vvEPA
United States
Environmental
Protection
Agency
Office of Air Quality
Planning and Standards
Technical Support Division
Research Triangle Park. NC 27711
EPA-450/4-90-002
March 1990
AIR
National Air Quality and
Emissions Trends Report,
1988
Areas Not Meeting the Ozone NAAQS, 1986-88
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EPA-450/4-90-002
\
National Air Quality and
Emissions Trends Report,
1988
Technical Support Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
March 1990
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DISCLAIMER
This report has been reviewed by the Office of Air Quality Planning and Standards,
U. S, Environmental Protection Agency, and has been approved for publication.
Mention of trade names or commercial products is not intended to constitute
endorsement or recommendation for use.
About the Cover: Areas Not Meeting the Ozone Standard During 1986-1988.
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PREFACE
This is the sixteenth annual report of air pollution trends issued by the U. S.
Environmental Protection Agency. The report is prepared by the Technical Support
Division and is directed toward both the technical air pollution audience and the
interested general public. The Division solicits comments on this report and welcomes
suggestions on our trend techniques, interpretations, conclusions, and methods of
presentation. Please forward any response to Dr. Thomas C. Curran, (MD-14) U. S.
Environmental Protection Agency, Technical Support Division, Research Triangle Park,
North Carolina 27711.
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Preceeding Page Blank
CONTENTS
LIST OF FIGURES vii
LIST OF TABLES xi
1. EXECUTIVE SUMMARY 1
1.1 INTRODUCTION 1
1.2 MAJOR FINDINGS 2
Particulate Matter 2
Sulfur Dioxide 4
Carbon Monoxide 6
Nitrogen Dioxide 8
Ozone 10
Lead 12
1.3 SOME PERSPECTIVE 14
1.4 REFERENCES 16
2. INTRODUCTION 19
2.1 DATA BASE 20
2.2 TREND STATISTICS 23
2.3 REFERENCES 28
3. NATIONAL AND REGIONAL TRENDS IN NAAQS POLLUTANTS 29
3.1 TRENDS IN PARTICULATE MATTER 31
3.1.1 Historical Perspective: 1960-88 32
3.1.2 Long-term TSP Trends: 1979-88 . . 34
3.1.3 Recent TSP Trends: 1984-88 37
3.1.4 Effect of Meteorology on Short-term Trends 38
3.1.5 Recent PM10 Air Quality 39
3.2 TRENDS IN SULFUR DIOXIDE 43
3.2.1 Long-term SO2 Trends: 1979-88 43
3.2.2 Recent SO2 Trends: 1984-88 50
3.3 TRENDS IN CARBON MONOXIDE 53
3.3.1 Long-term CO Trends: 1979-88 53
3.3.2 Recent CO Trends: 1984-88 56
3.4 TRENDS IN NITROGEN DIOXIDE 60
3.4.1 Long-term NO2 Trends: 1979-88 60
3.4.2 Recent NO2 Trends: 1984-88 62
3.5 TRENDS IN OZONE 65
3.5.1 Long-term 03 Trends: 1979-88 65
3.5.2 Recent 03 Trends: 1984-88 70
3.5.4 Preview of 1989 Ozone Trends 73
3.6 TRENDS IN LEAD 74
3.6.1 Long-term Pb Trends: 1979-88 74
3.6.2 Recent Pb Trends: 1984-88 ; . 80
3.7 REFERENCES 83
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4. AIR QUALITY STATUS OF METROPOLITAN AREAS, 1988 85
4.1 METROPOLITAN AREAS NOT MEETING OZONE AND CARBON
MONOXIDE NAAQS 85
4.2 POPULATION ESTIMATES FOR COUNTIES NOT MEETING
NAAQS, 1988 88
4.3 AIR QUALITY LEVELS IN METROPOLITAN STATISTICAL
AREAS 89
4.3.1 Metropolitan Statistical Area Air Quality Maps, 1988 90
4.3.2 Metropolitan Statistical Area Air Quality Summary, 1988 ... 98
4.5 REFERENCES . 110
5. TRENDS ANALYSES FOR FIFTEEN METROPOLITAN STATISTICAL
AREAS 111
5.1 AIR QUALITY TRENDS 114
5.1.1 TSP Trends 114
5.1.2 Lead Trends 115
5.1.3 SO2 Trends 116
5.1.4 CO Trends 116
5.1.5 NO2 Trends 117
5.1.6 O3 Trends 118
5.2 REFERENCES 140
VI
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LIST OF FIGURES
2-1. Ten Regions of the U.S. Environmental Protection Agency 24
2-2. Sample illustration of use of confidence intervals to determine statistically
significant change 27
2-3. Illustration of plotting conventions for boxplots 27
3-1. Comparison of 1970 and 1988 emissions 30
3-2. Historical trends in ambient TSP concentrations, 1960-1988 33
3-3. Historical trends in total paniculate emissions, 1960-1988 33
3-4. National trend in the composite average of the geometric mean total
suspended particulate at both NAMS and all sites with 95 percent
confidence intervals, 1979-1988 35
3-5. Boxplot comparisons of trends in annual geometric mean total suspended
particulate concentrations at 1750 sites, 1979-1988. . . 35
3-6. National trend in particulate emissions, 1979-1988 37
3-7. Boxplot comparisons of trends in annual mean total suspended particulate
concentrations at 1491 sites, 1984-1988 38
3-8. Regional comparisons of the 1986,1987,1988 composite averages of the
geometric mean total suspended particulate concentration 39
3-9. Boxplot comparisons of the 2-year change in PM10 concentrations (1987-
1988) at 119 sites with 1988 PM10 air quality at 432 sites 41
3-10. Boxplot comparisons of 24-hour PM10 peak value statistics for 1988 at 432
sites 41
3-11. Regional comparisons of annual mean and 90th percentile of 24-hour
PM,0 concentrations 42
3-12. National trend in annual average sulfur dioxide concentration at both
NAMS and all sites with 95 percent confidence intervals, 1979-1988. ... 44
3-13. National trend in the second-highest 24-hour sulfur dioxide concentration
at both NAMS and all sites with 95 percent confidence intervals,
1979-1988 44
3-14. National trend in the estimated number of exceedances of the 24-hour
sulfur dioxide NAAQS at both NAMS and all sites with 95 percent
confidence intervals, 1979-1988 45
3-15. Boxplot comparisons of trends in annual mean sulfur dioxide
concentrations at 374 sites, 1979-1988. 46
3-16. Boxplot comparisons of trends in second highest 24-hour average sulfur
dioxide concentrations at 364 sites, 1979-1988 47
3-17. National trend in sulfur oxides emissions, 1979-1988 49
3-18. Boxplot comparisons of trends in annual mean sulfur dioxide
concentratio s at 584 sites, 1984-1988 50
3-19. Regional comparisons of the 1986, 1987, 1988 composite averages of
the annual average sulfur dioxide concentration 51
3-20. National trend in the composite average of the second highest
nonoverlapping 8-hour average carbon monoxide concentration at both
NAMS and all sites with 95 percent confidence intervals, 1979-1988. ... 54
3-21, Boxplot comparisons of trends in second highest nonoverlapping 8-hour
average carbon monoxide concentrations at 248 sites, 1979-1988 54
vii
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3-22. National trend in the composite average of the estimated number of
exceedances of the 8-hour carbon monoxide NAAQS, at both NAMS and
all sites with 95 percent confidence intervals, 1979-88 55
3-23. National trend in emissions of carbon monoxide, 1979-1988 57
3-24. Comparison of trends in total National vehicle miles traveled and National
highway vehicle emissions, 1979-1988. 58
3-25. Boxplot comparisons of trends in second highest nonoverlapping 8-hour
average carbon monoxide concentrations at 359 sites, 1984-1988. ..... 58
3-26. Regional comparisons of the 1986, 1987, 1988 composite averages of the
second highest non-overlapping 8-hour average carbon monoxide
concentration 59
3-27. National trend in the composite average of nitrogen dioxide concentration
at both NAMS and all sites with 95 percent confidence intervals, 1979-
1988 61
3-28. Boxplot comparisons of trends in annual mean nitrogen dioxide
concentrations at 116 sites, 1979-1988. 61
3-29. National trend in nitrogen oxides emissions, 1979-1988 63
3-30. Boxplot comparisons of trends in annual mean nitrogen dioxide
concentrations at 194 sites, 1984-1988 64
3-31. Regional comparisons of 1986, 1987, 1988 composite averages of the
annual mean nitrogen dioxide concentration 64
3-32. National trend in the composite average of the second highest maximum
1-hour ozone concentration at both NAMS and all sites with 95 percent
confidence intervals, 1979-1988 66
3-33. Boxplot comparisons of trends in annual second highest daily maximum
1-hour ozone concentration at 388 sites, 1979-1988 67
3-34. National trend in the composite average of the estimated number of daily
exceedances of the ozone NAAQS in the ozone season at both NAMS
and all sites with 95 percent confidence intervals, 1979-1988 68
3-35. National trend in emissions of volatile organic compounds, 1979-1988. . . 69
3-36. Boxplot comparisons of trends in annual second highest daily maximum
1-hour ozone concentrations at 567 sites, 1984-1988 71
3-37. Regional comparison of percent increases in the average of the second
daily maximum 1-hour concentration between 1987 and 1988 71
3-38. Regional comparisons of the 1986, 1987, 1988 composite averages of the
second-highest daily 1-hour ozone concentrations 72
3-39. Regional comparisons of the number of days greater than 90ฐF in 1986,
1987, 1988 for selected cities 72
3-40. Preliminary estimate of the national trend in the composite average of the
second highest daily maximum 1-hour ozone concentration, 1979-89. ... 73
3-41. National trend in the composite average of the maximum quarterly
average lead concentration at 139 sites and 29 NAMS sites with 95
percent confidence intervals, 1979-1988. 76
3-42. Comparison of national trend in the composite average of the maximum
quarterly average lead concentrations at urban and point-source oriented
sites, 1979-1988 76
VIII
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3-43. Boxplot comparisons of trends in maximum quarterly average lead
concentrations at 139 sites, 1979-1988 77
3-44. National trend in lead emissions, 1979-1988 79
3-45. Boxplot comparisons of trends in maximum quarterly average lead
concentrations at 343 sites, 1979-1988. 80
3-46. Regional comparison of the 1986, 1987, 1988 composite average of the
maximum quarterly average lead concentration 82
4-1. Areas exceeding the ozone NAAQS based on 1986-1988 data. . 86
4-2. Areas exceeding the carbon monoxide NAAQS based on 1987-88 data. . 87
4-3. Number of persons living in counties with air quality levels above the
primary national ambient air quality standards in 1988 (based on 1986
population data) 88
4-4. United States map of the highest annual arithmetic mean PM10
concentration by MSA, 1988 91
4-5. United States map of the highest annual arithmetic mean sulfur dioxide
concentration by MSA, 1988. 92
4-6. United States map of the highest second maximum 24-hour average sulfur
dioxide concentration by MSA, 1988 93
4-7. United States map of the highest second maximum nonoverlapping 8-
hour average carbon monoxide concentration by MSA, 1988 94
4-8. United States map of the highest annual arithmetic mean nitrogen dioxide
concentration by MSA, 1988 ,. . 95
4-9. United States map of the highest second daily maximum 1-hour average
ozone concentration by MSA, 1988. . 96
4-10. United States map of the highest maximum quarterly average lead
concentration by MSA, 1988 97
5-1. Illustration of plotting conventions for concentration ranges used in
CMSA/MSA area trend analysis. 112
5-2. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Boston-Lawrence-Salem, MA-NH consolidated
metropolitan statistical area, 1979-1988, 1984-1988 trend years for
lead 120
5-3. Air quality trends in the composite mean and range of pollutant-specific
statistics for the New York-Northern New Jersey-Long Island, NY-NJ-CT
consolidated metropolitan statistical area, 1979-1988, 1984-1988 trend
years for lead 121
5-4. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Baltimore, MD metropolitan statistical area, 1979-1988,
1984-1988 trend years for NO2 122
5-5. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Philadelphia-Wilmington-Trenton, PA-NJ-DE-MD
consolidated metropolitan statistical area, 1979-1988 123
5-6. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Washington, DC-MD-VA metropolitan statistical area,
1979-1988, 1984-1988 trend years for SO2 and NO2 124
IX
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5-7. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Atlanta, GA metropolitan statistical area, 1979-1988,
1984-1988 trend years for SO2 and NO2 125
5-8. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Chicago-Gary-Lake County, IL-ln-WI consolidated
metropolitan statistical area, 1979-1988. 126
5-9. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Detroit-Ann Arbor, Ml consolidated metropolitan statistical
area 1979-1988, 1984-1988 trend years for lead 127
5-10. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Houston-Galveston-BrazQiia, TX consolidated metropolitan
statistical area, 1979-1988. 128
5-11. Air quality trends in the composite mean and range of pollutant-specific
statistics for the St. Louis, Mo-IL metropolitan statistical area, 1979-1988,
1984-1988 trend years for leaid 129
5-12. Air quality trends in the composite men and range of pollutant-specific
statistics for the Denver-Boulder, CO consolidated metropolitan statistical
area, 1979-1988 130
5-13. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Los Angeles-Anaheim-Riverside, CA consolidated
metropolitan statistical area, 1979-1988 131
5-14. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Phoenix, AZ metropolitan statistical area, 1979-1988. . . 132
5-15. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Portland-Vancouver, OR-WA consolidated metropolitan
statistical area, 1979-1988 133
5-16. Air quality trends in the composite mean and range of pollutant-specific
statistics for the Seattle-Tacoma, WA metropolitan statistical area, 1979-
1988 134
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LIST OF TABLES
2-1. National Ambient Air Quality Standards (NAAQS) in Effect in 1988 .... 21
2-2. Number of Sites for 10-Year and 5-Year Air Quality Trends 24
3-1. National Total Suspended Paniculate Emission Estimates, 1979-1988. . . 36
3-2. National Sulfur Oxides Emission Estimates, 1979-1988 49
3-3. National Carbon Monoxide Emission Estimates, 1979-1988 57
3-4. National Nitrogen Oxides Emission Estimates, 1979-1988 63
3-5. National Volatile Organic Compound Emission Estimates, 1979-1988. ... 69
3-6. National Lead Emission Estimates, 1979-1988 79
4-1. Selected Air Quality Summary Statistics and Their Associated National
Ambient Air Quality Standards (NAAQS) 89
4-2. Population Distribution of Metropolitan Statistical Areas Based on 1987
Population Estimates 90
4-3. 1988 METROPOLITAN STATISTICAL AREA AIR QUALITY
FACTBOOK 100
5-1. Air Quality Trend Statistics 113
5-2. Percent Change in Air Quality Trend Statistics 1979 Through 1988 .... 136
5-3. Percent Change in Air Quality Trend Statistics 1979 Through 1988 by
Geographic Regions 137
5-4. Percent Change in Air Quality Trend Statistics 1984-1988 138
5-5. Percent Change in Air Quality Trend Statistics 1984 Through 1988 by
Geographic Regions 139
XI
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT. 1988
1. EXECUTIVE SUMMARY
1.1 INTRODUCTION
This is the sixteenth annual report1"15 documenting air pollution trends in the
United States for those pollutants that have National Ambient Air Quality Standards
(NAAQS). These standards have been promulgated by the U. S. Environmental
Protection Agency (EPA) to protect public health and welfare. There are two types of
NAAQS, primary and secondary. Primary standards are designed to protect public
health, while secondary standards protect public welfare, including effects of air
pollution on vegetation, materials and visibility. This report focuses on comparisons
with the primary standards in effect in 1988 to examine changes in air pollution levels
over time, and to summarize current air pollution status. There are six pollutants that
have NAAQS: paniculate matter (formerly as total suspended paniculate (TSP) and now
as PM1D which emphasizes the smaller particles), sulfur dioxide (SOZ), carbon monoxide
(CO), nitrogen dioxide (NO2)ป ozone (O3) and lead (Pb). It is important to note that the
discussions of ozone in this report refer to ground level, or tropospheric, ozone and not
to stratospheric ozone. Ozone in the stratosphere, miles above the earth, is a
beneficial screen from the sun's ultraviolet rays. Ozone at ground level, in the air we
breathe, is a health and environmental concern.
-SSftPERCEffiLE
-90lh PERCINTIie
The trends in ambient air quality that follow are
presented as boxplots, which display the 5th, 10th,
25th, 50th (median), 75th, 90th and 95th percentiles of
the data, as well as the composite average. The 5th,
10th and 25th percentiles depict the "cleaner" sites,
while the 75th, 90th and 95th depict the "higher" sites
and the median and average describe the "typical"
sites. For example, the 90th percentile means that 90
percent of the sites had concentrations less than or
equal to that value, and only 10 percent of the sites
had concentrations that were higher. Boxplots
simultaneously illustrate trends in the "cleaner",
"typical" and "higher" sites.
The ambient air quality trends presented in this report are based upon actual
direct measurements. These air quality trends are supplemented with trends for
nationwide emissions, which are based upon the best available engineering calculations.
Chapter 4 of this report includes a detailed listing of selected 1988 air quality summary
statistics for every metropolitan statistical area (MSA) in the nation and maps
highlighting the largest MSAs. Chapter 5 presents 1979-88 trends for 15 cities.
-7Wl PERCENTILE
-COMPOSITE AVERAGE
-MEDIAN
-ZSIhPERCEMTHE
-IWlPERCENTtlE
-SltlPEHCENTilE
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1.2 MAJOR FINDINGS
AIR QUALITY
Total Suspended Participates (TSP)
1979-88: geometric mean: 20 percent decrease (1750 sites)
1984-88: geometric mean: less than 1 percent decrease (1491 sites)
1987-88: geometric mean: 2 percent increase (1491 sites)
EMio
1987-88: arithmetic mean: 4 percent decrease (119 sites)
EMISSIONS
1979-88: 22 percent decrease
1984-88: 7 percent decrease
1987-88: 1 percent decrease
COMMENTS
Although the 1979-81 TSP data were affected by a change in sampling filters,
average 1978 and 1979 TSP levels differed by only 1 percent. The 1978 data
were not affected by the filter change and are comparable to the 1982 and later
data. Therefore, the net changes presented above are essentially correct. The
1988 TSP emission estimate may be low because 1988 forest fire emissions data
are not yet complete. The PM1D network is still evolving and the western U.S. is
not fully represented in the 1987-88 data base. The PM)0 decrease between 1987
and 1988, in contrast to the TSP increase, may indicate that the extremely dry
weather in 1988 had more impact on the larger (TSP) particles.
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TSP AIR QUALITY
ANNUAL GEOMETRIC MEAN
100 -
80 -
60 - It
40 -
20 -
\*
15
10
TSP EMISSIONS
10* METRIC TONS/YEAR
SOURCE CATEGORY
I TRANSPORTATION
m FUEL
COMBUSTION
gg INDUSTRIAL PROCESSES
XX SOLID WASTE & MISC
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AIR QUALITY
1979-88: arithmetic mean; 30 percent decrease (374 sites)
24-hour second high: 36 percent decrease (364 sites)
24-hour exceedances: 90 percent decrease (364 sites)
1984-88: arithmetic mean: 13 percent decrease (584 sites)
1987-88: arithmetic mean: 1 percent increase (584 sites)
EMISSIONS fSOx)
1979-88: 17 percent decrease
1984-88: 4 percent decrease
1987-88: less than 1 percent increase
COMMENTS
The vast majority of SO2 monitoring sites do not show any exceedances of the
24-hour NAAQS and the exceedanee trend is dominated by source oriented sites.
The increase in sulfur oxides emissions between 1987 and 1988 is due to
increased industrial activity, which offset continued reductions in emissions from
fuel combustion. The difference between the air quality trends and the emission
trends result from the historica! ambient monitoring networks being population-
oriented while the major emission sources tend to be in less populated areas.
WORTH NOTING
Almost all monitors in U.S. urban areas meet EPA's ambient, SOe
standards, which apply to,ground level.concentrations. .Current .
concerns about sulfur dioxide focus on major emitters, total
atmospheric loadings, and the possible need for a shorter-term^i.e. 1-
hour) standard. Two-thirds of all national SO* emissions are generated
by electric utilities (93 percent of which come from coal fired power
plants). The majority of these emissions, however, are produced by a
small number of facilities. Fifty individual plants in 15 states account
for one-half of all power plant emissions.
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SO2 AIR QUALITY
CONCENTRATION, PPM
ANNUAL MEAN
374 SITES
K m -
SOx EMISSIONS
106 MEmiC TONS/YEAR
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AIR QUALITY
1979-88; 8-hour second high: 28 percent decrease (248 sites)
8-hour exceedances: 88 percent decrease
1984-88: 8-hour second high; 16 percent decrease (359 sites)
1987-88: 8-hour second high: 3 percent decrease (359 sites)
EMISSIONS
1979-88: 25 percent decrease
1984-88: 15 percent decrease
1987-88: 5 percent decrease
COMMENTS
While there is general agreement between the air quality and emission changes
over this 10-year period, it should be recognized that the emission changes
reflect estimated national totals while the ambient CO monitors are frequently
located to identify problems. The mix of vehicles and the change in vehicle
miles of travel in an area around a typical CO monitoring site may differ from
the national averages.
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'H^iKn'ci
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.-*
CO AIR QUALITY
:2Q
CONCBJTRATrON. PPM
SECOND HIGHEST 8-HOUR AVERAGE
15 -
10 -
5 -
248 SITES
CO EMISSIONS
SOURCE CATEGORY
TRANSPORTATION
B INDUSTRIAL PROCESSES
SOLID WASTE 1MISC
7
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AIR QUALITY
1979-88: Annual Mean: 7 percent decrease (116 sites)
1984-88: Annual Mean: Less than 1 percent increase (194 sites)
1987-88; Annual Mean: 1 percent increase (194 sites)
EMISSIONS (NOx)
1979-88: 8 percent decrease
1984-88: no change
1987-88: 3 percent increase
COMMENTS
The recent national trend in annual mean NO2 concentration continues to be flat.
The two primary source categories of nitrogen oxide emissions, and their
contribution in 1988, are fuel combustion (55 percent) and transportation (41
percent).
8
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NO2 AIR QUALITY
CONCENTRATION, PPM
ANNUAL MEAN
1.08
(.05 -
L04 -
5.03
).OZ
I J.OO
116 SITES
NOx EMISSIONS
30
tO" METRIC TONS/YEAR
25 -
20
15
10 H
5
0
SOURCE CATEGORY
TRANSPORTATION
m FUEL COMBUSTION
S8 INDUSTRIAL PROCESSES
5K SOUD WASTE & MISC.
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AIR QUALITY
1979-88: Second Highest Daily Max 1-hour: 2 percent increase (388 sites)
Exceedance Days: 10 percent decrease
1984-88: Second Highest Daily Max 1-hour: 9 percent increase (567 sites)
1987-88: Second Highest Daily Max 1-hour: 8 percent increase (567 sites)
Emissions (VOC)
1979-88; 17 percent decrease
1984-88: 8 percent decrease
1987-88: no change
COMMENTS
The volatile organic compound (VOC) emission estimates represent annual
totals. While these are the best national numbers now available, ozone is
predominantly a warm weather problem and seasonal emission trends would
seem preferable. New emission inventories will consider this seasonal effect.
WORTH NOTING
Ozone continues to be the most pervasive ambient air pollution
problem in the U.S. with 101 areas failing to meet the ozone NAAQS
for 1986-88. Recent trends have been affected by weather conditions.
The warm 1988 summer was conducive to ozone formation while
preliminary data suggests that a cooler, wetter 1989 resulted in lower
ozone levels. Just as fast year's report indicated that interpretation of
the 1988 increases should be tempered by an awareness of the effect
of weather conditions, interpretation of the likely decreases in 1989
warrants the same caution. The key point is not whether levels in
1989 were lower than in 1988 but how likely it is for the high ozone
levels seen in 1980, 1983, and 1988 to recur.
10
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OZONE AIR QUALITY
)30
CONCENTRATION, PPM
SECOND HIGH DAILY MAX 1-HOUR
1.25 -
)20 -
>.fS -
1.10 -
).05 -
J.OO
388 SITES
VOC EMISSIONS
35
10B METRIC TONS/YEAR
30 -
25
20
SOURCE CATEGORY
I TRANSPORTATION
ป; INDUSTRIAL PROCESSES
SS FUEL COMBUSTION
ป< SOLID WASTE &MISC
11
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AIR QUALITY
1979-88: Maximum Quarterly Average: 89 percent decrease (139 sites)
1984-88: Maximum Quarterly Average; 76 percent decrease (343 sites)
1987-88: Maximum Quarterly Average; 15 percent decrease (343 sites)
Emissions
1979-88: 93 percent decrease in total lead emissions - 97 percent decrease in
lead emissions from transportation sources.
1984-88: 81 percent decrease in total lead emissions - 93 percent decrease in
lead emissions from transportation sources.
1987-88: 5 percent decrease in total lead emissions - 13 percent decrease in
lead emissions from transportation sources,
COMMENTS
The ambient lead trends presented here primarily represent general urban
conditions predominantly reflecting automotive sources. Ambient trends are also
presented for a small number of lead monitoring sites (18) in the vicinity of point
sources of lead such as primary and secondary lead smelters,
12
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LEAD AIR QUALITY
2.5
CONCEHTRAT10N, IXyU*
MAXIMUM QUARTERLY AVERAGE
2 -
1.5
1 -
0.5 -
139 SITES
LEAD EMISSIONS
125
100
10J
TONS/YEAR
SOURCE CATEGORY
m TRANSPORTATION
m INDUSTRIAL PROCESSES
yป SOLID WASTE
^K>cv>wซ)ซXX>sKxXXX^^XX>LNJJytw>j^^^
13
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1.3 SOME PERSPECTIVE
A 10-year time period is convenient for considering ambient air pollution trends
because monitoring networks underwent many changes around 1980. However, it is
important not to overlook some of the earlier control efforts in the air pollution field.
Emission estimates are useful in examining longer term trends. Between 1970 and
1988, lead clearly shows the most impressive decrease (-96 percent) but improvements
are also seen for total suspended paniculate (-63 percent), sulfur oxides (-27 percent),
carbon monoxide (-40 percent), and volatile organic compounds (-26 percent). Only
nitrogen oxides did not show improvement with emissions estimated to have increased
7 percent, due primarily to increased fuel combustion by stationary sources and motor
vehicles. It is also important to realize that many of these reductions occurred even
in the face of growth. More detailed information is contained in a companion report.16
COMPARISON OF 1970 AND 1988 EMISSIONS
MILLION METRIC TONS/YEAR
120
100 -
80 -
THOUSAND
METRIC TONSYEAR
250
200
150
100
50
TSP
SOx
CO
1970
NOx
1988
VOC
LEAD
14
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\
While it is important to recognize that progress has been made, it is also
important not to lose sight of the magnitude of the air pollution problem that still
remains. About 121 million people in the U.S. reside in counties which did not meet
at least one air quality standard during 1988 and it is apparent why ground level ozone
is viewed as our most pervasive ambient air pollution problem. The 112 million people
living in counties that exceeded the ozone standard in 1988 are greater than the total
for the other five pollutants. These statistics, and associated qualifiers and limitations,
are discussed in Chapter 4. As noted, 1988 ozone levels were higher in some areas
due to the warm 1988 summer but even in 1987 there were 96.2 million people living
in counties that exceeded the ozone NAAQS (based on 1986 population data).
People in counties with 1988 air quality above
primary National Ambient Air Quality Standards.
pollutant
I
PM10
SO2
CO
NO2
Ozone
Lead
Any NAAQS
0
NOTE: Baaed on
iiiifahjii25-6
wm
W*-3
fir ' '
J,e
imp29-5
\ ^;
%
-
1'"
9
, 1 , (_ i 1 _, 1 , 1 . 1 i
20 40 60 80 100 120 140
millions of people
983 population data.
Finally, it should be recognized that this report focuses on what may be viewed
as the traditional air pollutants for which an established data base exists. As our
knowledge increases, we are becoming more aware of additional air pollution concerns
that warrant attention and, in many cases, we are learning of the increasing complexity
involved in solving existing problems.
15
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1.4 REFERENCES
1. The National Air Monitoring Program: Air Quality and Emissions Trends -
Annual Report. EPA-450/1-73-001 a and b, U. S. Environmental Protection Agency,
Office of Air Quality Planning and Standards, Research Triangle Park, NC 27711, July
1973,
2. Monitoring and Air Quality Trends Report. 1972. EPA-450/1-73-004, U. S.
Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC 27711, December 1973.
