&EPA
United States
Environmental
Protection
Agency
Office of Air Quality
Planning and Standards
Monitoring And Reports Branch
Research Triangle Park, NC 27711
EPA-450/4-89-001
March 1989
AIR
National Air Quality and
Emissions Trends Report,
1987
Ozone Concentrations in ppm
00-.06
>. 16
MAXIMUM ONE HOUR OZONE FOR JUNE 19, 1987
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NATIONAL AIR QUALITY AND EMISSIONS
TRENDS REPORT, 1987
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
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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: Isopleths of ozone daily maximum 1-hour
concentrations for June 19, 1987.
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PREFACE
This is the fifteenth 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.
The following people are recognized for their contributions
as principal authors of the sections of the report:
Section 1 - Thomas C. Curran
Section 2 - Warren P. Freas
Section 3 - Robert B. Paoro, Terence Fitz-Simons,
Neil H. Frank, and Warren P. Freas
Section 4 - Warren P. Freas
Section 5 - Stan Sleva, Neil Berg, Geri Dorosz, Ed Hanks,
David Lutz, and George Manire
Special mention should also be given to Helen Hinton and Cathy
Coats for typing the report, Whitmel Joyner for technical editing
and to William F. Hunt, Jr. for facilitating its preparation.
Also deserving special thanks are Sue Kimbrough for the
emission trend analyses, Tom Furmanczyk of Environment Canada for
the 1987 ozone data from Ontario, William Ivey for computer mapping
support and David Henderson and Coe Owen of EPA Region IX for
providing us with their software to generate the air quality maps
of the United States used in this report.
111
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IV
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CONTENTS
1. EXECUTIVE SUMMARY 3
1.1 INTRODUCTION . ..... 3
1.2 MAJOR FINDINGS ..... 6
TOTAL SUSPENDED PARTICULARS (TSP) 6
SULFUR DIOXIDE (S02) . 8
CARBON MONOXIDE (CO) . 10
NITROGEN DIOXIDE (NO2) 12
OZONE (0,,) 14
LEAD (Pb) 16
1.3 REFERENCES 18
2. INTRODUCTION 21
2.1 DATA BASE 23
2.2 TREND STATISTICS 25
2.3 REFERENCES . 29
3. NATIONAL AND REGIONAL TRENDS IN NAAQS POLLUTANTS .... 31
3.1 TRENDS IN TOTAL SUSPENDED PARTICULATE ....... 35
3,1.1 Long-term TSP Trends: 1978-87 ....... 35
3.1.2 Recent TSP Trends: 1983-87 41
3.2 TRENDS IN SULFUR DIOXIDE 43
3.2.1 Long-term SO2 Trends: 1978-87 43
3.2.2 Recent SO2 Trends: 1983-87 49
3.3 TRENDS IN CARBON MONOXIDE . ..... 51
3.3.1 Long-term CO Trends: 1978-87 51
3.3.2 Recent CO Trends: 1983-87 ......... 54
3.4 TRENDS IN NITROGEN DIOXIDE 59
3.4.1 Long-term NO2 Trends: 1978-87 59
3.4.2 Recent NO2 Trends: 1983-87 60
3.5 TRENDS IN OZONE 64
3.5.1 Long-term 03 Trends: 1978-87 ....... 64
3.5.2 Recent O3 Trends: 1983-87 65
3.5.3 Chronology of a Multi-Regional Ozone
Episode, June 17-20, 1987 71
3.5.4 Preview of 1988 Ozone Trends 76
3.6 TRENDS IN LEAD 80
3.6.1 Long-term Pb Trends: 1978-87 80
3.6.2 Recent Pb Trends: 1983-87 . 85
3.7 REFERENCES . 87
4. AIR QUALITY LEVELS IN METROPOLITAN STATISTICAL AREAS . . 90
4.1 SUMMARY STATISTICS ..... 94
4.2 MSA AIR QUALITY SUMMARY 94
4.3 REFERENCES 103
5. TRENDS ANALYSES FOR FOURTEEN METROPOLITAN STATISTICAL
AREAS 115
5.1 AIR QUALITY TRENDS FOR FIVE GEOGRAPHICAL AREAS. 119
5.1.1 TSP Trends 134
5.1.2 Pb Trends 134
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5.1.3 S02 Trends 135
5.1.4 CO Trends 135
5.1.5 NO2 Trends 135
5.1.6 03 Trends 136
5.2 REFERENCES 137
VI
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FIGURES
l-l. Number of persons living in counties with air
quality levels above the primary National Ambient
Air Quality Standards in 1987 (based on 1980
population data). 5
1-2. Illustrations of plotting conventions for boxplots. 5
1-3. Boxplot comparisons of trends in annual geometric
mean total suspended particulate concentrations
at 1726 sites, 1978-1987. 7
1-4. National trend in particulate emissions, 1978-1987. 7
1-5. Boxplot comparisons of trends in annual mean sulfur
dioxide concentrations at 347 sites, 1978-1987. 9
1-6. National trend in sulfur oxide emissions, 1978-1987. 9
1-7. Boxplot comparisons of trends in second highest
nonoverlapping 8-hour average carbon monoxide
concentrations at 198 sites, 1978-1987. 11
1-8. National trend in emissions of carbon monoxide,
1978-1987. ' ' 11
1-9. Boxplot comparisons of trends in annual mean
nitrogen dioxide concentrations at 84 sites,
1978-1987. 13
1-10. National trend in nitrogen oxides emissions,
1978-1987. 13
1-11. Boxplot comparisons of trends in annual second
highest daily maximum 1-hour ozone concentration
at 274 sites, 1978-1987. 15
1-12. National trend in emissions of volatile organic
compounds, 1978-1987. 15
1-13. Boxplot comparisons of trends in maximum quarterly
average lead concentrations at 98 sites, 1978-1987. 17
1-14. National trend in lead emissions, 1978-1987. 17
2-1. Ten Regions of the U.S. Environmental
Protection Agency. 28
3-1. Sample illustration of use of confidence intervals
to determine statistically significant change. 33
vii
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3-2, Illustration of plotting conventions for boxplots. 34
3-3. Status of PM10 monitoring network, 1987. 37
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/ 1978-1987 - 39
3-5. Boxplot comparisons of trends in annual geometric
mean total suspended particulate concentrations
at 1726 sites, 1978-1987. 39
3-6. National trend in particulate emissions, 1978-1987. 40
3-7. Boxplot comparisons of trends in annual mean total
suspended particulate concentrations at 1441 sites,
1983-1987. 42
3-8. Regional comparisons of the 1985, 1986, 1987
composite average of the geometric mean total
suspended particulate concentration. 42
3-9. National trend in the composite average of the
annual average sulfur dioxide concentration at both
NAMS and all sites with 95 percent confidence
intervals, 1978-1987. 44
3-10. National trend in the composite average of the
second-highest 24-hour sulfur dioxide concentration
at both NAMS and all sites with 95 percent
