.34
1.39
0.78
1.25
1.08
0.93
1.02
1.06
1.95
1.45
1.00
1.78
Average ratio
NMHC/THC
0.27
0.23
0.11
0.25
0.38
0.35
0.38
0.38
0.36
0.27
0.29
0.34
0.17
0.10
0.19
0.16
0.20
0.14
0.24
0.20
0.13
0.14
0.17
0.14
0.25
0.20
0.23
0.24
NMHC /CO
0.24
0.38
0.19
0.25
0.42
0.48
1.03
0.49
0.57
0.86
0.78
0.63
0.39
1.06
1.18
0.61
0.41
0.39
1.54
0.61
0.33
1.45
1.01
0.56
0.39
0.77
0.96
0.52
THC /CO
0.96
1.55
2.00
1.17
1.08
1.39
2.66
1.27
1.52
2.32
2.58
1.75
2.57
5.89
6.61
3.68
1.96
2.51
5.44
2.65
2.17
5.97
4.14
2.91
1.71
3.27
3.90
2.24
88
-------
estimates for the entire area. These areawide estimates show relatively
small differences between weekday and weekend concentrations of hydro-
carbons, including the nonmethane hydrocarbons, but, as would be expected,
large differences in the weekday and weekend concentrations of carbon
monoxide. Observed HC concentrations agree roughly with the THC emission
density maps presented in Section III, with the highest average concentra-
tions of both THC and NMHC being found at the West End Library and
Alexandria sites, followed by the CAMP site. On the average, nonmethane
hydrocarbons made up about 20 to 25 percent of the total hydrocarbons, but
the differences among the sites are large, ranging from 11 percent at
Bethesda to 36 percent at the West End Library. The largest weekday-
weekend differences in NMHC among the sites occurred at the CAMP station,
where by Sunday the average concentration had dropped to approximately
one-half of its weekday value. Because of its location in a commercial
area removed from major shopping centers, the progressive decrease in con-
centration from weekday to Saturday to Sunday at this site would be
expected.
Table 15b is organized in the identical fashion as Table 15a, but the
tabulated values are for the 0600 to 0900 a.m. period. The details of
the two tables differ, but the general conclusions to be drawn are much
the same. Again, the biggest weekend drop in NMHC occurs at the CAMP
station. Although the "all site" average NMHC concentration is lower on
Sundays than on weekdays, the Sunday concentration is actually higher than
the weekday concentration at four of the six sites, apparently reflecting
more complicated weekly emission cycles, particularly during the 0600 to
0900 a.m. period.
Figure 50 shows the relative changes in average concentration of carbon
monoxide and nonmethane hydrocarbons which occurred during the four
sampling periods of the day. Although there are pronounced differences
among sites and seemingly erratic behavior in many of the nonmethane
hydrocarbon curves for Saturday and Sunday when the number of observations
and the concentration levels were low, the combined site curves for
89
-------
WUKOAYS SATURDAY
SUNDAY.
ALL DAYS
• t
w to
t It
•.m.
It»«tl28*tl29«t
to to to to to to to to to to to to
9 • * It S • * It SC* It
•.*.
a.m.
9
to
C
IB
•AMPLINO PINIOO (NOUM OP DAY)
Figure 50. July and August 1976 average NMHC concentrations
(solid lines) and average CO concentrations
(dashed lines) normalized to 6 to 9 a.m. values
90
-------
weekdays and all days are quite regular. These curves show the typical
midday decrease in concentration that results from improved atmospheric
mixing, the decrease in emissions that results from a reduction in traffic
during that part of the day, and photochemical reactions. Also, the
diurnal change in carbon monoxide concentration is greater than that in
nonmethane hydrocarbons, presumably reflecting a more complete dependence
on emissions from vehicular sources.
NMHC/NOx RATIOS
Tables 16 and 17 list average NMHC concentrations obtained from the RTI
Beckman 6800 data, NO concentrations reported by the local agencies, and
the NMHC/NO ratios calculated from these averages for the CAMP and
Fairfax sites. This information is provided for Sundays, weekdays, and
Saturdays, and for all days, for each of the four sampling periods. The
same information is provided for the Bethesda and Suitland sites in
Table 18 except that no breakdown by day-of-the-week is given because of
the small number of days with both NMHC and NO data.
12
The isopleth technique proposed by Dimitriades for oxidant control
strategy development uses an average 0600 to 0900 a.m. NMHC/NO ratio.
Calculating a weighted average of the 0600 to 0900 a.m. ratios from the
four sites gives an overall, areawide estimate for this ratio of 9.7. A
better estimate for the Washington CBD is probably obtained by omitting
the Fairfax data; this procedure gives a weighted average of 6.7.
HC SPECIES DATA
Table 19 shows the periods during the July/August RTI sampling program for
which detailed hydrocarbon data were obtained. For most of these periods,
concentrations of THC, CH, , NMHC, and CO are also available from the
regular analysis. Because the concentrations of precursors during the
early morning are of particular importance, most of the observations
91
-------
Table 16. NMHC AND NO* AVERAGE CONCENTRATIONS AND
CORRESPONDING RATIOS AT THE CAMP
STATION
Sampling
period ,
EOT
0600-0900
0900-1200
1200-1500
1500-1800
Parameter
NMHC cone, (ppm)
NQx cone, (ppm)
NMHC/NCT
Number of cases
NMHC cone, (ppm)
NOx cone, (ppm)
NMHC/NCT
Number of cases
NMHC cone, (ppm)
NO* cone, (ppm)
NMHC/NCT
Number of cases
NMHC cone, (ppm)
NOx cone, (ppm)
NMHC/NO"
X
Number of cases
Average
Sunday
0.28
0.035
8.0
5
0.40
0.032
12.5
6
0.64
0.034
18.8
5
0.30
0.028
10.7
5
Weekdays
0.70
0.101
6.9
32
0.59
0.075
7.9
31
0.60
0.048
12.5
30
0.70
0.068
10.3
32
Saturday
0.47
0.046
10.2
6
0.40
0.044
9.1
6
0.30
0.034
8.8
4
0.40
0.030
13.3
5
All days
0.62
0.086
7.2
43
0.54
0.065
8.3
42
0.57
0.045
12.7
39
0.62
0.058
10.7
42
92
-------
Table 17. NMHC AND NQx AVERAGE CONCENTRATIONS AND
CORRESPONDING RATIOS AT FAIRFAX
Sampling
period,
EDT
0600-0900
0900-1200
1200-1500
1500-1800
Parameter
NMHC cone, (ppm)
NOx cone, (ppm)
NMHC/NCT
Number of cases
NMHC cone, (ppm)
NOx cone, (ppm)
NMHC/NC~
Number of cases
NMHC cone, (ppm)
NOx con . (ppm)
NMHC/NO
Number of cases
NMHC cone, (ppm)
NOx cone, (ppm)
NMHC/NO"
A
Number of cases
Average
Sunday
0.50
0.016
31.2
8
0.24
0.015
16.0
7
0.20
0.012
16.7
7
0.14
0.012
11.7
7
Weekdays
0.41
0.033
12.4
35
0.30
0.022
13.6
34
0.31
0.016
19.4
30
0.32
0.019
16.8
30
Saturday
0.21
0.033
6.4
8
0.29
0.021
13.8
8
0.18
0.014
12.9
6
0.27
0.014
19.3
6
All days
0.39
0.030
13.1
51
0.29
0.021
14.0
49
0.27
0.015
17.9
43
0.28
0.017
16.4
43
93
-------
Table 18. NMHC AND NOx AVERAGE CONCENTRATIONS AND
CORRESPONDING RATIOS AT BETHESDA AND
SUITLAND
Sampling
period,
EDT
0600-0900
0900-1200
1200-1500
1500-1800
Parameter
NMHC cone, (ppm)
NOx cone, (ppm)
NMHC/NO~~
X
Number of cases
NMHC cone, (ppm)
NOx cone, (ppm)
NMHC/NO""
X
Number of cases
NMHC cone, (ppm)
NOx cone, (ppm)
NMHC/NO"
X
Number of cases
NMHC cone, (ppm)
NO cone . (ppm)
A
NMHC/NO
*v
Number of cases
Average, all days
Bethesda
0.25
0.035
7.1
6
0.31
0.032
9.7
10
0.22
0.028
7.9
12
0.16
0.038
4.2
17
Suit land
0.55
0.118
4.7
11
0.41
0.044
9.3
16
0.52
0.014
37.1
16
0.53
0.035
15.1
26
94
-------
Table 19. PERIODS WITH DETAILED HYDROCARBON ANALYSES AT SIX SITES
Month
July
Aug.
I*y
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Fairfax
6-9
*
X
X
X
*
X
x*
X
X
X
X
X
x*
X
X
X
X
X
X
X
X
X
X
X
X
9-12
*
*
X
x*
X
X
X
X
X
X
X
X
X
X
X
12-15
^
<
X
*
X
X
X
X
X
15-18
JL
<
X
X
X
x*
X
X
X
X
lethewU
6-9
X*
X
X
X
X
x*
X
X
X
X
X*
9-12
X*
X
X
X
X
x*
X
12-15
x**
X
X
X
X
15-18
X*
X
X
X
Alanotrla
6-9
X
X
X
X^
X*
X^
X*
X
x*
X
X
9-12
X
12-15
X
15-18
X
X
X
Sulclud
6-9
*
9-12
X
12-15
X
15-18
X
i
1
CAMP
6-9
X.
X*
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
9-12
X
X
X
X
X
X
X
X
X
X
X
X
12-15
X*
X
X
X
X
X
X
X
X
15-18
X
X
X
X
X
UMt tad
6-9
X
X
9-12
12-15
15-18
X
Note: X indicates both detailed and routine data available.
X indicates detailed data only.
-------
were taken over the 0600 to 0900 a.m. period. Of the 76 samples analyzed
from this time period, 50 were collected at the CAMP and Fairfax sites,
23 at the Bethesda and Alexandria sites, and the remaining 3 at the West
End Library and Suitland sites. The results from this 0600 to 0900 a.m.
period are summarized in Tables 20 through 24 and in Figure 51. Table 20
presents the average and standard deviation of concentrations determined
from the detailed analyses (below) and the same information determined
from the corresponding routine analyses (above) to the extent that it was
available. As can be seen from the standard deviations, the range of
concentrations measured in most cases is very large. Average concentra-
tions of the 11 hydrocarbon components, plus that of nonmethane hydrocar-
bons, have been taken from Table 20 and ordered roughly by magnitude to
obtain the listing in Table 21. With a few exceptions, the component con-
centrations decrease in the order shown in the table at all four sites.
Concentrations are similar at the Alexandria and CAMP sites with the
principal exceptions of the ethylene/ethane and toluene components.
Taken together, these species make up much of the difference in NMHC
measured at the two sites. This suggests an impact on the Alexandria
site of very local sources of these hydrocarbons. Inspection of the
data shows 3 days (July 16th, July 18th, and August 24th) with exception-
ally high concentrations of ethylene/ethane during the 0600 to 0900 a.m.
sampling period, but as of now these high values have not been accounted
for. Concentrations are also quite similar at the subruban sites in
Fairfax and Bethesda and are typically less than half those at the center
city CAMP and Alexandria sites.
13 14
Lonneman, et al. ' offer a technique for estimating the total nonmethane
HC concentration due to vehicular tailpipe emissions from measured acety-
14
lene (C^H.) concentrations. In his most recent paper, Lonneman uses
15.5 as the NMHC/C2H2 ratio for this purpose. Multiplying this factor
by the average acetylene concentration in parts per billion carbon at
each monitoring site gives estimates which when compared with measured
concentrations indicate that vehicular emissions contribute approximately
96
-------
Table 20. AVERAGE CONCENTRATIONS OF HYDROCARBONS AND CARBON MONOXIDE
AT FOUR MONITORING SITES (0600-0900 EDT)
Component
Carbon monoxide
Total hydrocarbons
Methane
Sonme thane
hydrocarbons
Ecbylene/ethane
?r"pane
Propylene
Acetylene
N-butane
1-butene
Isobutane
Isopentane
Cyclopentane
N-pentane
Toluene
CAMP
N
24
24
24
24
26
26
26
26
26
26
26
26
26
26
26
Mean,
ppmc
2.61
2.31
1.65
0.67
(ppbv)
55.0
4.1-4
4.J7
16.7
17.8
0.92
5.09
18.6
0.45
5.48
15.4
3-
1.28
0.55
0.21
0.45
49.6
4.21
2.88
7.44
7.20
0.51
2.11
9.19
0.52
2.61
14.1
Alex. Health Dept.