3. Monitoring and Air Quality Trends Report. 1973. EPA- 450/1-74-007, U. S.
Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park,'NC 27711, October 1974.
4- Monitoring and Air Quality Trends Report. 1974. EPA-450/1-76-001, U. S.
Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC 27711, February 1976.
5. National Air Quality and Emissions Trends Report. 1975. EPA 450/1-76-002,
U. S. Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC 27711, November 1976.
6. National Air Quality and Emissions Trends Report. 1976.
EPA-450/1-77-002, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, December 1977.
7. National Air Quality and Emissions Trends Report. 1977.
EPA-450/2-78-052, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, December 1978.
8. 1980 Ambient Assessment - Air Portion. EPA-450/4-81-014,
U. S. Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC 277II, February 1981.
9- National Air Quality and Emissions Trends Report. 1981.
EPA-450/4-83-011, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, April 1983.
10. National Air Qualityjand Emissions Trends Report. 1982.
EPA-450/4-84-002, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, March 1984.
11. National Air Quality and Emissions Trends Report. 1983.
EPA-450/4-84-029, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, April 1985.
16
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12. National Air Quality and Emissions Trends Report. 1984.
EPA-45Q/4-86-QQ1, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, April 1986,
13. National Air Quality and Emissions Trends Report. 1985.
EPA-450/4-87-001, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, February 1987.
14. National Air Quality and Emissions Trends Report. 1986.
EPA-45Q/4-88-001, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, February 1988.
15. National Air Quality and Emissions Trends Report. 1987.
EPA-450/4-89-001, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC 27711, March 1989.
16. National Air Pollutant Emission Estimates. 1940-1988. EPA-450/4-90-001.
U. S. Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC 27711, March 1990.
17
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2. INTRODUCTION
This report focuses on both 10-year (1979-88) and 5-year (1984-88) national air
quality trends for each of the major pollutants for which National Ambient Air Quality
Standards (NAAQS) have been established, as well as Regional and, where
appropriate, short-term air quality trends. This Section presents many of the technical
details involved in these analyses; readers familiar with previous reports may prefer
initially to proceed directly to the remaining Sections. The national analyses are
complemented in Section 5 with air quality trends in 15 metropolitan areas for the
period 1979 through 1988, The areas examined are Atlanta, GA; Baltimore, MD;
Boston, MA; Chicago, IL-North western IN; Denver, CO; Detroit, Ml; Houston, TX; Los
Angeles-Long Beach, CA; New York, NY-Northeastern NJ; Philadelphia, PA-NJ;
Phoenix, AZ; Portland, OR-WA; St. Louis, MO-IL; Seattle, WA; and Washington, DC.
Due to limited 10-year data records, a 5-year period 1984-88 was used in some cases.
The national air quality trends are presented for all sites and for the National
Air Monitoring Station (NAMS) sites. The NAMS were established through monitoring
regulations promulgated in May 19791 to provide accurate and timely data to the U.S.
Environmental Protection Agency (EPA) from a national air monitoring network. The
NAMS are located in areas with higher pollutant concentrations and high population
exposure. These stations meet uniform criteria for siting, quality assurance, equivalent
analytical methodology, sampling intervals, and instrument selection to assure consistent
data reporting among the States. Other sites operated by the State and local air
pollution control agencies, such as the State and Local Air Monitoring Stations (SLAMS)
and Special Purpose Monitors (SPM), in general, also meet the same rigid criteria,
except that in addition to being located in the area of highest concentration and high
population exposure, they are located in other areas as well. The ambient levels
presented are the results of direct air pollution measurements.
Trends are also presented for annual nationwide emissions. These are estimates
of the amount and kinds of pollution being emitted by automobiles, factories, and other
sources, based upon the best available engineering calculations for a given time period.
The emission trends are taken from the EPA publication, National Air Pollutant
Emission Estimates. 1940-19882 and the reader is referred to this publication for more
detailed information. For particulates, emission estimates are intended to represent
total particulate emissions without any distinction of particle sizes. Area source fugitive
dust emissions (unpaved roads, construction activities, etc.) are not included at all.
Similarly, natural sources of particulates, such as wind erosion or dust, are not
included. (Forest fires, some of which result from natural causes are included,
however). In total, these fugitive emissions may amount to a considerable portion of
total particulate emissions. For CO, VOC and NOX, emission estimates for gasoline-
and diesel-powered motor vehicles were based upon vehicle-mile tabulations and
emission factors from the MOBILE 4,0 model.
Air quality status may be determined by comparing the ambient air pollution
levels with the appropriate primary and secondary National Ambient Air Quality
Standards (NAAQS) for each of the pollutants (Table 2-1). Primary standards protect
\ 19
\
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the public health; secondary standards protect the public welfare as measured by
effects of pollution on vegetation, materials, and visibility. The standards are further
categorized for different averaging times. Long-term standards specify an annual or
quarterly mean that may not be exceeded; short-term standards specify upper limit
values for 1-, 3-, 8-, or 24-hour averages. With the exception of the pollutants ozone
and PM10, the short-term standards are not to be exceeded more than once per year.
The ozone standard requires that the expected number of days per calendar year with
daily maximum hourly concentrations exceeding 0.12 parts per million (ppm) be less
than or equal to one. The 24-hour PM10 standard also allows one expected
exceedance per year.
Section 4 of this report, "Air Quality Levels in Metropolitan Statistical Areas"
provides greatly simplified air pollution information. Air quality statistics are presented
for each of the pollutants for all MSAs reporting monitoring data to EPA for 1988.
During Summer 1989, EPA continued the cooperative program with the State and
local air pollution agencies for the accelerated reporting of preliminary ozone data from
a subset of peak monitoring sites. These data have been merged with the trends data
base to provide a preliminary assessment of 1989 ozone trends.
2.1 DATA BASE
The ambient air quality data used in this report were obtained from EPA's
Aerometric Information and Retrieval System (AIRS). Air quality data are submitted
to AIRS by both State and local governments, as well as federal agencies. At the
present time, there are about 500 million air pollution measurements on AIRS, the vast
majority of which represent the more heavily populated urban areas of the nation.
Previously3, the size of the available air quality trends data base was expanded
by merging data at sites which had experienced changes in the agency operating the
site, the instruments used, or in the project codes, such as a change from population
oriented to special purpose monitoring. In contrast to the old Storage and Retrieval
of Aerometric Data (SAROAD) System, which created separate records in these cases,
the pollutant occurrence code (POC) was established in AIRS to create combined
summary records for these monitoring situations. However, in the case of Pb, the
previous procedure of merging data was employed to combine data collected using
different sampling intervals.
In order for a monitoring site to have been included in the national 10-year trend
analysis, the site had to contain data for at least 8 of the 10 years 1979 to 1988. For
the national 5-year trend, the site had to contain 4 out of 5 years of data to be
included as a trend site. Data for each year had to satisfy annual data completeness
criteria appropriate to pollutant and measurement methodology. The air quality data
are divided into two major groupings ~ 24-hour measurements and continuous 1-hour
measurements. The 24-hour measurements are obtained from monitoring instruments
that produce one measurement per 24-hour period and are typically operated on a
systematic sampling schedule of once every 6 days, or 61 samples per year. Such
20
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TABLE 2-1. National Ambient Air Quality Standards (NAAQS) in Effect in 1988
POLLUTANT
PRIMARY (HEALTH RELATED)
STANDARD LEVEL
AVERAGING TIME CONCENTRATION"
PM,,
SO.
Annual Arithmetic
Mean"
24-hour"
50
150 jig/nr1
SECONDARY (WELFARE RELATED)
AVERAGING TIME CONCENTRATION
Same as Primaiy
Same as Primary
CO
NO2
0,
Pb
Annual Arithmetic (0.03 pprn)
Mean 80 (
24-hout*
8-hour*
1-houf
3-hour0
1300 jig/m'
(0.50 ppm}
Annual Arithmetic
Mean
Maximum Daily 1-hour
Average"
Maximum Quarterly
Average
(0.14 ppm)
365 |ig/m3
9 ppm
(10 mglm3)
35 ppm
(40 mg/nf}
0.053 pprn
(100
0.12 ppm
(235 u.g/m3)
1JS
No Secondary Standard
No Secondary Standard
Same as Primary
Same as Primary
Same as Primary
* Parenthetical value is an approximately equivalent concentration.
" TSP was the indicator pollutant for the original paniculate matter (PM) standards. This standard has been
replaced with the new PM10 standard and it Is no longer in effect. New PM standards were promulgated in
1987, using PM,0 (particles less than 10|u. in diameter) as the new indicator pollutant The annual standard
is attained when the expected annual arithmetic mean concentration is less than or equal to 50 fig/m3; the
24-hour standard is attained when the expected number of days per calendar year above 150 us/m3 is
equal to or less than 1 ,* as determined in accordance with Appendix K of the PM NAAQS.
c Not to be exceeded more than once per year.
* The standard is attained when the expected number of days per calendar year with maximum hourly
average concentrations above 0.12 ppm is equal to or less than 1, as determined in accordance with
Appendix H of the Ozone NAAQS.
21
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instruments are used to measure TSP, PM10, SO2, NO2 and Pb. For PM10, more
frequent sampling of every other day or everyday is now also common. Bubbler data
were not used in the S02 and NO2 trends analyses because these methods have
essentially been phased out of the monitoring network. Total suspended paniculate
and PM10 data were judged adequate for trends if there were at least 30 samples for
the year. Both 24-hour and composite data were used in the Pb trends analyses.
The 24-hour Pb data had to have at least six samples per quarter in at least 3 of the
4 calendar quarters. Monthly composite Pb data were used if at least two monthly
samples were available for at least 3 of the 4 calendar quarters.
The 1-hour data are obtained from monitoring instruments that operate
continuously, producing a measurement every hour for a possible total of 8760 hourly
measurements in a year. For continuous hourly data, a valid annual mean for SO2
and NO2 trends requires at least 4380 hourly observations. This same annual data
completeness, of at least 4380 hourly values, was required for the CO standard related
statistics - the second maximum nonoverlapping 8-hour average and the estimated
number of exceedances of the 8-hour average CO standard. A slightly different
criterion was used for the SO2 standard related daily statistics - the second daily
maximum 24-hour average and the estimated number of daily exceedances of the SO2
standard. Instead of requiring 4380 or more hourly values, 183 or more daily values
were required. A valid day is defined as one consisting of at least 18 hourly
observations. This produces a slightly different data base of sites used in the national
analysis for the daily SO2 statistics.
Finally, because of the seasonal nature of ozone, both the second daily
maximum 1-hour value and the estimated number of exceedances of the 03 NAAQS
were calculated for the ozone season, which typically varies by State.4 For example,
in California, the ozone season is defined as 12 months, January through December,
while in New Jersey it is defined as 7 months, April through October. In order for a
site to be included, at least 50 percent of its daily data had to be available for the
ozone season. For all pollutants, the site must satisfy the annual completeness criteria,
specified above in at least 8 out of 10 years for it to be included in the 10-year air
quality trends data base, and 4 out of 5 years to be included in the 5-year trend data
base. Table 2-2 displays the number of sites meeting the completeness criteria for
both trends data bases.
The use of moving 10-year and 5-year windows for trends yields a data base
that is more consistent with the current monitoring network. In addition, this procedure
increased the total number of trend sites by 11 percent for the 10-year period, but
increased by less than 1 percent for the 5-year period relative to the data bases used
in the last annual report.5 The reader should note that the size of the TSP monitoring
network has been declining, especially since promulgation of the PM10 standard. This
decline in the number of TSP sites between the 10-year and 5-year data bases results
from the difference in the number of years required for the two time periods, if a site
discontinued operation in 1987, it would be included in the 10-year data base, but not
in the 5-year data base (since 2 of the 5 years would be missing). In general, the
22
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data from the post 1980 period should be of the highest quality. Focusing on the non-
TSP sites in Table 2-2, there is a 62% increase in the number of sites in the 5-year
data base as compared to the 10-year period. Except for NO2, trend sites can be
found in ail EPA Regions (Figure 2-1) for TSP, SQ2, CO, O3 and Pb for the 5-year
period,
2.2 TREND STATISTICS
The air quality analyses presented in this report comply with the
recommendations of the Intra-Agency Task Force on Air Quality Indicators.6 This task
force was established in January 1980 to recommend standardized air quality indicators
and statistical methodologies for presenting air quality status and trends. The Task
Force report was published in February 1981. The air quality statistics used in these
pollutant-specific trend analyses relate to the appropriate NAAQSs. Two types of
standard-related statistics are used - peak statistics (the second maximum 24-hour
SO2 average, the second maximum nonoverlapping 8-hour CO average, and the second
daily maximum 1-hour 03 average) and long-term averages (the annual geometric mean
for TSP, the annual arithmetic means for PM10, S02 and NO2, and the quarterly
arithmetic mean for Pb). In the case of the peak statistics, the second maximum value
is used, because this is the value which traditionally has been used to determine
whether or not a site has or has not met an air quality standard in a particular year.
For PM,0, with its variable sampling frequency, the 90th percentile of 24-hour
concentrations is used to examine changes in peak values. A composite average of
each of these statistics is used in the graphical presentations which follow. All sites
were weighted equally in calculating the composite average trend statistic. Missing
annual summary statistics for the second through ninth years for a site are estimated
by linear interpolation from the surrounding years. Missing end points are replaced with
the first valid year of data. This procedure results in a statistically balanced data set
to which simple statistical procedures can be applied. The procedure is also
conservative, because end-point rates of change are dampened by the interpolated
estimates.
The air quality trends information in Section 3 is presented using trend lines,
confidence intervals, boxplots7 and bar graphs. This report presents statistical
confidence intervals to facilitate a better understanding of measured changes in air
quality. Confidence intervals are placed around composite averages, which are based
on sites that satisfy annual data completeness requirements. The confidence intervals
can be used to make comparisons between years; if the confidence intervals for any
2 years do not overlap, then the composite averages of the 2 years are significantly
different (Figure 2-2). Ninety-five percent confidence intervals for composite averages
of annual means (arithmetic and geometric) and second maxima were calculated from
a two-way analysis of variance followed by an application of the Tukey Studentized
Range.8 The confidence intervals for composite averages of estimated exceedances
were calculated by fitting Poisson distributions9 to the exceedances each year and then
applying the Bonferroni multiple comparisons procedure.10 The utilization of these
procedures is explained in publications by Pollack, Hunt and Curran11 and Pollack and
Hunt.12
23
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Table 2-2. Number of Sites for 10-Year and 5-Year Air Quality Trends
SITES
POLLUTANT
Total Suspended Paniculate
(TSP)
Sulfur Dioxide (S02)
Carbon Monoxide (CO)
Nitrogen Dioxide (NO2)
Ozone (03)
Lead (Pb)
Total
NUMBER
1979-88
1750
374
248
116
388
139
3015
OF TREND
1984-88
1491
584
359
194
567
343
3538
Virgin
Figure 2-1. Ten Regions of the U.S. Environmental Protection Agency.
24
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A recent study examined the procedure for estimating the national means and
accompanying confidence intervals. A general linear model (GLM) approach to
estimating national averages without interpolating missing site-years was developed and
evaluated. The GLM approach was applied to the ozone and total suspended
partlculate trends data bases from last years' report.5 The TSP data set was chosen
for analysis because it was the pollutant with the largest number of monitoring sites.
The ozone data set was chosen, on the other hand, because it was expected to reveal
the largest differences between the two methods, as ozone is highly variable from year
to year. In the case of TSP, four of the ten composite means were the same value,
and the remaining six means differed by only 0.1 ug/m3 (less than one-half of one
percent) between the two approaches. For ozone, the estimated national composite
ozone averages were within 0.001 ppm in all cases but one. The single exception
was the 1978 composite average where the GLM estimate was 6 percent higher than
the traditional estimate. The size of this difference is likely due to the unusually high
number of missing sites (45 percent) for that year. Recall that the promulgation of the
monitoring regulations in 1979 precipitated network revisions, with greater network
stability since 1979.
The GLM approach is not appropriate for estimating missing exceedance counts.
However, work is continuing on developing an alternative approach for exceedances
and on integrating the GLM approach into the trends analysis procedures.
Boxplots are used to present air quality trends because they have the advantage
of displaying, simultaneously, several features of the data. Figure 2-3 illustrates the
use of this technique in presenting the 5th, 10th, 25th, 50th (median), 75th, 90th and
95th percentiles of the data, as well as the composite average. The 5th, 10th and 25th
percentiles depict the "cleaner" sites. The 75th, 90th and 95th depict the "higher"
sites, and the median and average describe the "typical" sites. For example, 90
percent of the sites would have concentrations equal to or lower than the 90th
percentile. Although the average and median both characterize typical behavior, the
median has the advantage of not being affected by a few extremely high observations.
The use of the boxplots allows us simultaneously to compare trends in the "cleaner",
"typical" and "higher" sites.
Bar graphs are introduced for the Regional comparisons with the 5-year trend
data base. The composite averages of the appropriate air quality statistic of the years
1986, 1987 and 1988 are presented. The approach is simple, and it allows the reader
at a glance to compare the short-term trends in all ten EPA Regions.
In addition to concentration related statistics, other statistics are used, when
appropriate, to clarify further the observed air quality trends. Particular attention is
given to the estimated number of exceedances of the short-term NAAQSs. The
estimated number of exceedances is the measured number of exceedances adjusted
to account for incomplete sampling. Trends in exceedances tend to be more variable
than in the other concentration related statistics, particularly on a percentage basis.
For example, a site may show a 50 percent decrease in annual exceedances, from 2
to 1 per year, and yet record less than a 5 percent decrease in average concentration
25
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levels. The change in concentration levels is likely to be more indicative of changes
in emission levels.
For a pollutant such as ozone, for which the level of the standard was revised
in 1979, exceedances for all years were computed using the most recent level of the
standard. This was done to ensure that the trend in exceedances is indicative of air
quality trends rather than of a change in the level of the standard.
Trends are also presented for annual nationwide emissions. These emissions
data are estimated using the best available engineering calculations. The emissions
data are reported as teragrams (one million metric tons) emitted to the atmosphere per
year, with the exception of lead emissions, which are reported as gigagrams (one
thousand metric tons).2 These are estimates of the amount and kinds of pollution
being generated by automobiles, factories and other sources. Estimates for earlier
years are recomputed using current methodology so that these estimates are
comparable over time.
26
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Z
o
cc
z
LU
o
2
O
Q
O
O
Q.
DC
COMPOSITE MEAN
RELATIONSHIPS (MULTIPLE COMPARISONS):
ป YEARS 1 AND 2 ARE NOT SIGNIFICANTLY
DIFFERENT.
* YEARS 2 AND 3 ARE NOT SIGNIFICANTLY
DIFFERENT.
YEAHS 1 AND 3 ARE SIGNIFICANTLY
DIFFERENT,
YEAR 4 IS SIGNIFICANTLY DIFFERENT FROM
ALL OTHERS.
95% CONFIDENCE
INTERVAL ABOUT
COMPOSITE MEAN
I
YEAR1
viAR 2
YEARS
YEAR 4
Figure 2-2. Sample illustration of use of confidence intervals to determine statistically
significant change.
S|P
PERCENTILE
-90lh PERCENTILE
-75th PERCENTILE
- COMPOSITE AVERAGE
-MEDIAN
-25th PERCENTILE
-10th PERCENTILE
-Sth PERCENTILE
Figure 2-3. Illustration of plotting conventions for boxplots.
27
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2.3 REFERENCES
1. Ambient Air Quality Surveillance. 44 FR 27558, May 10, 1979.
2. National Air Pollutant Emission Estimates. 1940-1988.
EPA-450/4-90-001, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC, March, 1990.
3. National Air Quality and Emissions Trends Report. 1986.
EPA-450/4-88-001, U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC, February 1988.
4. Ambient Air Quality Surveillance. 51 FR 9597, March 19, 1986.
5. National Air Quality and Emissions Trends Report, 1987.
EPA-450/4-88-001, U. S. Environmental Protection Agency, Office of Air Quality
Planning .and Standards, Research Triangle Park, NC, March 1989.
6. U.S. Environmental Protection Agency Intra-Agencv Task Force Report on Air
Quality Indicators. EPA-450/4-81-015, U. S. Environmental Protection Agency, Office
of Air Quality Planning and Standards, Research Triangle Park, NC, February 1981.
7, J. W. Tukey, Exploratory Data Analysis. Addison-Wesley Publishihg Company,
Reading, MA, 1977.
8. B. J. Winer, Statistical Principles in Experimental Design. McGraw-Hill, NY,
1971.
9. N. L Johnson and S. Kotz, Discrete Distributions. Wiley, NY, 1969.
10. R. G. Miller, Jr., Simultaneous Statistical Inference. Springer-Verlag, NY, 1981,
11. A. Pollack, W. F. Hunt, Jr., and T. C. Curran, "Analysis of Variance Applied
to National Ozone Air Quality Trends", presented at the 77th Annual Meeting of the
Air Pollution Control Association, San Francisco, CA, June 1984.
12. A. Pollack and W. Hunt, "Analysis of Trends and Variability in Extreme and
Annual Average Sulfur Dioxide Concentrations", presented at the Air Pollution Control
Association, American Society for Quality Control Specialty Conference on Quality
Assurance in Air Pollution Measurement, Boulder, CO, 1985.
13. A. Pollack and T. Stocking, "General Linear Models Approach to Estimating
National Air Quality Trends", Final Report, EPA Contract No. 68-02-4391, Systems
Applications, Inc., San Rafael, CA, 1989.
28
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3. NATIONAL AND REGIONAL TRENDS IN NAAQS POLLUTANTS
EPA has set National Ambient Air Quality Standards (NAAQS) for six pollutants
considered harmful to public health: paniculate matter [formerly as total suspended
particulates (TSP), now as particulates less than 10 microns in diameter (PM10)j, sulfur
dioxide (SO2)ป carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3) and lead (Pb).
This chapter focuses on both 10-year (1979-88) and 5-year (1984-88) trends, in air
quality and emissions for these six pollutants. Changes since 1987, and comparisons
between all the trend sites and the subset of National Air Monitoring Stations (NAMS)
are highlighted. Trends are examined for both the nation and the 10 EPA Regions.
As in previous reports, the air quality trends are presented using trend lines,
confidence intervals, bpxplots and bar graphs. The reader is referred to Section 2.2
for a detailed description of the confidence interval and boxplot procedures. The
plotting conventions for the confidence intervals and boxplots are shown in Figures
2-2 and 2-3, respectively. Boxplots of all trend sites are presented for each year in
the 10-year trend. In the recent 5-year trend, the boxplots are presented for the years
1984 through 1988. The 5-year trend was introduced in the 1984 report to increase
the number of sites available for analysis and to make use of data from more recently
established sites. The recent 5-year period is presented to take advantage of the
larger number of sites, and of sites meeting uniform siting criteria and quality assurance
procedures.
Trends are also presented for annual nationwide emissions of paniculate matter,
sulfur oxides (SOX), carbon monoxide, nitrogen oxides (NOX), volatile organic compounds
(VOC) and lead. These emissions data are estimated using best available engineering
calculations. The reader is referred to a companion report for a detailed description
of emission trends, source categories and estimation procedures.1 For particulates,
emission estimates are presented in terms of total particulate matter which include all
particles regardless of size. These estimates are comparable to ambient TSP. In the
future, trends reports will include particulate matter trends relating to PM10 air quality,
as data for the necessary engineering calculations are developed.
While the ambient data trends and the emission trends can be viewed as
independent assessments that lend added credence to the results, the emission
estimates can be used to provide information on trends over longer time periods.
Because of changes that have occurred in ambient monitoring measurement
methodology and the change over time in the geographical distribution of monitors, it
is difficult to provide ambient trends going back to 1970, other than for TSP, which is
discussed later, and yet it is important not to lose sight of some of the earlier progress
that was made in air pollution control. Emission estimates can provide some insight
in this area. Figure 3-1 depicts long-term change in emission estimates. Lead clearly
shows the most impressive decrease of 96 percent but improvements are also seen for
TSP (-63 percent), SOX (-27 percent), CO (-40 percent), and VOC (-26 percent). Only
NOX has not shown improvement with emissions estimated to have increased 7 percent,
due primarily to increased fuel combustion by stationary sources and motor vehicles.
29
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Because almost all areas meet the current NAAQS for NO2, it is probably not surprising
that the other pollutants are where the emission reductions have occurred.
Because of the continuing interest in ozone levels, EPA continued its 1988
cooperative program with the State and local air pollution agencies for the early
reporting of preliminary ozone data. The number of sites was greatly expanded in the
1989 survey, with 588 sites reporting preliminary data. A total of 311 of the 388 sites
in the 10-year data base were included in this year's survey. A preliminary estimate
of 1989 ozone trends is provided in Section 3.5.
COMPARISON OF 1970 AND 1988 EMISSIONS
MILUON METRIC TONS/YEAR
120
THOUSAND
METRIC TONS/YEAR
100
80
60
40
20
250
200 -
150
100
TSP
SOx
CO
NOx
VOC
LEAD
1970 1988
Figure 3-1. Comparison of 1970 and 1988 emissions.
30
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3.1 TRENDS IN PARTICULATE MATTER
Air pollutants called participate matter include dust, dirt, soot, smoke and liquid
droplets directly emitted into the air by sources such as factories, power plants, cars,
construction activity, fires and natural windblown dust as well as particles formed in the
atmosphere by transformation of emitted gases such as sulfur dioxide and volatile
organic compounds.
Annual and 24-hour National Ambient Air Quality Standards (NAAQS) for
partieulate matter were first set in 1971. Total suspended paniculate (TSP) was the
indicator used to represent suspended particles in the ambient air. TSP is measured
using a high volume sampler (Hi-Vol) which collects suspended particles ranging up to
approximately 45 micrometers in diameter.
On July 1, 1987 EPA promulgated new annual and 24-hour standards for
partieulate matter, using a new indicator, PM10, that includes only those particles with
aerodynamic diameter smaller than 10 micrometers. These smaller particles are likely
responsible for most adverse health effects of partieulate because of their ability to
reach the thoracic or lower regions of the respiratory tract. The original (TSP)
standards were an annual geometric mean of 75 jig/m , not to be exceeded, and a
24-hour concentration of 260 [ig/m3, not to be exceeded more than once per year. The
new (PM10) standards specify an expected annual arithmetic mean not to exceed 50
ng/m3 and an expected number of 24-hour concentrations greater than 150 ng/m3 per
year not to exceed one.
Now that the standards have been revised, PM10 monitoring networks are being
deployed nationally. There are basically two types of reference instruments currently
used to sample PM,0. The first is essentially a Hi-Vol, like the one used for TSP, but
with a different size selective inlet (SSI). This sampler uses an inert quartz filter. The
other type of instrument is a "dichotomous" sampler. It uses a different PM10 inlet,
operates at a slower flow rate, and produces two separate samples: 2.5 to 10 microns
and less than 2.5 microns, each collected on a teflon filter.
With the new PM10 standards, more emphasis is being placed on detection of
peak 24-hour concentrations. Unlike monitoring regulations for TSP which only required
once in 6 day sampling, new specifications for PM10 now dictate more frequent
sampling. Approximately one-fourth of all PM10 sampling sites operate either every
other day or everyday. In contrast, only 5 percent of TSP Hi-Vols operate more
frequently than once in 6 days.
Although some monitoring for PM10 was initiated prior to promulgation of the
new standards, most networks did not produce data with approved reference samplers
until 1987 or 1988. Thus, only a limited data base is currently available to examine
trends in PM10 air quality. Accordingly, partieulate matter trends presented in this
Section will be based primarily on TSP. Trends for TSP are presented in terms of
average air quality (annual geometric mean). In addition, available information on PM10
air quality will be used to report the 1987 - 1988 change in PM10 concentration levels.
31
-------
Two PM)0 statistics are presented. The annual arithmetic mean concentration is used
to reflect average air quality, and the 90th percentile of 24-hour concentrations is used
to represent the behavior of peak concentrations. Because PM10 sampling frequency
varies among sites and may have changed during the 2-year period, the 90th percentile
is used. This statistic is less sensitive to changes in sampling frequency than the peak
values. Finally, cross sectional PM10 data is included for the more comprehensive data
available for calendar year 1988.