confidence intervals, 1978-1987. 44
3-11. National trend in the composite average of the
estimated number of exceedances of the 24-hour
sulfur dioxide NAAQS at both NAMS and all sites
with confidence intervals, 1978-1987. 45
3-12. Boxplot comparisons of trends in annual mean sulfur
dioxide concentrations at 347 sites, 1978-1987. 47
3-13. Boxplot comparisons of trends in second highest
24-hour average sulfur dioxide concentrations at
347 sites, 1978-1987. 47
3-14. National trend in sulfur oxide emissions, 1978-1987. 48
3-15. Boxplot comparisons of trends in annual mean sulfur
dioxide concentrations at 603 sites, 1983-1987. 50
Vlll
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3-16. Regional comparisons of the 1985, 1986, 1987
composite average of the annual average sulfur
dioxide concentration. 50
3-17. 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,
1978-1987.. 52
3-18. Boxplot comparisons of trends in second highest
nonoverlapping 8-hour average carbon monoxide
concentrations at 198 sites, 1978-1987. 52
3-19. 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,
1978-87. 53
3-20. National trend in emissions of carbon monoxide,
1978-1987. 56
3-21. Comparison of trends in total National vehicle
miles traveled and National highway vehicle
emissions, 1978-1987. 57
3-22. Carbon monoxide 1987 second-maximum 8-hour
concentrations ordered by MSA population. 57
3-23. Boxplot comparisons of trends in second highest
nonoverlapping 8-hour average carbon monoxide
concentrations at 367 sites, 1983-1987. ' 58
3-24. Regional comparisons of the 1985, 1986, 1987
composite average of the second highest non-
overlapping 8-hour average carbon monoxide
concentration. 58
3-25. National trend in the composite average of
nitrogen dioxide concentration at both NAMS
and all sites with 95 percent confidence
intervals, 1978-1987. 61
3-26. Boxplot comparisons of trends in annual mean
nitrogen dioxide concentrations at 84 sites,
1978-1987. 61
3-27. National trend in nitrogen oxides emissions,
1978-1987.
62
ix
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3-28. Boxplot comparisons of trends in annual mean
nitrogen dioxide concentrations at 199 sites,
1983-1987. 63
3-29. Regional comparisons of 1985, 1986, 1987 composite
average of the annual mean nitrogen dioxide
concentration. 63
3-30. 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, 1978-1987. 66
3-31. Boxplot comparisons of trends in annual second
highest daily maximum 1-hour ozone concentration
at 274 sites, 1978-1987. 67
3-32. 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, 1978-1987. 67
3-33. National trend in emissions of volatile organic
compounds, 1978-1987. 68
3-34. Boxplot comparisons of trends in annual
second highest daily maximum l-hour ozone
concentrations at 522 sites, 1983-1987. 69
3-35. Regional comparisons of the 1985, 1986, 1987
composite average of the second-highest daily
l-hour ozone concentrations. 70
3-36. Regional comparisons of the number of days greater
than 90°F in 1985, 1986, 1987 for selected cities. 70
3-37. Isopleths of ozone daily maximum 1-hour
concentrations for June 17, 1987. 72
3-38. Isopleths of ozone daily maximum 1-hour
concentrations for June 18, 1987. 73
3-39. Isopleths of ozone daily maximum 1-hour
concentrations for June 19, 1987. 74
3-40. Isopleths of ozone daily maximum l-hour
concentrations for June 20, 1987. 75
3-41. Summer '88 was 3rd hottest since 1931. (Source:
USA Today, September 6, 1988). 77
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3-42. Ozone exceedances for selected cities in the North
Central and Northeastern U.S., 1988. 78
3-43. Ozone exceedances for selected cities in the
Southeastern U.S., 1988. 78
3-44. Boxplot comparison of 1983 and 1988 annual second
highest daily maximum 1-hour ozone concentrations
at 228 paired sites. 79
3-45. Preliminary estimate of the national trend in the
composite average of the second highest daily
maximum l-hour ozone concentration, 1978-1988. 79
3-46. National trend in the composite average of the
maximum quarterly average lead concentration
at 97 sites and 21 NAMS sites with 95 percent
confidence intervals, 1978-1987. 82
3-47. Comparison of national trend in the composite
average of the maximum quarterly average lead
concentrations at urban and point-source oriented
Sites, 1978-1987. 83
3-48. Boxplot comparisons of trends in maximum quarterly
average lead concentrations at 97 sites, 1978-1987. 83
3-49. National trend in lead emissions, 1978-1987. 84
3-50. Boxplot comparisons of trends in maximum quarterly
average lead concentrations at 394 sites, 1978-1987. 86
3-51. Regional comparison of the 1985, 1986, 1987
composite average of the maximum quarterly
average lead concentration. 86
4-1. Percent of U.S. population and land area within
MSA'S, 1986. 92
4-2. Number of persons living in counties with air quality
levels above the primary national ambient air quality
standards in 1987 (based on 1980 population data). 93
4-3. United States map of the highest annual arithmetic
mean PM10 concentration by MSA, 1987. 96
4-4. United States map of the highest annual arithmetic
mean sulfur dioxide concentration by MSA, 1987. 97
XI
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4-5. United States map of the highest second maximum
24-hour average sulfur dioxide concentration by MSA,
1987. 98
4-6. United States map of the highest second maximum
nonoverlapping 8-hour average carbon monoxide
concentration by MSA, 1987. 99
4-7. United States map of the highest annual arithmetic
mean nitrogen dioxide concentration by MSA, 1987. 100
4-8. United States map of the highest second daily
maximum 1-hour average ozone concentration by MSA,
1987. 101
4-9. United States map of the highest maximum quarterly
average lead concentration by MSA, 1987. 102
5-1. Illustration of plotting conventions for ranges used
in CMSA/MSA area trend analysis. 118
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, 1983-1987. 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,
1983-1987. 121
5-4. Air quality trends in the composite mean and range of