N
9
9
9
9
12
12
12
12
12
12
12
12
12
12
12
Mean,
ppmc
1.89
2.74
1.82
0.92
(ppbv)
225.
4.72
4.63
16.8
16.0
1.06
4.92
15.9
0.22
5.95
27.3
-
1.18
0.47
0.46
0.62
271.
2.42
1.91
8.06
6.58
0.55
2.57
7.55
0.39
4.73
57.7
Fairfax
N
19
19
19
19
24
24
24
24
24
"24
24
24
24
24
22
Mean,
ppmc
0.76
1.81
1.63
0.18
(ppbv)
52.6
2.51
2.07
5.64
7.63
0.30
2.10
6.95
0.08
2.87
16.9
-
0.45
0.20
0.12
0.20
38.3
1.22
1.30
4.24
5.08
0.27
1.55
4.60
0.19
1.92
27.0
Bethesda
N
8
8
8
8
11 '
11
11
11
11
11
11
11
11
11
11
Mean,
ppmc
1.08
1.86
1.64
0.22
(ppbv)
39.8
2.00
1.81
6.50
6.73
0.28
1.92
6.65
0.06
2.66
15.6
~
0.56
0.28
0.17
0.24
21.6
0.91
1.41
4.53
3.24
0.23
1.02
4.25
0.21
1.66
14.7
Note: N = number of samples; r = standard deviation of observations.
-------
Table 21. CONCENTRATIONS OF HYDROCARBONS AT FOUR MONITORING
SITES ORDERED BY MAGNITUDE (0600-0900 EOT)
Component
Nonmethane hydrocarbons3
E thy lene /ethane
Toluene
N-butane
Isopentane
Acetylene
N-pentane
Isobutane
Propane
Propylene
1-butene
Cyclopentane
Estimated NMHC from
vehicular sources
(after Lonneman1^)
Concentra t ions , ppbv
Alex.
Health Dept.
920
225
27.3
16.0
15.9
16.8
5.95
4.92
4.72
4.63
1.06
0.22
520
CAMP
670
55.0
15.4
17.8
18.6
16.7
5.48
5.09
4.84
4.37
0.92
0.45
518
Fairfax
180
52.6
16.9
7.63
6.95
5.64
2.87
2.10
2.51
2.07
0.30
0.08
175
Bethesda
220
39.8
15.6
6.73
6.65
6.50
2.66
1.92
2.00
1.81
0.28
0.06
202
Data reported by RTI in terms of ppbc,
98
-------
VO
Table 22. COMPARISON OF AVERAGE HYDROCARBON TO ACETYLENE RATIOS
WITH RATIOS OBTAINED IN TUNNEL AIR
Component
Ethylene/
ethane
Toluene
N-butane
Isopentane
N-pentane
Isobutane
Propane
Propylene
1-butene
Cyclopentane
Fairfax
9.3
10.5
2.7
3.1
1.3
0.74
0.67
0.56
0.10
0.03
Bethesda
6.1
8.4
2.1
2.6
1.0
0.59
0.46
0.42
0.08
0.02
Alex. Health Dept.
13.4
5.7
1.9
2.4
0.88
0.59
0.42
0.42
0.12
0.03
CAMP
3.3
3.2
2.1
2.8
0.82
0.61
0.44
0.39
0.12
0.07
Tunnel
aira
—
1.27
0.97
1.25
0.62
0.34
—
0.61
0.34b
0.76C
a 13
From Lonneman
Represents sum of 1-butene and isobutylene
Represents sum of cyclopentane and 2imethylpentane
-------
Table 23. COMMON SOURCES OF HYDROCARBONS
Hydrocarbon
Ethane
Ethylene
Acetylene
Propane
Propylene
(Propene)
Iso-butane
n-Butane
1-Butene
Iso-pentane
(2-methylbutane)
Cyclopentane
n-Pentane
Toluene
o-Xylene
Symbol
C2 H6
f. O
C2 H4
£. H
C2 H2
C3 Hg
J O
C3 H6
•J V
% H10
*t i.U
C4 H10
™ A**
CA H«
4 8
C5 H12
CS H10
j j.w
C5 H12
C, Ha
7 8
C8 H10
Category
Paraffin
Olefln
Acetylene
Paraffin
Olefin
Paraffin
Paraffin
Olefin
Paraffin
Paraffin
Paraffin
Aromatic
Aromatic
Sources
Primary
Natural gas
and petroleum
Automobile
exhaust
Automobile
exhaust
Industrial usaf
Secondary
Automobile
exhaust
Synthetic
plastic industry
Acetylene Prod.
and industrial
usage
;e, petrochemical
processes, natural gas, oil field
losses
Automobile
exhaust
Gasoline evapora-
tion, chemical
processes
Heating, city and industrial gas
manufacturing fuel evaporation
Fuel evaporation and automobile
exhaust
Automobile exhaust, gasoline eva-
poration, raw material for syn-
thetic rubber
Automobile exhaust, gasoline
evaporation
Automobile exhaust, gasoline
evaporation
Automobile exhaust, gasoline
evaporation
Petroleum and
coal tars
Petroleum and
coal tars
Automobile fuel
and exhaust*
and solvent
Fuel evaporation*
solvents
aAn Increase In concentrations of aromatic can be expected as lead in
fual is phased out.
100
-------
U)
Table 24. LINEAR CORRELATION COEFFICIENTS BETWEEN CARBON MONOXIDE AND
ACETYLENE AND VARIOUS HYDROCARBONS AT FOUR MONITORING SITES
(0600-0900 IDT)
de «*r*u» hydrocarbons
Site
CAW
Ala.
Health
Dept.
Fairfax
Bvthesda
r
n
r
n
r
n
r
n
THC
0.72*
54
0.44
48
0.67*
53
0.57*
52
Hithane
0.48*
54
0.53*
48
0.54*
53
0.81*
52
NHHC
0.63*
54
0.26
48
0.51*
53
0.14
52
Carbon
monoxide
1.00
54
1 . CC"'
48
1.00*
53
1.00*
52
Ethylene/
ethane
0.34
24
-0.36
9
0.14
19
-0.61
8
Propane
0.00
24
0.70*
9
0.43
19
0.61
8
Pro-
p/lene
0.73*
24
0.95*
9
0.46*
19
-0.04
8
Acet-
ylene
0.69*
24
0.69*
9
0.51*
19
0.62
8
M-
butane
0.74*
24
0.82*
9
0.67*
19
0.71
8
1-
butene
0.81*
24
0.55
9
0.51*
19
0.57
8
Iso-
butane
0.70*
24
C.77*
9
0.65*
19
0.61
8
Iso-
pentane
0.77*
24
0.7S*
9
0.64*
19
0.67
3
Cyclo-
pentane
0.40
24
-0.31
9
0.35
19
-0.27
8
N-
pentane
0.70
24
0.70*
9
0.56*
19
0.63
8
Toluene
0.11
24
0.77*
9
0.29
17
-0.20
8
(b) Acetylene versus other hydrocarbons and carbon monoxide
Site
CMff
Alex.
Health
Dept .
Fairfax
Bethesda
r
n
r
n
r
n
r
n
THC
0.49*
24
-0.07
9
if
0.69
19
0.63
8
Methane
0.50*
24
0.39
9
-0.04
19
0.19
8
NMHC
0.36
24
-0.34
9
*
0.70
19
0.66
8
Carbon
monoxide
0.69*
24
*
0.69
9
*
0.51
19
0.62
8
Ethylene/
ethane
0.51*
26
-0.09
12
0.38
24
C.CS
11
Propane
0.16
26
0.49
12
0.38
24
-V
0.9-i
11
Pro-
pylene
0.73*
26
A
0.73
12
*
0.85
24
0.50
11
Acet-
ylene
1.00*
26
*
1.00
12
*
1.00
24
&
1.00
11
N-
butane
0.70*
26
*
0.73
12
*
0.74
24
*
0.89
11
1-
butene
0.63*
26
0.40
12
*
0.65
24
*
0.66
11
Iso-
butar.e
C.72*
26
*
0.85
i:
*
0.70
24
-v
0.90
11
Iso-
pentane
0.70*
26
*
0.86
12
*
0.79
2^
*
0.94
11
Cyclo-
pentane
0.46*
26
0.3:
12
-0.14
24
-0.34
11
N-
pentane
0.55*
26
0.47
12
0.32
24
•it
0.86
11
Toluene
0.02
26
0.25
12
0.28
22
0.41
11
Indicates significance at 5 percent level.
-------
It
to
1"
5"
t it
' 10
t
o
(
tt
to
lit
8 to
8"
10
t
a
at
to
S"
« *°
. • t it
8 10
&
co.ni
<•> f tlH ft*, ttt NO. 1
it
50
|»
« 5 to
C .t
• S
• • * 10
• t
1 1 1 1 1 i a
•
.
•. .
CO, prm
in ttnaeot, tct HO. t
m •,
• :. '
'* •.*
• «..
•
H>*Ll**M»»l*, K* HO. «
CO, nm
HI ctuf, act HO it
-10
' 1^-0.82
i^
t t 4 I
lurtt /,*,#,/
Figure 51. Relationship between acetylene and carbon monoxide
concentrations at four sites (0600 to 0900 EDT)
102
-------
56, 77, 97, and 92 percent of the nonmethane hydrocarbons at the
Alexandria, CAMP, Fairfax and Bethesda sites, respectively. Because of
possible uncertainties in the total NMHC estimates as measured by the
FID instrument, comparisons of vehicular NMHC to total NMHC should be
made with caution. However, if one accepts the relationship between
hydrocarbon/acetylene ratios and the contribution of vehicular emissions
to NMHC concentrations assumed by Lonneman, it is clear that the contri-
bution from vehicles is approximately 3 times as great at the CAMP and
Alexandria sites as at the outlying sites of Fairfax and Bethesda. It
also appears that while other sources contribute significantly to NMHC
concentrations at the CAMP site, and to a great extent in Alexandria,
vehicular emissions are responsible for nearly all of the nonmethane
hydrocarbons in Bethesda and Fairfax.
13
Lonneman, et al. have also presented ratios, calculated from concentra-
tions expressed in parts per billion carbon, of the concentration of a
number of hydrocarbon species to that of acetylene in tunnel air. When
ratios determined from ambient urban air samples are significantly greater
than these tunnel ratios, it suggests the presence of other NMHC sources.
Table 22 lists such hydrocarbon/acetylene ratios determined from the
average concentrations of the species listed in Table 21 after conversion
to parts per billion carbon. Tunnel ratios for eight of these species,
taken from Lonneman, are also included in the table for comparison.
16
Table 23, from an unpublished paper by Sennett, shows the type of
source information that is available for use with these ratios in iden-
tifying source classes.
Some of the conclusions to be drawn from Table 22 with regard to vehicular
NMHC contributions do not appear to agree with the ones drawn earlier.
For example, the data in Table 21 indicate that vehicular emissions account
for approximately all of the NMHC at the Fairfax and Bethesda sites. If,
in fact, this were the case, one would expect close agreement between the
individual hydrocarbon/acetylene ratios obtained from the RTI data to the
103
-------
ratios obtained by Lonneman, et al. in the tunnel experiments. The data
in Table 22 indicate the ratios for n-pentane, and isopentane are a factor
of 2.3 higher than Lonneman's tunnel ratios. In the case of toluene at
the Fairfax and Bethesda sites, the ratios are 6.8 times higher. The dif-
ferences could be accounted for by: strong local sources of these com-
pounds, an active sink for C H_ or instrumental artifacts. An active
C2H2 sink seems very unlikely and the available data do not provide a
clear choice between the other two choices. It should be pointed out,
however, that there are very large day-to-day variations in many of the
ratios. Also, there is no data for a number of hydrocarbon species.
It is generally assumed that either carbon monoxide or acetylene may be
used as a normalizing species for automotive emissions. As a matter of
interest, the relationships between the two at the four sites are pre-
sented as scatter diagrams in Figure 51. Linear correlation coefficients
between each index and concentrations of the remaining components are
given in Table 24. The highest correlations between the indices and
the hydrocarbon species are found with propylene, n-butane, 1-butene,
iso-butane, iso-pentane and n-pentane; these correlation coefficients
frequently exceed those calculated between the two indices themselves.
The lowest correlations are found between the indices and ethylene/ethane,
cyclopentane, and toluene.
No attempt has been made in this report to associate daily concentrations
at individual sites, or concentration changes during transport, with the
detailed hydrocarbon emission field. The possibility of doing so, how-
ever, could be explored using the low-level trajectories provided in
Appendix E, plus the emissions data in Section III and Appendix C. If
such an approach proved to be promising, a more detailed COG hydrocarbon
inventory is available from the Council of Governments which lists con-
tributions to individual districts by source category.