3.1.1 Historical Perspective: 1960-88
TSP data have been collected throughout the nation for over 30 years, and
have exhibited substantial declines in pollutant concentration. The most recent 10-
year period merely represents the tail end of over 3 decades of improvements resulting
from nationwide air pollution control. Historical emission estimates are also available
and have also been compiled for this same 30-year period.
The TSP trends are constructed from an evolving network of particulate
samplers, and are presented as separate trend lines for each decade. During the
1960s, 122 TSP sampling locations from the relatively limited National Air Surveillance
Network (NASN) are used to characterize the early national particulate trend. These
early TSP samplers operated on a bi-weekly schedule. With the passage of the Clean
Air Act, TSP sampling networks operated by State and local air pollution control
agencies developed and typically sampled once in 6 days. The number of operating
samplers varied over time, with the national network peaking during the mid-1970's,
when almost 4500 sampling stations existed throughout the country. From these
stations, 1109 and 1750 sites with sufficient data continuity are used to define the
national trend for the 1970's and 1980's, respectively. It should be noted that TSP is
the only pollutant with a large national monitoring network, using a consistent sampling
methodology which permits this type of trend analysis.
Figure 3-2 reveats that the 3-decade decline in ambient particulate concentrations
is reasonably steady, with an obvious leveling off during the 1980's. Although the three
trend segments are derived from different sites, they present a nearly continuous
record. Year-to-year variability in the composite TSP concentrations during the early
years is attributed to the small number of operating samplers. The perturbation from
a generally declining trend, which occurred around 1980, is attributed to a change in
sampling filters and is discussed in more detail in the next section.
32
-------
120
Concentration, u
100-
80-
60-
40-
20-
TSP Air Qudtty Trends
1960-70 1970-79
1109 STTK
1979-88
1750:
%*-
1960
1965
1970
1975
1980
1985
Figure 3-2. Historical trends in ambient TSP concentrations, 1960-1988
10 metric tons/year
0
1960
1965
1970
1975
1980
1985
Figure 3-3. Historical trends in total particulate emissions, 1960-
33
-------
While ambient TSP concentrations have declined approximately 50 percent,
estimated emissions among inventoried sources have been cut by two thirds (Figure
3-3). Since these estimated emissions do not include many sources which contribute
to natural background and also do not include unpaved roads and construction activity,
the smaller improvement in ambient air quality is understandable.
3.1.2 Long-term TSP Trends: 1979-88
The 10-year trend in average TSP levels, 1979 through 1988, is shown in Figure
3-4 for 1750 sites geographically distributed throughout the Nation, Trends are also
shown for the subset of 450 National Air Monitoring Stations (NAMS) which are located
in areas of greater than 50,000 in population. The TSP levels are expressed in terms
of the composite average annual geometric mean,
, The curves in Figure 3-4 show identical trends for both the NAMS and the larger
group of sites, although composite particulate concentrations are higher for the NAMS.
For both curves, composite TSP concentrations declined during the early part of the 10-
year period and are relatively stable in the later years. The data collected during 1979-
1981 may have been affected by the type of filters used to collect the TSP.2 For this
reason, the portion of Figure 3-4 corresponding to the years 1979-1981 are stippled,
to indicate the uncertainty in the TSP measurements collected during this period.
Previous trends reports have determined that 1978 levels were produced with valid
filters and that composite 1979 levels were only one percent higher. Therefore, the 10-
year comparisons can be legitimately determined using 1979 as a base year.
Although the difference between 1979 and post-1981 is real, the pattern of the yearly
change in TSP between 1979 and 1981 is difficult to assess and most of the large
apparent decrease in pollutant concentrations between 1981 and 1982 can be attributed
to a change in these filters.2"5
The composite average of TSP levels measured at 1750 sites, distributed
throughout the Nation, decreased 20 percent during the 1979 to 1988 time period, and
the subset of 450 NAMS decreased 19 percent. Figure 3-4 also includes 95 percent
confidence intervals developed for the composite annual estimates.
It can be seen that the estimates for 1982 - 1988 are relatively stable and are
all significantly lower than those of 1979 - 1981. Upon close inspection, some slight
changes since 1982 are evident. First, the minimum composite TSP levels occurred
during the years 1985 and 1986. Second, statistically significant increases were
detected during the last three years, so that 1988 concentration levels have returned
to earlier levels observed during 1982 and 1984. These recent trends in total
suspended particulate matter will be discussed in more detail in Section 3.1.3,
The long-term trends in TSP are also illustrated in Figure 3-5. Using the same
national data base of 1750 TSP sites, Figure 3-5 shows the yearly change in the entire
national concentration distribution using boxplot displays. A decrease occurred at every
percentile level between 1979 and 1988, further indicating a broad national
improvement in ambient particulate concentrations throughout the country.
34
-------
80
70
60
50
40
30
20
10
0
CONCENTRATION, UG/M*
NAMS SiTES (450) AaSITCSjTS
1979 1980 1981 1982 1983 1984 1986 1986 1987 1988
Figure 3-4. National trend in the composite average of the geometric mean total
suspended participate at both NAMS and all sites with 95 percent
confidence intervals, 1979-1988.
CONCENTRATION,
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-5. Boxplot comparisons of trends in annual geometric mean total suspended
partlculate concentrations at 1750 sites, 1979-1988.
35
-------
Nationwide TSP emission trends show an overall decrease of 22 percent from
1979 to 1988 which coincidentally matches the TSP air quality improvement. (See
Table 3-1 and Figure 3-6). The trend in PM emissions is normally not expected to
agree precisely with the trend in ambient TSP levels due to unaccounted for natural
PM background and uninventoried emission sources such as unpaved roads and
construction activity. Such fugitive emissions could be of significant magnitude and
are not considered in estimates of the annual nationwide total. Due to delays in 1988
emissions data reporting, the impact of the massive forest fires which occurred in
Yellowstone National Park, are also not reflected in the 1988 estimates. The 10-year
reduction in inventoried particulate emissions occurred primarily because of reductions
in industrial processes. This is attributed to installation of control equipment, and also
to reduced activity in some industries, such as iron and steel. Other areas of TSP
emission reductions include reduced coal burning by non-utility users and installation
of control equipment by electric utilities that burn coal.1
Table 3-1. National Total Suspended Particulate Emission Estimates, 1979-1988,
(million metric tons/year)
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Source Category
Transportation
Fuel Combustion
Industrial
Processes
Solid Waste
Miscellaneous
Total
NOTE: The sums of sub-categoriaa may not equal total due to rounding.
1.4
2.5
3.i
0.4
0.9
8.9
1
2
3
0
1
8
.3
.4
.3
.4
.1
.5
1.3
2.3
3.0
0.4
0.9
8.0
1
2
2
0
0
7
.3
.2
.6
.3
.7
.1
1
2
2
0
1
7
.3
.0
.4
.3
.1
.1
1
2
2
0
0
7
.3
.1
.8
.3
.9
.4
1.
1.
2.
0.
0.
7.
4
8
8
3
8
1
1.4
1.8
2.5
0.3
0.8
6.8
1.4
1.8
2.5
0.3
1.0
7.0
1.4
1.7
2.6
0.3
0.9
6.9
36
-------
3.1.3 Recent TSP Trends: 1984-88
The TSP trends for the 5-year period 1984 through 1988 are presented in terms
of 1491 sites which produced data in at least 4 of these 5 years. The group of sites
qualifying for this analysis is smaller than the group used to analyze long-term trends,
reflecting the revisions to TSP SLAMS networks and the shift of paniculate monitoring
to PM10. Figure 3-7 presents a boxplot display of the 1984-1988 annual TSP
concentration distributions. Very little change in TSP concentrations is evident between
1984 and 1988. A small 2 percent increase was seen between 1987 and 1988. This
pattern in air quality, however, does not match the 5-year trend in national particulate
emission estimates.
Particulate emissions are reported to have decreased 7 percent from 1984 to
1988. This 5-year decline in inventoried sources may be overstated, somewhat,
because the major forest fires in Yellowstone during the summer of 1988 have not
been included in the 1988 estimates. Emissions from forest fires typically represent
10 to 14 percent of the national total. The estimate reported for 1988 is only 11
percent. Figure 3-8 focuses on the last 3 years with a bar chart of Regional average
TSP. Overall there were relatively small changes in most Regions. The largest
decrease in total particulate concentrations is seen in Region X, which experienced an
unusually high number of wildfires during 1987.6
TSP EMISSIONS, 10s METRIC TONS/YEAR
SOURCE CATEGORY
TRANSPORTATION
INDUSTRIAL PROCESSES
SOUD WASTE & MISC
0
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-6. National trend in particulate emissions, 1979-1988.
37
-------
3.1.4 Effect of Meteorology on Short-term Trends
The observed year-to-year variations in paniculate levels may in part be
attributable to meteorology. Among all meteorological parameters, precipitation has
been shown to have had the greatest influence on paniculate air quality. Rainfall has
the effect of reducing reentrainment of particles and of washing particles out of the air.
Generally drier conditions are also associated with an increase in forest fires.
During 1988, most of the nation experienced an extreme drought. Nationally,
this year was the driest since 1956 and the second driest in the last 50 years. While
the total precipitation decreased 13 percent from 1987, one fifth of the States
experienced decreases exceeding 20 percent. The dry conditions were most severe
in the southern Atlantic States (VA, NC, SC), the Midwest (IL, IA, MO, KS, NE)
extending southward (OK, TX) and included the West (CA, NV, AZ) and the Mountain
States (UT, WY, MT, ND).7
On a State-by-State basis, the largest decreases in precipitation were associated
with the larger observed increases in TSP. Among those States with more than 20
percent decrease in precipitation (CA, 1A, KS, NE, NV, OK, TX, UT, VA and WY), all
except California, Texas and Wyoming increased in average TSP.
110
100-
90-
80-
70
60 H
50
40-
30-
20-
10 -
0
CONCENTRATION,
1491 SITES
""KAAOS"
1984
1985
1986
1987
1988
Figure 3-7. Boxplot comparisons of trends in annual mean total suspended paniculate
concentrations at 1491 sites, 1984-1988.
38
-------
3.1.5 Recent PM10 Air Quality
The 1987-1988 change in the PM10 portion of total participate concentrations is
examined at a limited sample of 119 monitoring locations. This sample is.not truly
national, since it does not include any sampling stations in Region IX (CA, NV, AZ and
Hi) and only includes one site in Alaska to represent Region X. Nevertheless, it
provides us with an indication of the year-to-year behavior of this new indicator for
paniculate matter. A more comprehensive national sample of 432 sites is also
presented to provide a more representative indication of 1988 PM10 air quality produced
by reference PM10 samplers.
The sample of 119 trend sites reveal a statistically significant 4 percent decrease
in average PM10 concentrations. At the same sites, only an insignificant 1 percent
decrease was noted in peak 24-hr concentrations. The 2-year decrease of 4 percent
in average PM10 concentrations presents a somewhat different picture than the 2
percent increase described earlier for TSP. The contrast is even more notable for the
8 eastern most regions in which average TSP increased 3 percent.
CONCENTRATION,
ou -
70-
60-
50-
40-
30-
20-
10-
COMPOSITE AVERAGE
mi 1986 fli 1987 E2 1988
J
EPA REGION
/
<
/
y
/
/*
n
/
/
/
/
?
T -n
'
,
y
r ''
7
t
/
/
K
1
\
1
1
I
II III IV
^
f
?
f
/
/
s
/
/
V VI
_
/
x
'
/
/
7
ซ*
X
/
/
/
/
/
'
/
/
/
I
I
I
1
/
^
/
/
/
/
/
/
/
t
if
/
/
r.
/
/
s
/
J
/
VII VIII IX
f
t
t
/
/
/
/
^
*
/
X
NO. OF SITES 68 83 167 285 403 158 107 57 96 67
Figure 3-8. Regional comparisons of the 1986, 1987, 1988 composite averages of
the geometric mean total suspended particulate concentration.
39
-------
A subset of 63 sampling locations at which PM10 and TSP samplers were
collocated during both years confirm that the PM10 portion of the total paniculate, in
fact, decreased from 59 percent in 1987 to 56 percent in 1988. Again it should be
noted that the Western Regions are not well represented in this PM10 sample. The
extremely dry conditions during 1988 may have had more impact on the larger particles
(i.e. greater than 10 microns). However, the drought may have also affected PM10
concentrations, since the smallest changes in PM1D occurred in Regions VII and VIII
whose States experienced the biggest drop in precipitation.
Figure 3-9 displays box-plots of the concentration distribution for the two PM10
trend statistics - annual arithmetic mean and 90th percentile of 24-hour concentrations -
in order to place the 2-year change in air quality in the context of the more
representative national sample of 432 sites. The 1988 PM10 at the 119 trend sites
produced somewhat lower concentrations, both on average and for peak 24-hour
concentrations. This is attributed to regional variations in PM10 concentrations, which
are discussed later.
The more representative 1988 concentration distribution of annual arithmetic
means also provides a basis for direct comparison to the annual standard of 50 |ig/m3.
Approximately 8 percent of monitoring stations reported averages above the annual
standard.
Although the 90th percentile is a reasonable indicator for temporal comparisons,
it does not directly relate to the 150 ng/m3 level of the 24-hour PM10 standard. Since
this standard permits one expected exceedance per year, the maximum and second
maximum 24-hour concentrations provide a more direct indication of attainment status.
A comparison of the 90th percentile of 24-hour concentrations to these other indicators
of peak concentrations is presented in Figure 3-10 using box-plots of the 1988 national
concentration distribution. Although the 90th percentile concentrations are well below
150 |4.g/m3, maximum concentrations exceed the standard at 13 percent of the reporting
locations while the second maximum concentrations exceed at 6 percent.
40
-------
110
100-
90-
80-
70-
60-
50
40-
30-
20-
10
0
Annud Arithmetic
Means
90th %-tite
of 24hr caneenfnaHons
1987 t988
1987 1988
Figure 3-9. Boxplot comparisons of the 2-year change In PM10 concentrations (1987-
1988) at 119 sites with 1988 PM10 air quality at 432 sites.
Concentration, ug/n
90TH
%-TILE
2ND
MAX
ฃ. IU
180-
150-
120-
90-
60-
30-
n -
_
K
i
jl|
*ป
I
n
~
59
si
is
X
MAX
Figure 3-10. Boxplot comparisons of 24-hour PM10 peak value statistics for 1988 at 432
sites.
41
-------
Figure 3-11 presents the Regional distribution of PM10 concentrations for both
average and 90th percentile concentrations among the 432 stations producing reference
measurements in 1988. The highest average and peak 24-hr concentrations are seen
in Regions IX and X. High 24-hr concentrations are also observed for Region III,
although the limited number of 5 sampling stations in Pennsylvania does not provide
a regionally representative indicator.
The 90th percentile of 24-hour concentrations has been used as the indicator
of peak concentrations because of differences in sampling frequency among PM10
sampling locations. Note that average sampling frequency varies among Regions,
with Region VIIPs samplers operating at more than twice the frequency of Region IX's,
CONCENTRATION,
REG ONAL AVERAGE
ARITHMETIC ^ 90TH
MEAN PERCENTILE
EPA REGION I II III IV V VI VII VIII K X
NO. OFSrTES 27 21 5 64 84 35 21 59 64 52
Figure 3-11. Regional comparisons of annual mean and 90th percentile of 24-hour
PM,n concentrations.
42
-------
3.2 TRENDS IN SULFUR DIOXIDE
Ambient sulfur dioxide (SO2) results largely from stationary source coal and oil
combustion, refineries, pulp and paper mills and from nonferrous smelters. There are
three NAAQS for SO2; an annual arithmetic mean of 0.03 ppm (80 ng/m3}, a 24-hour
level of 0.14 ppm (365 (ig/m3) and a 3-hour level of 0.50 ppm (1300 ^ig/rn). The first
two standards are primary (health-related) standards, while the 3-hour NAAQS is a
secondary (welfare-related) standard. The annual mean standard is not to be
exceeded, while the short-term standards are not to be exceeded more than once per
year. The trend analyses which follow are for the primary standards. It should be
noted that EPA is currently evaluating the need for a new shorter-term 1-hour
standard.8
Although this report does not directly address trends in acid deposition, of which
SO2 is a major contributor, it does include information on total nationwide emissions
which is a measure relating to total atmospheric loadings.
The trends in ambient concentrations are derived from continuous monitoring
instruments which can measure as many as 8760 hourly values per year. The SO2
measurements reported in this section are summarized into a variety of summary
statistics which relate to the SOZ NAAQS. The statistics on which ambient trends will
be reported are the annual arithmetic mean concentration, the second highest annual
24-hour average (summarized midnight to midnight), and the expected annual number
of 24-hour exceedances of the 24-hour standard of 0.14 ppm.
3.2.1 Long-term SO2 Trends: 1979-88
The long-term trend in ambient SO2, 1979 through 1988, is graphically presented
in Figures 3-12 through 3-14. In each figure, the trend at the NAMS is contrasted with
the trend at all sites. For each of the statistics presented, a steady downward trend
is evident through 1987, followed by a slight upturn in 1988. Nationally, the annual
mean SO2, examined at 374 sites, decreased at a median rate of approximately 4
percent per year; this resulted in an overall change of about 30 percent (Figure 3-12).
The subset of 116 NAMS recorded higher average concentrations and also declined
at the same median rate, with a net change of 33 percent for the 10-year period.
The annual second highest 24-hour values displayed a similar improvement
between 1979 and 1988. Nationally, among 364 stations with adequate trend data,
the median rate of change was 4 percent per year, with an overall decline of 36
percent (Figure 3-13). The 118 NAMS exhibited an overall decrease of 34 percent.
The estimated number of exceedances also showed declines for the NAMS as well
as for the composite of all sites (Figure 3-14). The national composite estimated
number of exceedances decreased 90 percent from 1979 to 1988. However, the vast
majority of SO2 sites do not show any exceedances of the 24-hour NAAQS. Most of
the exceedances as well as the bulk of the improvements occurred at source-oriented
sites.
43
-------
0.035
CONCENTRATION, PPM
0.030
0.025-
0.020-
0.01S-
0.010-
0.005
0.000
NAAQS-
NAMS SITES (116) o AU.JOES|5W
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-12. National trend in annual average sulfur dioxide concentration at both
NAMS and all sites with 95 percent confidence intervals, 1979-1988.
CONCENTRATION, PPM
0.16
0.14
0.12-
0,10-
0.08-
0.06-
0.04
0.02-
0.00
NAAQS
NAMS SITES (118) ฐ ALLSjTESi364l
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-13. National trend in the second-highest 24-hour sulfur dioxide concentration
at both NAMS and all sites with 95 percent confidence intervals,
1979-1988.
44
-------
1 .5
ESTIMATED EXCEEDANCES
1 -
0.5-
0-
NAMS SHIS (118) a AJljrrESj364l
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-14. National trend in the estimated number of exceedances of the 24-hour
sulfur dioxide NAAQS at both NAMS and all sites with 95 percent
confidence intervals, 1979-1988.
45
-------
The statistical significance of these long-term trends is graphically illustrated in
Figures 3-12 to 3-14 with the 95 percent confidence intervals. For both annual
averages and peak 24-hour values, the SO2 levels In 1987 are the lowest in 10 years
but are statistically indistinguishable among the last three. Expected exceedances of
the 24-hour standard experienced a more rapid decline. For each statistic, 1988
averages are significantly lower than levels before 1983.
The inter-site variability for annual mean and annual second highest 24-hour
SO2 concentrations is graphically displayed in Figures 3-15 and 3-16. These figures
show that higher concentrations decreased more rapidly and that the concentration
range among sites has also diminished from the late 1970s to the present.
PPM
0.040
0.035-
0.030
0.025-
0.020-
0.015-
0.010
0.005-
O.300
374SfTES
1375 iS50 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-15. Boxplot comparisons uf iiends in annual mean sulfur dioxide
concentrations at 374 sites, 1979-1988.
46
-------
0.20
CONCENTRATION, PPM
0.15-
0.10-
0.05-
o.oo
364 SITES
KAAQSi
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-16. Boxplot comparisons of trends in second highest 24-hour average sulfur
dioxide concentrations at 364 sites, 1979-1988.
47
-------
Nationally, sulfur oxide emissions decreased 17 percent from 1979 to 1988
(Figure 3-17 and Table 3-2), reflecting the installation of flue gas desuifurization controls
at new coal-fired electric generating stations and a reduction in the average sulfur
content of fuels consumed. Emissions from other stationary source fuel combustion
sectors also declined, mainly due to decreased combustion of coal by these consumers.
Sulfur oxides emissions from industrial processes are also significant. Emissions from
industrial processes have declined, primarily as the result of controls implemented to
reduce emissions from nonferrous smelters and sulfuric acid manufacturing plants, as
well as shutdowns of some large smelters.1 Sulfur oxide emission increases between
1987 and 1988 can be attributed to increased industrial activity, which offset continued
reductions in emissions caused by fuel combustion.
The disparity between the 30 percent improvement in SO2 air quality and the
17 percent decrease in SOX emissions can be attributed to several factors. SO2
monitors with sufficient historical data for trends are mostly urban population-oriented,
and as such, do not monitor many of the major emitters which tend to be located in
more rural areas. Among the 374 trend sites used in the analysis of average S02
levels, approximately two-thirds are categorized as population-oriented. The remaining
sites include those monitors in the vicinity of large power plants, nonferrous smelters
and other industrial sources such as paper mills and steel producing facilities.
The residential and commercial areas, where most monitors are located, have
shown sulfur oxides emission decreases comparable to SO2 air quality improvement
These decreases in sulfur oxides emissions are due to a combination of energy
conservation measures and the use of cleaner fuels in the residential and commercial
areas.1 Comparable SO2 trends have also been demonstrated for monitors located in
the vicinity of nonferrous smelters which produce some of the highest SO2
concentrations observed nationally.9 Smelter sources represent a majority of SOX
emissions in the intermountain region of the western U.S. Although one-third of the
trend sites are categorized as source-oriented, the majority of SOX emissions are
dominated by large point sources. Two-thirds of all national SO, emissions are
generated by electric utilities (93 percent of which come from coal fired power plants).
The majority of these emissions, however, are produced by a small number of facilities.
Fifty individual plants in 15 states account for one-half of all power plant emissions.
In addition, the 200 highest SOX emitters account for more than 85 percent of all SO,
power plant emissions. These 200 plants account for 59 percent of all SOX emissions
nationally.10
Another factor which may account for differences in SOX emissions and ambient
air quality is stack height. At large utilities and smelters, SO2 is generally released into
the atmosphere through tall stacks. Under these circumstances, measured ground level
concentrations in the vicinity of these sources may not reflect local emissions. Total
atmospheric loading impacts also arise, in part, as a consequence of tall stacks.
48
-------
Table 3-2. National Sulfur Oxides Emission Estimates, 1979-1988.
1979 1980
Source Category
Transportation 0.9 0.9
Fuel Combustion 19.5 18.7
Industrial
Processes
Solid Waste
Miscellaneous
Total
(million metric tona/yaar)
1981 1982 1983 1984 1985 1986 1987 1988
0.9
0.8
0.8
0.8
0.9
0.9
0,9
0.9
17.8 17.3 IS.7 17.4 17.0 16.9 16.6 16.-
4.4
0.0
0.0
3.8
0.0
0.0
3.9
0.0
0.0
3.3
0.0
0.0
3.3
0.0
0.0
3.3
0.0
0.0
3.2
0.0
O.O
3.1
0.0
0.0
3.2
0.0
0.0
3,4
0.0
0.0
NOTE
24.8 23.4 22.6 21.4 20.7 21.5 21.1 20.9 20.6 20.7
: The sums of suB-categories may not equal total due to rounding.
SO, EMISSIONS, 10* METRIC TONS/YEAR
SOURCE CATEGORY
El TRANSPORTATION B FUEL COUBUST10H
0
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-17. National trend in sulfur oxides emissions, 1979-1988.
49
-------
3.2.2 Recent S02 Trends: 1984-88
Figure 3-18 presents boxplots for the 1984-1988 data using 584 SO2 sites. The
5-year trend shows an 13 percent decline in average concentrations, indicating that the
long term trend has continued but has been leveling off. Correspondingly, -SOX
emissions have decreased only 4 percent over the last 5 years. Between 198/ and
1988, average ambient concentrations have increased 1 percent, corresponding to a
less than 1 percent increase in total emissions.
Regional changes in composite average SO2 concentrations for the last 3 years,
1986-1988, are shown in Figure 3-19. Several Regions show moderate increases
between 1987 and 1988. Only Region X shows a consistent decline, resulting from
lower monitored concentrations in the vicinity of State of Washington pulp mills.
0.040
CONCENTRATION, PPM
0.035-
0.030
0.025
0.020-
0.015-
0.010
0.005 -
0.000
584 SITES
"*
ป"-ป*ป*.
">ซ-
1984
1985
1986
1987
1988
Figure 3-18. Boxplot comparisons of trends in annual mean sulfur dioxide
concentrations at 584 sites, 1984-1988.
50
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CONCENTRATION, PPM
0.014-
0.012-
0.010-
0.008-
0.006-
0.004-
0.002-
EPA REGION
NO. OF SITES 5ฃ
/
/
/
/
I
f
^
/ J
/
1
/
^
if
/
COMPOSITE AVERAGE
^ 1986 ^ 1987 Q 1988
/
'
/
/
/>
/
^
/
/
/
/
t
?
I
\
I
/
/
/
f
/
/
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/
/
I
/
^
II 111 IV V VI VII Vill
\ 46 74 fO 183 57 25 10
IX
57
jf
f
/
?
4>
s
/
ฃ.
X
11
Figure 3-19. Regional comparisons of the 1986, 1987, 1988 composite averages of
the annual average sulfur dioxide concentration.
51
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Preceeding Page Blank
3.3 TRENDS IN CARBON MONOXIDE
Carbon monoxide (CO) is a colorless, odorless, and poisonous gas produced
by incomplete burning of carbon in fuels. Two-thirds of the nationwide CO emissions
are from transportation sources, with the largest contribution coming from highway
motor vehicles. The NAAQS for ambient CO specify upper limits for both 1-hour and
8-hour averages that are not to be exceeded more than once per year. The 1-hour
level is 35 ppm, and the 8-hour level is 9 ppm. This trends analysis focuses on the
8-hour average results because the 8-hour standard is generally the more restrictive
limit. In fact, only six exceedances of the CO 1-hour NAAQS were recorded for the
nation during 1988.
Trends sites were selected using the procedures presented in Section 2.1 which
yielded a data base of 248 sites for the 10-year period 1979-88 and a data base of
359 sites for the 5-year 1 984-88 period. There were 72 NAMS sites included in the
10-year data base and 100 NAMS sites in the 5-year data base. This 45 percent
increase in the number of trend sites available for the more recent time period is
consistent with the improvement in size and stability of current ambient CO monitoring
programs.
3.3.1 Long-term CO Trends: 1979-88
The 1979-88 composite national average trend is shown in Figure 3-20 for the
second highest non-overlapping 8-hour CO value for the 248 long-term trend sites and
the subset of 72 NAMS sites. During this 10-year period, both the national composite
average and the subset of NAMS decreased by 28 percent. The median rate of
improvement for this time period is slightly less than 4 percent per year. After leveling
off to no significant change from 1985 to 1986, the trend resumed downward in 1987
and 1988. Long-term improvement was seen in each EPA Region with median rates
of improvement varying from 2 to 5 percent per year. This same trend is shown in
Figure 3-21 by a boxplot presentation which provides more information on the year-to-
year distribution of ambient CO levels at the 248 long-term trend sites. While there is
some year to year fluctuation in certain percentiles, the general long-term improvement
in ambient CO levels is clear.
Figure 3-22 displays the 10-year trend in the composite average of the estimated
number of exceedances of the 8-hour CO NAAQS. This exceedance rate was adjusted
to account for incomplete sampling. The trend in exceedances shows long-term
improvement but the rates are much higher than those for the second maximums. The
composite average of estimated exceedances decreased 88 percent between 1979 and
1988 for the 248 long-term trend sites, while the subset of 72 NAMS showed an 82
percent decrease. These percentage changes for exceedances are typically much
larger than those found for peak concentrations, such as the annual second maximum
8-hour value, which is more likely to reflect the change in emission levels.