pollutant-specific statistics for the Baltimore,
MD metropolitan statistical area, 1983-1987. 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, 1983-1987. 123
5-6. Air quality trends in the composite mean and range of
pollutant-specific statistics for the Atlanta, GA
metropolitan statistical area, 1983-1987. 124
5-7. 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, 1983-1987. 125
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5-8. Air quality trends in the composite mean and range of
pollutant-specific statistics for the Detroit -
Ann Arbor, Ml consolidated metropolitan statistical
area, 1983-1987. 126
5-9. Air quality trends in the composite mean and range of
pollutant-specific statistics for the Houston -
Galveston - Brazoria, TX consolidated metropolitan
statistical area, 1983-1987. 127
5-10. Air quality trends in the composite mean and range of
pollutant-specific statistics for the St. Louis, MO-
IL metropolitan statistical area, 1983-1987. 128
5-11. Air quality trends in the composite mean and range of
pollutant-specific statistics for the Denver -
Boulder, CO consolidated metropolitan statistical
area, 1983-1987. 129
5-12. Air quality trends in the composite mean and range of
pollutant-specific statistics for the Los Angeles -
Anaheim - Riverside, CA consolidated metropolitan
statistical area, 1983-1987. 130
5-13. Air quality trends in the composite mean and range of
pollutant-specific statistics for the Phoenix, AZ
metropolitan statistical area. 131
5-14. Air quality trends in the composite mean and range of
pollutant-specific statistics for the Portland -
Vancouver, OR-WA consolidated metropolitan
statistical area, 1983-1987. 132
5-15. Air quality trends in the composite mean and range of
pollutant-specific statistics for the Seattle -
Tacoma, WA metropolitan statistical area,
1983-1987. 133
Xlll
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TABLES
2-1. National Ambient Air Quality Standards (NAAQS) in
Effect in 1987 22
2-2. Comparison of Number of Sites for 10-Year and
5-Year Air Quality Trends 27
3-1. National Total Suspended Particulate Emission
Estimates, 1978-1987. 40
3-2. National Sulfur Oxide Emission Estimates,
1978-1987. 48
3-3. National Carbon Monoxide Emission Estimates,
1978-1987. 56
3-4. National Nitrogen Oxides Emission Estimates,
1978- 1987. 62
3-5. National Volatile Organic Compound Emission
Estimates, 1978-1987. 68
3-6. National Lead Emission .Estimates, 1978-1987. 84
4-1. Population Distribution of Metropolitan Statistical
Areas Based on 1986 Population Estimates. 92
4-2. Selected Air Quality Summary Statistics and Their
Associated National Ambient Air Quality Standards
(NAAQS). 93
4-3. 1987 Metropolitan Statistical Area Air Quality
Factbook Peak Statistics for Selected Pollutants
by MSA 104
5-1. Air Quality Trend Statistics and Their Associated
National Ambient Air Quality Standards (NAAQS) 118
5-2- Percent Change in Air Quality Trend Statistics 1983
through 1987. 119
xiv
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NATIONAL AIR QUALITY AND EMISSIONS TRENDS REPORT. 1987
EXECUTIVE SUMMARY
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NATIONAL AIRQUALITYAND EMISSIONS TRENDS REPORT. 1987
1. EXECUTIVE SUMMARY
1.1 INTRODUCTION
Air pollution in the United States continues to exhibit
considerable progress over the years, offset by concerns that many
areas still do not meet applicable air quality standards. These
National Ambient Air Quality Standards (NAAQS) 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 1987 to examine changes in air pollution
levels over time, and to summarize current air pollution status.
There are six pollutants that have NAAQS: particulate matter
(formerly as total suspended particulate (TSP) and now as PMlfl which
emphasizes the smaller particles), sulfur dioxide (S02), carbon
monoxide (CO), nitrogen dioxide (NO2), 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.
Almost 102 million people in the U.S. reside in counties which
exceeded at least one air quality standard during 1987. Figure 1-
1 displays these totals for each individual pollutant, and it is
apparent why ground level ozone is viewed as our most pervasive
ambient air pollution problem. The 88.6 million people living in
counties that exceeded the ozone standard in 1987 are greater than
the total for the other five pollutants.
For the 10-year period (1978 through 1987) improvements were
seen nationally for all six pollutants: TSP, S02r CO, NO2, 03 and
Pb. Similar improvements have been documented in earlier air
quality trends reports issued by EPA.1"" This 1987 report requires
that 10-year trend sites have data for at least 8 of these years.
To incorporate data from newer sites that began operation in the
1980s, trends are also presented for the 5-year period (1983-87).
Because of the interest in ozone levels during the summer of 1988,
a preliminary estimate is given of the impact of 1988 on ozone
trends.
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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 (Figure 1-2). 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. The use of the boxplots allow us simultaneously to
compare 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 by trends for nationwide emissions, which are
based upon the best available engineering calculations. Chapter
4 of this report includes a detailed listing of selected 1987 air
quality summary statistics for every metropolitan statistical area
(MSA) in the nation and maps highlighting the largest MSAs.
Chapter 5 presents 1983-87 trends for fourteen cities.
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pollutant
S02
CO
N0
Pb
Any
NAAQS
21.5
88.6
101.8
3 20
i
40
i
60
80
100
12
.0
Figure 1-1.
millions of persons
Number of persons living in counties with air
quality levels above the primary National Ambient
Air Quality Standards in 1987 (based on 1980
population data).
I
95th PERCENTHE
*•*-
I
90thPiRC£KTlLE
•TSthPERCENTTLE
COMPOSITE AVERAGE
•MEDIAN
-aSfhPERCENTM
-KMhPERCENTUE
•SttiPEReENITLE
Figure 1-2. Illustration of plotting conventions for boxplots.