104
-------
SECTION VII
SUMMARY AND CONCLUSIONS
The principal findings of this study to characterize the Washington, B.C.
oxidant problem can be summarized as follows:
1. The emission density of both hydrocarbons and nitrogen
oxides decreases rapidly with distance from the city
center. Except along major highways, the emission
densities drop by roughly one order of magnitude in
about 8 kilometers outward from the center of Washington,
and roughly another order of magnitude in an additional
16 kilometers.
2. On all but 10 days during June, July and August of 1976,
the oxidant standard was equalled or exceeded at one or
more monitors within the study area. No evidence was
found for a trend in the number of violations; recent
year-to-year variations in the severity of the oxidant
problem are attributed to differences in meteorological
conditions.
3. Ozone concentrations at all sites almost always behave
in the classical way, with low concentrations at night,
a minimum near 0600 a.m., and the daily maximum shortly
after noon. When the maximum does occur at night, it
rarely exceeds the standard. This suggests domination
by locally generated ozone.
4. Changes in the rate of ozone formation appears to occur
on an areawide scale with concentrations rising and
falling in response to meteorological conditions. Thus
violations usually occur at many locations within the
study area on a high ozone day.
5. High ozone concentrations are typically associated with
high temperatures, at least a moderate amount of solar
radiation, and a slowly moving or stagnating air mass
that has accumulated a variety of pollutants during
its recent history.
105
-------
6. Although ozone is an areawide phenomenon, substantial
differences in maximum concentrations occur at nearby
locations as a result of very local influences, such
as strong sources of nitric oxide. The practice of
monitoring ozone near heavily traveled streets and
highways severely limits the usefulness of some of
the data for meso and larger scale field studies.
7. No significant difference in the time of the ozone
maximum was detected between the upwind and downwind
edges of Washington. On the average, however, after-
noon concentrations downwind were nearly 20 percent
higher than concentrations upwind. Because of dif-
ficulty in eliminating the impact of localized site
interferences, this conclusion should be considered
provisional. Also, the main effects of Washington's
emissions downstream could well be occurring outside
the monitoring network.
8. An average value of 9.7 was found for the NMHC/NOX
ratio, using data from the Fairfax, Bethesda, Suitland,
and CAMP sites and NMHC concentrations determined by
flame ionization detection. When data from Fairfax
(a residential/commercial site approximately 20 kilo-
meters west of Washington, D.C.) was removed, the ratio
was 6.7.
9. NMHC concentrations, averaged from six sites over the
0600 to 0900 a.m. period showed Saturday and Sunday con-
centrations to be 77 and 91 percent, respectively, of
weekday concentrations.
10. Application of Lonneman's procedures for estimating the
vehicular contribution to ambient NMHC concentrations
was impaired by the limited number of hydrocarbon species
that were measured by gas chromatographic analysis. The
use of his approach with an estimate of total NMHC ob-
tained by flame ionization detection, indicated that, on
the average, vehicular emissions accounted for approxi-
mately 56, 77, 97, and 92 percent of the total NMHC
measured at the Alexandria, CAMP, Fairfax, and Bethesda
sites, respectively.
11. Although individual hydrocarbon/acetylene ratios varied
widely at the same site, the average ratios, with the
notable exceptions of ethylene/ethane and toluene, showed
good agreement among sites. Comparison of the average
ratios with the values reported by Lonneman from tunnel
experiments showed ratios at the four study sites from
2.5 to 8 times higher than tunnel ratios for toluene;
106
-------
roughly 2 times higher for n-butane, isopentane, n-pentane,
and isobutane; and slightly lower for propylene. No tunnel
ratio for ethylene/ethane was available for comparison.
The amounts of 1-butene and cyclopentane found wera too
small to impact significantly on the total amount of
NMHC, and were less than would have been expected from
the tunnel experiments. Providing measured levels are valid,
these comparisons suggest the presence of major sources of
toluene (and of ethylene/ethane) in addition to motor vehicles,
plus lesser, more uniformly distributed nonvehicular sources of
the other principal hydrocarbon species. The lack of better
agreement between the tunnel ratios and the ratios at Bethesda
and Fairfax where NMHC concentrations had been estimated to be
primarily from motor vehicles (see 10, above) is unexplained.
12. Although significant differences in ozone concentration
were encountered in horizontal flight, aircraft sampling
at an altitude of about 670 meters (2200 ft) failed to
show any major increase in ozone that could be directly
related to Washington's emissions. However, flight
restrictions prevented a careful search for the
Washington plume which may not have been located at
flight altitude at the sampling distances employed.
107
-------
REFERENCES
1. Midurski, T.P., R.M. Patterson, and F.A. Record. Review of Data
Base Adequacy and Proposed Modifications to Scope of Work. GCA/
Technology Division, Bedford, Massachusetts. EPA Contract No.
68-02-1376, Task Order No. 27. 29 June 1976.
2. Fairfax County Air Quality, Annual Summary, 1976. Fairfax County
Air Pollution Control, 4080 Chain Bridge Road, Fairfax, Virginia.
3. Meyer, E.L., W.P. Freas, J.E. Summerhays, and P.L. Youngblood.
The Use of Trajectory Analysis for Determining Empirical Relation-
ships Among Ambient Ozone Levels and Meteorological and Emissions
Variables. International Conference on Photochemical Oxidant
Pollution and Its Control, Proceedings: Volume II. January 1977.
4. RTI. Investigation of Ozone and Ozone Precursor Concentrations at
Nonurban Locations in the Eastern United States. EPA 450/3-74-034.
May 1974.
5. RTI. Investigation of Rural Oxidant Levels as Related to Urban
Hydrocarbon Control Strategies. EPA 450/3-75-036. March 1975.
6. Hartwell, T.D. and H.L. Hamilton, Jr. Examination of the Relation-
ships Between Atmospheric Oxidant and Various Pollutant and Meteo-
rological Variables. RTI. U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina. Contract No. 68-021096.
December 1975.
7. Karl, T.R. and G.A. Demarrais. Meteorological Conditions Conducive
to High Levels of Ozone. International Conference on Photochemical
Oxidant and Its Control, Proceedings: Volume II. January 1977.
8. Bruntz, S.M., W.S. Cleveland, T.E. Groedel, B. Kleiner, and
J.L. Warner. Ozone Concentration in New Jersey and New York:
Statistical Association with Related Variables. Science. October
1974.
9. McCurdy, T.R. Descriptive Analyses of Oxidant Data on the East
Coast. Presented at the American Institute of Chemical Engineers
83rd National Meeting, Houston, Texas. March 1977.
10. Air Quality Maintenance Planning, Emission Inventory, by Metropolitan
Washington Council of Governments. Contract No. 68-02-1817.
December 1975.
11. Decker, C.E., R.W. Murdoch, and J.A. Scheibe. Field Investigation
of Ambient Hydrocarbon Levels in Washington, D.C. During Summer
1976, Final Data Report. EPA Contract No. 68-02-1893.
108
-------
12. Dimitriades, B. An Alternative to the Appendix J Method for Calcu-
lating Oxidant- and N02~Related Control Requirements. International
Conference on Photochemical Oxidant Pollution and Its Control,
Proceedings: Volume II. Raleigh, North Carolina. September 12-17,
1976.
13. Lonneman, W.A., S.L. Kopezynski, P.E. Darby, and F.D. Sutterfield.
Hydrocarbon Composition of Urban Air Pollution. Environ Sci Technol.
8(3). March 1974.
14. Lonneman, W.A. Ozone and Hydrocarbon Measurements in Recent Oxidant
Transport Studies. International Conference on Photochemical Oxidant
Pollution and Its Control, Proceedings: Volume I. Raleigh, North
Carolina. September 12-17, 1976.
15. RTI. Evaluation of EPA Reference Method for Measurement of Nonmethane
Hydrocarbons. Draft Final Report. U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina. EPA Contract No.
62-02-1800. June 1977.
16. Sennett, D.H. A Survey of Tracer Characteristics of Nonmethane
Hydrocarbon Species. Unpublished manuscript. U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina. March
1977.
109
-------
APPENDIX A
AIR POLLUTION ALERTS CHRONOLOGICAL HISTORY
(Provided by the Metropolitan Washington Council of Governments)
A-l
-------
AIR POLLUTION ALERTS CHRONOLOGICAL HISTORY
Highest reading ever recorded:
August 1, 1975 -(180)in Suitland
Longest alert ever recorded:
August 2S-September 6, 1973
Only winter alert:
January 18-19, 1973
Only Carbon Monoxide alert:
January 18-19, 1973
First Sunday alert:
July 8-11, 1973
Earliest hot weather alert:
April 19-21, 1976
1970
1. July 28
(oxidants)
1971
2. July 22
highest reading:
(oxidants)
.124 ppm (110) recorded in Fairfax
1972
3. July 17-24 (oxidants)
highest reading: .19 ppm (145) recorded in Hyattsville
on July 21.
4. August 14-15 (oxidants)
highest reading: .15 ppm (125) recorded in Bethesda on
August 14.
S. August 24-27 (oxidants)
highest reading: .20 ppm (150) recorded in Hyattsville
on August 26.
6. September 8-9 (oxidants)
highest reading: .19 ppm (145) recorded in Silver Spring
on September 8.
Note: Numbers in parentheses indicate Air Quality Index.
A-2
-------
19 73
7
10.
11.
12.
January 18-19 (carbon monoxide)
First winter alert recorded
First carbon monoxide alert
highest reading: SO ppm (80) recorded in Bethesda on
January 18.
June 11-12
highest reading:
on June 11.
July 8-11
highest reading:
July 9.
July 18-20
highest reading:
July 18.
August 6-11
highest reading:
on August 10.
(oxidants)
.19 ppm (145) recorded in 7 Corners, Fairfax
(oxidants)
,14 ppm (120) recorded at Suitland on
(oxidants)
,14 ppm (120) recorded in Fairfax on
(oxidants)
,15 ppm (125) recorded at Arlington
August 25-September 6 (oxidants)
Longest alert ever called
highest reading: .23 ppm (165) recorded in Alexandria
on August 29.
1974
13.
July 8-11
highest reading:
on July 9.
(oxidants)
.17 ppm (135) recorded at Hyattsville
1975
14. May 22-24
highest reading:
on May 2 2 .
15. June 24-26
highest reading:
on June 24.
16. July 23-25
highest reading:
July 24.
17. July 29-August S
highest reading:
August 1.
(oxidants)
,19 ppm (145) recorded in Alexandria
(oxidants)
,18 ppm (140) recorded in Suitland
(oxidants)
,15 ppm (125) recorded in Fairfax on
(oxidants)
.26 ppm (180) recorded at Suitland on
A-3
-------
-3-
1976
18. April 19-21
highest reading:
station on April
19. June 9-13
highest reading:
on June 9.
20. June 29-30
highest reading;
on June 29.
21. July 6-7
highest reading:
on July 6.
22. August 4-6
highest reading:
August 6.
23. August 12-15
highest reading:
August 14.
24. August 24-27
highest reading:
August 25.
25. September 13-15
highest reading:
September 14.
(oxidants)
.145 ppm (123) recorded at DC CAMP
20.
(oxidants)
.180 ppm (140) recorded at Alexandria
(oxidants)
,135 ppm (120) recorded at Alexandria
(oxidants)
.135 ppm (120) recorded at Alexandria
(oxidants)
.135 ppm (120) recorded in Bethesda on
(oxidants)
,143 ppm (122) recorded in Bethesda on
(oxidants)
.158 ppm (129) recorded in Bethesda on
(oxidants)
.193 ppm (145) recorded in Bethesda on
A-4
-------
APPENDIX B
MIXING HEIGHTS AT STERLING, VIRGINIA
The mixing heights in this appendix were calculated by EPA, using the
Holzworth procedure, from the three daily soundings taken at Sterling,
Virginia during July and August 1976. The morning mixing height was cal-
culated as the height above ground at which the dry adiabatic extension
of the morning minimum surface temperature plus 2 C intersected the ob-
served vertical temperature profile. The maximum surface temperature was
used in calculating the afternoon mixing height. For the 1700 GMT sound-
ing, the surface temperature corresponding to this time period was obtained
from the LCD's for Washington, D.C.