53
-------
CONCENTRATION, PPM
NAAQS
NAMS SITES (72) ซ AI_L_SrTES_(248)_
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-20. National trend in the composite average of the second highest
nonoverlapping 8-hour average carbon monoxide concentration at both
NAMS and all sites with 95 percent confidence intervals, 1979-1988.
20
CONCENTRATION, PPM
15-
10-
5-
0
248SfTES
K.
I
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-21. Boxplot comparisons of trends in second highest nonoveriapping 8-hour
average carbon monoxide concentrations at 248 sites, 1979-1988.
54
-------
20
EST. 8-HR EXCEEDANCES
15-
10-
0
NAMS SITES (72) ฐ ALLSITES_(248l
*i 1 1 ~i r
1979 ^980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-22. National trend in the composite average of the estimated number of
exceedances of the 8-hour carbon monoxide NAAQS, at both NAMS and
all sites with 95 percent confidence intervals, 1979-88.
55
-------
The 10-year 1979-88 trend in national carbon monoxide emission estimates is
shown in Figure 3-23 and in Table 3-3. These estimates show a 25 percent decrease
between 1979 and 1988. Transportation sources accounted for approximately 72
percent of the total in 1979 and decreased to 67 percent of total emissions in 1988.
Emissions from highway vehicles decreased 30 percent during the 1979-88 period,
despite a 33 percent increase in vehicle miles of travel.1 Rgure 3-24 contrasts the 10
year increasing trend in vehicle miles travelled (VMT) with the declining trend in carbon
monoxide emissions from highway vehicles. This indicates that the Federal Motor
Vehicle Control Program (FMVCP) has been effective on the national scale, with
controls more than offsetting growth during this period. While there is general
agreement between changes in air quality and emissions over this 10-year period, it is
worth noting that the emission changes reflect estimated national totals, while ambient
CO monitors are frequently located to identify problems. The mix of vehicles and the
change in vehicle miles of travel in the area around a specific CO monitoring site may
differ from the national averages.
Despite the progress that has been made, CO remains a concern in many urban
areas. The characterization of the CO problem is complicated because of the growth
and possible changes in traffic patterns that have occurred in many major urban areas.
There are a variety of possible factors to consider, such as topography, meteorology,
and localized traffic flow. The goal is to ensure that the monitoring networks continue
to characterize the ambient CO problem adequately. However, these concerns should
not overshadow the genuine progress documented over time in areas that have
traditionally been the focus of the CO problem.
3.3.2 Recent CO Trends: 1984-88
This section examines ambient CO trends for the 5-year period 1984-88. As
discussed in section 2.1, this allows the use of a larger data base, 359 sites versus
248. Figure 3-25 displays the 5-year ambient CO trend in terms of the second highest
non-overlapping 8-hour averages. These sites showed a 16 percent decrease between
1984 and 1988. The general patterns are consistent with the longer term data base
and, after no change between 1985 and 1986, levels resumed their decline. The 1988
composite average is 3 percent lower than the 1987 composite average. Table 3-3
indicates that estimated total CO emissions decreased 15 percent during this 5-year
period and that emissions from transportation sources decreased 19 percent.
56
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Table 3-3, National Carbon Monoxide Emission Estimates, 1979-1988.
(million metric tono/yaar)
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Source Category
Transportation 59.1 56.1 55.4 52.9 52.4 50.6 47.9 44.fi 43.2 41.2
Fuol Combuation 6.7 7.4 7.7 8.2 8.2 8.3 7.4 7.5 7.6 7.6
Industrial
Procaaaea
Solid Waatซ
Miacallaneoua
Total
7.1 6.3 5.9 4.3 4.3 4.7 4.4 4.3 4.5 4.7
2.3 2.2 2.1 2.0 1.9 1.9 2.0 1.7 1.7 1.7
6.5 7.6 6.4 4.9 7.7 6.3 5.3 5.0 7.1 6.0
81.7 79,6 77.4 72.4 74.5 71.8 67.0 63.1 64.1 61.2
NOTE: Tho sumo of sub-catagorฑaซ nay not: equal total duซ to rounding.
120
100
CO EMISSIONS, 10s METRIC
SOURCE CATEGORY
m TRANSPORTATION
123 FUEL
COMBUSTiON
EB INDUSTRIAL PROCESSES
SOLID WASTE & M1SC
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-23. National trend in emissions of carbon monoxide, 1979-1988.
57
-------
140
% of 1979 level
Highway Vehic es
CO Emissions
1979 1980' 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-24. Comparison of trends in total National vehicle miles traveled and National
highway vehicle emissions, 1979-1988.
20
CONCENTRATION, PPM
15-
10-
0
T
359 SITES
iNAAQS
1984
1985
1986
1987
1988
Figure 3-25. Boxplot comparisons of trends in second highest nonoverlapping 8-hour
average carbon monoxide concentrations at 359 sites, 1984-1988.
58
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Figure 3-26 shows the composite Regional averages for the 1984-88 time period.
Eight of the ten Regions have 1988 composite levels lower than 1987 levels. The
composite average in Region IX increased 9 percent, while Region IV showed no
change. These Regional graphs are primarily intended to depict relative change.
Because the mix of monitoring sites may vary from one area to another, this graph is
not intended to indicate Regional differences in absolute concentration levels.
CONCENTRATION, PPM
1 . --
1 *+
12-
10-
8-
6-
4-
2-
C
B
JOMPOSITE AVERAGE
3 19B6 1987 ED 1988
I
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f/
x
/
I
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/
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1^-
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*ป
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/
/
s
f
p
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EPA REGION
i'
/
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/
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x
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!/
5
I
1
1
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II III IV V VI VII VII! IX X
NO. OF SITES 15 27 48 50 49 29 18 17 83 23
Figure 3-26. Regional comparisons of the 1986, 1987,1988 composite averages of the
second highest non-overlapping 8-hour average carbon monoxide
concentration.
59
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3.4 TRENDS IN NITROGEN DIOXIDE
Nitrogen dioxide (NO2) is a yellowish brown, highly reactive gas which is present
in urban atmospheres. The major mechanism for the formation of NO2 in the
atmosphere is the oxidation of the primary air pollutant, nitric oxide (NO). It plays a
major role, together with volatile organic compounds, in the atmospheric reactions that
produce ozone. Nitrogen oxides form when fuel is burned at high temperatures. The
two major emissions sources are transportation and stationary fuel combustion sources
such as electric utility and industrial boilers.
Nitrogen oxides can irritate the lungs, cause bronchitis and pneumonia, and
lower resistance to respiratory infections. Los Angeles, CA is the only urban area that
has recorded violations of the annual NO2 standard of 0.053 ppm during the past 10
years.
NO2 is measured using a continuous monitoring instrument which can collect
as many as 8760 hourly observations per year. Only annual means based on at least
4380 hourly observations were considered in the trends analyses which follow. A total
of 116 sites were selected for the 10-year period and 194 sites were selected for the
5-year data base.
3.4.1 Long-term NO2 Trends: 1979-88
The composite average long-term trend for the nitrogen dioxide mean
concentrations at the 116 trend sites and the 27 NAMS sites, is shown in Figure 3-27.
Nationally, composite annual average N02 levels decreased from 1979 to 1983, and
have remained essentially constant since 1984. The 1988 composite average NO2 level
is 7 percent lower than the 1979 level, indicating an overall downward trend during this
period. A similar trend is seen for the NAMS sites which, for NO2, are located only in
urban areas with populations of 1,000,000 or greater. As expected, the composite
averages of the NAMS are higher than those of all sites, and they recorded a 6 percent
decrease during this period.
In Figure 3-27, the 95 percent confidence intervals about the composite means
allow for comparisons among the years. There are no significant differences among
the recent years, for all sites and for the NAMS. The 1987 and 1988 composite mean
NO2 levels are not significantly different from one another, but 1988 is significantly less
than 1979.
Long-term trends in NO2 annual average concentrations are also displayed in
Figure 3-28 with the use of boxplots. The improvement in the composite average
between 1979 and 1988 can generally be seen in the upper percentiles until 1984.
The lower percentiles show little change, however.
60
-------
0.06
CONCENTRATION, PPM
0.05-
0.04-
0.03-
0.02-
0.01 -
0.00
NAAQS-
i i
-i i
ป W_____ _ jy _____
* MAMS SITES (27) ป ALLS(|ES_(1J6)_
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-27. National trend in the composite average of nitrogen dioxide concentration
at both NAMS and all sites with 95 percent confidence intervals, 1979-
1988.
0.07
0.06-
0.05-
0.04-
0.03
0.02-
0.01 -
CONCENTRATION, PPM
0.00
116 sms
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-28. Boxplot comparisons of trends in annual mean nitrogen dioxide
concentrations at 116 sites, 1979-1988.
61
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The trend in the estimated nationwide emissions of nitrogen oxides (NCy is
similar to the NOZ air quality trend. Table 3-4 shows NOX emissions decreasing from
1979 through 1983 then increasing in 1984 and 1985. Total 1988 nitrogen oxide
emissions decreased by 8 percent from 1979 levels. Highway vehicle emissions
decreased by 24 percent during this period. Figure 3-29 shows that the two primary
source categories of nitrogen oxide emissions are fuel combustion and transportation,
composing 55 percent and 41 percent, respectively, of total 1988 nitrogen oxide
emissions.
3.4.2 Recent NO2 Trends: 1984-88
Figure 3-30 uses the boxplot presentation to display recent trends in nitrogen
dioxide annual mean concentrations for the years 1984-88. Focusing on the past 5
years, rather than the last 10 years, increases the number of sites, from 116 to 194,
available for the analysis. The composite means from the recent period are essentially
the same as the long-term means and the trends are consistent for the two data bases.
The composite average NO2 level for the 194 trend sites has remained relatively
constant during the last 5 years. The 1988 composite mean is less than 1 percent
higher than the composite mean for 1984. The 1988 composite mean concentration
is 1 percent higher than the 1987 level. During this same period, 1988 total nationwide
emissions of nitrogen oxides returned to 1984 levels after declining In 1986. Between
1987 and 1988, total emissions of nitrogen oxides increased 3 percent, primarily due
to fuel combustion emissions resulting from increased industrial activity.
Regional trends in the composite average NO2 concentrations for the years
1986-88 are displayed in Figure 3-31 with bar graphs. Region X, which did not have
any NO2 sites which met the 5-year trends data completeness and continuity criteria,
is not shown. The pattern of the year-to-year changes is mixed among the Regions.
Although the national composite average showed no change during this period, seven
Regions showed small increases from 1986 to 1987. Between 1987 and 1988, five
Regions recorded decreases in the composite average NO2 levels, three Regions
recorded increases and one Region was unchanged.
62
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Table 3-4. National Nitrogen Oxides Emission Estimates, 1979-1988.
(million metric tons/year)
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Source Category
Transportation 10.1 9.8 10.0 9.4 8.9 8,8 6,9 8.3 8.0 8.1
Pual Combustion 10.5 10.1 10.0 9.8 9.6 10.2 10.2 10.0 10.S 10.8
Industrial
Prooasaea 0.7 0.7 0.6 0.5 0.5 0.6 0.6 0.6 0.6
Solid Wasta 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1
Miscellaneous
0.2 0.2 0.2 0.1 0.2 0.2 0.1 0.1 0.1
0.6
0.1
0.2
Total
21.6 20.9 20.9 20.0 19.3 19.8 19.8 19.0 19.3 19.8
NOTE: The sums of nub-categories may not equal total dua to rounding.
30
NOX EMISSIONS, 106 METRIC TONS/YEAR
25-
20-
0
SOURCE CATEGORY
m TRANSPORTATION
in Fua coMiusnoN
INDUSTRIAL PROCESSES
SOLID WASTE & MISC.
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-29. National trend in nitrogen oxides emissions, 1979-1988.
63
-------
0.07
CONCENTRATION, PPM
0.06-
0.05-
0.04-
0.03-
0.02-
0.01
0.00
194 SITES
HHJKI
in]
|::m(|
Inaa
IS
I";:ii:|
j|||
p5=
ill
1984 1985 1986 1987 1988
Figure 3-30. Boxpiot comparisons of trends in annual mean nitrogen dioxide
concentrations at 194 sites, 1984-1988.
CONCENTRATION, PPM
0.035-
0.030-
0,025-
0.020-
0.015-
0,010-
0.005-
/
s
/
/
/
/
/
/
/
/
s
/
/
/
/
1*
J
/
s
/
f'
COMPOSITE AVERAGE
m 1986 1987 O 1988
f
/
it
/
/
/
/
/
/
/
7
/
/
\
w-
/
/
/
/
/
/
i>
/
/
7
/
/
/
/
/
/
/
/
/
/
s
/
/
I
f
/
/
/
/
/
/
/
7
/
f
/
/
/
/
/
/
EPA REGION 1
NO. OF SITES 7
14
40
IV
9
V
25
VI
18
VII
10
8
IX
63
Figure 3-31. Regional comparisons of 1986, 1987, 1988 composite averages of the
annual mean nitrogen dioxide concentration.
64
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3.5 TRENDS IN OZONE
Ozone (03) is a photochemical oxidant and the major component of smog.
While ozone in the upper atmosphere is beneficial to life by shielding the earth from
harmful ultraviolet radiation given off by the sun, high concentrations of ozone at ground
level are a major health and environmental concern. Ozone is not emitted directly into
the air but is formed through complex chemical reactions between precursor emissions
of volatile organic compounds and nitrogen oxides in the presence of sunlight. These
reactions are stimulated by sunlight and temperature so that peak ozone levels occur
typically during the warmer times of the year. Both volatile organic compounds and
nitrogen oxides are emitted by transportation and industrial sources. Volatile organic
compounds are emitted from sources as diverse as autos, chemical manufacturing, and
dry cleaners, paint shops and other sources using solvents. The strong seasonality of
ozone levels makes it possible for areas to limit their ozone monitoring to a certain
portion of the year, termed the ozone season. The length of the ozone season varies
from one area of the country to another. May through October is typical but states in
the south and southwest may monitor the entire year. Northern States would have
shorter ozone seasons such as May through September for North Dakota. This
analysis uses these ozone seasons on a State by State basis to ensure that the data
completeness requirements apply to the relevant portions of the year.
The O3 NAAQS is defined in terms of the daily maximum, that is, the highest
hourly average for the day, and it specifies that the expected number of days per year
with values greater than 0.12 ppm should not be greater than one. Both the annual
second highest daily maximum and the number of daily exceedances during the ozone
season are considered in this analysis.
The trends site selection process, discussed in Section 2.1, resulted in 388 sites
being selected for the 1979-88 period, an increase of 114 sites (or 42%) from the
1978-87 trends data base. A total of 567 sites (45 more sites than in 1983-87) are
included in the 1984-88 data base. The NAMS compose 165 of the long-term trends
sites and 196 of the sites in the 5-year trends data base. In both cases, the 5-year
data base is much larger than the 10-year data base, which reflects the growth in
ambient ozone monitoring networks.
3.5.1 Long-term 03 Trends: 1979-88
Figure 3-32 displays the 10-year composite average trend for the second highest
day during the ozone season for the 388 trends sites and the subset of 165 NAMS
sites. The 1988 composite average for the 388 trend sites is 2 percent higher than the
1979 average, and 9 percent higher than the 1987 composite average. The 1988
composite average is less than 1 percent lower than 1983, which is the highest
average during this ten year period, 1979-88. The relatively high ozone concentrations
in both 1983 and 1988 are likely attributed in part to meteorological conditions in some
areas of the country that were more conducive to ozone formation than other years.
65
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The summer of 1988, with its very hot, dry weather and stagnant conditions,
was highly conducive to peak ozone levels. Nationally, 1988 was the third hottest
summer since 1931. In the north central states, it was the hottest summer in almost
60 years.11 Unusually high ozone levels and numerous exceedances were reported
beginning in early June. In response to public concern and media attention, EPA
initiated a cooperative program with the state and local air pollution control agencies
for the early reporting of ozone summary data.12 During the 1988 survey, preliminary,
unvalidated data were reported to EPA approximately 3 to 4 months ahead of the
schedule typically required for quality assurance and data subrnittal. Data were
obtained from a subset of 272 sites, which yielded a preliminary estimate of a 14
percent increase between 1987 and 1988 composite ozone levels.13'14 The differences
between the preliminary and current estimates, a 14 percent increase versus 9 percent,
result from three primary factors: (1) revisions in the preliminary data due to quality
assurance checks, (2) the use of interpolated 1987 ozone levels for missing 1988 data
at 30 trend sites, and (3) the preliminary data for Region IX showed a greater increase
than the full data set. The last factor is responsible for most of the difference given
the large number of Region IX sites in the trends data base (about 25 percent). The
four Region IX survey sites recorded an 11 percent increase, whereas the composite
for the current 89 trend sites increased by only 2 percent. In contrast, the composite
average for non-California sites increased by 12 percent between 1987 and 1988.
0.1&-
J. 16
0,14
0.12
0.10
0,08
0.06
0.04
0.02
XOC'-
CONG NTRATON, PPM
NAMS SITES (165) - ALL_SITES_(388j_
1979 1980 1J81 ''982 1983 1984 1985 1986 1987 1988
Figure 3-32. National trend in the composite average of the second highest maximum
1-hour ozone concentration at both NAMS and all sites with 95 percent
confidence intervals, 1979-1988.
66
-------
This same 10-year trend for the annual second highest daily maximum for the
388 site data base is displayed in Figure 3-33 by the boxplot presentation. The years
1979, 1980, 1983 and 1988 values are similarly high, while the remaining years in the
1979-87 period are generally lower, with 1986 being the lowest, on average. In 1987,
ozone concentrations generally returned to the levels recorded during 1984 and 1985
except for the peak sites, which were considerably lower than these earlier years.
Except for the 90th and 95th percentiles, all the remaining percentiles for 1988 are
higher than the comparable percentiles in 1983. The median for 1988 is the highest
in the 1980's and is almost one percent higher than the median for 1983. Figure 3-
34 depicts the 1979-88 trend for the composite average number of ozone exceedances.
This statistic is adjusted for missing data, and it reflects the number of days that the
ozone standard is exceeded during the ozone season. Since 1979, the expected
number of exceedances decreased 10 percent for the 388 sites and 4 percent for the
165 NAMS. Between 1987 and 1988, the composite average of the expected number
of exceedances increased 38 percent. As with the second maximum, the 1979, 1980,
1983 and 1988 values are higher than the other years in the 1979-88 period.
a. 30
CONCENTRATION, PPM
0.25-
0,20-
0.15
0.10-
0.05-
0.00
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-33. Boxplot comparisons of trends in annual second highest daily maximum
1-hour ozone concentration at 388 sites, 1979-1988.
67
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Table 3-5 and Figure 3-35 display the 1979-88 emission trends for volatile
organic compounds (VOC) which, along with nitrogen oxides, are involved in the
atmospheric chemical and physical processes that result in the formation of O3. Total
VOC emissions are estimated to have decreased 17 percent between 1979 and 1988.
Between 1979 and 1988, VOC emissions from highway vehicles are estimated to have
decreased 28 percent, despite a 33 percent increase in vehicle miles of travel during
this time period (see Figure 3-24).
15
NO. OF EXCEEDANCES
10
5-
0
NAMS SfTCS (165) a ALLSlTE5_(38^_
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-34. National trend in the composite average ot me estimated numoer of daily
exceedances of the ozone NAAQS in the ozone season at both NAMS
and all sites with 95 percent confidence intervals, 1979-1988.
68
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Table 3-5. National Volatile Organic Compound Emission Estimates, 1979-1988.
(million roatrio tonซ/yซซ.r)
1979 1980 1981 1982 1983 1984 1985 1986 1987 1908
Sourca Cat*goxy
Trซnซ|ปort*tlon 8.0 7.5 7.4 7.2 7.1 7.2 6.9 6.5 6.4 S.I
Fuel Combustion 0.9 0.9 0.9 1.0 1.0 1.0 0.9 0.9 0.9 0.9
Industrial
Bxacmmam* 9.9 9.2 8.3 7.S 7.9 8.8 8.5 8.1 8.3 8.5
Solid Haซtซ 0,7 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6
Miacell&neoua 2.9 2.9 2.5 2.2 2.7 2.7 2.2 2.2 2.4 2.4
TOTAL
22.4 21.1 19.8 18.4 19.3 20.3 19.1 18.3 18.6 18.6
NOTE: Thซ aunuj of aub-catปgoriซo nay not equal total duo to rounding.
VOC EMISSIONS, 10s METRIC TONS/YEAR
SOURCE CATEGORY
TRANSPORTATION
INDUSTRIAL PROCESSES
FUEL COMBUSTION
SOUD WASTE & MISC
0
1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-35. National trend in emissions of volatile organic compounds, 1979-1988.
69
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3.5.2 Recent 0, Trends: 1984-88
This section discusses ambient 03 trends for the 5-year time period 1984-88.
Using this period permits the use of a larger data base of 567 sites, compared to 388
for the 10-year period. Figure 3-36 uses a boxplot presentation of the annual second
maximum daily value at these 567 sites. The national composite average increased
9 percent between 1984 and 1988. The composite average increased 8 percent from
1987 to 1988, likely due to the hot, dry meteorological conditions experienced in much
of the Eastern U.S. during the last summer. The most obvious feature of Figure 3-36
Is that 1988 levels were clearly higher than those of the other years. Table 3-5
indicates that total VOC emissions are estimated to have decreased by 8 percent
during this period. However, these emissions estimates are annual totals based on
annual average temperatures and may not reflect the possible impact of the above
average temperatures on evaporative emissions during the past two summers.
The composite average of the second daily maximum concentrations increased
in every region of the country. As Figure 3-37 indicates, the largest increases were
recorded in the northeastern states, composing EPA Regions I through 111. Figure 3-38
presents a Regional comparison for 1986, through 1988 of the composite average
second highest daily maximum 1-hour ozone concentration. Except for Region VIII,
the 1988 values were higher than in 1986 and 1987 in the remaining nine regions.
Studies have shown that peak ozone levels are highly correlated with maximum
daily temperature and with the number of days with greater than 90 degrees Fahrenheit
(ฐF).15 Figure 3-39 uses the Regional bar chart format to present the number of days
greater than 90ฐ F in 1986-88 for selected cities in these Regions.16 Although there is
considerable similarity between the patterns for the air quality data (Figure 3-37} and
the patterns for this simple meteorological indicator, peak ozone levels result from a
complex process, and this single indicator may not be sufficient to adequately describe
year-to-year variability in ozone levels.
70
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0.30
CONCENTRATION, PPM
0.25-
0.20-
0.15-
0.10-
0.05-
0.00
567SrTES
-M
"HMOS"
1984
1985
1986
1987
1988
Figure 3-36. Boxplot comparisons of trends in annual second highest daily maximum
1-hour ozone concentrations at 567 sites, 1984-1988.
change
EPA REGION 1 H HI IV V V! VII VI K X
NO. OFSfTES 32 29 75 77 120 58 30 15 124 7
Figure 3-37. Regional comparison of percent increases in the average of the second
daily maximum 1-hour concentration between 1987 and 1988.
71
-------
CONCENTRATION, PPM
0.18-
0.12-
0.06-
EPA REGION
-j
^
t
s
f
/
/
/
ff
/
'*
'
t
J
ff
-\
s
#
f
f
>
f
?
f
VII VIB K
^
/
/
f
/
y
J
t
tf
t
/
s
/
/
X
f
f
/
f
/
/
f
/
j
s
t
/
NO. OFSfTES 32 29 75 77 120 58 30 15 124 7
Figure 3-38. Regional comparisons of the 1986,1987,1988 composite averages of the
second-highest daily 1-hour ozone concentrations.
80
Days > 90ฐ F
70-
60-
50-
40-
30-
20-
10-
YEAR
^ 1986 1987 C2 WSS
City
(Region)
^^^^v^^*
^SW'^fj^*
Figure 3-39. Regional comparisons of the number of days greater than 90ฐF in 1986,
1987, 1988 for selected cities.
72
-------
3.5.4 Preview of 1989 Ozone Trends
The voluntary survey that was initiated in 1988 for the early reporting of
preliminary, unvalidated ozone summary data was expanded in 1989 with 588 sites
reporting on an accelerated schedule. Preliminary 1989 data indicate that the direction
of the trend is that 1989 ozone levels are much lower than those of 1988. Data from
the National Climatic Center indicate that in 1989 excessive rain replaced the drought
as the weather phenomenon of the year.17'18 In the rain-soaked East, the period from
January through July was among the wettest on record in nine states. Maryland had
more rain from January through July 1989 than in any other January through July
period in the last 95 years. Only 1 year in the last 95 was wetter than 1989 in
Delaware, Pennsylvania, Tennessee and West Virginia. Only 2 years were wetter in
New Jersey and North Carolina, only 3 in Kentucky and only 4 in Ohio. The absence
of favorable conditions for ozone formation in the eastern U.S. during summer 1989 is
likely responsible for the decrease in ozone levels between 1988 and 1989. Recall
that ozone is not emitted directly, but is formed in the atmosphere through a complex
chemical reaction between volatile organic compounds and nitrogen oxides in the
presence of sunlight and higher temperatures.
Figure 3-40 shows a preliminary estimate of the trend in the composite average
of the annual daily maximum 1-hour concentration for the period 1979 through 1989.
The 1989 composite average estimate is 15 percent lower than the 1988 level and is
comparable to the 1986 level. This estimate is based on a subset of 311 of the 388
long-term trend sites and was adjusted for the mix of sites in the trends database.
Although based on a larger number of sites than last year's preliminary 1988 estimate,
this 1989 estimate should be viewed as preliminary, because the 1989 data have not
yet been subjected to the complete quality assurance process.
CONCENTRATION. PPM
o.zo-
0.18-
0. 16-
0. 14-
0. 12-
0,10-
O.OB-
0.06-
0.04-
0.02-
n rปrv-
\,
19BS
prel.
BSt.
( " "- j
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989
Figure 3-40. Preliminary estimate of the national trend in the composite average of the
second highest daily maximum 1-hour ozone concentration, 1979-89.
73
-------
3.6 TRENDS IN LEAD
Lead (Pb) gasoline additives, nonferrous smelters and battery plants are the
most significant contributors to atmospheric Pb emissions. Transportation sources in
1988 contributed 34 percent of the annual emissions, down substantially from 73
percent in 1985. Total lead emissions from all sources dropped from 21.1 x 103 metric
tons in 1985 to 8.0 x 103 and 7.6 x 10*'metric tons, respectively in 1987 and 1988.
The decrease in lead emissions from highway vehicles accounts for essentially all of
this drop. The reasons for this drop are noted below.
Two air pollution control programs implemented by EPA before promulgation of
the Pb standard in October 1978 have resulted in lower ambient Pb levels. First,
regulations issued in the early 1970s required gradual reduction of the Pb content of
all gasoline over a period of many years. Most recently the Pb content of the leaded
gasoline pool was reduced from an average of 1.0 grams/gallon to 0.5 grams/gallon on
July 1, 1985 and still further to 0.1 grams/gallon on January 1, 1986. Second, as part
of EPA's overall automotive emission control program, unleaded gasoline was
introduced in 1975 for use in automobiles equipped with catalytic control devices.
These devices reduce emissions of carbon monoxide, volatile organics and nitrogen
oxides. In 1988 unleaded gasoline sales accounted for 82 percent of the total gasoline
market. These programs have essentially eliminated violations of the lead standard in
urban areas, except in those areas with lead point sources. Programs are also in
place to control Pb emissions from stationary point sources. Pb emissions from
stationary sources have been substantially reduced by control programs oriented toward
attainment of the TSP and Pb ambient standards, however, significant ambient
problems still remain around some lead point sources. Lead emissions in 1988 from
industrial sources, e.g. primary and secondary lead smelters dropped by more than
one-half from levels reported in the late 70s. Emissions of lead from solid waste
disposal are down 38 percent since the late 70s. In 1988 emissions from solid waste
disposal (2.5 x 103 metric tons) represent the second largest category of lead emissions
just behind the 2.6 x 103 metric tons from transportation. The overall effect of these
three control programs has been a major reduction in the amount of Pb in the ambient
air.
3.6.1 Long-term Pb Trends: 1979-88
Early trend analyses of ambient Pb data20'21 were based almost exclusively on
National Air Surveillance Network (NASN) sites. These sites were established in the
1960's to monitor ambient air quality levels of TSP and associated trace metals,
including Pb. The sites were predominantly located in the central business districts
of larger American cities. In September 1981, ambient Pb monitoring regulations were
promulgated.22 The siting criteria in the regulations resulted in finding many of the old
historic TSP monitoring sites unsuitable for the measurement of ambient Pb
concentrations and many of the earlier sites were moved or discontinued.