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1.2 MAJOR FINDINGS
TOTAL SUSPENDED PARTICULATE (TSP)
Air Quality
1978-87: geoietric lean: 21 percent decrease (1726 sites) (Figure 1-3)
1983-87; geoietric lean: less than 1 percent decrease (1441 sites)
1986-87: geoietric lean: 2 percent increase (1441 sites)
Emissions
1978-87: 23 percent decrease (Figure 1-4)
1983-87: 1 percent decrease
1986-87: 3 percent increase
Comments
The 1979-81 data were affected by a change in the filters used
to collect TSP, so the decrease between 1981 and 1982 was
probably less abrupt than shown in Figure 1-3.
Recent TSP trends have been very flat, with slight changes
such as the 1984-85 decrease and the 1986-87 increase likely
due to changes in meteorological conditions such as
precipitation. The increase in particulate emissions from
1986 to 1987 results from increased forest fire activity in
1987.
Worth Noting
On July 1, 1987, EPA promulgated new standards for
particulate matter using a new indicator, PMlo, rather than
TSP. PM10 focuses on those particles with aerodynamic
diameters smaller than 10 micrometers, which are likely to be
responsible for adverse health effects because of their
ability to reach the thoracic or lower regions of the
respiratory tract. PMia networks are now being deployed
nationally but do not as yet have sufficient historical data
for trends analysis. However, summary statistics for 1987
are presented in Section 4.
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110
CONCENTRATION, UG/Kf
100-
90-
80-
70-
60-
50-
40-
30-
20-
10-
0
1726 SITES
NAAQS
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-3, Boxplot comparisons of trends in annual geometric
mean total, suspended particulate concentrations
at 1726 Sites, 1978-1987.
15
ISP EMISSIONS, 106
10-
SOURCE CATEGORY
m TRANSPORTATION
E3 FUEL
COMBUSTION
INDUSTRIAL PROCESSES
SOLID WASTE & MISC
:3=s;!;=:=SFi;;
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-4. National trend in particulate emissions, 1978-1987,
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SULFUR DIOXIDE (SOa)
Air Quality
1978-87; arittaetic mean: 35 percent decrease (347 sites) (Figure 1-5)
24-bour second high: 40 percent decrease
24-hour exceedances: 94 percent decrease
1983-87: arittaaetie lean: 10 percent decrease (603 sites)
1986-87: arithmetic lean: 3 percent decrease (603 sites)
Emissions (as SOK)
1978-87: 17 percent decrease {Figure 1-6)
1983-87: 1 percent decrease
198i-87: 1 percent decrease
Comments
The vast majority of SOS monitoring sites do not show any
exceedances of the 24-hour NAAQS, hence the exceedance trend
is dominated by source oriented sites.
Worth Noting
Ambient SO2 is well in conformance with the current ambient
standards in most U.S. urban areas. Current concerns about
ambient SO2 focus on major emitters which tend to be located
in more rural areas. This is the major reason for the
disparity between air quality and emission trends for sulfur
dioxide. The residential and commercial areas, where most
monitors are located, have shown sulfur oxide emission
decreases comparable to SO2 air quality improvement.
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0,040
CONCENTRATION, PPM
0,035-
0.030
0.025-
0,020-
0.015-
0.010-
0.005-
0.000
347 SITES
•"-NAAQS-
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-5. Boxplot comparisons of trends in annual mean sulfur
dioxide concentrations at 347 sites, 1978-1987.
30
SCL EMISSIONS, 10* METRIC TONS/YEAR
SOURCE CATEGORY
H TRANSPORTATION 0 FUEL COMBUSTION • INDUSTRIAL PROCESSES
10
0
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-6. National trend in sulfur oxide emissions, 1978-1987,
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CARBON MONOXIDE (CO)
Air Quality
1978-87; 8-hour second high: 32 percent decrease (198 sites) (Figure 1-7)
8-hour exceedances; 91 percent decrease
1983-87: 8-hour second high: 16 percent decrease (367 sites)
1986-87: 8-hour second high: 6 percent decrease (367 sites)
Emissions
1978-87: 25 percent decrease (Figure 1-8)
1983-87; 14 percent decrease
1986-87: less than 1 percent increase
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. The
increase in CO emissions from 1986 to 1987 results from
increased forest fire activity in the West.
Worth Noting
The 1978-87 improvement in ambient CO levels, and in estimated
national CO emissions, has occurred despite a 24 percent
increase in vehicle miles traveled during this 10-year period.
in particular, CO emissions from highway vehicles are
estimated to have decreased 38 percent in these 10 years
because controls have more than offset growth.
10
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25
CONCENTRATION, PPM
20-
15-
10-
5-
198 SHIS
NAAQS
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-7. Boxplot comparisons of trends in second highest
nonoverlapping 8-hour average carbon monoxide
concentrations at 198 sites, 1978-1987.
120
CO EMISSIONS, 106 METRIC
100-
80
60
SOURCE CATEGORY
m TRANSPORTATION
EH FUEL
COMBUSTION
INDUSTRIAL PROCESSES
SOUD WASTE & MISC
0
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-8. National trend in emissions of carbon monoxide,
1978-1987.
11
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NITROGEN DIOXIDE (NOa)
Air Quality
1978-87; Annual Hean; 12 percent decrease (84 sites) (Figure 1-9}
1983-87: Annual Hean: 2 percent increase (199 sites)
1986-87: Annual Hean: No change (199 sites)
Emissions (NO*)
1978-87: 8 percent decrease (Figure 1-10)
1983-87: 3 percent increase
1986-87; l percent increase
Comments:
The national trend in annual mean NO2 concentration has been
flat during the last 4 years. The increase in emissions from
1983 to 1984 and from 1986 to 1987 were primarily because of
increases in stationary source fuel combustion.
Worth Noting:
Los Angeles County is the only county in the country that
currently violates the NO2 NAAQS.