B-l
-------
SUUNUiNG
80UNUI*G
SOUNDING
SOUNDING
SOUNDING
SOUNU1NG
SOUNDING
SOUNDING
SOUNDING
SHOWING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUND I UG
SOUNDING
SOUNDING
SOUNDING
iOUNDJNG
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SUUNUiNG
SOUNDING
SUUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNUlKG
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SUUNOlNC
SOUNDING
3/1 DAU
372 UATE
373 DATt
374 UATt
375 DATt
1/6 OATfc
377 UATt
378 DATt
379 DATt
380 DATt
381 DAIt
382 OATt
383 OATt
384 DATt
385 UATt
386 OATt
387 OATt
388 DAIt
389 OATt
3«0 DATt
392 OATt
393 DATE
394 DATt
195 DATt
396 DATE
397 UATt
398 DATt
399 DATt
'">0 UATt
•401 UATt
402 DATt
403 DATE
404 DATE
405 DATE
406 DATt
407 OA1E
408 DATE
409 DATE
410 OATt
411 DATE
412 DATE
413 DATt
414 OATt
415 OATt
416 OAIt
417 DATE
418 UATt
419 UATt
420 OAIt
421 UAIt
422 DATt
423 OAIE
424 UATt
425 OATt
426 OATt
427 UATt
428 DAIt
429 OATt
430 UATt
431 DATE
•Hi DATE
433 UATt
6/30 TIMt
7/01 TJMt
7/01 TIMt
7/01 TIME
7/02 IIMt
7/02 IIMt
7/02 IIMt
7/03 IlMfc
7/03 IIME
7/04 IIMt
7/04 IIMt
7/04 TIME
7/05 TIMt
7/05 TIMt
7/05 IIMt
7/06 TIMt
7/06 IIMt
7/06 TIMt
7/07 IIMt
7/07 IIMt
7/08 TIME
7/08 TIMt
7/08 TIME
7/09 TIMt
7/09 TIMt
7/09 TIMt
7/10 TIME
7/10 TIME
7/10 TIMt
7/11 TIMt
7/U TIME
7/11 TIMt
7/12 TIMt
7/12 IIMt
7/12 TIMt
7/lS TIMt
7/13 TIMt
7/13 TIME
7/14 TIME
7/14 Tlrtt
7/1 '1 TIMt
7/15 TIMt
7/15 TIMt
7/16 IIMt
7/16 TIME
7/16 TIMt
7/17 TIMt
//!/ IIMt
7/17 IIMt
7/18 TIME
7/18 IIMt
7/lS IIMt
7/19 IIMt
7/19 TIMt
7/19 IIMt
7/20 TIMt
7/20 TIME
7/20 IIMt
7/21 TIMt
7/21 IIMt
7/21 IIMt
7/22 TIMfc
2300 MIXING not x
1100 MJxHG MGI x
17UU MIXING nGT »
diou MIXING HGI x
1100 MIXING HGI z
l 'oo MIXING HGT *
2300 MIXING HGT x
liov MIXING HGI =
1700 MIXING HGT *
lioo MIXING HGI x
1700 MIXING HGI x
2100 MIXING HGI *
iiou MIXING HGI *
l/oo MIXING HGI x
2300 MIXING HGT =
1100 MIXING HGI 3
1700 MIXING HGT a
2300 MIXING HGT *
1100 MIXING HGI *
1700 MIXING HGI =
1100 MIXING HGI >
I7oo MIXING HGI *
2300 MIXING HGI *
1100 MIXING HGI =
170U MIXING HGI -
230U MIXING HGI x
1100 MIXING HOT x
1700 MIXING HGT -
2300 MIXING HGI *
lioo MIXING HGI 3
1700 MIXING HGT x
2300 MIXING HGI x
lioo MIXING HGT «
1700 MIXING HGI x
2300 MIXING HGT s
lioo MIXING HGT x
1700 MIXING HGT x
2300 MIXING HGI =
1100 MIXING HGT x
1700 MIXING HGT x
2300 MIXING HGT =
1100 MIXING HGT s
2300 MIXING HGT x
lioo MIXING HGT i
1700 MIXING HGI a
2300 MIXING HGT x
1100 MIXING HGT x
i/uo MIXING HGI *
230U MIXING HGI -
liao MIXING HGI x
1/00 MIXING HGI x
2300 MIXING HGT =
1100 MIXING Ht,I :
1700 MIXING HGI =
2300 MIXING HUI =
iiuu MIXING ML, i x
i/oo MIXING HGI x
2300 MIXING HGI x
lioo MIXING HGI x
i/oo MIXING HGI x
230U MIXING HGI *
iiou MIXING HGI x
2483
97
2329
2445
40
2888
3377
63
3223
127
2135
2263
515
2001
2907
331
2026
2578
4b3
1480
148
1366
1603
522
2009
2217
117
1753
1448
71
178
133
28
2121
2*17
466
2120
2234
705
1213
1058
230
1286
112
1901
2540
856
2017
2638
110
2300
2697
68
1/98
2085
162
1063
2075
193
1658
2280
375
B-2
-------
SOUNDING
SOUHOINb
SOUND INS
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
fDUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
•OUUOING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
SOUNDING
fSMftOING
MHMOING
SOUNDING
SUUNOlNli
4)4 OATE
4)5 OATE
4)6 DATE
4)7 DATE
4)8 OATE
4)9 DATE
440 OATE
441 OATE
442 OATE
44) OATt
444 OATt
445 DATE
446 DATE
447 DATE
446 DATE
449 OA1E
450 OATE
451 DATE
452 OATE
45) DATE
454 OATE
455 DATE
456 DATE
457 OATE
458 OATt
459 DATE
460 DATE
461 OATE
<«62 OATt
46) OATE
464 DATE
465 OA1E
466' DATf
467 DATE
466 DATE
469 OATt
470 DATE
471 DATE
472 DATE
47) DATE
474 DATE
475 DATE
476 OATt
U/7 DATE
476 OATt
479 OATE
480 DATE
481 OATt
462 DATE
48) OATE
464 OATE
485 DATE
466 DATE
487 DATE
486 OATt
489 OATt
490 DATE
491 OATE
492 OATt
49) DATE
494 OATt
495 DATE
7/22 TIME
7/22 TiMt
7/2) TIME
7/2) TIME
7/2) U«t
7/24 TIME
7/24 TIME
7/24 TIME
7/25 TIME
7/25 TIME
7/25 IIME
7/26 TIME
7/26 TIME
7/26 TIME
7/27 TIME
7/27 TIME
7/27 TIME
7/26 TIME
7/28 TIME
7/28 TIME
7/2<>"TlME
7/29 TIME
7/29 TIME
7/)0 TIME
7/)0 TIMt
7/)0 TIME
7/)l TIME
7/11 TIME
7/)l TIMt
8/01 TIME
8/01 TIME
6/01 TIME
8/02 TIME
8/02 TIME
8/02 TIME
8/0) TIME
6/0) TIME
6/0) TIME
6/Ou TIME
8/04 TIMt
8/04 TIMt
6/05 TIME
8/05 TIMt
8/05 TIMt
8/06 TIME
6/06 TIME
8/06 TIME
8/07 TIME
8/07 TIME
8/07 TIME
8/OU TIME
6/08 TIME
6/08 TIME
8/09 TIME
6/09 TIMt
8/09 TIME
8/10 UMt
8/10 IIME
8/10 TIME
6/11 TIME
B/ll TIME
6/11 UMt
1700 MIXING HGT *
2)00 MIXING HGT *
1100 MIXING HGT x
i 7uo MIXING HGT x
2)00 MIXING HGT *
1100 MIXING HGT x
1700 MIXING HGT 3
2)00 MIXING HGT x
1100 MIXING HGT x
1700 MIXING HGI »
2)00 MIXING HGT x
1100 MIXING HGT s
1 100 MIXING HGT «
2)00 MIXING HGT a
1100 MIXING HGT 3
1700 MIXING HGT x
2)00 MIXING HGT 3
1100 MIXING HGT s
1700 MIXING HGT 3
2)00 MIXING HGT =
1100 MIXING HGT x
1 700 MIXING HGT 3
2)00 MIXING HGT x
1100 MIXING HGT 3
1700 MIXING HGT >
2)00 MIXING HGT >
1100 MIXING HGT *
1700 MIXING HGT *
2300 MIXING HGT x
1100 MIXING HGT x
1700 MIXING HGf x
2)00 MIXING HGT 3
1100 MfXlNG HGT »
1700 MIXING HGT x
2)00 MIXING HGT •
1100 MIXING HGT 3
1700 MIXING HGT »
2)00 MIXING HCT x
1100 MIXING HGT x
1700 MIXING HGT 3
2)00 MIXING HGT x
1100 MIXING HGT x
i7oo MIXING HGT x
2)00 MIXING HGT 3
11UO MIXING HGT x
1700 MIXING HGI x
2)00 MIXING HGT x
1100 MIXING HGT *
i7oo MIXING "GT -
2)00 MIXING HGT x
1100 MIXING HGT x
i 700 MIXING HGT s
2)00 MIXING nGT x
1100 MIXING HGI s
1700 MIXING HGT s
2)00 MIXING HGT 3
1100 MIXING nGI x
1700 MIXING HGT x
2)00 MIXING HGT x
1100 MIXING HGT s
1700 MIXING HGT x
2JOO MIXING HGT 3
966
1)56
439
1659
690
322
17)4
2217
149
1575
1747
152
16)4
1595
2)5
1)62
1695
351
1642
2117
2Z9
1297
1765
94
16))
1597
145
19)0
2011
)86
205)
2497
146
1806
1927
187
2)01
2768
172
2467
2)05
219
1566
2559
148
19Q4
2691
554
504
595
567
597
6)0
256
624
972
190
1769
21)6
179
1660
1641
B-3
-------
•OUNOING
MUMOIN6
••UNO ING
•OUNOING
fOUNDlNC
•OUNOING
•OUNOING
MtNOiNG
liUNOINtt
•OUNOING
•OUNUING
•OUNDING
•OUNOING
•O.UNOING
•OUNDIrtG
•OUNDING
•OUNDING
•OUNOING
•OUNOING
•OUNDING
•WINDING
•OUNOING
•OUNOING
•OONOING
•OUNOING
BOUNDING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
MMNJUNG
HUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
MUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
•OUNOING
MUN01M6
MMM01NC
•OWWOING
496 DATE
497 DATE
4»8 DATE
4«»9 OATt
500 0»TE
SOI OATE
502 OAtt
501 OAIt
SOa OAIE
505 OATE
506 OATE
507 OAIE
508 DATE
509 OATE
510 OATE
511 OATE
512 DATE
51) DATE
514 OATE
515 OATE
51* DATE
517 OATE
518 OATE
S19 DATE
520 OATE
521 DATE
522 DATE
523 DATE
524 DATE
525 DATE
526 DATE
527 DATE
526 DATE
529 OATE
510 DATE
551 DATE
512 OATE
513 OATE
5J'» OAfE" "
515 DATE
516 OATE
517 OAfE
518 DATE
519 OAIE
540 OAIE
541 OATE
542 OATE
541 OATE
544 OATE
545 OATE
546 DATE
547 DATE
548 OATE
549 OATE
550 OATE
551 OAtt
5W OATE
Mi OATE
5»« DATE
8/12 UMt
8/12 TIME
8/12 TIME
8/li UMfc
8/11 TIME
8/11 lIMt
8/14 TIME
8/14 UME
8/14 TIME
8/15 TIME
8/15 TIME
8/15 lIMt
8/16 TIME
8/16 TIME
8/16 TIME
8/17 TIME
8/17 TIME
8/17 TIME
8/18 TIME
8/18 TIMt
8/18 TIME
8/19 TIME
8/19 TIME
8/19 TIME
8/20 TIME
8/20 TIME
8/20 TIME
8/21 TIME
8/21 TIME
8/21 TIMt
8/22 tlME
6/22 TIME
8/22 TIME
6/21 TIME
6/21 TIME
8/21 TIME
6/24 TIME
6/24 JIME
6/24 TIME
8/25 IIME
6/25 TIME
8/25 TIME
6/26 IIME
8/26 IIME
8/26 IIME
6/27 TIME
8/27 TIMt
8/27 TIMt
6/28 TIME
8/28 IIME
8/26 TIME
6/29 TIME
8/29 TIME
8/29 TIME
8/10 TIME
6/10 TIME
6/10 TIME
8/11 TIME
6/11 TIME
1100 MIXING HGI
I7oo MIXING HGT
2100 MIUNG MGI
1100 MIXING HGT
1/00 MIXING HGT
HOD MIXING HGT
1100 MIXING HGT
1700 MIXING HGI
2100 MIXING HGI
itoo MIXING HGT
1700 MIXING HGT
2100 MIXING HGI
1100 MIXING HGT
1700 MIXING HGI
2100 MIXING HGT
1100 MIXING HGT
1700 MIXING HGT
2100 MIXING HGT
1 100 MIXING HGT
1700 MIXING HGI
2100 MIXING HGI
lioo MIXING HGI
i 700 MIXING HGT
2100 MIXING HGt
lioo MIXING HGT
1700 MIXING HGI
2100 MIXING HGT
1100 MIXING HGT
1700 MIXING HGT
2100 MIXING HGT
lioo MIXING HGT
1700 MIXING HGT
2300 MIXING HGI
lioo MIXING HGI
1700 MIXING HGT
2100 MIXING HGT
1100 MIXING HGT
I7oo MIXING HGI
2100 MIXING HGT
1100 MIXING HGT
1700 MIXING HGT
2100 MIXING HGI
lioo MIXING HGT
1700 MIXING HGT
2100 MIXING HGT
1100 MIXING HGT
1700 MIXING HGI
2100 MIXlNU HGI
1100 MIXING HGT
i/oo MIXING HGT
2300 MIXING HGT
lioo MIXING HGI
l too MIXING HGT
2100 MIXING HGT
1 100 MIXING HGT
1 700 MIXING HGT
2100 MIXING HGI
1100 MIXING HGT
1700 MIXING HGT
150
920
1891
125
1698
20*8
126
16)6
2229
329
50
1554
555
1641
1760
202
1611
1917
91
1616
2400
146
1662
1737
222
1268
1205
218
1132
1127
711
1092
1569
265
1169
1405
306
1795
1655
S04
1030
1166
272
752
1/71
410
1116
1099
197
618
1072
116
1922
2111
•SI
1559
1647
W
1619
B-4
-------
APPENDIX C
AREA AND POINT SOURCE EMISSIONS OF
HYDROCARBONS AND NITROGEN OXIDES
(1973 inventory as supplied by the Metropolitan Washington Council of
Governments. Area emissions are by Policy Analysis Districts.)