As with the other pollutants, the sites selected for the long-term trend analysis
had to satisfy annual data completeness criteria of at least 8 out of 10 years of data
74
-------
in the 1979 to 1988 period. A year was included as "valid" if at least 3 of the 4
quarterly averages were available. As In last year's report, composite lead data, i.e.,
individual 24-hour observations are composited together by month or quarter and a
single analysis made, are being used in the trend analysis. Thirty-seven sites qualified
for the 10-year trend because of the addition of composite data. Eighty-six additional
sites qualified for the 5-year trend, which will be discussed later. A total of 139 urban-
oriented sites, representing 30 States, met the data completeness criteria. Twenty-
nine of these sites were NAMS, the largest number of lead NAMS sites to qualify for
the 10-year criteria. Twenty-four (17 percent) of the 139 trend sites were located in the
State of California, thus this State is over-represented in the sample of sites satisfying
the long-term trend criteria. However, the lead trend at the California sites was almost
identical to the trend at the non-California sites; so that these sites did not distort the
overall trends. Sites that were located near lead point sources such as primary and
secondary lead smelters were excluded from the urban trend analysis, because the
;- magnitude of the levels at these sources could mask the underlying urban trends.
| Trends at lead point source oriented sites will be discussed separately in the next
! section.
The means of the composite maximum quarterly averages and their respective
95 percent confidence intervals are shown in Figure 3-41 for both the 139 urban sites
\ and 29 NAMS sites (1979-1988). There was an 89 percent (1979-88) decrease in the
average for the 139 urban sites. Lead emissions over this 10-year period also
decreased. There was a 93 percent decrease in total lead emissions and a 97 percent
decrease in lead emissions from transportation sources. The confidence intervals for
these sites indicate that the 1979-80 averages are significantly different from the 1981-
- 88 averages. Because of the smaller number (29) of NAMS sites with at least 8 years
of data, the confidence intervals are wider. However, the 1988-88 averages are still
significantly different from all averages before 1985. It is interesting to note that the
average lead concentrations at the NAMS sites in 1988 are essentially the same (0.084
vs. 0.085 u.g/nf) as the "all sites" average; whereas in the late 70s the average of the
NAMS sites was significantly higher. Figure 3-42 shows the trend in average lead
concentrations for the urban-oriented sites and for 18 point-source oriented sites which
met the 10-year data completeness criteria. The improvement in average ambient lead
concentrations at the point-source oriented sites, which are near industrial sources of
lead, e.g. smelters, battery plants, is about the same on a percentage basis as the
urban oriented sites. However, the average at the point-source oriented sites dropped
in magnitude from 2.9 to 0.4 u,g/m3 a 2.5 difference; whereas, the average at the urban
site dropped only from 0.8 to 0.1 u.g/m3. This improvement at the point-source oriented
reflects both industrial and automotive lead emission controls, but in some cases, the
industrial source reductions are because of plant shutdowns. Figure 3-43 shows
boxplot comparisons of the maximum quarterly average Pb concentrations at the 139
urban-oriented Pb trend sites (1979-88). This figure shows the dramatic improvement
in ambient Pb concentrations for the entire distribution of trend sites. As with the
composite average concentration since 1979, most of the percentiles also show a
monotonically decreasing pattern. The 139 urban-oriented sites that qualified for the
1979-88 period, when compared to the 97 sites for the 1978-87 period in last year's
report,14 indicate an expansion of the trends data base in more recent years.
75
-------
2
1.8
1.6
1 .4
1.2
1
0.8
0.6
0.4
1.2
0
CONCENTRATION,
NAAQS<
NAMS SITES (29) a ALL SITES (139)
T 1 1 1 1 \ 1 1 1 r
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-41. National trend in the composite average of the maximum quarterly average
lead concentration at 139 sites and 29 NAMS sites with 95 percent
confidence intervals, 1979-1988.
3.5
CONCENTRATION, UC/M3
3-
2.5-
2-
1 .5
1 -
0.5-
0
POINT SOURCE SfTES (18) a yงtANSrjESj39J_
NAAQS
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-42. Comparison of national trend in the composite average of the maximum
quarterly average lead concentrations at urban and point-source oriented
sites, 1979-1988.
76
-------
2.5
CONCENTRATION, UG/M*
0.5-
1979 1980' 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-43. Boxplot comparisons of trends in maximum quarterly average lead
concentrations at 139 sites, 1979-1988.
77
-------
The trend in total lead emissions is shown in Figure 3-44. Table 3-6
summarizes the Pb emissions data as well. The 1979-88 drop in total Pb emissions
was 93 percent. This compares with a 89 percent decrease (1979-88) in ambient Pb
noted above. The drop in Pb consumption and subsequent Pb emissions since 1979
was brought about by the increased use of unleaded gasoline in catalyst-equipped cars
and the reduced Pb content in leaded gasoline as noted above. The results of these
actions in 1988 amounted to a 64 percent reduction nationwide in total Pb emissions
from 1985 levels. As noted above, unleaded gasoline represented 82 percent of 1988
total gasoline sales. Although the good agreement among the trend in lead
consumption, emissions and ambient levels is based upon a limited geographical
sample, it does show that ambient urban Pb levels are responding to the drop in lead
emissions.
78
-------
Table 3-6, National Lead Emission Estimates, 1979-1988.
Source Category
Transportation
Fuol Combuation
Industrial
Solid Hast a
Total
(thousand metric tone/year)
1979 1980 1961 1982 1983 1984 1985 1986 1987 1988
'4.6
4,9
5.2
4.0
18.7
59
3
3
3
70
.4
.9
.6
.7
.6
46.9
2.8
3.0
3.7
56.4
46.9
1.7
2.7
3.1
54,4
40.8
0.6
2.4
2.6
46.4
34.7
0.5
2.3
2.6
40.1
15.
0.
2.
2.
21.
5
5
3
a
i
3.5
0.5
1.9
2.7
8.6
3.0
0.5
1.9
2.6
8.0
2.6
0.5
2.0
2.5
7.6
NOTE: The sun* of ub-categorlea nay not equal total due to rounding.
150
LEAD EMISSIONS, 103 METRIC TONS/TEAR
100-
0
SOURCE CATEGORY
E3 TRANSPORTATION
EZJ FUEL
COMBUSTION
INDUSTRIAL PROCESSES
SOUD WASTE
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-44. National trend in lead emissions, 1979-1988.
79
-------
3.6.2 Recent Pb Trends: 1984-88
Ambient Pb trends were also studied over the shorter period 1984-88 (Figure
3-45). A total of 343 urban sites in 44 States met the minimum data requirement of
at least 4 out of the 5 years of data. The number of sites qualifying for the 5-year
trend data base is down about 50 from last years' report. This drop ensues because
of the elimination of some TSP monitors from State and local air monitoring programs.
Some monitors were eliminated due to the change in the paniculate matter standard
from TSP to PM10 while others were discontinued because of the very low lead
concentrations measured in many urban locations. Although some further attrition may
occur, the core network of NAMS lead sites together with supplementary State and
local sites should be sufficient to access national ambient lead trends, this larger and
more representative set of sites showed an improvement of 76 percent in average Pb
concentrations during this time period. This corresponds to reductions in total Pb
emissions of 81 percent and a reduction of 93 percent in lead emissions from
transportation sources. Most of this decrease in total nationwide Pb emissions, 99
percent, was due to the decrease in automotive Pb emissions. Even this larger group
of sites was disproportionately weighted by sites in California, Illinois, and Texas.
These States had about 30 percent of the 343 sites represented. However, the percent
changes in 1984-88 average Pb concentrations for these three States were very similar
to the percent change for the remaining sites, thus the contributions of these sites did
not distort the national trends.
2.5
CONCENTRATION,
2-
1 .5
1 -
0.5-
0
343 SITES
1984 1985 1986 1987
1988
Figure 3-45. Boxplot comparisons of trends in maximum quarterly average lead
concentrations at 343 sites, 1979-1988.
80
-------
Indeed, as will be shown later, all sections of the country are showing declines in
average lead concentrations. Fifty-eight (58) point source oriented sites showed an
average drop of 36 percent over the 1984-88 time period. Thus, the decrease in
ambient lead concentrations near lead point sources has been less pronounced than
in urban areas. It is worth noting that the sites in the 10-year data base also showed
a 75 percent decrease during this 5-year period, suggesting that, despite the
geographical imbalance, their patterns may adequately depict national trends.
Because of the much larger sample of sites represented in the 5-year trends
(1984-88), compared with the 10-year, the larger sample will be used to compare the
more recent individual yearly averages. The largest single year drop in average lead
concentrations, 44 percent, occurs as expected between 1985 and 1986, because of
the shift of the lead content in leaded gasoline. 1988 average lead concentrations
show the more modest decline of 15 percent from 1987 levels. Examining only the 266
sites which had data in both 1987 and 1988, revealed a 17 percent decrease in
average lead concentrations which is almost the same as when the 5-year trends data
base is used. Lead emissions between 1987 and 1988 decreased both for the total
(5 percent) and from only transportation sources (13 percent). This trend is expected
to continue primarily because the leaded gasoline market will continue to shrink. Some
major petroleum companies have discontinued refining leaded gasoline because of the
dwindling market, so that in the future the consumer may find it more difficult to
purchase regular leaded gasoline.
Figure 3-46 shows 1986, 1987 and 1988 composite average Pb concentrations,
by EPA Region. Once again the larger more representative 5-year data base of 343
sites was used for comparison. The number of sites varies dramatically by Region
from 8 in Region VIII to 76 in Region V. In all Regions, there is a decrease in average
Pb urban concentrations between 1986 and 1988. These results confirm that average
Pb concentrations in urban areas are continuing to decrease in all sections of the
country, which is exactly what is to be expected because of the national air pollution
control program for Pb.
81
-------
CONCENTRATION,
1.4-
1.2-
1 -
0.8-
0.6-
0.4-
0.2-
EP4 REGIQ
MO. OF Sf
COMPOSITE AVERAGE
^ 1986 1987 C23 1988
fc,fcfcfc^to^tfcfc
N 1 II III IV V VI VII V1U IX X
FES 45 19 42 33 76 41 27 8 37 15
Figure 3-46. Regional comparison of the 1986, 1987, 1988 composite average of the
maximum quarterly average lead concentration.
82
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3.7 REFERENCES
1- National Air Pollutant Emission Estimates. 1940-1988. EPA-450/4-90-001,
U. S, Environmental Protection Agency. Office of Air Quality Planning and Standards,
Research Triangle Park, NC, March 1990.
2. National Air Quality and Emissions Trends Report. 1983. EPA-450/4-84-029,
U. S. Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC, April 1985.
3- National Air Quality and Emissions Trends Report. ...1985, EPA-450/4-87-001,
U. S. Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC, February 1987.
4. N. H. Frank, "Nationwide Trends in Total Suspended Particulate Matter and
Associated Changes in the Measurement Process", presented at the Air Pollution
Control Association, American Society for Quality Control Specialty Conference on
Quality Assurance in Air Pollution Measurement, Boulder, CO, October 1984.
5. Written communication from Thomas R. Hauser, Environmental Monitoring
Systems Laboratory, U. S. Environmental Protection Agency, Research Triangle Park,
NC, to Richard G. Rhoads, Monitoring and Data Analysis Division, U. S. Environmental
Protection Agency, Research Triangle Park, NC, January 11, 1984.
6. 1987 Annual Air Quality Report. Oregon Department of Environmental Quality,
Portland, Oregon, July, 1988.
7. J. Steigerwald, "Meteorological Data Compilation for the Contiguous United
States: 1988 Update of Palmer Drought Severity Index and Total Precipitation Data",
EPA Contract No. 68-02-4390, PEI Associates, Inc., Durham, NC, July 1989.
8. Proposed Decision Not to Revise the National Ambient Air Quality Standards for
Sulfur Oxides (Sulfur Dioxidei 53 FR 14926, April 26, 1988.
9. National Air Quality and Emissions Trends Report, 1984. EPA-450/4-86-001,
U. S. Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC, April 1986.
10. 1986 NEDS Data Base, U. S. Environmental Protection Agency, Research
Triangle Park, NC, September 1988.
11. USA Today. September 6, 1988.
12, New York Times. July 31, 1988.
83
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13. "Preliminary Comparison of 1988 Ozone Concentrations to 1983 and 1987
Ozone Concentrations", U. S. Environmental Protection Agency, Office of Air Quality
Planning and Standards, Research Triangle Park, NC, February 17, 1989.
14. National Air Quality and Emissions Trends Report. 1987. EPA-450/4-89-001,
U. S. Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC, March 1989.
15. Use of Meteorological Data in Air Quality Trend Analysis. EPA-450/3-78-024,
U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards,
Research Triangle Park, NC, May 1978.
16. J. Steigerwald, "Using Publicly Reported Air Quality Index Data to Provide
Updated Trends Information: 1987 Data Compilations - Updated Max Temperature File",
EPA Contract No. 68-02-4390, PEI Associates, Inc., Durham, NC, November 1988.
17. R. H. Heim, Jr., "United States July Climate in Historical Perspective", National
Climatic Data Center, NOAA, Ashville, NC, August 1989.
18. New York Times News Service, August 1, 1989.
19. National Primary and Secondary Ambient Air Quality Standards for Lead. 43 FR
46246, Octobers, 1978.
20. R. B. Faoro and T. B. McMullen, National Trends in Trace Metals Ambient Air,
1965-1974, EPA-450/I-77-003, U. S. Environmental Protection Agency, Office of Air
Quality Planning and Standards, Research Triangle Park, NC, February 1977.
21. W. Hunt, "Experimental Design in Air Quality Management," Andrews Memorial
Technical Supplement, American Society for Quality Control, Milwaukee, Wl, 1984.
22. Ambient Air Quality Surveillance. 46 FR 44159, September 3, 1981.
84
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4. AIR QUALITY STATUS OF METROPOLITAN AREAS, 1988
This chapter provides general information on the current air quality status of
metropolitan areas1 within the United States. Four different summaries are presented
in the following sections. First, maps depicting the metropolitan areas failing to meet
the National Ambient Air Quality Standards (NAAQS) for ozone and carbon monoxide
standards are presented. Next, an estimate is provided of the number of people living
in counties which did not meet the NAAQS based on 1988 air quality data. Third,
pollutant-specific maps are presented to provide the reader with a geographical view
of how peak 1988 air quality levels varied throughout the 90 largest Metropolitan
Statistical Areas (MSAs) in the continental United States. Finally, the peak pollutant-
specific statistics are listed for each MSA with 1988 air quality monitoring data.
4.1 METROPOLITAN AREAS NOT MEETING OZONE AND CARBON MONOXIDE
NAAQS
On July 27, 1989 the U.S. Environmental Protection Agency listed2 those
metropolitan areas which failed to meet the ozone and carbon monoxide NAAQS based
on ambient monitoring data for 1986 through 1988. The areas include Consolidated
Metropolitan Statistical Areas (CMSA), which are composed of groups of MSAs, and
individual MSAs and non-metropolitan counties.
Attainment of the ozone standard is determined using the three most recent
years of air quality monitoring data. These data showed that 101 areas, mostly major
metropolitan areas, failed to meet the ozone standard for the years 1986-88, an
increase of 37 areas as compared to the 1985-87 period. All but one of these new
areas are located east of the Mississippi River. The sharp increase in the number of
areas failing to meet the ozone standard likely resulted from the hot, dry, stagnant
conditions which dominated Summer 1988 in the eastern U.S. Nationally, 1988 was
the third hottest summer since 1931. Figure 4-1, "Areas Exceeding the Ozone NAAQS
Based on 1986-88 Data," displays the 101 areas failing to meet the ozone standard
based on 1986-88 monitoring data. The areas on the map are shaded according to
the level of the ozone design value for that area. The ozone design value serves as
an indicator of the magnitude of the problem in terms of peak concentrations.
Typically, the ozone design value would be the fourth highest daily maximum value
during the three year period.
For carbon monoxide, attainment of the standard is determined using the two
most recent years of monitoring data. The design value for CO is evaluated by
computing the second maximum 8-hour concentration for each year and then using the
higher of these two values. Figure 4-2, "Areas Exceeding the Carbon Monoxide
NAAQS Based on 1987-88 Data," shows the 44 areas that failed to meet the carbon
monoxide standard for the years 1987-88, a decrease of eight areas from the 1986-
87 period. This decrease in the number of areas failing to meet the standard is
consistent with the long-term improvement in ambient carbon monoxide levels.
85
-------
AREAS EXCEEDING THE OZONI NAAQS
BASED ON 1986-88 DATA
-------
AREAS EXCEEDING THE CARBON MONOXIDE NAAQS
BASED ON 1987-88 DATA
-------
4.2 POPULATION ESTIMATES FOR COUNTIES NOT MEETING NAAQS, 1988
Figure 4-3 provides an estimate of the number of people living in counties in which
the levels of the pollutant-specific primary health NAAQS were not met by measured
air quality in 1988. These estimates use a single-year interpretation of the NAAQS to
indicate the current extent of the problem for each pollutant. Table 4-1 lists the
selected air quality statistics and their associated NAAQS. Figure 4-3 clearly
demonstrates that O3 was the most pervasive air pollution problem in 1988 for the
United States with an estimated 111.9 million people living in counties which did not
meet the O3 standard. Carbon monoxide follows, with 29,5 million people; PM10 with
25.6 million people; NO2 with 8.3 million people; SO2 with 1.7 million people; and Pb
with 1.6.million people. A total of 121 million persons resided in counties not meeting
at least one air quality standard during 1988. In contrast to the last annual report
which used 1980 county population data, these estimates are based on current 1986
county population estimates. Thus, the 6 percent growth in total U.S. population since
1980 is reflected in these estimates. Also, the estimate for PM10 is considered a lower
bound estimate, because the PM10 monitoring network is still evolving and the required
sampling schedules are being determined.
pollutant
PM10
SO2
CO
NO2
Ozone
Lead
\ny NAAQS
c
NOTE: Based on
People in counties with 1988 air quality above
primary National Ambient Air Quality Standards.
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Figure 4-3. Number of persons living in counties with air quality levels above the
primary national ambient air quality standards in 1988 (based on 1986
population data).
88
-------
These population estimates are intended to .provide a relative measure of the
extent of the problem for each pollutant. The limitations of this indicator should be
recognized. An Individual living in a county that violates an air quality standard may
not actually be exposed to unhealthy air. For example, if CO violations were confined
to a traffic-congested center city location during evening rush hours in the winter, it is
possible that an individual may never be in that area, or may be there only at other
times of the day or during other seasons. However, it is worth noting that ozone,
which appears to be the most pervasive pollution problem by this measure, is also the
pollutant most likely to have fairly uniform concentrations throughout an area.
Table 4-1, Selected Air Quality Summary Statistics and Their Associated National
Ambient Air Quality Standards (NAAQS)*
POLLUTANT STATISTICS PRIMARY NAAQS
Paniculate Matter (PM10) annual arithmetic mean 50 ug/m3
Sulfur Dioxide (SO2) annual arithmetic mean 0.03 ppm
second highest 24-hour
average 0.14 ppm
Carbon Monoxide (CO) second highest nonover-
lapping 8-hour average 9 ppm
Nitrogen Dioxide (NOZ) annual arithmetic mean 0.053 ppm
Ozone (03) second highest daily
maximum 1-hour average 0.12 ppm
Lead (Pb) maximum quarterly average 1 .5 ug/m
3
_ m\crQgfams per cubic meter ppm = parts per million
"Single year interpretation. For a detailed listing of the NAAQS see Table 2-1 .
4.3 AIR QUALITY LEVELS IN METROPOLITAN STATISTICAL AREAS
This section provides information for general air pollution audiences on 1988 air
quality levels in each Metropolitan Statistical Area (MSA) in the United States. For
those large MSAs with populations greater than 500,000, the 1988 annual air quality
statistics are also displayed geographically on three-dimensional maps.
89
-------
The general concept of a metropolitan area is one of a large population center,
with adjacent communities which have a high degree of economic and social integration
with the urban center. Metropolitan Statistical Areas contain a central county(ies), and
any adjacent counties with at least 50 percent of their population in the urbanized
area.1 Although MSAs compose only 16 percent of the land area in the U.S., they
account for 77 percent of the population. Table 4-2 displays the population distribution
of the 339 MSAs, based on 1987 population estimates.1 The New York, NY MSA is
the nation's largest metropolitan area with a 1987 population in excess of 8 million.
The smallest MSA is Enid, OK with a population of 60,000.
TABLE 4-2. Population Distribution of Metropolitan Statistical Areas Based on 1987
Population Estimates
Population Range
< 100,000
100,000 < population <
250,000 < population <
500,000 < population <
1 ,000,000 < population
population > 2,000,000
Number of MSAs
27
250,000 147
500,000 73
1,000,000 48
< 2,000,000 26
18
Total 339
Total Population
2,274,000
23,372,000
25,218,000
34,367,000
38,685,000
65,747,000
189,663,000
4.3.1 Metropolitan Statistical Area Air Quality Maps, 1988
Figures 4-4 through 4-10 introduce air quality maps of the United States that show
at a glance how air quality varies among the largest MSAs within the contiguous United
States. To enable the reader to distinguish individual urban areas, only the 90 MSAs
within the continental U.S. having populations greater than 500,000 are shown. Two
large MSAs, Honolulu, HI and San Juan, PR are not shown. In each map, a spike is
plotted at the city location on the map surface. This represents the highest pollutant
concentration recorded in 1988, corresponding to the appropriate air quality standard.
Each spike is projected onto a back-drop for comparison with the level of the standard.
The backdrop also provides an east-west profile of concentration variability throughout
the country.
90
-------
The map for PM10 shows the 1988 maximum annual arithmetic means in
metropolitan areas greater than 500,000 population. Concentrations above the level
of the annual mean PM10 standard of 50 ug/m3 are found in fourteen of these
metropolitan areas (Figure 4-4).
PM10
ANNUAL ARITHMETIC MEAN
Figure 4-4. United States map of the highest annual arithmetic mean PM
concentration by MSA, 1988.
10
91
-------
The map for sulfur dioxide shows maximum annual mean concentrations in 1988.
Among these large metropolitan areas, the higher concentrations are found in the
heavily populated Midwest and Northeast and near point sources in the west. All
these large urban areas have ambient air quality concentrations lower than the current
annual standard of 80 ug/m3 (0.03 ppm). Because this map only represents areas with
population greater than one half million, it does not reflect air quality in the vicinity of
smelters or large power plants in rural areas (Figure 4-5).
SULFUR DIOXIDE
ANNUAL ARITHMETIC MEAN
Figure 4-5. United States map of the highest annual arithmetic mean sulfur dioxide
concentration by MSA, 1988.
92
-------
The map for sulfur dioxide shows the highest second highest 24-hour average
sulfur dioxide concentration by MSA in 1988. Among these large urban areas, only
a site in Pittsburgh, PA which is impacted by major SO2 sources, exceeds the standard.
All other major urban areas have ambient concentrations below the 24-hour NAAQS
of 365 ug/m (0.14 ppm) (Figure 4-6).
SULFUR DIOXIDE
2ND MAX 24-HR AVG
Figure 4-6. United States map of the highest second maximum 24-hour average sulfur
dioxide concentration by MSA, 1988.
93
-------
The map for carbon monoxide shows the highest second highest 8-hour value
recorded in 1988. Nineteen of these urban areas in all geographic regions have air
quality exceeding the 9 ppm level of the standard. The highest concentration recorded
in 1988 is found in Los Angeles, CA (Figure 4-7).
CARBON MONOXIDE
2ND MAX 8-HR AVG
Figure 4-7. United States map of the highest second maximum nonoverlapping 8-
hour average carbon monoxide concentration by MSA, 1988.
94
-------
The map for nitrogen dioxide displays the maximum annual mean measured in
the nation's largest metropolitan areas during 1988. Los Angeles, California, with an
annual NO2 mean of 0.061 ppm is the only area in the country exceeding the N02 air
quality standard of 0.053 ppm (Figure 4-8).
NITROGEN DIOXIDE
ANNUAL ARITHMETIC MEAN
Figure 4-8. United States map of the highest annual arithmetic mean nitrogen dioxide
concentration by MSA, 1988.
95
-------
The ozone map shows the second highest daily maximum 1-hour concentration
in the 90 largest metropolitan areas in the Continental U.S. As shown, 65 of these
areas did not meet the 0.12 ppm standard in 1988. The highest concentrations are
observed in Southern California, but high levels also persist in the Texas Gulf Coast,
Northeast Corridor, and other heavily populated regions (Figure 4-9).
OZONE
2ND DAILY MAX 1-HR AVG
Figure 4-9. United States map of the highest second dally maximum 1-hour average
ozone concentration by MSA, 1988.
96
-------
The map for Pb displays maximum quarterly average concentrations in the nation's
largest metropolitan areas. Exeeedances of the Pb NAAQS are found in the vicinity
of nonferrous smelters or other point sources of lead. The highest concentration is
found at a site near a primary lead smelter in Herculaneum, MO (St. Louis MSA).
Because of the switch to unleaded gasoline, areas primarily affected by automotive
lead emissions show levels below the current standard of 1.5 ug/m3 (Figure 4-10).
LEAD
MAX QUARTERLY MEAN
Figure 4-10. United States map of the highest maximum quarterly average lead
concentration by MSA, 1988.
97
-------
4.3.2 Metropolitan Statistical Area Air Quality Summary, 1988
Table 4-3 presents a summary of 1988 air quality for each Metropolitan Statistical
Area (MSA) in the United States. The air quality levels reported for each metropolitan
area are the highest levels measured from all available sites within the MSA. The
MSAs are listed alphabetically, with the 1987 population estimate and air quality
statistics for each pollutant.1
In the case of O3, the problem is pervasive, and the high values associated
with the pollutant can reflect a large part of the MSA. However in many cases, peak
ozone concentrations occur downwind of major urban areas, e.g., peak ozone levels
attributed to the Chicago metropolitan area are recorded in and near Racine,
Wisconsin. In contrast, high CO values generally are highly localized and reflect areas
with heavy traffic. The scale of measurement for the pollutants - PM10, SO2 and NO2
- falls somewhere in between. Finally, while Pb measurements generally reflect Pb
concentrations near roadways in the MSA, if a monitor is located near a point source
of lead emissions it can produce readings substantially higher. Such is the case in
several MSAs. Pb monitors located near a point source are footnoted accordingly in
Table 4-3.
The pollutant-specific statistics reported in this Section are summarized in Table
4-1, with their associated primary NAAQS concentrations for a single year of data.
For example, if an MSA has three ozone monitors in 1988 with second highest daily
hourly maxima of 0.15 ppm, 0.14 ppm and 0.12 ppm, the highest of these, 0.15 ppm,
would be reported for that MSA for 1988.
In the case of Pb, the quarterly average is based on either up to 90 24-hour
measurements or one or more chemical composite measurements.8 Most of the
maximum quarterly Pb averages are based on multiple 24-hour measurements.
The same annual data completeness criteria used in the air quality trends data
base was used here for the calculation of annual means, (i.e., 50 percent of the
required samples). If some data have been collected at one or more sites, but none
of these sites meet the annual data completeness criteria, then the reader will be
advised that there are insufficient data to calculate the annual mean.
In contrast to the trends analyses in Sections 3 and 5 which used a more relaxed
indicator, only maximum quarterly average Pb concentrations meeting the AIRS validity
criteria of 12 observations per quarter are displayed in Table 4-3. With respect to the
summary statistics on air quality levels with averaging times less than or equal to
24-hours, all sites are included, even if they do not meet the annual data completeness
requirement
aA chemical composite measurement can be either a measurement for an entire
month or an entire quarter.
98
-------
This summary provides the reader with information on how air quality varied
among the nation's metropolitan areas in 1988, The highest air quality levels measured
in each MSA are summarized for each pollutant monitored in 1988. Individual MSAs
are listed to provide more extensive spatial coverage for large metropolitan complexes.