12
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0.07
CONCENTRATION, PPM
0.06-
0.05-
0.04-
0.03-
0.02-
0.01-
0.00
84 SITES
'«— NAAQS
, &
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-9. Boxplot comparisons of trends in annual mean
nitrogen dioxide concentrations at 84 sites,
1978-1987.
30
NO- EMISSIONS, 108 METRIC TONS/YEAR
25-
SOURCE CATEGORY
m TRANSPORTATION ffl INDUSTRIAL PROCESSES
ED FUEL COMBUSTION • SOUD WASTE & MISC.
UjyiiiJjjJUyMUMayMdd^^
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-10.
National trend in nitrogen oxides emissions,
1978-1987.
13
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OZONE (03)
Air Quality
1979-8?*: Second Highest Daily Max 1-hoiur: 9 percent decrease (274 sites) (Figure 1-11)
Exceedance Days: 38 percent decrease
*9-year period (see coments)
1983-87: Second Highest Daily Max 1-hour: 8 percent decrease (522 sites)
1986-87: Second Highest Daily Hax 1-hour: 5 percent increase
Emissions (VOC)
1978-87: 17 percent decrease (Figure 1-12)
(NOT!; 9-year 1979-87 decrease was 17 percent)
1983-87: 4 percent decrease
1986-87: 2 percent increase
Comments:
Air quality trends are presented for the 9-year period 1979-
87 because ozone data before 1979 are affected by a
calibration change. The 10-year period showed a 16 percent
improvement in air quality, but this includes the effect of
the calibration change, which is difficult to quantify.
Worth Noting:
Ground level ozone is the most pervasive pollutant in urban
areas in the U.S. The interpretation of ozone trends is
complicated by the impact of meteorological conditions,
particularly the summers of 1987 and 1988, which were hotter
than 1985 and 1986 in some areas. It is difficult to
precisely quantify the impact of these hotter summers and it
remains to be seen which weather patterns more likely
represent future years.
14
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0.30
CONCENTRATION, PPM
0.25-
0.20-
0.!5-
0.10-
0.05-
0.00
274 SITES
1978 1079 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-11. Boxplot comparisons of trends in annual second
highest daily maximum 1-hour ozone concentration
at 274 sites, 1978-1987,
35
VOC EMISSIONS, 10* METRIC TONS/TEAR
SOURCE CATEGORY
m TRANSPORTATION
9 INDUSTRIAL PROCESSES
ra FUEL COMBUSTION
• SOUD WASTE & MISC
SSsafrlHSs *iii23iiB~i~sS HESOiii =1===!=!:::::
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 1-12,
National trend in emissions of volatile organic
compounds, 1978-1987.
15
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LEAD (Pb)
Air Quality
1978-87; Maxima Quarterly Average: 88 percent decrease (97 sites) (Figure 1-13)
1983-87: Haxiiui Quarterly Average; 71 percent decrease (394 sites) ;
1986-87; JfaximiB Quarterly Average: 19 percent decrease (394 sites) I
Emissions '";
1978-87: 34 percent decrease in total lead emissions - 97 percent decrease in lead Missions fro« ;
transportation sources. ;
1983-87; 83 percent decrease in total lead eiissions - 93 percent decrease in lead eiissions fron
transportation sources.
1986-87: 6 percent decrease in total lead eiissions - 14 percent decrease in lead euissions fron
transportation sources.
Comments:
The ambient lead trends presented here represent for the most
part general urban conditions predominantly reflecting
automotive sources. For the first time, ambient trends are
also presented for a small number of lead monitoring sites
(24) in the vicinity of point sources of lead such as primary
and secondary lead smelters.
Worth Noting:
Ambient lead concentrations in urban areas throughout the
country continue to drop because of both the increased usage
of unleaded gasoline and the reduction of the lead content in
leaded gasoline. Also, lead concentrations at monitoring
sites near lead point sources show a dramatic decline, as a
result of the general factors noted above, as well as the
closing of some of these sources, and the reduction of lead
emissions by improved control measures.
16
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2.5
CONCENTRATION, U
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1 . 3 REFERENCES
1 • The National Air Monitoring: Program; Air Quality and
Emissions Trends - Annual Report, EPA-450/l-73-001a 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 f 1976 f
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 27711 ,
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 Quality and 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.
18
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11. National Air Quality and JSmissions^ Trends^ Report^ J.983,
EPA-450/4-84-029, 0. S. Environmental Protection Agency, Office
of Air Quality Planning and Standards, Research Triangle Park, NC
27711, April 1985.
12, National Air Quality and EmissJ.pns Trends Report, 1984.
1PA-450/4-86-001, u. s. Environmental protection Agency, Office
I of Air Quality Planning and Standards, Research Triangle Park, NC
f- 27711, April 1986.
1
!" 13. National Air ^>ual ity and EnLisslQns_TrendsJRegprt ^_L985 ,
» 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 ajid^ 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
27711, February 1988.
19
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20
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2. INTRODUCTION
This report focuses on both 10-year (1978-1987) and 5-year
(1983-1987) national -air quality trends for each of the inajor
pollutants for which National Ambient Air Quality Standards have
been established, as well as Regional and, where appropriate,
short-term air quality trends. The national analyses are
complemented in Section 5 with air quality trends in selected
metropolitan areas for the period 1.933 through 1987. The areas
examined are Atlanta, GA; Baltimore, MD; Boston, MA; Chicago,
IL-Northwestern IN? Denver, CO; Detroit, MI; Houston, TX; Los
Angeles-Long Beach, CA; New York, NY-Northeastern NJ; Philadelphia,
PA-NJ; Phoenix, AZ; Portland, OR-WA; St. Louis, MO-IL; and Seattle,
WA. In both the national 5-year trends and the metropolitan area
trends, the shorter time period was used to expand the number of
sites available for trend analysis.
The national air quality trends are presented for all sites
and for the National Air Monitoring Station (NAMS) sites Tho
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 high
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 Ail"
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.