C-l
-------
Table C-l. POINT SOURCE EMISSIONS OF NITROGEN OXIDES
MrylMd
coordinate!,
woe, rn
7182*7
'•5390
7995/1
7*94/1
•03303
799382
7»4560
7465S4
•1230«
799379
7182S6
7102S6
•12300
*932S3
710240
79/577
•1250«
7975/7
7993/9
7991/9
/162&6
• Mi8/
M02S6
79/377
wosob
*«OS05
•125HO
»902b»
/H509
7fcl309
729515
731521
•10453
•10453
7714*4
• 00401
• 00401
747372
•i*S»«
•|0«*J
NO,
T/Y x 102
71200
S5250
4630
0257
/b900
24/00
SbOO
VoOO
62600
1200
222000
192000
99/00
1500
205
17000
40500
96000
24070
1200
100100
40000
4/t>300
45000
400300
960/00
114600
157POOO
1633
5266
4700
9000
210
4430
7bO
2100
900
bbOO
340
«20
St«ck
ht.,
ft x 10
210
1520
25SO
2200
1540
1670
1/00
4000
1770
2040
1770
1750
1770
310
470
1780
2410
400
2040
2040
17bO
2000
r/so
1700
4000
4000
2410
4000
400
400
600
bOO
400
7SO
bOO
450
730
235
60*
150
Stack
dU...
ft x 10
500
132
1S7
197
202
22-J
250
2bO
416
300
421
5b2
774
504
126
221
982
6bb
440
440
410
205
704
)/4
40/
795
152
710
216
210
500
500
200
200
1*0
Ibb
96
6
ISO
200
Stack
v«l.,
ft/sec x 10
02
1 1 "
00
1 00
1 05
1 10
1 1 0
90
110
120
1 50
1 50
AS
50
50
1 60
/i
95
120
120
1 50
1HO
150
1 60
Ibb
161}
12S
2bO
iS
4^
r
ST tLlZ HOS*"
31 iLlt HUSH
CtNTHAU r(l HT
CAHHUL HK HT
AKL CT 1N(.IN
Alt* !!»(. IN
HtNNlM. 1
MASH NAVY YD
PUSSUM Pf 5
POSSUM PT 2
OtNNiNG 2
MCH QUAMTICO
MCb OUANI1CO
tiVii Ii2
btN^lNG 4
tiUlt SGI 1-16
MASH NAVY YD
MASH NAVY YD
POSSUM HI 1
SOL MAS HC 1
POSSUM PI a
tiUll 5-6
D1CKLHSUN 2
UICKEKSUN 1
ritNIVlNlt 3
CHALK PT
FONT btLVUl«
FUHt UttVUlK
LUHfutv rtkFUKM
LOHTO'M HEKOHM
NAV URl) LAN
NAV OMU LA0
N1H BLlHtSUA
CATHOLIC U
CATHOLIC U
NAT AIHPOHT
ANO«t"S AtB
i^AV UNO LAM
C-2
-------
Table C-l (continued). POINT SOURCE EMISSIONS OF NITROGEN OXIDES
Maryland
coor4i»atM ,
WM, yyy
713249
710240
**54S5
7**5i6
772579
7/2379
•30436
•J4354
•1*354
•3*354
•14446
•44446
•1043J
773425
771424
77*392
7»**67
••1374
713249
W389
7«*577
7«*57/
•30436
717252
730314
7«*37/
•10436
7»J46J
7*1560
7***98
741416
7**401
79*401
•••302
7»»3««
7M3S5
•0137V
79439B
7*1416
7M555
NO
T/Y x 102
9660
2013
4500
3600
3300
400
1660
220
9B97
8245
2150
100
3SO
25850
1VOOO
seso
4290
2H1S
11340
14600
917S
IttibO
37bb
BOO
BOO
917b
130
36600
llblO
6410
I3^oo
4140
730
bOOO
90
611400
1410
7020
b300
IBblOO
Stack
ht.,
ft x 10
770
470
600
4BO
360
11SO
400
ISO
400
750
750
1250
920
1750
750
500
400
600
900
1500
700
700
1750
1430
1400
700
2250
860
530
927
1500
1850
1750
1250
927
1090
350
1280
1500
1090
Stack
diaa.,
ft x 10
50
30
45
30
40
40
40
40
40
40
45
35
30
40
40
5u
40
50
60
49
40
40
40
60
70
40
40
107
45
95
10
90
90
80
42
80
15
50
70
BO
Stack
vel.,
ft/eec x 10
200
500
1U9
ie/
400
62
iOO
30U
300
20U
130
100
200
200
500
2/0
315
200
200
190
530
630
30U
100
232
/70
300
100
560
124
229
75
75
154
191
400
400
512
229
385
Stack
temp. ,
F x 10
3630
4500
3240
5400
5000
3500
4000
4000
5000
5000
5300
6000
5000
4000
3300
3050
UOOO
40UO
i500
4500
5760
5900
UOOO
4000
5500
6110
4000
6000
6000
5000
5550
5B20
49UO
U400
2000
2500
«000
5000
5550
3500
Source name
MCB UUANT1CO
MCB UUANUCU
lb* MANASSAS
FORT btlVUIW
FU*T MYtK
FOHT MYtW
A&RIC wts cr
ANOHE.NS Afb
ANOKErtS Afti
ANO«t«5 AK8
WIN PIU CUHH
M1IM H1U tUHP
NAV UHU L»b
IMAT NAV MO Cl
MM BElMtSU*
G£UW&£IUrtiN U
BOLL INC. AKtt
ANACOSI1A MS
MCH UUANTICU
INASM TtHM CU
PtNTAliON PP
PtNTAOON PH
AGWIC HtS CT
MCb UUAMFiCO
LUMlUN HtFUHM
PfeNTAGUN PP
AC.HIC HtS CT
*c MUN INC IN
NAVAL Ktb L»B
MASH HOSP CT
WALT KttO AMC
US SOLD HljMt
U3 SOLD HUMt
DC OtM "JSP
WASH HOSP CT
POTOMAC 3-5
ANACOSUA KS
HOWARD UNiV
MALT RttO AMC
P01UKAC 1. 2
C-3
-------
Table C-2. AREA SOURCE EMISSIONS
Planning
district
i
2
3
4
S~
6
101
102
103
104
105
106
107
1AI
131
ia>
tfl
ape
20 f
Mi.
»3
204
MS
CO6
B»7
2*8
•09
231
ait"
293
KM
2M
2M
237
300
301
30 1
303
304
309
'316
307
308
309
33 •
•33
~J5*
339
334
337
HC emissions,
tons/6-9 a.m.
0.4014
0.5236
0.6095
0.3259
0.2983
0.389?
0.3214
0.3488
0.5355
•.4342
0.4016
0.1617
0.4294
.0.1 48j?
0.6019
0.3329
0.3749
0.6165
0.9*73
0.8347
0.7671
0.5404
•.5757
•.2790
O.T843
0.3413
0.5441
•.67T2
•.7532
0.1718
•.3502
0.650*
0.1212
0.1795
0.3011
0.34)74
-------
Table C-2 (continued). AREA SOURCE EMISSIONS
Planning
district
HC emissions,
tons/6-9 a.m.
NO emissions,
tons/6-9 a.m.
Area,
acres
»«_
411
_41?
413
414
415
4i«L
'421
_422
423*
4*4_
4*8
4*6
42*7
428
429"
442_
"443
484
488
496
487
Ml
M*
JU-
JU.
81*
8*4
•*•
tMt
«n
M?
0.6848
4*74.00
0.7625
1.3678
0.8170
0.7220
0.7589
1.1715
1.4620
1.9874
1.4340
1.2093
1.2880
0.9663
1.1047
0.3760
1..2423
0~.3320
8.899*
ij.spos
1.2474
0.7111
0.4905
0.72 35
0*614?
0.8648.
~»i*367
0.94*8
_«_••«*
0.1448
JsiTJ?*
8.1441
q.oj_ie
'•'.6734
1.6628
9.4 T«4
0*4834
0,4679
jO.7625
0*6 167
0.4764
0.4905
Q, 8.636
0.7812
O.S7PJ5
1.1596
1.1238
0.7530
0.7695
0.6142
O.75O2
0.1*338
0.7758
O.I 424
O.O1M.
0.3*81
0.9S26
0.7983
0.4248
0.6223
0.5297
0.39B6
0.514*
6.3216
O.I 80*
0.3674
0.1088
0.3917
0.04*5
0.OO23
0.3128
.0.«»*73_
0.6844
0.369ft
o.aatr
0.25*4
0.4
C-5
-------
Table C-2 (continued). AREA SOURCE EMISSIONS
Planning
district
614
6(5
616
621
623
624
628
J*«
6*7
«**
6t¥"
691
693
654
68 R
69*
697
71 1
712
?•*_
™*
791
799
754
799
79 6~"
797
766"
7*7
771
m
7T»
911
•>•
•JlT
•fJL
•»•
*•*
M4~
•67
irT
9T»
•74
975_
HC emissions,
tons/6-9 a.m.
0.9483
0.650S
0.3901
0.99?2
0.7456
0.7168
0.9302
0.2699
0.1802
0.2999
0.1326
0.4133
6.9938
0^5750
0.6234
0.1726
0.1986
O.O36f
0.2M9
1.1014
0.0764
0.1534
6.O743
0.1379
0/336?
0.3716
'0.3C37
0.3028
•.286*
0.2246
0.8420
**9*««
V.OJSO
8.0180
9.0190
"o.o"Js4
OrOJ^34
•.01 10
0.0189
0. 1 079
0.0394
O.Y496
J..03M«_
V.017ir
0.0221
NO emissions,
tons/6-9 a.m.
0.4207
0.452?
0.2730
0.8204
6.5612
0.4958
O.4798
0.2197
0.1200
0.2974
0.107-S
0.1339
0.6714
0.3107
O.4284
O.I 279
0 . 1 497
O.0204
0.1244
0.9722.
0.0595
..?•!*??
0.0756
0.1348
0.4253
0.3688
0.3026
0.1644
0.2814
0.1642
0.7O78"
0.4?62.
0.3129*
0.01J5
0.0088
0.0195
6.0309
O.JJ326
0.0097
0.0191
0.0656
0.0271
0.0709
0.0123
0.01*9
0.0240
Area
acres
14B37.
J41P9.
15289.
0365.
6797.
2I7P9.
19043.
22382.
1B90I .
14381.
7043.
11242.
16915.
_10321 .
^299.
1 7763 .
i?681.
17200.
18802.
1JT199.
8283.
14452.
" 8265.
16342.
2010O.
19782.
16420.
16512.
7»S49.