"
industrial compo^
^^^^^^^^^^^^H^I^^^ffi^H^^^^^^^i^^^^K^
.v,,,,,,_,,,ซ|^^^
99
-------
TABLE 4-3. 1988 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
ABILENE, TX
AGOADILLA, PR
AKRON, OH
ALBANY, GA
ALBANY-SCHENECTADY-TROY, NY
ALBUQUERQUE, NM
ALEXANDRIA, LA
ALLENTOWN-BETHLEHEM, PA-NJ
ALTOONA, PA
AMARILLQ, TX
ANAHEIM-SANTA ANA, CA
ANCHORAGE, AK
ANDERSON, IN
ANDERSON, SC
ANN ARBOR, MI
ANNISTON, AL
APPLETON-OSHKOSH-NEENAH, WI
ARECIBO, PR
ASHEVILLE, NC
ATHENS, GA
ATLANTA, GA
ATLANTIC CITY, NJ
AUGUSTA, GA-SC
AURORA-ELGIN, IL
AUSTIN, TX
BAKERSFIELD, CA
BALTIMORE, MD
BANGOR, ME
BATON ROUGE, LA
BATTLE CREEK, MI
BEAUMONT-PORT ARTHUR, TX
BEAVER COUNTY, PA
BELLINGHAM, WA
BENTON HARBOR, MI
BERGEN-PASSAIC, NJ
BILLINGS, MT
BILOXI-GULFPORT, MS
BINGHAMTON, NY
BIRMINGHAM, AL
1987
POPULATION
123,
156,
647,
111,
846,
486,
140,
666,
132,
197,
2,219,
223,
133,
141,
268,
122,
309,
170,
171,
142,
2,657,
303,
392,
352,
738,
505,
2,303,
84,
538,
138,
371,
191,
115,
165,
1,294,
118,
206,
260,
917,
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
PM10
AM
(UGM)
ND
ND
38
ND
30
43
ND
31
31
IN
43
27
ND
ND
ND
ND
ND
ND
29
ND
46,
IN
27
ND
25
61
43
31
28
37
ND
ND
30
ND
46
ND
ND
ND
47
S02
AM
JPPM)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ND
ND
,015
ND
,015
ND
ND
.012
.011
ND
.005
ND
ND
ND
ND
ND
ND
ND
ND.
ND
.009
,006
.003
ND
.003
.006
.013
ND
.007
ND
.009
.014
.005
ND
.013
.021
.006
ND
IN
S02
24-HR
_(PPM)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ND
ND
.056
ND
.061
ND
ND
.048
.051
ND
.018
ND
ND
ND
ND
ND
ND
ND
ND
ND
.052
.025
.015
ND
.011
.021
.043
ND
.029
ND
.047
.057
.026
ND
.058
.118
.040
ND
.072
CO
8HR
(PPM).
ND
ND
5
ND
6
11
ND
7
ND
ND
10
12
ND
ND
ND
ND
ND
ND
ND
ND
8
ND
ND
ND
3
7
10
ND
- 4
ND
3
3
8
ND
7
7
ND
'ND
9
N02
AM
(PPM)
0
0
0
0
0
0
0
0
0
ND
ND
ND
ND
ND
.018
ND
,020
ND
ND
.046
ND
ND
ND
ND
ND
ND
ND
ND
ND
.030
ND
ND
ND
IN
.032
.034
ND
.021
ND
IN
.020
ND
ND
.036
ND
ND
ND
ND
OZONE
2ND DMX
(PPM)
ND
ND
0.17
ND
0.13
0.11
ND
0.16
0.14
ND
0.24
ND
ND
0.13
0.13
ND
0.11
ND
0.11
ND
0.17
0.15
ND
0.11
0.12
0.17
0.19
ND
0.16
ND
0.16
0.13
ND
ND
0.19
0.08
ND
ND
0.15
PB
QMAX
(UGM)
ND
ND
0.07
ND
0.05
0.04
ND
1.30
ND
ND
ND
0.03
ND
ND
0.02
ND
ND
ND
ND
ND
0.05 '
0.04
0,00
0.02
ND
0.13
0.11
0.05
0.10
ND
0.03
0.21
ND
ND
0.09
ND
ND
ND
4.81*
-------
BISHARK, ND
BLOOMINGTON, IN
BLOQMINGTON-NORMAL, IL
BOISE CITY, ID
BOSTON, MA
BOULDER-LONGMONT, CO
BRADENTON, FL
BRAZORIA, TX
BREMERTON, MA
BRIDGSPORT-MILFORD, CT
BRISTOL, CT
BROCKTON, MA
BROWNSVILLE-HARLINGEN, TX
BRYAN-COLLEGE STATION, TX
BUFFALO, NY
BURLINGTON, NC
BURLINGTON, VT
CAGDAS, PR
CANTON, OH
CASPER, WY
CEDAR RAPIDS, IA
CHAMPAIGN-URBANA-RANTOUL, IL
CHARLESTON, SC
CHARLESTON, WV
CHARLOTTE-GASTONIA-ROCK HILL, NC-SC
CHARLOTTESVILLE, VA
CHATTANOOGA, TN-GA
CHEYENNE, WY
86,000
104,000
124,000
196,000
2,842,000
217,000
184,000
187,000
174,000
444,000
78,000
185,000
264,000
118,000
958,000
105,000
127,000
275,000
397,000
67,000
170,000
173,000
502,000
261,000
1,091,000
123,000
432,000
76,000
ND
ND
ND
46
38
35
ND
ND
ND
31
18
ND
ND
ND
36
ND
23
ND
35
ND
35
ND
34
37
36
40
42
19
ND
ND
ND
ND
0,018
ND
ND
ND
ND
0.014
ND
ND
ND
ND
0.015
ND
0.007
ND
0.011
ND
0.008
0.005
0.005
0.017
0 . 003
ND
ND
ND
ND
ND
ND
ND
0.057
ND
ND
ND
ND
0.064
ND
ND
ND
ND
0.097
ND
0,027 "
ND
0.039
ND
0.066
0.024
0.063
0.064
0.020
ND
ND
ND
ND
ND
ND
6
7
6
ND
ND
9
7
ND
ND
ND
ND
6
ND
4
ND
3
ND
4
ND
8
3
8
ND
ND
ND
ND
ND
ND
ND
0.033
ND
ND
ND
ND
0.027
ND
ND
ND
ND
0.022
ND
0.019
ND
ND
ND
ND
ND
ND
0.024
ND
ND
ND
ND
ND
ND
ND
ND
0.17
0.12
ND
0.14
ND
0.22
ND
0.13
ND
ND
0.15
ND
0,10
ND
0.15
ND
0.09
0.10
0.11
0.16
0.16
ND
0.13
ND
ND
ND
ND
0.10
0.07
ND
ND
ND
ND
0.09
0.05
ND
ND
ND
0.08
ND
ND
ND
ND
ND
ND
ND
0.03
0.04
0.07
ND
ND
ND
PM10 = HIGHEST PARTICULATE (PM10) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 50 ug/m3)
S02 = HIGHEST SULFUR DIOXIDE (S02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.03 ppm)
HIGHEST SULFUR DIOXIDE (S02) SECOND MAXIMUM 24-HOUR CONCENTRATION (Applicable NAAQS is 0.14 ppm)
CO = HIGHEST CARBON MONOXIDE (CO) SECOND MAXIMUM NONOVERLAPPING 8-HOUR CONCENTRATION (Applicable NAAQS is 9 ppm)
N02 = HIGHEST NITROGEN DIOXIDE (N02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.053 ppm)
03 = HIGHEST OZONE (03) SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION (Applicable NAAQS is 0.12 ppm)
PB = HIGHEST LEAD (PB) QUARTERLY MAXIMUM CONCENTRATION (Applicable NAAQS is 1.5 ug/m3)
ND = INDICATES DATA NOT AVAILABLE
IN = INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
UGM = UNITS ARE MICROGRAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
* - Impact from an industrial source in Leeds, AL.
Birmingham, AL is 0.23 ug/m3.
Highest population oriented site in
-------
TABLE 4-3, 1988 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
CHICAGO, IL
CHICO, CA
CINCINNATI, OH-KY-IN
CLARKSVILLE-HOPKINSVILLE, TN-KY
CLEVELAND, OH
COLORADO SPRINGS, CO
COLUMBIA, MO
COLUMBIA, SC
COLUMBUS, GA-AL
COLUMBUS, OH
CORPUS CHRISTI, TX
CUMBERLAND, MD-WV
DALLAS, TX
DANBURY, CT
DANVILLE, VA
DAVENPORT-ROCK ISLAND-MOLINE, IA-IL
DAYTON-SPRINGFIELD, OH
DAYTONA BEACH, FL
DECATUR, AL
DECATUR, IL
DENVER, CO
DBS MOINES, IA
DETROIT, MI
DOTHAN, AL
DUBOQUE, IA
DULUTH, MN-WI
EAU CLAIRE, WI
EL PASO, TX
ELKHART-GOSHEN, IN
ELMIRA, NY
ENID, OK
ERIE, PA
EUGENE-SPRINGFIELD, OR
EVANSV1LLE, IN-KY
FALL RIVER, MA-RI
FARGO-MOORHEAD, ND-MN
FAYETTEVILLE, NC
FAYETTEVILLE-SPRINGDALE, AR
FITCHBURG-LEOMINSTER, MA
FLINT, MI
1987
POPULATION
6,
1,
1,
1,
2,
1,
4,
199,
169,
438,
157,
851,
390,
101,
451,
246,
320,
360,
102,
456,
189,
109,
367,
939,
332,
131,
125,
645,
385,
362,
130,
91,
242,
137,
573,
150,
90,
60,
279,
265,
281,
153,
147,
259,
110,
96,
435,
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
PM10
AM
(UGH)
47
44
45
ND
57
35
31
34
ND
35
29
ND
39
26
ND
34
33
ND
ND
40
45
40
52
ND
ND
28
ND
62
ND
ND
ND
35
52
41
ND
ND
33
ND
ND
25
i
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
S02
AM
PPM)
.012
ND
.018
.010
.017
ND
.009
.003
ND
.008
.003
.013
.005
.009
ND
.004
.006
.002
ND
.015
.008
ND
.015
ND
.005
.016
ND
.017
ND
.007
ND
.014
ND
.020
.010
ND
ND
ND
ND
.005
S02
24-HR
i
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
PPM)
.044
ND
.061
.066
.069
ND
.068
.017
ND
.040
.029
.055
.017
.051
ND
.024
.026
.008
ND
.162
.025
ND
.056
ND
.052
.156
ND
.065
ND
.027
ND
.050
ND
.136
.040
ND
ND
ND
ND
.016
CO
8HR
(PPM)
7
10
5
ND
7
12
ND
7
ND
7
. ND
5
8
ND
ND
4
5
ND
ND
".ND
16
5
8
ND
7
5
ND
11
ND
ND
ND
5
7
3
ND
ND
7
MD
ND
ND
N02
AM
(PPM)
0.032
0.016
0.030
ND
0.031
ND
ND
ND
ND
IN
ND
ND
0.021
ND
ND
ND
ND
ND
ND
ND
0.039
ND
0.023
ND
ND
ND
ND
0.021
ND
ND
ND
0.016
ND
0.022
ND
ND
ND
ND
ND
ND
OZONE
2ND DMX
(PPM)
0.22
0.10
0.17
ND
0.14
0.09
ND
0.13
0.10
0.15
0.11
ND
0.13
0.20
ND
0.11
0.14
ND
ND
0.11
0.12
0.06
0.16
ND
ND
ND
ND
0.17
ND
0.12
ND
0.15
0.12
0.13
ND
ND
0.13
ND
ND
0.13
PB
QMAX
(PGM)
0.14
ND
'0.18
' ND
1.09
0.01
ND
0.05
ND
0.09
ND
ND
0.87*
0.05
ND
0.17
0.09
SD
ND
0.10
0.08
ND
0.24
ND
ND
0.04
ND
0.41
ND
ND
ND
ND
0.03
ND
ND
ND
ND
ND
ND
0.02
-------
FLORENCE, AL
FLORENCE, SC
FORT COLLINS, CO
FORT LAUDERDALE-HOLLYWOOD-POMPANO, PL
FORT MYERS-CAPE CORAL, FL
FORT PIERCE, FL
FORT SMITH, AR-OK
FORT WALTON BEACH, FL
FORT WAYNE, IN
FORT WGRTH-MLINGTON, TX
FRESNO, CA
GADSDEN, AL
GAINESVILLE, FL
GALVESTON-TEXAS CITY, TX
GARY-HAMMOND, IN
GLENS FALLS, NY
GRAND FORKS, ND
GRAND RAPIDS, MI
GREAT FALLS, MT
GREELEY, CO
GREEN BAY, WI
GREENSBORO-WINSTON SALEM-HIGH POINT, NC
GREENVILLE-SPARTANBURG, SC
HAGERSTOWN, MD
HAMILTON-MIDDLETOWN, OH
HARRISBURG-LEBANON-CARLISLE, PA
HARTFORD, CT
136,000
117,000
180,000
1,163,000
295,000
215,000
176,000
145,000
364,000
1,269,000
597,000
103,000
205,000
211,000
604,000
112,000
70,000
657,000
78,000
135,000
188,000
916,000
612,000
116,000
276,000
584,000
748,000
ND
ND
28
22
ND
ND
ND
ND
IN
26
60
37
ND
25
49
ND
ND
25
IN
39
23
38
38
ND
42
34
30
0.007
ND
ND
ND
ND
ND
ND
ND
0.005
0.002
0.003
ND
ND
ND
0.014
0.005
ND
0.003
ND
ND
. 0.009
0.008
ND
ND
0.011
0.009
0.011
0.049
ND
ND
ND
ND
ND
ND
ND
0.019
0.010
0.013
ND
ND
ND
0.069
0.040
ND
0.016
ND
ND
0.040
0.032
ND
ND
0.048
0.031
0.076
ND
ND
11
5
ND
ND
ND
ND
7
6
13
ND
ND
ND
5
ND
ND
4
9
9
ND
10
ND
ND
ND
6
10
ND
ND
ND
ND
ND
ND
ND
ND
0.010
0.014
0.032
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.018
ND
ND
ND
0.021
0.020
ND
ND
0.10
0.1S
0.06
ND
ND
ND
0.13
0.14
0.17
ND
ND
ND
0.17
ND
ND
0.1S
ND
0.10
0.10
0.15
0.11
ND
0.14
0.14
0.19
ND
0.04
ND
0.04
ND
ND
ND
ND
ND
0.05
0.07
ND
ND
0.04
1.00+
ND
ND
0.05
ND
ND
ND
ND
0.08
ND
ND
ND
0.07
PM10 = HIGHEST PARTICOLATE (PM10) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is. 50 ug/m3)
S02 = HIGHEST SULFOR DIOXIDE (S02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.03 ppm)
HIGHEST SULFUR DIOXIDE (SQ2) SECOND MAXIMUM 24-HOUR CONCENTRATION (Applicable NAAQS is 0.14 ppm)
CO = HIGHEST CARBON MONOXIDE (CO) SECOND MAXIMUM NONOVERLAPPING 8-HOOR CONCENTRATION (Applicable NAAQS is 9
N02 = HIGHEST NITROGEN DIOXIDE (N02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.053 ppm)
03 = HIGHEST OZONE (03) SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION (Applicable NAAQS is 0.12 ppm)
PB = HIGHEST LEAD (PB) QUARTERLY MAXIMUM CONCENTRATION (Applicable NAAQS is 1.5 ug/m3)
ppm)
ND = INDICATES DATA NOT AVAILABLE
IN = INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
OGM = UNITS ARE MICROGRAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
* - Impact from an industrial source in Collin County, TX. Highest site in Dallas, TX is 0.47 ug/m3.
+ - Impact from an industrial source in Hammond, In.
-------
TABLE 4-3.
1988 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
HICKORY, NC
HONOLULU, HI
HOUMA-THIBODAUX,. LA
HOUSTON, TX
HUNTINGTON-ASHLAND, WV-KY-OH
HUNTSVILLE, AL
INDIANAPOLIS, IN
IOWA CITY, IA
JACKSON, MI
JACKSON, MS
JACKSON, TN
JACKSONVILLE, FL
JACKSONVILLE, NC
JANESVILLE-BELOIT, WI
JERSEY CITY, NJ
JOHNSON CITY-KINGSPORT-BRISTOL, TN-VA
JOHNSTOWN, PA
JOLIET, IL
JOPLIN, MO
KALAMAZOO, MI
KANKAKEE, IL
KANSAS CITY, MO-KS
KENOSHA, WI
KILLEN-TEMPLE, TX
KNOXVILLE, TN
KOKOMO, IN
LA CROSSE, WI
LAFAYETTE, LA
LAFAYETTE, IN
LAKE CHARLES, LA
LAKE COUNTY, IL
LAKELAND-WINTER HAVEN, FL
LANCASTER, PA
LANSING-EAST LANSING, MI
LAREDO, TX
LAS CROCES, NM
LAS VEGAS, NV
LAWRENCE, KS
LAWRENCE-HAVERHILL, MA-NH
LAWTON, OK
1987
POPULATION
219,
831,
185,
3,228,
323,
231,
1,229,
86,
147,
396,
78,
878,
126,
135,
547,
443,
252,
377,
134,
219,
98,
1,546,
120,
234,
594,
101,
95,
212,
125,
172,
494,
387,
404,
428,
124,
129,
600,
75,
375,
119,
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
ob o
000
PM10
AM
(UGM)
ND
24
ND
32
43
38
41
ND
ND
30
33
31
ND
ND
36
37
ND
34
ND
ND
ND
45
ND
ND
42
ND
ND
ND
37
ND
ND
ND
ND '
24
IN
39
63
ND
ND
32
S02
AM
S02
24-HR
(PPM) I
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ND
.001
ND
.008
.011
ND
.014
ND
ND
ND
ND
.008
ND
IN
.017
.012
.017
ND
ND
ND
ND
.008
.005
ND
.014
ND
ND
ND
.005
.003
ND
.004
.007
.006
ND
.003
ND
ND
.010
.006
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
PPM)
ND
,003
ND
.053
,060
ND
.056
ND
ND
ND
ND
.066
ND
.017
.065
.058
.055
ND
ND
ND
ND
.031
.019
ND
.037
ND
ND
ND
.025
.010
ND
.019
.028
.019
ND
.050
ND
ND
.041
.013
CO
8HR
(PPM)
ND
4
ND
8
4
5
6
ND
ND
5
ND
7
ND
ND
8
4
4
ND
ND
ND
ND
5
ND
ND
6
ND
ND
ND
1
ND
ND
ND
3
ND
ND
7
14
ND
ND
ND
1
0
0
0
0
0
0
0
0
0
0
N02
AM
PPM)
ND
ND
ND
.028
.016
ND
.024
ND
ND
ND
ND
.019
ND
IN
.033
IN .
.019
ND
ND
ND
ND
.014
.014
ND
ND
ND
ND
ND
ND
ND
ND
ND
.020
ND
ND
ND
.031
ND
ND
ND
OZONE
2ND DMX
(PPM)
0.09
0'.03
ND
0.22
0.17
0.13
0.14
0.09
ND
0.10
ND
0.12
ND
0.11
0.20
0.12
0.14
0.12
ND
ND
ND
0.15
0.19
ND
0.14
ND
ND
0.11
0.13
0.13
0.16
ND
0.13
0.12
ND
0.11
0.12
ND
0.16
ND
PB
QMAX
JOGMX
ND
0.01
ND
0.09
0.21
ND
1.39*
ND
ND
0.08
ND
0.07
ND
ND
0.10
ND
0.30
0.02
ND
0.03
ND
0.57
ND
ND
ND
ND
ND
ND
0.03
ND
ND
ND
0.07
0.03
ND
0.20
ND
ND
ND
ND
-------
LEWIST0N-AUBURN, ME
LEXINGTQN-FAYETTE, KY
LIMA, OH
LINCOLN, NE
LITTLE ROCK-NORTH LITTLE ROCK, AR
LONGVIEW-MARSHALL, TX
LORAIN-ELYRIA, OH
LOS ANGELES-LONG BEACH, CA
LOUISVILLE, KY-IN
LOWELL, MA-NH
LOBBOCK, TX
LYNCHBURG, VA
MACON-WARNSR ROBINS, GA
MADISON, WI
MANCHESTER, NH
MANSFIELD, OH
MAYAGUEZ, PR
MCALLEN-EDINBURG-MISSION, TX
MEDFORD, OR
MSLBOURNE-TITUSVILLE-PALM BAY, FL
MEMPHIS, TN-AR-MS
MERCED, CA
MIAMI-HIALEAH, FL
MIDDLESEX-SOMERSET-HONTERDON, NJ
MIDDLETOWN, CT
MIDLAND, TX
MILWAUKEE, WI
85,
342,
156,
208,
512,
167,
268,
8,505,
967,
260,
228,
143,
283,
347,
146,
128,
210,
379,
143,
375,
972,
166,
1,791,
966,
85,
108,
1,389,
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
ND
ND
ND
ND
35
ND
IN
65
45
ND .
39
31
ND
ND
27
ND
ND
ND
72
ND
28
47
30
IN
IN
ND
36
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
007
007
006
ND
002
ND
Oil
007
010
ND
ND
ND
004
005
009
IN
ND
ND
ND
ND
008
ND
001
012
ND
ND
006
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.044
.027
.024
ND
.016
ND
.040
.021
.050
ND
ND
ND
.016
.019
.049
.024
ND
ND
ND
ND
.051
ND
.002
.043
ND
ND
.042
ND
5
ND
9
ND
ND
ND
23
6
6
ND
ND
ND
4
9
ND
ND
ND
11
ND
7
ND
8
5
ND
ND
6
0
0
0
0
0
0
0
0
0
ND
.018
ND
ND
.010
ND
ND
.061
.023
ND
ND
ND
ND
ND
.024
ND
ND
ND
ND
ND
.034
ND
.017
.025
ND
ND
.027
0.12
0.13
0.11
0.08
0.11
0.12
0.12
0.33
0.18
ND
ND
ND
ND
0.10
0.14
ND
ND
ND
0.11
0.07
0.14
ND
0.13
0.21
0.18
ND
0.19
0.07
ND
0.42
ND
0.99
ND
ND
0.15
0.09
0.05
ND
ND
ND
ND
0.04
ND
ND
ND
0.05
ND
0.13
ND
0.09
0.38
0.03
ND
0.13
PM10 = HIGHEST
SO2 = HIGHEST
HIGHEST
CO = HIGHEST
N02 = HIGHEST
03 = HIGHEST
PB = HIGHEST
PARTICULATE (PM10) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 50 ug/m3)
SULFUR DIOXIDE (S02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.03 ppm)
SULFUR DIOXIDE (S02) SECOND MAXIMUM 24-HOUR CONCENTRATION (Applicable NAAQS is 0.14 ppm>
CARBON MONOXIDE (CO) SECOND MAXIMUM NONOVERLAPPING 8-HOUR CONCENTRATION (Applicable NAAQS is 9
NITROGEN DIOXIDE (N02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.053 ppm) -
OZONE (03) SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION (Applicable NAAQS is 0.12 ppm)
LEAD (PB) QUARTERLY MAXIMUM CONCENTRATION (Applicable NAAQS is 1.5 ug/m3)
ppm)
ND = INDICATES DATA NOT AVAILABLE
IN = INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
UGM = UNITS ARE MICROGRAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
Impact from a-n industrial source in Indianapolis, IN,
-------
TABLE 4-3. 1988 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED. POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
MINNEAPOLIS-ST, PAUL, MN-WI
MOBILE, AL
MODESTO, CA
MONMOUTH-OCEAN, NJ
MONROE, LA
MONTGOMERY, AL
MUNCIE, IN
MUSKEGON, MI
NAPLES, PL
NASHUA, NH
NASHVILLE, TN
NASSAU-SUFFOLK, NY
NEW BEDFORD, MA
NEW BRITAIN, CT
NEW HAVEN-HERIDEN, CT
NEW LONDON-NORWICH, CT-RI
NEW ORLEANS, LA
NEW YORK, NY
NEWARK, NJ
NIAGARA FALLS, NY
NORFOLK-VIRGINIA BEACH-NEWPORT NEWS, VA
NORWALK, CT
OAKLAND, CA
OCALA, FL
ODESSA, TX
OKLAHOMA CITY, OK
OLYMPIA, WA
OMAHA, NE-IA
ORANGE COUNTY, NY
ORLANDO, FL
OWENSBORO, KY
OXNARD-VENTURA, CA
PANAMA CITY, PL
PARKERBURG-MARIETTA, WV-OH
PASCAGOULA, MS
PAWTUCKET-MOONSOCKET-ATTLEBORO, RI-MA
PENSACOLA, FL
PEORIA, IL
PHILADELPHIA, PA-NJ
PHOENIX, AZ
1987
POPULATION
2,336,000
483,000
327,000
957,000
146,000
297,000
121,000
159,000
128,000
172,000
956,000
2,631,000
166,000
147,000
519,000
259,000
1,321,000
8,529,000
1,891,000
216,000
1,346,000
126,000
1,968,000
181,000
127,000
975,000
151,000
616,000
288,000
935,000
88,000
628,000
122,000
156,000
128,000
322,000
344,000
339,000
4,866,000
1,960,000
PM10
AM
(UGM)
38
41
41
ND
ND
23
ND
ND
ND
ND
42
ND
ND
IN
48
IN
37
56
38
ND
33
IN
23
ND
25
28
ND
45
ND
34
IN
34
ND
ND
ND
31
ND
23
47
57
S02
AM
(PPM)
0.013
0.008
0.004
ND
0.005
ND
ND
IN
ND
0.008
0.012
0.011
ND
0.010
0.017
0.009
0.004
0.024
0.014
0.015
, 0.007
IN
0.003
ND
ND
0.010
ND
0.003
ND
0.002
0.010
ND
ND
0.015
0.006
0.013
0.007
0.009
0.016
0.001
SO 2
24-HR
(PPM)
0.095
0.054
0.011
ND
0.024
ND
ND
0.013
ND
0.042
0.089
0.065
ND
0.076
0.079
0.047
0.015
0.083
0.056
0.068
0.025
0.055
0.013
ND
ND
0.041
ND
0.011
ND
0.010
0.040
ND
ND
0.076
0.013
0.054
0.057
0.065
0.068
0.001
CO
8HR
(PPM)
10
ND
10
7
ND
ND
ND
2
ND
7
8
9
ND
ND
7
ND
7
14
9
4
8
ND
6
ND
ND
7
ND
8
ND
5
6
3
ND
ND
ND
ND
ND
8
8
12
N02
AM
(PPM]
0.020
ND
0.027
ND
ND
ND
ND
ND
ND
ND
0.012
0.033
ND
ND
0.029
ND
0.024
0.041
0.040
ND
0.017
ND
0.026
ND
ND
0.029
ND
ND
ND
ND
0.015
0.018
ND
ND
ND
ND
ND
ND
0.039
ND
OZONE
2ND DMX
(PPM)
0.11
0.11
0.13
ND
0.11
0.11
ND
0.1S
ND
0.13
0.14
0.16
0.16
ND
0.17
0.15
0.12 '
0.18
0.18
0.14
0.13
ND
0.14
ND
ND
0.11
ND
0.10
ND
0.10
0.14
0.18
ND
0.17
0.11
ND
0.10
0.11
0.20
0.12
PB
QMAX
(UGM)
1.77*
ND
ND
ND
ND
ND
ND
0.03
ND
0.04
2.04+
0.07
ND
0.03
0.10
0.04
0,10
0.21
0.84
ND
0.10
0.04
0.20
ND
ND
0.10
ND
1.638
1.181
0.06
0.07
ND
ND
0.02
ND
ND
ND
0.04
0.44
ND
-------
PINE BLUFF, AR
PITTSBURGH, PA
PITTSFIELD, MA
PONCE, PR
PORTLAND, ME
PORTLAND, QR-WA
PORTSMOUTH-DOVER-ROCHESTER, NH-ME
POUGHKEEPSIE, NY
PROVIDENCE, RI
PROVQ-OREM, UT
PUEBLO, CO
RACINE, WI
RALEIGH-DDRHAM, NC
RAPID CITY, SD
READING, PA
REDDING, CA
RENO, NV
RICHLAND-KENNEWICK-PASCO, WA
RICHMOND-PETERSBURG, VA
RIVERSIDE-SAN BERNARDINO, CA
HOANOKE, VA
ROCHESTER, MN
ROCHESTER, NY
ROCKFORD, IL
SACRAMENTO, CA
SAGINAW-BAY CITY-MIDLAND, MI
ST. CLOUD, MN
ST. JOSEPH, MO
2
1
2
1
91,
,105,
80,
235,
210,
,168,
215,
258,
643,
242,
127,
173,
665,
80,
324,
136,
232,
150,
825,
,119,
224,
98,
979,
281,
,336,
404,
177,
85,
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
ND
54
ND
IN
25
40
23
ND
34
54
35
ND
37
37
ND
23
ND
37
30
95
35
32
34
17
48
34
28
46
0
0
0
0
0
0
a
0
0
0
0
0
0
0
0
ND
.028
ND
ND
,010
.006
.006
,014
.016
ND
ND
ND
ND
ND
.014
ND
ND
ND
.00.9
.,003
.004
.003
.014
ND
.010
ND
.002
.004
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ND
.210
ND
ND
,044
.018
.034
.061
.065
ND
ND
ND
ND
ND
.057
ND
ND
ND
.042
.019
.018
.016
.046
ND
.020
ND
.013
.023
ND
8
ND
ND
5
9
ND
ND
8
11
ND
7
10
ND
5
ND
10
ND
4
7
3
7
4
8
12
2
ND
ND
ND
0.030
ND
ND
ND
IN
ND
ND
IN
0.028
ND
ND
ND
ND
0.024
0.013
ND
ND
0.026
0.047
0.016
ND
ND
ND
0.025
IN
ND
ND
ND
0.16
ND
ND
0.17
0.13
0.11
0.14
0.17
0.11
ND
0.18
0.16
N0
0.15
0.11
0.19
ND
0.15
0.28
0.13
ND
0.14
0.11
0.17
ND
ND
ND
ND
0.20
ND
ND
0.09
0.18
0.00
ND
0.07
ND
0.04
ND
ND
ND
0.65
ND
ND
ND
ND
0.09
ND
ND
0.09
0.00
0.09
0.04
ND
ND
PM10
S02
CO
N02
03
PB
ND
IN
HIGHEST PARTICULATE (PM10) ARITHMETIC MEAN CONCENTRATION {Applicable NAAQS is 50 ug/m3)
HIGHEST SULFUR DIOXIDE (S02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.03 ppin}
HIGHEST SULFUR DIOXIDE (S02) SECOND MAXIMUM 24-HOUR CONCENTRATION (Applicable NAAQS is 0.14 ppm)
HIGHEST CARBON MONOXIDE (CO) SECOND MAXIMUM MONOVERLAPPING 8-HOUR CONCENTRATION (Applicable NAAQS is 9 pptn)
HIGHEST NITROGEN DIOXIDE (N02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.053 ppm)
HIGHEST OZONE (O3) SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION (Applicable NAAQS is 0.12 ppm)
HIGHEST LEAD (PB) QUARTERLY MAXIMUM CONCENTRATION (Applicable NAAQS is 1.5 ug/m3)
INDICATES DATA NOT AVAILABLE
INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
UGM = UNITS ARE MICROGRAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
* - Impact from an industrial source in Eagan, MN. Highest site in Minneapolis, MN is 0.07 ug/m3.