As well as for ambient air quality, 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, 1940-1987' and the reader is referred to this
publication for more detailed information. 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. Emission estimates for
gasoline-and diesel-powered motor vehicles were based upon vehicle-
mi.ln tabulations and upon emission factors from the. MOBILE ') 9
'21
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TABLE 2-1. National Anbient Air Quality Standards (WAAQS) in Effect in 1987
POLLUTANT
PRIHAIY (HEALTH MATED)
SECOHDAM (BE1FASE HLAfED)
S02
STANDARD LEVEL
AVERAGING TIHE CONCENfRfflON"
Annual Geoaetric 75 (if/i*
Hean
Annual Arithietic 50 (ig/n3
Hean
24-iboir
150
Annual Arithmetic (0.03 ppi)
Kean 80
AVERAGIHG TIME COBCEWMKOH
Saie as Priiary
Sane as Priiary
3-hour
1300
(0.50
CO
HO,
Pb
24-hour
8-aour
1-hour
(0.14 ppa)
365
9 ppa
(10
35 ppn
(40 (iq/l3)
Annual Aritimetic 0.053 ppi
Hean
(100
Hasfiiiuii Daily 1-hour 0.12 ppid
Average (235
Maximal Quarterly
Average
1.5
Parenthetical value is an approxinately equivalent concentration,
Ho Secondary Standard
Bo Secondary Standard
Saie as Priiary
Sane as Priiary
Saie as PriKary
b ISP was the indicator pollutant for the original particulate latter (PH) standards.
This standard has been replaced with the nev PI10 standard and it is no longer in effect.
c Sew PH standards were promilgated in 1987, using PH,a (particles less than ion in dianeter) as the new
indicator pollutant, ae 21-hour standard is attained when the expected number of dap pr calendar year
above 150 |ig/i3 is equal to or less than l, as detemined in accordance rith Appendix K of the PH NAAQS,
d The standard is attained when the expected nunber of days per calendar year with Baxinuii hourly average
concentrations above 0.12 ppi is equal to or less than 1, as detrained in accordance »ith Appendix H of
the Ozone HAAQS.
22
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model. Except for lead emissions, which are reported in gigagrams
(one thousand metric tons), the emission data are reported as
teragrains {one million metric tons) emitted to the atmosphere per
year.2
Air quality status may be measured 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 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
new 24-hour PM,0 standard also allows one expected exceedance per
year.
Section 4 of this report, "Air Quality Levels in Metropolitan
Statistical Areas" provides 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 monitoring data for 1987.
Finally, two additional analyses of ozone air quality data have
been included in this report. The first analysis is an application
of a Geographical Information System (CIS) to display the
chronology of a large scale regional ozone episode which occurred
in June 1987. The second new analysis presents a preview of 1988
ozone trends. In response to indications of high ozone levels in
early Summer 1988, EPA implemented a 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 1988 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.
23
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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 SO2 and
Pb, the previous procedure of merging data was employed since the
POCs have not yet been resolved on the new data system for many of
the sites experiencing such changes.
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 1978 to 1987. For the national 5-year
trend and metropolitan area analyses, 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 instruments are used to measure TSP, S02, NO2 and Pb. Bubbler
data were not used in the SO2 and NO2 trends analyses because these
methods have essentially been phased out of the monitoring network.
Total suspended particulate 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 S02 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 S02 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.
24
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Finally, because of the seasonal nature of ozone, both the
second daily maximum 1-hour value and the estimated number of
exceedances of the 0, NAAQS were calculated for the ozone season,
which varies by state." 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 from 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 both the 5-year trend and metropolitan area trend data
bases. Table 2-2 displays the number of sites meeting the
completeness criteria for both trends data bases. The shorter time
period was used in the metropolitan area analyses to expand the
number of sites available for trend analyses.
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 16 percent for the 10-year period,
but decreased by 14 percent for the 5-year period relative to the
data bases used in the last annual report.3 The size of the TSP
monitoring network has declined during the past 2 years because of
promulgation of the PM1Q 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 1986, 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). The trend from 1983
on reflects the period following the implementation of the
monitoring regulations.1 The regulations required uniform siting
of monitors and placed greater emphasis on quality assurance. In
general, the data from the post 1980 period should be of the
highest quality. As would be expected, there are considerably
more trend sites for the 5-year period than for the 10-year period
- 3526 total trend sites versus 2726 trends sites, respectively
(Table 2-2). This 29 percent increase in the number of trends
sites for the 5-year period over the 10-year period reflects the
greater utilization of ambient air quality data that is achieved
by examining the shorter time period. Focusing on the non-TSP
sites, there is a 108% 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 all IPA Regions (Figure 2-1) for TSP,
S02, 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
25
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Indicators.5 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 SOZ 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 violated an air
quality standard in a particular year. A composite average of
each of these statistics is used in the graphical presentations
which follow. In all cases, all sites were weighted equally in
calculating the composite average trend statistic.
In addition to the standard related statistics, other
statistics are used, when appropriate, to provide further
.clarification of 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.
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.
26
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Table 2-2, Coiparison of Number of Sites for 10-Year and 5-Year Air Quality trends
1 CHANGE IM THE
NUHBEI OF SITES TO. OF fBEHD SITES
POLLOTAIf 1978-87 TREND 1983-87 TREND 1978-87 VS. 1983-87
Total Suspended Particulate
(TSP)
Sulfur Dioxide (S02)
Carbon Monoxide (CO)
Nitrogen Dioxide (H02)
Oione (Oj)
Lead (Pb)
1726
347
198
84
274
97
1441
603
367
199
522
394
-171
+741
+851
+1371
+911
+304!
Total 2726 3526 +291
27
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Guam
Boaton
"**"*
Philadclphio
Puerto Rico,
Virgin Islands
Figure 2-1.
Ten Regions of the U.S. Environmental Protection
Agency.
28
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2.3 REFERENCES
1. Ambient Air Quality Surveillance, 44 FR 27558, May 10,
1979.
2. National Air Pollutant Emission Estimates. 1940-1987,
EPA-450/4-88-022, U. S. Environmental Protection Agency, Office of
Air Quality Planning and Standards, Research Triangle Park, NC,
January, 1989.
3. National Air Quality and Emissions Trends Report, 1.986,
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. U.S. Environmental Protection Agency Intra-Agency 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.
29
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30
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3. NATIONAL AND REGIONAL TRENDS IN NAAQS POLLUTANTS
This chapter focuses on both 10-year (1978-1987) and recent
5-year (1983-1987) trends for each of the six major pollutants, as
well as short term air quality trends. Comparisons are made
between all the trend sites and the NAMS subset. Trends are
examined for both the nation and the ten EPA Regions.