192OO.
7456.
44305.
124*0.
2088.
4O240.
31065.
5O490.'
64919..
•594.
77775.
194111.
92259.
18707.
70240.
27142.
42846.
C-6
-------
APPENDIX D
CHARACTERISTICS OF MONITOR SITES
These written comments were received from local agencies following dis-
cussions concerning possible local influences on oxidant measurements.
D-l
-------
department of Environmental Protection
MONTGOMERY COUNTY, MARYLAND
ROOM 320 • 6110 EXECUTIVE BOULEVARD, ROCKVILLE, MARYLAND 20852
March 30, 1977
Mr. Frank Record
GCA/Technology Division
Burlington Road
Bedford Road
Bedford, Mass. 01730
Dear Mr. Record;
On March 29, 1977 you requested an agency statement concerning
the manner in which the ozone data provided to you for the intersection
of Deer Park Drive and Frederick Road (Highway Route 355) was obtained.
Enclosure (l) provides you with the horizontal dimensions and the
direction of True North. The monitoring facility lies in a depression
at the upper end of the Muddy Branch drainage basin which drains to the
southwest.
The data was obtained using a McMillan Electronics Company Series
1100 Ozone Monitor calibrated using the neutrally-buffered potassium
iodide method and a McMillan 1100A Ozone Generator.
Because monitoring was accomplished next to an intersection,
enclosure (2) is forwarded providing traffic counts for July 26, 1976
at that intersection. It has been observed that the carbon monoxide
level, which is monitored at an adjacent station, rises and falls
with the movement of the traffic at that intersection. The intersection
traffic volume rises during the rush hours.
It should be noted that due to a change in air monitoring policy
by the Department of Environmental Protection, there will be no air
pollution monitoring at this intersection during the summer of 1977-
If I can be of further assistance to you, please keep me advised.
Very>truly yourj
REL:pmd
Robert E. Lee, Chief
Division of Research and Monitoring
Department of Environmental Protection
Encl: (l) Location of Ozone and CO Probes w/respect to Intersection
(2) Traffic movement graphic summary, Deer Park & Fred. Rd. 7/29/76
cc: 10.2.6
1.10.2
D-2
-------
•TATA HIGHWAY ADHINISTRATICN OP MARYLAND
•OREAO OP TRAFFIC ENGINEERING
TRAFFIC MOVEMENT GRAPHIC SUMMARY
.j> '•.
•-14-TS
D-3
-------
Mta
e.
/* t«» »»«
Wtofter
^
Conpllrt tgr.
Cflflffl
TRAFFIC MOVOCKT SUMMARY TABLE
Hem Cartel 7a«v> •
T<*m_£W
O
l
•P-
Rt» Kartk
8-9
O-H
« B-i
1-2
•a-s
4-5
2.1
r?
n
s
7V)
37?
3?
-w,
17
Ho
ir
Ttat
•sn?
MX1
Mr.M
Swift
101
1-75
MHS
Jfi2
JzCL
Tot
t-<- P/^rV Or
FhmEoct
UH7_
010.
tu
4?
,7.
'1
21
4O
**
Tot
106
\t>!
17
^f
^bt«
, Pa r t
From V,<»st
Crontf
MA
HO
ST.
"VO
70
TL
"bl
"MO
H3Hiv,Hl5
tlO-17-iQI
1-35'?
I40H
I3M1
ITS'
-------
A V V
D-5
-------
NEIL SOLOMON. M D
SECRETARY
DEPARTMENT OF HEALTH AND MENTAL HYGIENE
ENVIRONMENTAL HEALTH ADMINISTRATION
P.O. BOX 13387
201 WEST PRESTON STREET
BALTIMORE, MARYLAND 21203
PHONE • 301-313- 3460
March 30, 1977
DONALD H NO
D I R t_' C TOW
Mr* Frank Record
GCA/Technology Division
Burlington Road
Bedord, Massachusetts 01730
Dear Sir:
As per our conversation of this morning, Included herein Is the Information
requested regarding locations of our four air monitoring stations in the
metropolitan Washington area.
There are four AIRMON remote monitoring stations in the subject area.
of these stations are located in Prince George's County and they are desig-
nated as Sultland #03 and Cheverly #04. Similarly, there are two stations
in Montgomery County and they are designated as Argyle/Sllgo #05 and
NIH/Bethesda #06* Each of these remote stations is a small 8 x 16 feet in
plot size building with sampling probe opening approximately 13 feet above
ground level*
Sultland #03 is located on the U*S. Census Bureau property in a field off
of Sultland Road (Route #218), Suitland Road runs north and south; and
the remote station is located approximately 170 feet west of this road,
I should also note that it is not a heavily traveled road. There are
no other similar roads within 500 feet of the station*
Cheverly #04 is located on the property of the Cheverly Community Park,
i*e*9 Town of Cheverly property* The nearest road is John Hanson
Highway (Route #50); and the station is directly west of the road at this
point* The probe opening is approximately 80 feet from the edge of this
highway} however, I should note that the highway is lower than the
station and that there is a steep bank between the highway property and
the property on which the station is located*
Argyle/Sligo #05 is in the Silver Spring area of Maryland. It is located
on the Argyle Sligo Recreation Center* To get into this property one comes
off Forest Green Road through a driveway to the back part of the property
D-6
-------
page 2
Mr. Frank Record
where the station is located* Forest Green Head is a residential street,
and the station is over 500 feet due south of Forest Green Road, However,
the property is bounded by the Baltimore/fashington Expressway (Route #495)
along its southern property line; and the station probe is within 30 to 50
feet from the edge of Route #495. There is a steep embankment, and the
station sits up on the level part of said embankment. As you can see, the
station is due north of this heavily traveled highway,
NIH/Bethesda #06 is located on an old golf course of the National Institute
of Health property, which is a large government complex whose main entrance
is off of Georgia Avenue, The rear of the property is bounded by Roosevelt
Street, The station is more than a thousand feet south of Georgia Avenue
and more than 250 feet north of Roosevelt Street*
Of the four stations,we believe that the photochemical oxidant data
generated at our Suitland #03 and NIH/Bethesda #06 stations are not in-
fluenced by vehicular emissions* Similarly, we believe that the data
generated at our Cheverly #04 station is not influenced to any signifi-
cant amount by said activity* The data generated at Argyle/Sligo #05,
we believe, is definitely affected. We have noticed the effect of nitric
oxide scavenging* Also, even though we are measuring nitrogen dioxide by
a now not considered appropriate method analyzer, we have observed that
the nitrogen dioxide levels at this station tend to be higher than those
at our other stations* I, therefore, would caution the use of photo*.
chemical oxidant data generated at Argyle/Sligo #05 in your report.
In closing, I hope that this is the information you desired and that it
will be of value to you* I would appreciate receiving a copy of this
report if you can supply same*
Very truly yours,
Robert H* Beman, Chief,
Division of Air Monitoring
Bureau of Air Quality
and Noise Control
cc: George P, Ferreri
Doug Proctor
RHBspmf
D-7
-------
FAIRFAX COUNTY HEALTH DEPARTMENT
AIR POLLUTION CONTROL
4080 CHAIN BRIDGE ROAD
FAIRFAX, VIRGINIA 22030
April k, 1977
AIH POLLUTION CONTROL ~ PHONE: 691-2541
Dr. Frank Record
GCA Technical Division
Burl ington Road
Bedford, Massachusetts 01730
Dear Dr. Record:
This is in response to your telephone request for information con-
cerning the physical and geographical location of our Continuous Monitoring
Stations and road networks In the immediate vicinity.
Seven Corners
The Seven Corners station Is located near the SW corner of the roof parking
area of a 2-story department store. The grade north of the building is
slightly higher than roof level. Parking on the roof is principally by
store employees; transient (customer) parking is principally south of
building. There are 3 major traffic arteries in the vicinity. Wilson
Blvd. (17,000 vehicles per day, 1975) is 1500 ft. north, Route 50 (41,500
veh/da) is 350 ft. southwest and Route 7 (31,000 veh/da) is one-half mile
southwest. These routes intersect approximately 0.7 miles WNW of the
station. The intersection is surrounded by commercial development that
extends outward some 0.4 miles between Routes 50 and 7. A mixture of
high-rise, low-rise and single residential occupies all non-commercial
areas.
Enqleside
The Engleslde station is located on flat terrain 80 ft. NW of a major
traffic artery (Route 1) that is lined on both sides by nearly continuous
strips of small business establishments. An oil-heated school is across
the highway, and the remainder of the area is occupied principally by
single-family residences. Traffic on Route 1 averaged 24,000 veh/da
in 1975. A small parking lot 50 ft. west of the station contains a
gasoline pump used only for police vehicles.
Massey
The Massey station is located adjacent to and slightly above a limited
access police parking lot that contains a gasoline pump. Lot grade is
somewhat depressed, which may reduce ventilation during periods of at-
mospheric stagnation. Nearest major highways are Route 236 (26,000 veh/da)
1000 ft. to the north, and Route 123 (15,000 veh/da) 1100 ft. east. Develop-
ment is single-family residential south and west of the station; office and
limited commercial north and east.
D-8
-------
Dr. Frank Record
P<-ge 2
April 4, 1977
Lewinsvl1le
The Lewinsville station is located on the edge of a police parking lot in
open and slightly elevated terrain. A gasoline pump is approximately 250
ft. away. There are no developments in the immediate vicinity, but scat-
tered single-family dwellings are south and east; extensive office-type
development is 0.7 miles west, and a major shopping center is 1,5 miles
west. Route 123 (32,000 veh/da) is 260 ft. south of the station, and
Lewinsville Road (10,000 veh/da) intersects Route 123 ^50 ft. west. The
Capital Beltway (82,000 veh/da) passes 0.6 miles WNW of the station.
Note: Traffic data are based on counts made during C.Y. 1975.
Sincerely,
Daniel G. Helms, Director
Air Pollution Control Division
DGH/slp
D-9
-------
GOVERNMENT OF THE DISTRICT OF COLUMBIA
DEPARTMENT OF ENVIRONMENTAL SERVICES
ENVIRONMENTAL HEALTH ADMINISTRATION
WASHINGTON, D. C. 2OOO2
April 5, 1977
Dr. Frank Record
GCA/Technology Division
Burlington Road
Bedford, Massachusetts 01730
Dear Frank:
Our ozone monitoring sites were chosen to be as free from automotive
traffic as possible to avoid a problem with nitric oxide removing
ozone from the air. The discussion given below rates the sites
from best to worst in the way they fulfill this.
(1) Melvin Sharpe Health School
This station is set well back from a street used
primarily for rush hour activity.
(2) West End Library
This station is on the corner of two lightly
travelled streets and is about a block away
from a heavily travelled but wide street.
(3) Cleveland Park Library
This station is on a heavily travelled street
but the probe is elevated and set back from
the street.
D-10
-------
- 2 -
(4) CAMP STATION
There is a lot of traffic on this street, and
since last summer, considerable amount of idling
of taxicabs across the street.
(5) D. C. General Hospital
Although this site is set well back from heavily
travelled streets the probe is quite long.
I hope this will be of help to you.
Sincerely,
ENVIRONMENTAL HEALTH ADMINISTRATION
BAILUS WALKER, JR., PH.D., M. P. H.
Administrator
Herbert T. Wood, Ph.D., Chief
Air Monitoring Division
Bureau of Air and Water Quality Control
D-ll
-------
APPENDIX E
TRAJECTORIES
These trajectories were calculated using the trajectory subroutine of the
DIF KIN model. Hourly positions are indicated by the sequence of letters,
beginning with A. The calculations were performed so that the trajectory
would pass over a central point in Washington, D.C. at 1400 EST. The
first figure locates the Washington, D.C. "square", the central point
and the ozone monitoring stations. Note that the x and y scales of the
grid are not identical.