+ - Impact from an industrial source in Williamson County, TN. Highest site in Nashville, TN is 0.13 ug/m3.
8 - Impact from an industrial source in Omaha, NE.
I - Impact from an industrial source in Orange County, NY.
-------
TABLE 4-3. 1988 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
ST. LOUIS, MO-IL
SALEM, OR
SALEM-GLOUCESTER, MA
SALINAS-SEASIDE-MONTEREY, CA
SALT LAKE CITY-OGDEN, OT
SAN ANGELO, TX
SAN ANTONIO, TX
SAN DIEGO, CA
SAN FRANCISCO, CA
SAN JOSE, CA
SAN JUAN, PR
SANTA BARBARA-SANTA MARIA-LOMPOC, CA
SANTA CRDZ, CA
SANTA FB, NM
SANTA ROSA-PETALUMA, CA
SARASOTA, FL
SAVANNAH, GA
SCRANTON-WILKES-BARRE, PA
SEATTLE, WA
SHARON, PA
SHEBOYGAN, WI
SHERMAN-DENISON, TX
SHREVEPORT, LA
SIOUX CITY, IA-NE
SIOUX FALLS, SD
SOUTH BEND-MISHAWAKA, IN
SPOKANE, WA
SPRINGFIELD, IL
SPRINGFIELD, MO
SPRINGFIELD, MA
STAMFORD, CT
STATE COLLEGE, PA
STEUBENVILLE-WEIRTON, OH-WV
STOCKTON, CA
SYRACUSE, NY
TACOMA, WA
TALLAHASSEE, FL
TAMPA-ST. PETERSBURG-CLEARWATER, FL
TERRE HAUTE, IN
TEXARKANA, TX-AR
1987
POPULATION
2,458,000
266,000
258,000
343,000
1,055,000
99,000
1,301,000
2,286,000
1,590,000
1,415,000
1,541,000
341,000
222,000
111,000
354,000
256,000
241,000
731,000
1,796,000
123,000
102,000
100,000
364,000
115,000
124,000
242,000
355,000
191,000
229,000
517,000
193,000
115,000
149,000
443,000
647,000
545,000
223,000
1,965,000
132,000
120,000
PM10
AM
(OGM)
69
ND
ND
20
54
ND
29
40
28
36
45
34
IN
17
27
ND
ND
30
40
37
ND
ND
24
31
22
31
3
ND
23
44
28
ND
47
44
29
45
ND
33
40
ND
S02
AM
(PPM)
0,017
ND
ND
ND
0.022
ND
0.001
0.005
0,002
ND
0.003
0.002
0.001
ND
ND
0.002
. 0.007
0.010
0.008
0.011
0.003
ND
0.003
ND
ND
0.007
ND
0.007
0.009
0.012
0.010
ND
0.039
0.003
0.005
0.008
ND
0.010
0.009
ND
S02
24-HR
(PPM>
0.091
ND
ND
ND
0.093
ND
0.010
0.022
0.012
ND .
0.027
0.015
0.007
ND
ND
0.012
0.046
0.052
0.029
0.054
0.021
ND
0.009
ND
ND
0.024
ND
0.074
0.095
0.074
0.062
ND
0.125
0.010
0.032
0.035
ND
0.042
0.037
ND
CO
8HR
(PPM)
8
6
ND
ND
8
ND
6
10
9
10
6
7
1
4
5
ND
ND
6
10
ND
ND
ND
ND
ND
ND
4
14
5
7
7
7
ND
20
8
8
13
ND
7
ND
ND
N02
AM
(PPM)
0.025
ND
ND
ND
0.035
m
IN
0.035
0.026
0.032
ND
0.017
0.008
ND
0.016
ND
ND
0.019
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.010
IN
ND
ND
. 0.021
0.026
ND
ND
ND
0.021
ND
ND
OZONE
2ND DMX
(PPM)
0.15
ND
ND
0.08
0.14
ND
0.12
0.19
0.10
0.12
0.09
0.12
0.08
ND
0.10
0.10
ND
0.15
0.11
0.14
0.17
ND
0.11
ND
ND
0.14
ND
0.11
0.11
0.17
0.22
ND
0.12
0.13
0.12
0.11
0.09
0.12
0.08
ND
PB
QMAX
(UGM)
8.59*
ND
ND
ND
0.19
ND
0.06
0.09
0.16
0.14
0.05
0.04
ND
ND
0.05
ND
ND
ND
0.84
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.09
0.08
ND
0.05
0.06
0.06
0.04
ND
ND
ND
ND
-------
TOLEDO, OH
TOPEKA, KS
TRENTON, NJ
TUCSON, AZ
TULSA, OK
TUSCALOOSA, AL
TYLER, TX
UTICA-ROME, NY
VALLEJO-FAIRFIELD-NAPA, CA
VANCOUVER, WA
VICTORIA, TX
VINELAND-MILLVILE-BRIDGETON, NJ
VISALIA-TULARE-PORTERVILLI, CA
WACO, TX
WASHINGTON, DC-MD-Vft
WATERBURY, CT
WATERLOO-CEDAR FALLS, IA
WAUSAU, WI
WEST PALM BEACH-BOCA RATON-DELRAY,
WHEELING, WV-OH
WICHITA, KS
WICHITA FALLS, TX
KILLIAMSPORT, PA
WILMINGTON, DE-NJ-MD
WILMINGTON, NC
WORCESTER, MA
YAKIMA, WA
YORK, PA
YODNGSTOWN-WARREN, OH
YUBA CITY, CA
PL
611,
162,
321,
619,
733,
144,
153,
314,
404,
216,
75,
138,
292,
189,
3,646,
213,
149,
111,
790,
173,
475,
126,
117,
559,
116,
410,
183,
404,
503,
116,
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
000
35
IN
32
68
45
ND
ND
ND
27
ND
ND
ND
IN
ND
35
33
ND
ND
ND
32
32
ND
ND
35
29
30
44
33
33
32
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
.009
ND
.009
.003
.010
ND
ND
ND
.002
ND
ND
.008
.002
ND
.015
.010
ND
.009
.001
.025
ND
ND
.009
.017
ND
.009
ND
.007
.009
ND
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
,039
ND
.044
.010
.054
ND
ND
ND
.006
ND
ND
.034
.008
ND
.053
.074
ND
.050
.004
.077
ND
ND
.035
.074
ND
.042
ND
.029
.037
ND
5
ND
4
9
5
ND
ND
ND
9
10
ND
ND
6
ND
16
ND
ND
ND
4
4
S
ND
ND
5
ND
6
9
4
ND
ND
0
0
0
0
0
0
0
0
0
0
ND
ND
ND
.017
.017
ND
ND
ND
.019
ND
ND
ND
.023
ND
.030
ND
ND
ND
.013
.018
ND
ND
ND
.033
ND
.029
ND
.023
ND
ND
0.16
ND
0.20
0.09
0.12
ND
ND
0.12
0.12
ND
ND
0.15
0.13
ND
0.18
ND
ND
ND
0.10
0.12
0.12
ND
0.12
0.19
*0.09
ND
ND
0.14
0.12
0.13
0.76
0.02
ND
0.09
0.13
ND
ND
ND
0.11
ND
ND
ND
ND
ND
0.05
0.08
ND
ND
ND
0.20
0.04
ND
ND
0.19
ND
0.06
ND
ND
ND
ND
PM10 = HIGHEST
S02 = HIGHEST
HIGHEST
CO = HIGHEST
N02 = HIGHEST
O3 = HIGHEST
PB = HIGHEST
PARTICOLATE (PMlO) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 50 ug/m3>
SULFUR DIOXIDE (S02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.03 ppm)
SULFUR DIOXIDE (S02) SECOND MAXIMUM 24-HOOR CONCENTRATION (Applicable NAAQS is 0.14 ppm}
CARBON MONOXIDE (CO) SECOND MAXIMUM NONOVERLAPPING 8-HOUR CONCENTRATION (Applicable NAAQS is 9
NITROGEN DIOXIDE (N02) ARITHMETIC MEAN CONCENTRATION (Applicable NAAQS is 0.053 ppm)
OZONE (03) SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION (Applicable NAAQS is 0.12 ppm)
LEAD (PB) QUARTERLY MAXIMUM CONCENTRATION (Applicable NAAQS is 1.5 ug/m3)
ppm)
ND = INDICATES DATA NOT AVAILABLE
IN = INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
UGM = UNITS ARE MICROGRAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
- Impact from a lead smelter in Herculaneum, MO. Highest site in St. Louis, MO is 0.33 ug/ra3.
-------
4.5 REFERENCES
1. Statistical Abstract of the United States, 1989. U. S. Department of
Commerce, U. S. Bureau of the Census, Appendix II.
2. "EPA Lists Places Failing To Meet Ozone or Carbon Monoxide Standards",
Press Release, U.S. Environmental Protection Agency, Washington, D.C., July 27,
1989.
110
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5. TRENDS ANALYSES FOR FIFTEEN METROPOLITAN STATISTICAL AREAS
This chapter presents trends and analyses of ambient air quality for the period
1979 through 1988 in 15 consolidated metropolitan statistical areas (CMSA) or
metropolitan statistical areas (MSA). Consolidated metropolitan statistical areas are
metropolitan complexes of one million or more population which have separate
component areas designated primary metropolitan statistical areas. For example, the
New York-Northern New Jersey-Long Island, NY-NJ-CTCMSA contains 12 MSAs which
are listed separately in Chapter 4. There are 21 metropolitan complexes designated
as CMSAs, 10 of which have been selected for trends analysis. The 15 areas included
in these analyses are Atlanta, GA MSA; Baltimore, MD MSA; Boston-Lawrence-Salem,
MA-NH CMSA; Chicago-Gary-Lake County, IL-IN-WI CMSA; Denver-Boulder, CO
CMSA; Detroit-Ann Arbor, MI CMSA; Houston-Galveston-Brazoria, TX CMSA; Los
Angeles-Anaheim-Riverside, CA CMSA; New York-Northern New Jersey-Long Island,
NY-NJ-CTCMSA; Philadelphia-Wilmington-Trenton, PA-NJ-DE-MD CMSA; Phoenix, AZ
MSA; Portland-Vancouver, OR-WA CMSA; Seattle-Tacoma, WA CMSA; St. Louis, MO-
IL MSA; and Washington, DC-MD-VA MSA. These areas have been selected because
they are among the largest cities in each of the EPA Regions.
Where sufficient data were available, 10-year trends in these areas are presented
for the NAAQS pollutants TSP, S02, CO, NOt, O3, and Pb. If data for the 10-year
trends were not available, then 5-year trends are shown where sufficient data were
available. Also, the CMSA/MSA areas are grouped into seven broad geographic
regions: Northeast, Midatlantic, Midwest, South, Rocky Mountain, South Coast, and
Northwest, and composite averages calculated for each pollutant are presented and are
compared to the national averages.
The air quality data used for the trend statistics in this chapter have been
obtained from the EPA Aerometric Information Retrieval System (AIRS). This section
employs the same data completeness and historical continuity criteria as the 10-year
trends analyses in Chapter 3. That is, only those monitoring sites meeting the historical
continuity criterion of 8 out of 10 years of "complete" data for the years 1979 through
1988 were selected for the trends analyses. Each year with data also needed to
satisfy the annual data completeness criterion. For carbon monoxide, nitrogen dioxide
and sulfur dioxide continuous instruments, data containing at least 4380 hourly
observations from each year were used. Bubbler data were not used in these
analyses. In the case of ozone, the second daily maximum 1-hour concentration was
selected only from those sites with at least 50 percent of the daily data for the ozone
season. Total suspended particulate data met the completeness criterion if there were
at least 30 samples for the year. Finally, in the case of the pollutant lead, both 24-
hour and composite data were used in the trends analyses. For the 24-hour data, the
annual maximum quarterly mean needed to satisfy the criterion of at least six samples
per quarter in at least 3 of the 4 calendar quarters. Composite data were judged valid
if at least two monthly samples were available for at least 3 of the 4 possible quarters.
As mentioned previously, the 5-year trends are presented where no sites in the area
met the above criteria. The same criteria described above were used except the site
needed 4 out of 5 years to meet the historical continuity criterion.
111
-------
Because this chapter only Includes sites with sufficient data for trends, it is
possible that an area could be violating a NAAQS, yet the trend graph still shows the
area as not violating. The air quality trends for each of the pollutants show in most
cases a "highest air quality statistic among trend sites." For example, the annual
second maximum nonoverlapping 8-hour average in parts per million is used for CO.
In St. Louis, the second maximums for 1986 and 1987 are below the NAAQS (9 ppm).
However, a site which was not included (because it did not meet the historical
continuity criterion of 8 out of 10 years) reported data not meeting the NAAQS. In
1988, EPA proposed that the St. Louis area be designated nonattainment and imposed
a requirement to amend the area's implementation plan for air quality (SIP). Other
areas may be violating the NAAQS but the statistics on the graphs do not show a
violation because sites not meeting the completeness criteria were not included.
The CMSA/MSA area air quality trends focus on the period 1979 through 1988,
complementing the 10-year national trends analyses in Chapter 3. The air quality
trends in this chapter are based on information from monitoring sites within the
CMSA/MSA areas as defined in the Statistical Abstract of the United States prepared
by the U. S. Bureau of Census.1
Figure 5-1 shows the plotting convention used in trends analyses. For 1979
through 1988, maximum and minimum values are shown as well as the composite
average of the sites used. The maximum and minimum values are measured
concentrations. The values for the average concentration may include interpolated
values from sites having incomplete data for a given year. In some years, the average
value includes interpolated values from one or more sites, however in all years at least
one measured value is included in the average. When only one site is available, or
when the average concentratfon (which includes one or more interpolated values)
exceeds the measured maximum value or is less than the measured minimum value,
a maximum or minimum value is not plotted. Table 5-1 shows the air quality statistics
used in the trends analyses for the 15 cities.
HIGHEST AIR QUALITY STATISTIC AMONG TREND SITES
COMPOSITE AVERAGE OF ALL TREND SITES
LOWEST AIR QUALITY STATISTIC AMONG TREND SITES
Figure 5-1. Illustration Of Plotting Conventions For Concentration Ranges Used In
CMSA/MSA Area Trend Analysis.
112
-------
The air quality data and trends presented in this chapter should not be used to
make direct city-to-city comparisons, since the mix, configuration, and number of sites
composing the area networks are different. Furthermore, other parameters, such as
population density, transportation patterns, industrial composition, emission sources, and
meteorological characteristics, also need to be considered.
TABLE 5-1. AIR QUALITY TREND STATISTICS
POLLUTANT TREND STATISTICS *
Total Suspended
Particulate annual geometric mean
Sulfur Dioxide
annual arithmetic mean
Carbon Monoxide second highest nonoveriapping
8-hour average
Nitrogen Dioxide annual arithmetic mean
Ozone
Lead
second highest daily
maximum 1-hour average
maximum quarterly average
* See Table 2-1 for a more detailed description
of NAAQS
113
-------
5.1 AIR QUALITY TRENDS
Figures 5-2 through 5-16 show the CMSA/MSA area trends for 1979 through 1988
for the six NAAQS pollutants. Tables 5-2 through 5-5 present a pollutant-specific
summary of the overall concentration changes in each of the 15 areas. These areas
are grouped into seven geographic regions: Northeast, Midatlantic, Midwest, South,
Rocky Mountain, Southcoast, and Northwest.
Northeast - Boston, New York, Philadelphia
Midatlantic - Baltimore, Washington, DC
Midwest - Chicago, Detroit, St. Louis
South - Atlanta, Houston
Rocky Mountain - Denver, Phoenix
South Coast - Los Angeles
Northwest - Portland, Seattle
Composite geographic area averages of the 5- and 10-year change in air quality
concentrations were calculated. In the individual geographic area averages, each city
has equal weight, regardless of the number of monitors operating. For comparison to
the national trends, however, each city's input is weighted by the number of monitors
operating for a given pollutant. The following discussion addresses the findings.
5.1.1 TSP Trends
Long-term TSP Trend
The 15-city weighted average shows a 19 percent decrease over the 10-year
period. Similarly, the national 10-year trend shows a 20 percent decrease. However,
as mentioned previously in Chapter 3 of this report, EPA has determined that the
measurements produced during the years 1979-1981 may be biased high due to the
type of filters used to collect TSP. On a regional basis the South Coast had the least
improvement with a 5 percent decrease, which was followed by the Midatlantic with a
11 percent decrease. The Midwest, Rocky Mountain, and the Northwest areas
exceeded the national average by recording improvements of 23, 25, and 21 percent,
respectively. The South at 17 percent and the Northeast at 15 percent, were just
slightly below the national average.
On a city specific basis the cities with the most improvement in air quality were
Houston with a 35 percent decrease in concentrations, Denver with a 29 percent
decrease, and Chicago with a 28 percent decrease. All these areas were affected by
the controls developed in the early 1980s and the later economic slowdown and
recession in the energy fields. Also, these three cities had relatively high TSP levels
in the base year 1979 of the trend. Conversely, the two cities which showed the least
improvement over the last 10 years were Los Angeles and Atlanta. Los Angeles TSP
concentrations only improved 5 percent for TSP over the last 10 years, primarily
because their strict source controls were fully implemented in 1979 and they have
experienced phenomenal growth during the trend period. Atlanta also has held its own
114
-------
in the face of rapid growth although they actually suffered a 1 percent increase in TSP
levels over the trend period. The TSP concentrations in 1979, however, were relatively
low when compared to the cities which experienced high levels of improvement.
Short-term TSP Trend
During the last 5 years, the overall TSP concentrations have flattened out. The
national trend as well as the 15-city composite weighted average each indicate an
improvement with a 1 percent decrease in the air quality. On a geographic basis, the
Northeast, Midatiantic, Midwest, and South Coast areas show increasing trends in TSP
concentrations of 3, 1, 6, and 1 percent, respectively. The South, Rocky Mountain, and
Northwest areas show decreases in TSP concentrations of 8, 2, and 6 percent,
respectively. On a city-specific basis, Denver and Portland have shown the greatest
decrease of TSP concentrations of 15 percent and 9 percent, while St. Louis and
Phoenix had the largest increases of 18 and 11 percent, respectively. Denver's
improvement was apparently due in great part to the short-term slowdown in building
construction. The increase In measured concentrations in the St. Louis area was due
to growth in industrial emissions near Granite City, while the higher levels in Phoenix
can be attributed to drier climatic conditions.
5.1.2 Lead Trends
Long-term Lead Trend
Because the 10-year trend period precedes the implementation of the lead
standard, this pollutant had the fewest sites (26) which met the 10-year trend criteria
in these 15 areas. The cities of Boston, New York, Detroit, St. Louis, and Atlanta had
no sites, all the other cities had between 1 and 3 monitors with the exception of
Chicago which had 10. The composite average, however, agreed remarkably well with
the national trend with an 86 percent decrease in concentration versus an 89 percent
decrease. This demonstrates the point that when a source's impact is truly ubiquitous
i.e., lead from automobiles, and that source is reduced, the effectiveness of the source
reduction can be tracked with a limited number of monitors.
The city of Seattle is an exception to this rule with its one site showing only a 44
percent decrease in concentration. This site was source oriented and near a smelter
which was shut down in 1986.
Short-term Lead Trend
By looking at a 5-year trend, the number of sites qualifying in the 15 cities
increased from 26 to 115. The only two cities which do not have a 5-year trend, are
Atlanta and Portland. Seattle's 5-year trend did not include the source oriented lead
site, but did include two traffic oriented sites which were not included in the 10-year
trend. Seattle's 5-year trend showed a 75 percent decrease. The 5-year composite
trend for the 15 cities shows a 50 percent decrease in concentrations. When the source
oriented sites in New York and St. Louis are not considered, the trend decrease of 74
115
-------
percent more closely matches the national trend of 75 percent The source oriented
sites in New York and St. Louis are plotted and show a decrease of 20 percent in New
York and an increase of 203 percent in St. Louis. The source oriented sites for New
York are in Wallkill around an automobile battery reprocessing facility, and the sites in
St. Louis are in Herculaneum around a primary lead smelter. The State of Missouri is
currently pursuing the installation of better control technology for lead emissions.
5.1.3 SO2 Trends
Long-term SO2 Trend
The weighted average of 11 of the 15 cities which had sites that qualified for the
trend analysis yielded a 23 percent reduction in concentrations as opposed to the
national average reduction of 30 percent. The cities which did not qualify for the trend
analysis, Washington, Atlanta, Phoenix, and Portland, all have low SO2 levels and few
if any large SO2 sources. Chicago, Denver, and Seattle had reductions of 46, 45, and
43 percent, respectively, which are a result of control programs, economic and energy
recessions, and the shutdown of the ASARCO smelter near Seattle.
Geographically, the Midatlantic (Baltimore data only) showed the least improvement
with a 4 percent decline in concentrations and is followed by the Northeast at 9, percent
and the South (Houston data only) at 17 percent. Those areas which equalled or
exceeded the national average were the Midwest at 30 percent, the Rocky Mountain
area at 33 percent, the South Coast at 33 percent, and the Northwest (Seattle data
only) at 43 percent improvement.
Short-term SO, Trend
By looking at the 5-year trends, the number of SOZ sites increased from 90 to 118
and the cities of Washington, and Atlanta are now included. With the exception of
Philadelphia which showed no change over the past 5 years, all the cities except
Washington, (+7 percent) and Atlanta (+1 percent) had decreasing trends. The
increases are evidently due to greater electrical power demand. During the last 5 years
the composite average of the 15 cities exceeded that of the national average with a
decrease of 17 percent compared to 13 percent in air quality, respectively. Seattle
leads the way with a 42 percent decrease during the last 5 years due to the closing
of the ASARCO smelter.
5.1.4 CO Trends
Long-term CO Trend
With the exception of lead, CO has shown the most improvement. At the
beginning of the 10-year trend, 13 cities had some second high 8-hour maximum
averages above the level of the standard and 10 cities had composite means of all
their monitors' second high maximum values over the standard. By 1988, only 8 cities
had data used in the trends analyses with second high maximum values over the
116
-------
standard and only 2 cities had composite means of the second high maximum value
above the level of the standard.
The national average and the 15-city weighted average are identical with a 28
percent improvement. Regionally, the largest improvement was registered in the
Northeast with 42 percent improvement followed by the Midwest and Northwest at 35
and 34 percent, and the Rocky Mountain, Midatlantic and South at 29, 23, and 22
percent, respectively. Portland, with a vigorous motor vehicle inspection and
maintenance (I/M) program and a massive effort in rapid transit systems (bus and light
rail) over the last 10 years, and St. Louis showed the most improvement with a
decrease of 46 percent in concentration. These cities were followed closely by Boston
and New York at 45 percent each, and Chicago with 42 percent, each due to the
implementation of I/M programs, transportation control measures, and the Federal Motor
Vehicle Control Program. Houston and Los Angeles registered only one-half of the
national average improvement of 14 percent. Houston had only 1 CO site that met the
10-year criteria and had relatively low readings at the beginning of the trend period.
Los Angeles had already implemented the strictest controls in the country and has
continued to register improvement in spite of growth.
Short-term CO Trend
Once again the composite weighted average of the 15 cities mimicked the national
average with a decrease of 15 percent versus 16 percent, respectively. Although all
the cities had decreasing trends in the 10-year period, Houston, Seattle, and Los
Angeles had deteriorations of 5, 8, and 10 percent, respectively during the last 5 years.
In the case of Houston, the apparent increase is due to the inclusion of higher values
from additional monitors used for the 5-year trend and an increase in emissions due
to additional vehicle miles traveled in the area. The expanded network in the last 5
years has identified increasing trends. The Los Angeles increase is also a function of
its growth and possibly changing traffic patterns. Recently, Los Angeles does not
appear to have a pronounced morning and evening rush hour period, but is congested
for all normal daylight driving hours, thus masking any diurnal pattern of CO emissions
and concentrations.
5.1.5 NO2 Trends
Long-term NO2 Trend
This is the pollutant with the most cities missing data although the 8 cities
contributing to the trend showed an improvement almost twice that of the national
average, 13 percent versus 7 percent. The cities that had no site which met the 10-
year trend criteria were Baltimore, Washington, Detroit, Atlanta, Phoenix, Portland, and
Seattle, Of the cities that had trend data from five or more monitors, the trends were
remarkably consistent with Los Angeles at 14 percent improvement, Philadelphia at 15
percent, and St. Louis at 17 percent improvement.
117
-------
The only areas which showed a lack of improvement were Chicago with no
change, 2 percent deterioration in New York, and a 12 percent deterioration in Boston.
This change was based on 2, 3, and 1 monitors, respectively. On a Regional basis
there was no data from the Midatlantic and Northwest. No change was recorded in the
Northeast, and there was a 9 percent improvement in the Midwest, a 14 percent
improvement in the Rocky Mountain, and a 39 percent improvement in the South. The
39 percent improvement in the South is based upon only 2 monitors in Houston.
Short-term NO, Trend
2
The 5-year trend picked up 3 of the 7 cities that were missing in the 10-year trend.
The additional cities included in the trend are Baltimore, Washington, and Atlanta. The
total number of sites used increased from 35 to 72 as well. The recent 5-year trend
for NO2 has been almost flat with the national trend increasing by 1 percent and the
15-eity composite weighted average decreasing by 1 percent. Boston and Atlanta
continue to show the greatest increase in NO2 levels over the last 5 years with 10
percent and 13 percent increases, respectively. Washington leads the way in
decreases with 10 percent.