" The air quality trends information is presented using trend
lines, confidence intervals, boxplots1 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 3-1). 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.2 The
confidence intervals for composite averages of estimated
exceedances were calculated by fitting Poisson distributions3 to
the exceedances each year and then applying the Bonferroni multiple
comparisons procedure." The utilization of these procedures is
explained in publications by Pollack, Hunt and Curran3 and Pollack
and Hunt.6
The boxplots have the advantage of displaying, simultaneously,
several features of the data. Figure 3-2 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.
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 1983 through 1987. The recent 5-year trend
was introduced in the 1984 report7 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 the fact that the
data from this period should be of the highest quality, with sites
meeting uniform siting criteria and high standards of quality
assurance.
31
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Jjai graphs are used for the Regional comparisons with the
'j-year trend data base. The composite averages of the appropriate
air quality statistic of the years 1985, 1986 and 1987 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 levels. The change
in concentration levels is likely to be more indicative of changes
in emission levels.
Trends sre also presented for annual nationwide emissions.
These emissions data are estimated using the best available
engineering calculations. The emissions data are reported as
"ceragrams (one million metric tons) emitted to the atmosphere per
year, with the exception of lead emissions, which are reported as
gigagrartiS (one thousand metric tons).8 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.
Finally, two additional analyses of ozone air quality data
have been included in this report. The first analysis is an
application of a Geographical Information System (CIS) to display
the chronology of a large scale regional ozone episode which
occurred, in June 1987. The second analysis presents a preview of
1988 o2one trends based on preliminary 1988 ozone data from a
subset of peak monitoring sites.
32
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COMPOSITE MEAN OF AIR
POLLUTION STATISTIC
o
•—I
•a:
ce
»—
LU
O
z
o
o
o.
a:
952 CONFIDENCE
INTERVAL ABOUT
COMPOSITE MEAN
RELATIONSHIPS: (MULTIPLE COMPARISONS)
• YEAR 4 IS SIGNIFICANTLY LESS THAN
' YEARS 1, 2, AND 3
• NEITHER YEARS 1 AND 2 NOR 2 AND 3 ARE
' SIGNIFICANTLY DIFFERENT FROM ONE ANOTHER
• YEARS 1 AND 3 ARE SIGNIFICANTLY
' DIFFERENT FROM ONE ANOTHER
YEAR 1
YEAR 2
YEAR 3
YEAR 4
Figure 3-1.
Sample illustration of use of confidence intervals
to determine statistically significant change.
33
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1
95th PERCENTILE
90th PERCENT1LE
75th PERCENT1LE
COMPOSITE AVERAGE
MEDIAN
25fh PERCENTILE
K)th PERCENT1LE
5th PERCENT1LE
Figure 3-2. Illustration of plotting conventions for boxplots.
34
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3.1 TRENDS IN TOTAL SUSPENDED PARTICUIATE
Air pollutants called particulate 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.
Total suspended particulate (TSP) was the indicator of
suspended particles in the ambient air prior to the promulgation
of the new particulate matter standards. TSP is measured using a
high volume sampler (Hi-Vol) which collects suspended particles
ranging up to approximately 45 micrometers in diameter. Annual and
24-hour National Ambient Air Quality Standards (NAAQS) for
particulate matter were set in 1971, with TSP as the indicator
pollutant.
On July 1, 1987, EPA promulgated new annual and 24-hour
standards for particulate matter, using a new indicator, PMia, that
includes only those particles with aerodynamic diameter smaller
than 10 micrometers. These smaller particles are likely
responsible for most adverse health effects of particulate 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 M-g/m3, 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 ^.g/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. Figure 3-3 depicts the
geographic coverage of the State and Local Air Monitoring Networks
(SLAMS). Unfortunately, the PM1B SLAMS do not yet provide
sufficient information on which to base meaningful trends.
Therefore, the particulate matter trends presented in this section
will continue to be based on TSP. The annual geometric mean for
TSP is a more stable indicator of air quality than the observed
24-hour peak values, and will be used as the trend statistic.
When sufficient information is available on PMto air quality trends,
future reports will present analyses based on the new particulate
matter indicator.
3.1.1 Long-term TSP Trends: 1978-87
The 10-year trend in average TSP levels, 1978 through 1987,
is shown in Figure 3-4 for 1726 sites geographically distributed
throughout the Nation and is presented for historical perspective.
Trends are also shown for the subset of 431 National Air Monitoring
35
-------
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
concentratioris are higher for the NAMS. For both curves, composite
TSP concentrations are high and relatively stable in the 1978-1980
period and are lower and relatively stable in the 1982-1987 period.
A large decrease is apparent in the intervening years, particularly
from 1981 to 1982. As previously reported, EPA has determined that
the measurements produced during the years 1979, 1980 and 1981 may
be biased high due to the type of filters used to collect the TSP.S
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. Although the
difference between 1978 and post-1981 is real, the pattern of the
yearly change in TSP between 1978 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.9""
The composite average of TSP levels measured at 1726 sites,
distributed throughout the Nation, decreased 21 percent during the
1978 to 1987 time period, and the subset of 431 NAMS decreased 22
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 - 1987 are all significantly lower than
those of 1978. Also, 1985 and 1986 are statistically
indistinguishable, and indicate the lowest particulate levels in
the 10-year period. These recent trends in particulate matter will
be discussed in more detail in Section 3.1.2.
The long-term trends in TSP are also illustrated in Figure 3-
5. Using the same national data base of 1726 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 1978 and 1987, further indicating a broad
national improvement in ambient particulate concentrations
throughout the country.
36
-------
PM10 SITES, 1987
*• / <-', '
/ { < *
/ \—.,/
Figure 3-3. Status ^/ .'J,win raoiiitoring network, 1987.
37
-------
Nationwide TSP emission trends show an overall decrease of 23
percent from 1978 to 1987 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. 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.8
38
-------
"Trt
70 -
C A
D U
50 -
40 -
30 ~
20-
In
0 -
x— <
jfff !