E-l
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Numbered locations are ozone monitoring stations
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-------
APPENDIX F
ADDITIONAL AERIAL SURVEY DATA
F-l
-------
I
ro
NO. 2
ST I9TB 0859-1051 EOT
ALT.~6TOm
ok
o
vu o
O d
o
d)
SPIRAL
NQI
,-08=
08=47 EOT
SPIRAL
N0.3
TRACKING POWER PLANT
PLUME-
SPIRAL
NQ4
ELOPSED TIHE (MIN)
t
A2
n52l5SiJ 4(5so1§3 T^ §3 §3 Tfto ^o flo"
Figure F-l. Ozone concentrations during horizontal sampling, Flight No. 2
-------
1
FLIGHT NO. 2
18 AlKWST I97C, 0899-1091 EOT
.T.-6TO w
yP-08'
/JL
A, 6 C, C2 0 E
1 H 4 U •
ee
. o
V SPIRAL 'o SPIRAL
^ NO. I . NO 2
'47 COT
TRACKING POWER
PLANT PLUME
(MAX*9»ppb)
J
e
e
9
a SPIRAL ° SPIRAL
N0.3 »o» N0.4
e a
o o
»-, Co 0
e
e
«—»r
10 2Q 30 ID
ELAPSED TINE (MINI
BTj"~*W"
TIB
Figure F-2. Nitrogen oxide concentrations during
horizontal sampling, Flight No. 2
F-3
-------
ABC
ill
OE,
M
F C, H I J K. K_
iiiii? r
L, M
r i n
SPIRAL
NQ4
,,-oesct
Y BEGIN
NT
BEGINS
SPIRAL
NQ5
ELRPSED TIME (HIM)
Figure F-3. Nitrogen oxide concentrations during horizontal sampling, Flight No. 3
-------
NO. 4
It AJtUST I97«.09f2-ll34 EOT
ALT ~ 660m
ui
o
i
in
£°.l
s°
o
o
dD
e
oe° J9
«.°
s>
SPIRAL $> y«» SPIRAL
NO. I
0906 EOT
t t
A B
ELflPSED TIME IHIN)
•*
*o
WO. 2
t t
C 0,
oo SPIRAL
" N0.3
3
SPIRAL
NO. 4
t t
G H,
t !
H2 I
DESCENT
BEGINS
6(5
1^0 Tfo Fft ilo"
150
Figure F-4. Ozone concentrations during horizontal sampling, Flight No. 4
-------
FLIGHT NO. 4
WAMUST 1976,0922-1134 COT
SMUt.*2. LOCATION *9
a •
efl
r T T < s e 7 a 9
FLIGHT NO 4
a
NOX IPH)
-r—rr
Figure F-5. NO and NO profiles, Flight No. 4
F-6
-------
T L V A
FLIGHT 6
20 AUGUST 1976
06H2-OI-43 EOT
ALT. ~IIOOm
JOEL AWAKI
Figure F-6. Sampling track during Flight No. 6. Ozone
concentration in ppb is shown at selected
points, followed by time in parentheses.
Transport wind at flight altitude is shown
by dashed arrow (Concentrations have not
been adjusted for final calibration.)
F-7
-------
FLIGHT NO r
20 AUGUST 1976,1604-1803 EOT
SPMAL 02, LOCATION if 4
I I
§
a a e
d)r r
TlHftMTlMf C
12 IS
27
FCIOHT NO r
10 «UGU$T l*Tt M04 -H03 (OT
I***!.*t. LOCATION*4
I. II I.
«. W 1.1
0.105T||
Figure F-7. Temperature and ozone profiles, Flight No. 7
F-8
-------
TJ
I
VO
FLMHT 9
IS AUGUST 1976
M'I2-09<3O COT
MT. ~T20; 340 •
87(0*05)
~I40O ft
(0842)
~ 770 fl.
END
77(0* IS) ~400ft.
Figure F-8. Sampling track during Flight No. 9. Ozone concentration in ppb is
shown at selected points, followed by time in parentheses. Trans-
port wind at flight altitude is shown by dashed arrow
-------
PENNiVLV AMI A
ru«MT I* " " " M
28 AUOUST I9TS
IS'OI-16'44 EOT
ALT. ~IMO J 20001ft
^»
v\
A * » L A N \\0
(IB'Ml
Figure F-9.
Sampling track during Flight No. 13. Ozone
concentration in ppb is shown at selected
points, followed by time in parentheses.
Major wind shift with height is shown by
transport winds at 1000 and 6000 feet
F-10
-------
14
M AlMUiT ltT»,
OJ'00-0«'50E
ALT. 610-IS'O"
»E«\NSYLVA«II t
Figure F-10. Sampling track during Flight No. 14. Ozone concentration
in ppb is shown at selected points, followed by time in
parentheses. Transport wind at flight altitude is shown
by dashed arrow
F-ll
-------
C900-O6SO COT
NJ
--ISOOi--
-I |~CC»||~WO| L
inrir
6K>m
\-amm
-eeom
e
-02 32 EOT
53 ?5 iJ~
ttflfsto TIDE mim
1 1
i
i Joitoito\tS iff"
190
Figure F-ll. Ozone concentrations during horizontal sampling, Flight No. 14
-------
Table F-l. AVERAGE CONCENTRATIONS OF OZONE AND NITROGEN OXIDES
WITHIN A 300 M DEEP LAYER (650-950 MSL) ABOVE STUDY
AREA
Flight
number
1
2
3
4
5
6
7
8
9
10
Date
8/17/77
8/18/77
8/18/77
8/19/77
8/19/77
8/20/77
8/20/77
8/21/77b
8/23/77
8/23/77
Time,
EDT
11:00
09:12
09:35
10:01
10:24
16:40
17:05
17:44
18:04
18:37
09:47
10:11
10:41
11:05
16:18
16:38
17:04
17:27
06:26
06:51
07:03
16:15
16:39
17:20
17:39
12:01
12:26
12:44
13:12
13:38
06:28
16:28
Spiral
location
1
2
3
4
1
4
1
5
6
2
8
9
7
10
8
9
7
10
7
4
4a
7
4
9
8
7
11
12
1
13
7
7
Concentration, ppb
03
38
42
41
42
46
99
94
85
99
108
40
52
43
45
76
81
101
104
67
70
78
118
100
91
89
87
105
94
78
113
64
64
NO
—
3.6
0.9
2.5
2.1
2.1
1.0
1.1
1.2
1.4
7.5
3.0
13.3
8.8
2.1
2.3
4.5
3.6
2.6
—
1.4
8.0
2.5
2.1
3.1
1.4
1.6
0.25
0.24
(0.4)
0.06
0.05
NOx
—
—
—
—
—
—
—
—
—
—
—
8.0
35.4
21.4
9.1
10.6
32.2
25.2
10.6
16.5
14.4
46.4
16.7
14.2
14.1
5.5
9.4
3.6
2.5
4.0
1.3
1.2
At ~1140 m
Concentrations decrease rapidly with height
F-13
-------
APPENDIX G
SUMMARY TABLES OF HYDROCARBON
AND CARBON MONOXIDE DATA
(RTI Field Data Collected Daily
from 3 July 1976 Through
1 September 1976)
G-l
-------
Table G-l. SUMMARY OF HYDROCARBON AND CARBON MONOXIDE
DATA FOR SUNDAYS
SITr *16
SITE 015
SITE #4
SITS *2
SITE #12
SIT;
;E CONC^TKATION IPPMI AVERAGE KATIO
INTERVAL THC CH-» NMHC Co NMHC/THC NMHC/CO
Tnc/cn
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
TIM? INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
C3-06 P.M.
TIMJ INTERVAL
06-OV A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
TIME INTERVAL
06-09 A.M.
09-1 2 A.M.
12-03 P.M.
03-06 P.M.
1.96
1.88
1.95
1.64
AVE-U
THC
2.40
t.30
2.40
1.71 n.2-,
1.54 ->.i4
l.<»6 0.49
1.39 0.25
1.31
1 . 1 0
0.84
i^E CJ'«l.ifMTRATION (PPM)
CH4 NMHC CO
1.67 1.13
1.57 0.83
1.50 0.80
1.57 0.33
1.07
1.00
0.97
1.10
AVERAGE CONCENTRATION (PPM)
THC CH4 NMHC CO
2.50
2.4*
2.22
2.30
AVE«<
THC
2.15
1.30
1.73
1.67
THC
2.26
2.10
c.07
1.87
THC
2.10
1.92
1.53
1.59
1.75 0.75
1.57 0.35
1.52 0.70
1.52 I. 00
1.20
1.14
1.06
f .11
0.15
r..20
0. 13
NMHC/THC
0.3d
0.34
C.35
0.34
NMHC/THC
0.29
0.34
0.30
0.45
i.",r CONCENTRATION (PPM)
CH4 NMrlC CO NMH^/THL
1.65 0.50
1.55 0.24
1.53 0.20
1.53 0.1«»
0.65
0.41
0.50
0.51
iGC CONCENTRATION (HPM)
CH4 NMHC CO
1.66 0.60
1.62 0.43
1.62 0.45
1.60 0.27
0.73
0.75
0.66
0.85
k'i£ CONCENTRATION (PPV)
CH4 NMHC CO
1 . 70 0 . 40
1.54 0.33
1.49 0.04
1.49 0.10
1.02
0.60
0.66
0.60
(•.19
0.12
0.09
0.07
NMHC/THC
0.20
0.17
0.14
N.MHC/THC
0.17
0.18
0.02
0.05
0.19
0.4C
0.35
0.59
AVERAGc KATIO
NMHC/CO
1.03
0.32
0.91
0.75
AVtrtAGL KATIO
NMHC/CO
0.78
0.89
0.38
2.03
AVtKAGt KATIU
NMHC/CO
1.18
2.03
0.35
0.75
AVEHAC.E KATIO
NMHC/CO
1.54
0.68
0.53
0.39
AVEKAG.S KATIO
NMHC/CO
1.01
2.62
0.02
0.29
c.OG
2.52
2.94
THC/CO
2.66
2.43
2^17
THC/CO
2.58
2.46
3.51
3.35
THC/CO
b.61
9.43
6.43
6.73
THC/CO
5.44
3.72
3.64
2.86
THC/CO
4.14
7.90
3.04
3.53
G-2
-------
Table G-2. SUMMARY OF HYDROCARBON AND CARBON MONOXIDE
DATA FOR MONDAYS
SIT.- #16
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
13-06 P.M.
AVERAGE CONCENTRATION (PPM)
THC CH4 NMHC CO
.-'.25 1.71 0.54 2.76
1.97 1.50 0.^7 1.60
1.93 1.50 0.43 1.63
1.91 1.46 0.46 2.09
0.19
0.21
AV6RAC,1: RATIO
"*»HC/CO
C.5S
0.23
0.21
THC/CO
0.35
^.29
1.20
0.94
SITr #15
INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
^3-06 P.M.
Ay/E^AGS CONCENTRATION (MfM) AVERAGE RATIO
TrIC CH4 NMHC CO NMHC/THC NMHC/CO
2.4!? 1.60 0.8b 1.52
2.38 1.67 0.70 2.72
2.13 l.AO 0.57 1.38
2.87 1.52 1.35 2.07
G.33
0.29
0.26
0.69
0.38
0.50
THC/CO
1 .37
1.31
1.33
1.72
SITE »4
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTKATION (PPM) AVtRAGE RATIO
THC CH4 NMHC CO NMHC/THC NMHC/CO
2.67 1.63 1.03 2.17
2.40 1.57 0.83 1.96
2.30 1.56 0.74 1.70
2.39 1.57 0.81 2.10
0.33
0.34
0.31
0.32
0.56
0.88
0.56
0.44
THC/CO
1.38
2.18
1.88
1.45
SITE »2
" INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) AVtRAG^ RATIO
THC CH4 NMHC CO NMHo/THC NMHC/CO
1.84 1.60 0.24 0.84
1.85 1.55 0.30 0.64
1.69 1.56 0.13 0.60
1.80 1.57 0.23 0.73
0.11
0.14
0.07
C.10
0.21
0.48
0.26
0.19
TriC/CO
3.74
4.06
-------
Table G-3. SUMMARY OF HYDROCARBON AND CARBON MONOXIDE
DATA FOR TUESDAYS
SITE »16
TIH5 INTERVAL
06-09 A.M.
19-12 A.M.
12-03 P.M.
03-06 P.M.
E CONCENTRATION (PPM)
CH4
NMHC
2.25 1.60 3.65 2.84
1.99 1.52 0.46 2.34
2.01 1.50 0.51 2.15
2.0
-------
Table G-4. SUMMARY OF HYDROCARBON AND CARBON MONOXIDE
DATA FOR WEDNESDAYS
SITb *16
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) AVERAGE RATIU
THC CH* NMHC co NMHC/THC NMHC/CJ
2.19 1.64 0.54 2.63
1.09 1.5? ".51 2.23
1.97 1.50 0.47 2.09
^.16 1.5-* 0.61 3.06
0.24
0.23
0.23
0.26
0.30
0.29
0.26
0.20
THC/CO
1.54
1.43
1.08
0.73
SITE »15
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATIJN (PPM) AVfcRAGE RATIO
THC CH4 NMHC CO NMHC/THC NMHC/CO
2.6* 1.53 1.04 3.20
2.53 1.56 1.02 2.24
2.58 1.52 1.06 1.54
2.52 1.50 1.02 2.16
0.39
0.38
0.38
0.39
0.38
0.46
0.72
0.-+9
THC/CO
1.00
1.24
1.74
1.24
SITE *4
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) AVtRAGE RATIO
THC CH4 NMHC CO NMHC/THC NMHC/CO
2.87 1.59 1.29 2.46
2.44 1.66 0.77 1.65
2.39 1.49 0.90 1.00
2.57 1.51 1.06 1.27
0.38
0.30
0.36
0.36
0.54
0.59
1.02
0.81
THC/CO
1.27
1.77
2.64
2.12
SITE «2
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) A^EKAGc ,
-------
Table G-5. SUMMARY OF HYDROCARBON AND CARBON MONOXIDE
DATA FOR THURSDAYS
SITE #16
INTERVAL
06-09 A.M.