5.1.6 O3 Trends
Long-term O3 Trend
The national trend showed a 1 percent deterioration between 1979 and 1988 while
the 15-city weighted average showed a 4 percent increase in ozone levels over the
same period. This increase has been in part attributed to summer meteorology for
1988. On the average, 1988 was the third hottest summer in the past 50 years and
this effect was most noticeable in the Northeast, Midatlantic, and Midwest regions
where the average city increase was 15 percent over the 10-year period. The two
cities which showed the most decrease in ozone levels over the last 10-year period
were those cities which have been historically associated with high levels of ozone and
where the concentrations in 1979 were high enough to compensate for the elevated
values in 1988. These cities are Los Angeles (22 percent decrease) and Houston (24
percent decrease). Denver was the only other city to show a decrease (14 percent)
and did not experience the general increase in 1988 that was seen primarily in the
Midwest, Northeast, and Midatlantic areas.
Phoenix showed the greatest deterioration of 35 percent over the 10-year period.
The cause of this increase is that the base year of 1979 was unusually low (.079 ppm)
and the lowest of the 10-year period. Note that the trend was highly variable from year
to year over the period.
Short-term O3 Trend
The recent trend, as was the 10-year trend, was dominated by the hot summer of
1988. Nationally, ozone levels increased 9 percent and the 15 city average increased
11 percent. The increases were most apparent in the Eastern part of the United States
118
-------
; as noted above where the summer of 1988 was the third hottest summer since 1931,
> and this contributed to the increase in O3 levels. In the Northeast, Midatlantic, and
Midwest, average increases of 18, 25, and 19 percent, respectively, were recorded.
I In the Rocky Mountain area, where the summer of 1988 was typical compared to the
50-year average temperature, the ozone levels actually decreased by 1 percent.
119
-------
ANNUAL GEOMETRIC MEAN JJQM3)
100
40-
20 -
SSfTES
TSP
1879 1980 1361 1962 1963 19(4 1985 1986 1987 1988
YEAR
ANNUAL MAXI MUM QUARTERLY MEAN (UG/M3)
1.5
3 SITES Pb
1985 1988
YEAR
1S87 198S
ANNUAL ARITHMETIC AVEflAGE (PPM)
0,04
0.03
0,01 -
5 SUES
S02
1879 I960 1961 1982 1983 1984 1985 1888 1987 1888
ViAH
ANNUAL SECOND DAILY MAX 1-HR (PPM)
0,2 -
3 SITES O3
I 1 I I I I I I I
1979 1S80 1881 19B2 1983 1384 1985 IgSS 1987 1988
YEAR
ANNUAL ARITHMETIC AVEHAGE (PPM)
0.04 -
0.03
0,02
0.01
1SITE
NO2
1979 1980 1981 1S82 1883 1984 198S 1986 1987 1968
YEAR
ANNUAL SECOND MAXIMUM 8-HR AVERAGE (PPM)
20
5-
2 SITES CO
WWKH- ^ ^
1979 1980 1981 1882 1883 1984 1985 1988 1M7 1988
YEAR
Figure 5-2. Air Quality Trends In the Composite Mean and Range of PoHutant-Speetfie Statistics for the
Boston-Lawrence-Salem, MA-NH Consolidated Metropolitan Statistical Area, 1979-1988,1984-1988
Trend Years for Lead.
-------
ANNUAL GEOMETRIC MEAN (UQ/M3)
ANNUAL MAXIMUM QUARTERLY MEAN (UQM3)
ANNUAL ARITHMETIC AVERAGE (PPM)
120
80
20 -
39 SITES
TSP
1979 1980 1981 1882 1983 1964 1885 ISM 1967 1943
YEAH
2.S -
1.5 -
1984
lass less
YEAR
1987 1988
0.03
0.02
17S[TES
SO2
1979 1980 1981 1983 1983 1984 1989 1986 1987 1988
YEAR
ANNUAL SECOND DAILY MAX 1 -HR (PPM)
ANNUAL ARITHMETIC AVERAGE (PPM)
ANNUAL SECOND MAXIMUM MR AVERAGE (PPM)
0,85 -
0.15 -
1976 1980 1911 1982 1983 1984 1985 19SS 1987 1988
YEAR
0.07
0.06
0.05
0.03 -
0.02
0.01
3 SITES
NO2
1979 1980 1981 1982 1903 1984 1985 1966 1987 1988
YEAR
30
20
10
12 SITES
CO
1979 1980 1SB1 1992 1983 1984 19SS 1986 1987 1988
YEAR
Figure 5-3. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
New York-Northern New Jersey-Long Island, NY-NJ-CT Consolidated Metropolitan Statistical Area,
1979-1988, 1984-1988 Trend Years for Lead.
-------
ANNUAL GEOMETRIC MEAN (UG-M3)
120
100 -
80-
60 -
11 SITES
TSP
1978 1880 1961 1882 1883 1964 1989 1988 1887 1966
YEAR
1,5-
0.5 -
ANNUAL MAXIMUM QUARTERLY MEAN (UG/M3)
2 SITES
ANNUAL ARITHMETIC AVERAGE (PPM)
Pb
1979 1960 1981 1982 1983 1884 1965 1986 1987 1988
YEAR
0.04
O.OJ-
0.02-
0,01 -
4 SITES
SO2
1979 1980 18S1 1982 1983 1864 1985 1986 1987 1988
YEAH
ANNUAL SECOND DAILY MAX 1 -MR (PPM)
0.2*
0,2-
0.15-
7S1TiS
103
1979 1960 1081 1882 1S83 1684 1965 1986 1987 1966
YEAR
ANNUAL ARITHMETIC AVERAGE (PPM)
0.07
o.os
0.04
0,03
0,02 -
0,01
3 SITES
NO2
1BM 1B8S
1987 1968
YEAR
ANNUAL SECOND MAXIMUM B-HR AVERAGE (PPM)
18-
10-
2 SITES CO
i I I i I I I I i
1979 1980 1981 1982 1983 1984 188S 1886 1987 1968
YEAR
Figure 5-4. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Baltimore, MD Metropolitan Statistical Area, 1979-1988,1984-1988 Trend Years for NO2.
-------
ANNUAL GEOMETRIC MEAN (U6/M3)
40 -
20-
31 SITES
TSP
1979 1980 19B1 1982 1883 1984 1985 19S6 1987 1988
YEAR
ANNUAL MAXIMUM QUARTERLY MEAN (Uaซ3)
2 SITES
Pb
1978 1980 1981 1M2 1983 1984 19ง5 1986 1987 1968
YEAR
ANNUAL ARITHMETIC AVERAGE (PPM)
0.04
0.03
0.02 -
0.0! -
14 SITES
SO2
1980 1981 1982 1983 1984 1S85 1986 1987 1988
YEAH
ANNUAL SECOND DAILY MAX 1-HH (PPM)
ANNUAL ARITHMETIC AVERAGE !PPM)
ANNUAL SECOND MAXIMUM 8-HR AVERAGE (PPM)
0.25
0.1
0.05 -
1979 1380 1981 1982 1983 1984 1985 1986 1987 1S88
YEAR
0.07
0,06 -
0,05
0.04
0.03
0-02
e SITES NO2
i i i
1976 1980 1881 1M2 1SB3 1984 1SSS 198S 1987 1988
YEAR
IS-
7 SITES
CO
1979 1S80 1881 1982 1983 1984 168S 1988 1987 1988
YEAR
Figure 5-5. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Philadelphia-Wilmington-Trenton, PA-NJ-DE-MD Consolidated Metropolitan Statistical Area, 1979-1988.
-------
ANNUAL GEOMETRIC MEAN !UGM3j
60 -
40 -
19SfTES
TSP
1979 1980 1981 1982 1963 19B4 1985 1386 13S7 1MB
YEAR
ANNUAL MAXIMUM QUARTERLY MEAN (UG/M3)
1.5
D.S-
2 STIES
Pb
1979 1080 1961 1982. 1983 16S4 1985 1988 193?
YEAR
ANNUAL ARITHMETIC AVERAGE (PPM)
TSFTES
SO2
1984
1985 1936
YEAR
1987 1886
ANNUAL SECOND DAILY MAX 1-HR (PPM)
0,2 -
0.1
0.05 -
11 SITES
O3
ma, J_ _f_ _ J--=
1979 1980 1981 1882 19S3 1984 1SBS 1986 1387 1988
YEAR
ANNUAL ARITHMETIC AVERAGE (PPM!
0.06 -
0.05
0.03 -
0.02
0.01
S SITES
N02
1984
IBBi 1980
YiAB
1387 1388
ANNUAL SECOND MAXIMUM 8-HR AVERAGE (PPM)
20
10'
9 SITES
I CO
1B79 I960 19B1 1982 1963 1964 1965 1968 1987 1988
YEAR
Figure 5-6. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Washington, DC-MD-VA Metropolitan Statistical Area, 1979-1988,1984-1988 Trend Years for SO2
and NO2.
-------
ANNUAL GEOMETRIC MEAN (UOM3)
100
80 -
60*
40-
SSfTES
JTSP
i I i 1 i i * i i I
1979 1980 1981 1992 1983 1964 1985 1988 1987 1968
YEAH
Pb
NO SITES MEET DATA SELECTION CRITERIA
ANNUAL ARITHMETIC AVERAGE (PPM;
0.04
0,03
0.02
IfflTE
SO2
1884 1985 1988
YEAH
1967 1388
ANNUAL SECOND DAILY MAX 1 -HR jPPMj
0.25
0,2
0.15 -
O.OS
2 SITES
03
* iiiiiiii
1879 18SO 1981 1882 1983 1884 1985 1B88 198? 1988
YEAH
ANNUALARfTHMETtCAVEHAQE JPPM)
2 SITES
NO2
1984
1985 1986
YiAH
1S87 1988
15
14 -
10 -
6-
ANNUAL SECOND MAXIMUM 8-Hfl AVERAGE (PPM)
1 SITE CO
1179 1980 1S81 1982 1333 1984 1985
YEAH
1887 1988
Figure 5-7. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Atlanta, GA Metropolitan Statistical Area, 1979-1988,1984-1988 Trend Years for SO2 and NO2.
-------
ANNUAL GEOMETRIC MEAN (UQ/M3)
ANNUAL MAXIMUM QUARTERLY MEAN (UC/M3J
ANNUALAfflTHMETICAVERAGE (PPMj
i I^i1^ I i I I I I
1979 1980 1981 1982 1983 1984 1985 1886 1987 1988
YEAR
1.5 -
0,5 -
1979 1930 1981 1982 1983 1984 1965 1988 1987 1S88
YEAH
0.01 -
13SrTES
SO2
III I I I I III
1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
YEAR
ANNUAL SECOND DAILY MAX 1-HR (PPM)
0,4
0.3
0.2
0.1
10STTES O3
I I I i I I I I i I
1979 1980 1981 1982 1983 1984 1SSS 1986 1987 1338
YEAH
ANNUAL ARITHMETIC AVERAGE (PPJfl
ANNUAL SECOND MAXIMUM 8-HR AVERAGE (PPM)
0.07
0.05 -
0.04 -
2 SifTES NO2
n
1979 1980 1981 1382 1983 18i4 19B5 1886 1987 1988
YEAR
2 SITES CO
1979 1980 1981 1982 1983 1984 1985 1386 1987 1988
YEAH
Figure 5-8. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Chicago-Gary-Lake County, IL-IN-WI Consolidated Metropolitan Statistical Area, 1979-1988.
-------
ANNUAL GEOMETRIC MEAN (UG/M3)
200
150
100 -
28 SITES
TSP
r i i 1 i i I i i
1979 I960 1981 1982 1983 1984 1985 1986 1987 1998
YEAR
ANNUAL MAXIMUM QUARTERLY MIAN (UG/M3)
1,5 -
0.5
2SIT6S
Pb
19B4 1995 1988 199? 198i
YEAR
ANNUALARITHMETIC AVERAGE (PPM)
0.03
0.02
0.01 -
6 SITES
S02
i T i r i i i r i
1979 1360 1981 1982 1953 1984 1985 1986 198? 19*8
YEAR
ANNUAL SiCOND DAILY MAX 1-HR (PPM)
0,2
0,1 S -
O.OS -
8 SITES O3
1979 1980 1381 1982 1983 1984 1985 19W 1987 1988
YEAfl
NO2
NO SITES MEET DATA SELECTION CRITERIA
ANNUAL SECOND MAXIMUM S-HR AVERAGE (PPM)
2-
7 SITES CO
1979 1980 1981 1982 1983 1984 1985 19* 1987 1988
YEAH
Figure 5-9. Air Quality Trends In the Composite Mean and Range of Pollutant-Specific Statistics for the
Detroit-Ann Arbor, Ml Consolidated Metropolitan Statistical Area. 1979-1988,1984-1988 Trend Years for
Lead.
-------
ANNUAL GEOMETRIC MEAN (UG/M3)
200 -
ISO-
100-
24 SITES
TSP
1979 I960 1961 1332 1983 1884 1965 1968 1987 1966
YEAR
ANNUAL MAXIMUM QUARTERLY MEAN (UQ/M3)
1.5
t -
as-
1SfTE Pb
1979 1910 1981 1982 1903 1984 1985 1988 1987 1989
YEAR
ANNUAL ARITHMETIC AVERAGE (PPM)
0.02
2 SITES
SO2
1978 1980 1981 1982 1BB3 1984 1985 1986 1987 1988
YEAH
ANNUAL SECOND DAILYMAX 1-HR (PPM)
ANNUAL ARITHMETIC AVERAGE (PPM)
ANNUAL SECOND MAXIMUM S-HR AVERAGE {PPM)
0-25 -
0,2-
2 SITES
1979 1980 1981 1982 1983 1S84 1985 1988 1987
YEAR
0,06 -
0.05 -
0.04
0,03 -
0.01 -
2 SITES NO2
I I 1
1978 1980 1981 1882 1983 1984 1965 1888 1987 1988
YEAR
14 -
la-
ic-
s'
8-
1 SITE CO
ill i r i i i i i
1879 1980 1961 1982 19&3 1984 1985 1986 1987 1988
YEAR
Figure 5-10. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Houston-Galveston-Brazoria, TX Consolidated Metropolitan Statistical Area, 1979-1988.
-------
ANNUAL GEOMETRIC MEAN (UQM3)
ANNUAL MAXIMUM QUARTERLY MEAN (UG/M3)
ANNUAL ARfTHMETIC AVERAGE (PPM)
225
200
150
100-
50 -
0
i
1
iwofl
^^
|
24 SITES
TSP
N
1
4
i
> <
i<
r '
1
i
i i i 1 r t i iii
1979 1980 1381 1962 1983 1964 1985 1886 1987 1981
YEAR
10
8-
6 -
2-
0
i
6 SOURCE,
8 TRAFFIC,
>
\
^_
I :
.
SITES
SITES
/
9
I , 1 1 T
1984 1985 1986 1987
YEAH
Pb
'
-4
r
1988
0.04
O.OZ -
0.01
9 SITES
SO2
1979 1980 1991 1982 19(3 1984 198S 1936 198? 1988
YEAR
ANNUAL SECOND DAILY MAX 1-HR (PPM)
0.2
0.1
0.05-
9 SITES
Q3
IT^I II IIiI
1979 1980 1981 1982 1983 1984 19B5 1986 1987 1988
YEAR
ANNUAL ARITHMETIC AVERAGE (PPM)
0.0?
0.06 -
0.01 -
ssrres NO2
1979 1380 1981 1982 1363 1SS4 198S -1916 19S7 1988
YEAR
ANNUAL SECOND MAXIMUM 8-HR AVERAGE (PPM)
9 SITES CO
1881 19B2 1983 1884 19BS 1086 1887 1888
YEAR
Figure 5-11. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
St. Louis, MO-IL Metropolitan Statistical Area, 1979-1988,1984-1989 Trend Years for Lead.
-------
ANNUAL CEOMETHiC MiAN (UG/M3)
ANNUAL MAXIMUM QUARTERLY MEAN CUG/M3)
ANNUAL ARITHMETIC AVERAGE (PPM)
250
200
T979 1980 1981 1982 1963 1984 1985 1986 19B7 1968
Y6AR
3 SITES Pb
1979 1380 1981 1982 1963 1984 1965 1986 1987 1968
YEAR
0.02 -
0,01 -
2 SITES
SO2
H-H
1979 1680 1981 1982 1983 1984 198S 1966 1M7 1988
YEAR
AWWAL SECOND DAILY MAX 1-HR (PPM)
ANNUALARITHMETIC AVERAGE (PPMJ
ANNUAL SECOND MAXIMUM B-HR AVERAGE (PPM)
0.25
0.2 -
0.1S -
0.1 -
0,05 -
3 SITES
O3
1979 1880 1981 1812 1683 1984 1965 198i 1S87 1988
YEAR
0.06
0.05
0,04
0,02
0,01
asms
NO2
1979 I960 1981 1982 1983 1984 1985 1986 1987 1988
YEAR
20 -
10
< SITES
CO
1979 1980 1981 1982 1363 1984 1905 1966 1987 1SS8
YEAR
Figure 5-12. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Denver-Boulder, CO Consolidated Metropolitan Statistical Area, 1979-1988.
-------
ANNUAL GEOMETRIC MEAN (UQ/M3)
200
100 -
18 SFTES
TSP
1979 1980 1981 1982 1983 1964 1985 1986 1987 1988
YEAR
1.S -
0,5 -
ANNUAL MAXIMUM QUARTERLY MEAN !USM3!
3 SITES
ANNUALAHITHMETlCAVEFlAeE (PPM)
Pb
i i i i i i i i i
1979 1980 1981 1882 1383 19M 1985 1986 1987 1888
YEAR
0.02
0.01 -
SO2
1979 1980 1981 1982 1983 1984 1995 1986 1987 1988
YEAR
ANNUAL SECOND DAILY MAX 1-HR (PPM)
1979 1980 1981 1982 1933 1984 198$ 198* 1987 1938
YEAH
ANNUAL ARITHMETIC AVSRAGi (PPM)
ANNUAL SECOND MAXIMUM 8-HR AVERAGE (PPM)
0.1
0-06
14-SfTES
NO2
F I I 1 I I I I I
1979 1980 1981 1982 1963 1984 1985 1986 1967 1988
YiAH
10-
19 SITES CO
1979 1980 1961 1992 1983 1984 1945 1986 1S87 1988
YEAR
Figure 5-13. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Los Angeles-Anaheim-Riverside, CA Consolidated Metropolitan Statistical Area, 1979-1988,
-------
ANNUAL GEOMETRIC MEAN (US/MS)
200 -
150
100
4 SITES
TSP
1979 1980 1*81 1982 1983 1984 1985 1986 1387 1988
YEAR
ANNUAL MAXIMUM QUARTERLY MEAN (US/M3)
2,5
2-
1.5
1SITE
Pb
1978 1680 1981 1982 1983 19M 1S85 198S 1987 1988
YEAR
SO2
NO SITES MEET DATA SELECTION CRITERIA
ANNUAL SECOND DAILY MAX 1-HR (PPM)
0.3
0,25 -
0,15 -
0.1
7SFTES
O3
1979 1980 1981 1982 1983 1B84 1985 1986 1987
YEAR
NO2
NO SITES MEET DATA SELECTION C RITERIA
ANNUAL SECOND MAXIMUM 8-HR AVERAGE (PPM)
15 -
10
A SITES CO
1 I 1 I I I 1 1 T I
1979 1980 1911 1B82 1983 1984 1985 1988 1987 1988
YEAH
Figure 5-14. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Phoenix, AZ Metropolitan Statistical Area, 1979-1988.
-------
ANNUAL GEOMETRIC MEAN (LK3/M3)
ANNUAL MAXIMUM QUARTERLY MEAN (U6/M3)
120
100
80 -
50
10 -
20 "
14 SITES TSP
I I I I I I I I I
1979 1980 1981 1842 1983 1984 1935 198S 1987 1988
YEAH
0.5
1 SITE Pb
I ill 1 ill i i
1979 1980 1981 1982 1983 1984 1985 1986 1967 1988
YEAR
S02
NO SITES MEET DATA SELECTION CRITERIA
ANNUAL SECOND DAILY MAX 1-HR (PPM)
0,05 -
3 SITES ' O3
i I I I i I I I I
1979 1980 1981 1982 1S83 1984 1985 19SS 1387 1888
YEAR
NO2
NO SITES MEET DATA SELECTION CRITERIA
ANNUAL SECOND MAXIMUM 8-HR AVERAGE {PPM;
i SITES
CO
1979 1960 1SB1 1982 1983 ISM 1995 1986 1937 1988
YEAR
Figure 5-15. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Portland-Vancouver, OR-WA Consolidated Metropolitan Statistical Area, 1979-1988.
-------
ANNUAL GEOMETRIC MEAN {U&M3)
100-
40-
20 -
TSP
1979 1980 1881 1982 1983 1984 1985 1988 1987 1988
YEAR
ANNUAL MAXIMUM QUARTERLY MEAN (US/M3)
1.5-
1 SITE Pb
I I i I i i { I i i
1979 1880 1981 1982 1S83 1984 1i85 1S88 1387 1911
YEAH
ANNUAL AWTHMET1C AVERAGE (PPM)
0.04
0.03
4 SITES
SO2
1879 1980 1SS1 1982 1903 1984 1985 1S86 1987 1988
YEAR
ANNUAL SECOND DAILY MAX 1-HR (PPM)
ANNUAL SECOND MAXIMUM S-HR AVERAGE (PPM)
0,15 -
0.1 -
0.05 -
i SITES
O3
1879 1980 19S1 1862 1983 1914 1365 1986 1987 138t
YEAR
NO2
NO SITES MEET DATA SELECTION CRITERIA
1879 1980 1981 1982 1983 19S4 1985 1988 1987 1988
YEAR
Figure 5-16. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics for the
Seattle-Tacoma, WA Consolidated Metropolitan Statistical Area, 1979-1988.
-------
Preceeding Page Blank
TABLE 5-2. Percent Change in Air Quality Trend Statistics 1979 Through 1988
National Average
Northeast
Midatlantic
Midwest
South
Rocky Mtn.
South Coast
Northwest
Boston
New York
Philadelphia
Baltimore
Washington, DC
Detroit
Chicago
St. Louis
Atlanta
Houston
Denver
Phoenix
Los Angeles
Portland
Seattle
TSP
- 20
- 13
- 12
- 21
- 12
- 10
- 23
- 28
- 19
4- 1
- 35
- 29
- 21
- 5
- 16
- 25
Pb
- 89
.
-
- 87
- 93
- 92
_
-85
-
.
- 87
- 91
- 88
-92
-80
- 44
SO,
-30
- 10
- 14
- 3
. 4
-
-25
-46
- 20
.
- 17
-45
-
- 33
.
-43
CO
- 28
-45
-45
-37
- 24
- 21
- 18
- 42
- 46
-30
- 14
- 33
- 25
- 14
- 46
- 22
NO,
- 7
+ 12
+ 2
- 15
_
-
.
0
- 17
.
-39
. - 17
-
- 14
.
-
PJ
+ 1
+ 16
0
+ 12
+ 17
+ 21
+ 17
+ 15
+ 8
+ 1
- 24
- 14
+ 35
- 22
+ 19
+ 10
Composite
Average
(weighted)
- 19
-86
- 23
- 28
13
+ 4
136
-------
TABLE 5-3. Percent Change in Air Quality Trend Statistics
1979 Through 1988 by Geographic Regions
TSP Pb SO, CO NO, Q,
National Average - 20 - 89 - 30 - 28 - 1 +1
Composite -19 - 86 - 23 - 28 - 13 + 4
Northeast - 15 - 87 -9 - 42 0 +9
Midatlantic - 11 - 93 - 4 - 23 - +19
Midwest - 23 - 85 - 30 - 35 - 9 +13
South - 17 - 87 - 17 - 22 - 39 - 12
Rocky Mtn. - 25 - 90 - 45 - 29 - 17 +11
South Coast - 5 - 92 - 33 - 14 - 14 - 22
Northwest -21 - 62 -43 - 34 - +15
137
-------
TABLE 5-4. Percent Change in Air Quality Trend Statistics 1984-1988
National Average
Northeast
Midatlantic
Midwest
South
Rocky Mtn.
South Coast
Northwest
Boston
New York
Philadelphia
Baltimore
Washington, DC
Detroit
Chicago
St. Louis
Atlanta
Houston
Denver
Phoenix
Los Angeles
Portland
Seattle
ISP
- 1
+ 8
+ 2
- 2
0
+ 3
- 2
+ 2
+18
- 5
-11
-15
+11
+ 1
-9
-3
Pb
-75
-68
-34
-79
-86
-86
-78
-82
+121
-
-72
-71
-74
-81
-
-75
SO,
- 13
+ 2
- 8
- 14
- 14
+ 7
- 6
-23
- 19
+ 1
-20
- 17
-
-29
-
- 42
co
-16
-44
-26
-28
-31
-20
-36
-13
-18
-26
+ 5
-25
-19
+10
-15
+ 8
NO,
+ 1
+10
+ 2.
-8
-3
-10
-
- 2
- 5
+13
-3
- 6
-
+ 3
-
-
o,
+ 9
+15
+21
+18
+20
+29
+38
+19
+ 1
+11
0
+ 4
-5
- 6
+11
+22
Composite
Average
(weighted)
-50
- 17
-15
-1
+11
138
-------
TABLE 5-5. Percent Change in Air Quality Trend Statistics
1984 Through 1988 by Geographic Regions
TSP Pb SO. CO NO, O,
National Average -1 -75 -13 -16 +1 +9
Composite -1 -50 -17 -15 -1 +11
Northeast . +3 -60 - 2 -33 +1 +18
Midatlantic +1 -86 - 4 -26 -7 +25
Midwest +6 -13 -16 -22 -4 +19
South -8 -72 -10 -11 +5 +6
Rocky Mtn. -2 -73 -17 -22 -6 - 1
South Coast +1 -81 -29 +10 +3 - 6
Northwest -6 -75 -42 - 4 - +17
139
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5.2 REFERENCES
1. Statistical Abstract of the United States. 109th Edition, U.S. Bureau of the Census,
Washington, DC, January 1989.
140
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1, REPORT NO.
EPA 450/4-90-002
2.
3. RECIPIENT'S ACCESSIO(*NO.
4, TITLE AND SUBTITLE
5. REPORT DATE
National Air Quality and Emissions Trends
Report, 1988
6. PERFORMING ORGANIZATION CODE
7, AUTHOR(S)
T. Curran, R. Faoro, T. Fte-Simons, N. Frank
W. Freas, W. F. Hunt, Jr., S. Kimbrough, O. Gerald,
N. Berg, E. Hanks, D, Lutz, G. Manire, & G. Dorosz
8. PERFORMING ORGANIZATION REPORT NO.
, PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Environmental Protection Agency
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
The computer graphics were prepared by W. Freas and the typing
by H. Hinton and C. Coats.
16. ABSTRACT
This report presents national and regional trends in air quality from 1979
through 1988 for total suspended paniculate, sulfur dioxide, carbon monoxide, nitrogen
dioxide, ozone and lead. Air pollution trends were also examined for the 5-year period
(1984-88). Both national and regional trends in each of these pollutants are examined.
National air quality trends are also presented for both the National Air Monitoring Sites
(NAMS) and other site categories. In addition to ambient air quality, trends are also
presented for annual nationwide emissions. These emissions are estimated using the
best available engineering calculations; the ambient levels presented are averages of
direct measurements.
This report also includes a section, Air Quality Levels in Metropolitan Statistical Areas
(MSAs). Its purpose is to provide interested members of the air pollution control
community, the private sector and the general public with greatly simplified air pollution
information. Air quality statistics are presented for each of the pollutants for all MSAs
with data in 1988.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATl Field/Group
Air Pollution Trends
Emission Trends
Carbon Monoxide
Nitrogen Dioxide
Ozone
Sulfur Dioxide
Total Suspended Particulates
Lead
Air Pollution
Metropolitan
Statistical Area (MSA)
Air Quality Standards
National Air Monitoring
Stations (NAMS)
13. DISTRIBUTION STATEMENT
Release Unlimited
19, SECURITY CLASS (ThisReport)
21. NO. OF PAGES
153
20. SECURITY CLASS (Thispage)
22. PRICE
EPA Form 2220-1 (9-73)
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