09-12 A.M.
U-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) AVERAGc RATIO
THC :H4 NMHC CO T1HC/TrlC NMHC/CO
2.60 1.66 0.94 3.29
2.26 1.55 0.71 3.02
2.i7 1.57 0.70 2.80
^.60 1.63 0.97 4.61
0.33
0.30
0.29
0.36
''.23
0.29
THC/CO
0.80
0.77
0.88
0.58
SITE #15
TIM: INTERVAL
06-09 A.M.
09-12 A.H.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) AVERAGE RATIO
THC CH4 NMHC CO NMHC/THC NMHC/CO
<:.76 1.56 1.20 3.36
2.62 1.50 1.12 2.36
2.40 1.50 0.90 2.00
2.3a 1.57 0.80 3.42
0.42
0.42
0.37
0.33
0.39
0.54
0.52
0.31
TriC/CO
0.90
1.25
1.37
0.87
SITE #4
TIM: INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) AVERAGE RATIO
THC CH4 NMHC CO NHHC/THC NMHC/CO
2.47 1.60 0.87 1.74
2.56 1.51 1.04 1.23
2.34 1.50 0.84 1.34
2.24 1.50 0.74 1.69
0.30
0.39
0.34
0.31
0.52
0.85
0.77
0.47
THC/CO
1.72
2.24
^.13
1.57
SITc #2
TIME INTERVAL
06-09 A.M.
09-12 A.H.
12-03 P.M.
03-06 P.M.
AVtRAGf: CONCENTRATION (PPM) AVERAGE RATIO
THC CH4 NMHC CO NMHC/THC NMHC/CO
2.24 1.59 0.66 0.97
2.12 1.60 0.52 0.78
1.97 1.63 0.34 0.71
1.77 1.54 0.23 0.81
0.24
0.19
0.14
0.12
0.61
0.55
0.3J
THC/CO
2.35
3.25
3.87
2.87
SIT; #12
TIM?
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION IPPM) AVrkASE RATIO
THC CH4 MMHC CO NMHC/THC NMHC/CO
2.01 1.60 0.41 1.04
1.89 1.65 C.24 0.81
1.93 1.54 0.39 0.69
2.06 1.64 0.41 0.90
0.19
0.12
O.lB
0.17
0.41
0.35
0.47
0.41
THC/CO
2.33
2.77
3.08
<:.59
SITE «9
TIME INTERVAL
06-09 A.M.
09-17 A.H.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) AVcRAGc KATIO
THC CH4 NMHC CO NMHC/THC NMHC/CO
2.00 1.63 0.32 1.15
1.73 1.52 0.2T 1.03
1.70 1.60 0.10 0.36
1.63 1.50 0.13 0.90
0.14
0.14
0.05
0.07
0.32
0.23
0.09
0.12
THC/CO
1.98
1.96
2.33
2.20
G-6
-------
Table G-6. SUMMARY OF HYDROCARBON AND CARBON MONOXIDE
DATA FOR FRIDAYS
:IT= #16
TIM'
06-09 A.M.
09-12 A.*.
12-03 P.*.
n3-06 P.M.
AVERAGE CONCENTRATION (PPM) AVERAGc kATIO
THC CH4 NMHC CO NMHC/THC NMHC/CO
2.37 1.64 0.73 3.63
2.30 1.61 0.69 3.20
2.02 1.51 P.51 2.34
2.55 1.86 0.69
-------
Table G-7. SUMMARY OF HYDROCARBON AND CARBON MONOXIDE
DATA FOR SATURDAYS
SIT; »16
TIH? INTERVAL
SITE *15
;IT=
SIT: *2
"ITS »12
SITE #9
AV=*Aj= CJNCENT44TUN (PPM) AVcRAGt RATin
THC :H4 N*HC co NMHC/TH: NMHC/CO
THC/CO
06-09 A.M.
^-12 A.M.
12-C3 P.M.
03-06 P.M.
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-C3 P.M.
03-06 P.M.
THfc INTERNAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
TIM = INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-C6 P.M.
TTM= INT=:WAL
06-09 A.M.
09-12 A.M.
1?-03 P.M.
03-06 P.M.
THE INTERVAL
r'j-09 A.M.
f*-\2 A.M.
12-03 P.M.
03-06 P.M.
2.07
2.11
1.95
1.37
AV^A
THC
2.93
3.30
2.23
2.6"!
AV5TA
THC
2.45
2.72
2.57
2.45
1.59 0.49 1.37
1.63 0.4-y 1.9O
1.53 0.37 1.6C
1.54 0.33 1.50
GE CrJCiivTRATION (PPM)
CH4 NMHC CO
1.9C 1.C3 2.13
1.30 <:.00 1.97
1.73 0.50 1.90
1.53 1.10 1.57
,:,£• CJNCiNnATION (PPM)
CH4 NMHC CO
1.75 0.70 1.75
1.65 1.07 1.32
1.60 0.97 1.22
1.57 0.88 0.98
AVERAGE CONCENTRATION (PPM)
THC CH4 NMHC CO
1.36
1. 91
1.75
1.83
AVE-tA
THC
2.30
2.00
1.97
«..30
WE**
THC
2.04
1.30
1.67
1.67
1.65 0.21 0.65
1.52 0.29 0.52
1.57 0.18 0.50
t.57 0.27 0.55
il>c CONCENTRATION (PPM)
C>14 NMHC CO
1.99 0.31 1.39
1.61 0.39 0.77
1.55 C.42 0.72
1.56 0.74 0.86
iGL CONCENTRATION (PPM)
CH4 NMHC CO
1.73 C.31 0.93
1.47 0.33 0.90
1.54 0.13 0.77
1.56 0.11 0.81
r.22
0.2*.
0.13
0.17
NMHC/THC
o.Jb
0.51
0.22
0.40
NMHC/THC
0.27
0.36
0.36
0.35
ixUHC/THC
0.10
0.15
0.09
0.12
NMHC/THC
0.14
C.12
0.20
0.23
NMHC/THC
0.14
0.15
C. 07
0.0->
0.3J
0.40
0.35
0.33
AVtRAGf RATID
NMHC/CO
0.48
1.01
0.29
0.77
WEKAG?. KATIO
NMHC/CO
C.86
1.11
1.07
1.62
AVERAC.5 HATIO
NMHC/CO
1.06
1.18
1.40
1 .48
AVERAC,? RATIO
NMHC/CO
0.39
1.30
1.65
0.99
AVtKAo; KATIO
NMHC/CO
1.45
1.23
r.36
C.35
1.55
1.57
1.68
1.62
THC/CO
1.39
1.96
1.23
1.8
-------
Table G-8. SUMMARY OF HYDROCARBON AND CARBON MONOXIDE
DATA FOR WEEKDAYS
SITE #16
TIM? INTERVAL
3S-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AvEnAi? C;JNC=NT,0
3.93
3.25
SITE »9
TIM' INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PP*J AVERAGE
THC CH4 NMHC CO NMHC/THC NMHC/CU
1.92 1.64 0.23 1.08
1.76 1.52 0.24 0.94
1.71 1.54 0.18 0.75
1.71 1.51 0.21 0.85
3.13
0. U
O.OP
0.1C
0.33
0.40
0.63
0.33
THC/CJ
2.17
2.51
3.97
2.6-
G-9
-------
Table G-9. SUMMARY OF HYDROCARBON AND CARBON MONOXIDE
DATA FOR ALL DAYS
SITS fli
THE INTERVAL
^S-09 A.M.
C9-12 A.M.
12-03 P.M.
0^-06 P.M.
AVERAGE CONCENTRATION (PPM) AVERAGc' RATIO
THC CH4 ' 0.53 2.2^
2.02 1.52 0.51 <:.00
i.13 1.5s 0.56 2.84
C.23
0.25
C.25
0.33
C.2V
0.26
THC/CO
1.17
1.46
1.32
1.15
SITE »15
= INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.*.
03-06 P.M.
AVtRAGt CONCENTRATION (PPM) AVcRAGi: RATIO
THC CH4 NMHC CO NMHC/TnC MMHC/CO
2.73 1.66 1.07 2.78
2.61 1.54 1.03 2.22
2.32 1.54 0.78 1.64
2.58 1.53 1.05 2.11
Ci.38
0.37
0.32
0.39
0.49
0.55
0.56
C.59
THC/CO
1.27
1.43
1.65
1.48
SITE
TIME INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVEKAGE CONCENTRATION IPPM) AVERAGE RATIO
THC CH4 NMHC CO NMHC/TrtC NMHC/CO
2.65 1.67 0.97 2.03
2.45 1.60 0.85 1.42
2.35 1.53 0.81 1.26
2.37 1.55 0.85 1.45
0.34
C.33
0.33
0.34
0.63
C.79
0.80
0.87
THC/CO
1.75
2.19
2.40
2.26
SITE »2
THE INTtRVAt
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVEKAGE CONCENTRATION (PPM) AVERAS? KATIO
THC CH4 NMHC CO VMHC/TriC NMHC/CO
2.01 1.62 0.39 0.90
1.84 1.55 0.29 0.64
1.86 1.57 0.28 0.65
1.81 1.55 0.26 0.69
0.16
0.14
0.12
C.12
0.61
0.68
0.77
0.69
THC/CO
3.63
5.13
5.06
4.45
SITS »12
TIME INTERVAL
06-09 A.M.
-9-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) AVERAGE RATIO
THC CH4 NMHC CO VMHC/THC N.MdC/CO
2.19 1.72 0.47 1.25
1.97 1.62 0.35 0.92
1.95 1.53 0.37 0.74
2.04 1.60 0.44 0.87
0.17
C.17
0.18
0.61
0.68
D.76
C.60
TriC/CO
2.65
3.60
4.12
3.45
SITE
TIM? INTERVAL
06-09 A.M.
09-12 A.M.
12-03 P.M.
03-06 P.M.
AVERAGE CONCENTRATION (PPM) AVERAGE
THC CH4 NMHi. CJ NMrC/THC NMrC/CO
1.95 1.66 0.30 1.06
1.78 1.51 0.27 0.90
T.68 t.53 0.15 0.74
1.69 1.51 0.18 0.81
0.14
0.13
0.07
0.09
0.56
C..74
0.50
O.J3
THC/CO
2.91
3.60
3.83
G-10
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-450/3-77-054
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
Characterization of the Washinqton, D.C.
Oxidant Problem
5. REPORT DATE
October, 1977
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
GCA-TR-77-n-G(l)
9. PERFORMING ORGANIZATION NAME AND ADDRESS
GCA Corporation
GCA/Technology Division
Burlington Road
Bedford. Massachusetts 01730
10. PROGRAM ELEMENT NO.
2AA635
11. CONTRACT/GRANT NO.
68-02-1376
Task Order 27
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, N.C. 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report describes the results of a study to characterize the oxidant prob-
lem in the Washington, D.C., metropolitan area. Emphasis is placed on ambient moni-
toring data on ozone, nitrogen oxides and nonmethane hydrocarbon concentrations
observed during Summer, 1976. Additional data collected during the study and sum-
marized in the report include: surface and upper air meteorological data, aircraft
observations of Oo, NO, NO , S02. and condensation nuclei, and hydrocarbon species
data. Both horizontal and vertical ozone profiles obtained during the two weeks of
aircraft sampling in and around the Washington, D.C., area are presented. Results
of trajectory studies, hydrocarbon composition analyses, and analyses of the ambient
concentration data are summarized in numerous figures and tables. HC and NOX emis-
sion inventories compiled by MWCOG are provided.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Held/Group
Oxidant
Ozone
Hydrocarbons
Washington, D.C,
Air Quality
Emissions
Trajectories
Aerial Sampling
NMHC/NOV Ratios
/\
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
238
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
G-ll
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