• p
- •
m
_- , , ^u
.A ....... TS^,.. , . .
I~ ~^CI__ ^**1«lJ»-
H ^*HI«». At
Vs^!^ >l
* * v ° "
,..,..,......,.!,
a SITES (431)
k I * * /\«»
V.
k. ^T- T — — ~ — ^~-~— •«•
•NV -^ ,_ * i — — *•
aBf- - m^ _ — " "'™**-»* ^^_ ^
^P'"^~ " °^D" —
• ALL SmSjt72|)_
Figure 3-4.
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
National trend in the composite average of
the geometric mean total suspended particulate
at both HAMS and all sites with 95 percent
confidence intervals, 1978-1987.
no
100
90
80
70
60
50
40
30
20
10
0
CONCENTRATION, UG/M*
1726 SITES
NAAQS
Figure 3-5,
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Boxplot comparisons of trends in annual geometric
mean total suspended particulate concentrations
at 1726 sites, 1978-1987.
39
-------
fable 3-1. Hational Total Suspended Particulate Bdssion Estimates, 1978-1987.
(nillion netrie tons/year)
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Source Category
transportation
Fuel Coubustion
Industrial
Processes
Solid Baste
Miscellaneous
Total
1.4
2.5
4.0
0.4
0.8
§.1
1.4
2,5
3.8
0.4
0.9
8.9
1.3
2,4
3.3
0.4
1.1
8.5
1.3
2.3
3.0
0.4
0.9
8.0
1.3
2.2
2.6
0.3
0.7
7.1
1.3
2.0
2.4
0.3
1.1
7.1
1.3
2.1
2.8
0.3
0.9
7.4
1.4
1.8
2.8
0.3
0.8
7.0
1.4
1.8
. 2.5
0.3
0.8
6.8
1.4
1,8
2.5
0.3
1.0
7.0
NOTE: The suns of sub-categories nay not equal total due to rounding.
15
TSP EMISSIONS, 10* METHIC TONS/YEAR
10-
SOURCE CATEGORY
E3 TRANSPORTATION
en FUEL
COMBUSTION
m INDUSTRIAL PROCESSES
• SOLID WASTE & MISC
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-6. National trend in particulate emissions, 1978-1987,
40
-------
3.1.2 Recent TSP Trends: 1983-87
The trends for the 5-year period, 1983 through 1987 are
presented in terms of 1441 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 in previous trends reports,
reflecting the revisions to TSP SLAMS networks and the shift of
particulate monitoring to PM10. Figure 3-7 presents a boxplot
display of the 1983-1987 annual TSP concentration distributions.
Very little change in TSP concentrations is evident between 1983
and 1987. As mentioned in Section 3.1.1, generally lower
concentrations were measured in 1985 and 1986, and TSP levels in
1984 were generally the highest in the 5-year period. A small 2
percent increase was seen between 1986 and 1987. This pattern in
air quality generally matches the 5-year trend in national
particulate emission estimates.
Particulate emissions showed little change from 1983 to 1987.
They were highest in 1984 because of increases in industrial
processes. Emissions were at their lowest in 1986, through
subsequent reductions in the industrial sector. Because of an
increase in forest fires in 1987, national total emissions returned
to their earlier levels. The major fires in Yellowstone during the
summer of 1988 could cause these levels to continue to climb.
Emissions from forest fires now typically represent 10 to 14
percent of the national total. Since particulate emissions from
fires are primarily small particles, future trends report emphasis
on PM10 may put more attention on fires as an important source of
air pollution.
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. Many Regions had their lowest levels of TSP in
1986 with small increases in 1987.
The observed year-to-year variations in total suspended
particulate levels may in part be attributable to meteorology.
Among all meteorological parameters, precipitation has been shown
to have had the greatest influence on particulate air quality.
Rainfall has the effect of reducing reentrainment of particles and
of washing particles out of the air. An examination of Regional
precipitation patterns shows that the eight Regions with 1986-1987
TSP increases were also the only Regions which experienced
decreases in total precipitation, relative to normal." Although
these decreases in precipitation were only 5 to 10 percent, they
could possibly have contributed to the particulate matter increases
in these areas. The generally drier conditions undoubtedly are
responsible, in part, for the increase in forest fires which was
noted earlier. The largest year-to-year change in particulates
occurred in the northwest (Region X), where both 1985 and 1987 were
unusually dry and had higher particulates, while 1986 produced
normal precipitation and lower average particulate concentrations.
41
-------
110
CONCENTRATION, UG/%14
100-
90-
80
70-
60-
50-
40
30-
20-
10-
0
»•—'—-• I .—... I NAAQS —
1441 SITES
1983
1984
1985
1986
1987
Figure 3-7. Boxplot comparisons of trends in annual mean total
suspended particulate concentrations at 1441 sites,
1983-1987.
CONCENTRATION, UG/M*
ou -
/o-
60-
50-
40-
30-
20-
10-
COMPOSITE AVERAGE
@ 1985 • 1986 E3 1987
i
\
g
T
/>
t
t>
/
S
s
/
/
/
f
t
t
J
t
t
t
{
/
/
/
/
/
/
/
/
/
/
/
11
/ 't
' 1
\ 1
i'l
• \
t
?
*
/
>
*
t
t
/
/
/
\
1
1
/
t
/
t
s
t
/
f
t
/
t
t
/
/
/
t
/
/
/
t
\ 1
<', \
'. \
'
'
/ 'l
' !
: \
?
/
/
/
/
/
/
/
/
t
/
t
t
t
<
/
/
/
/
g
1
'
t
f
t
/
t
t
t
t
f
/
t
t
EPA REGION I
NO. OF SITES 53
89 139
IV
273
V
392
VI
160
VII
104
VIII
70
IX
94
X
67
Figure 3-8. Regional comparisons of the 1985, 1986, 1987
composite averages of the geometric mean total
suspended particulate concentration.
42
-------
3.2 TRENDS IN SULFUR DIOXIDE
Ambient sulfur dioxide (S02) results largely from stationary
source coal and oil combustion and from nonferrous smelters. There
are three NAAQS for SO2: an annual arithmetic mean of 0.03 ppm
(80 M-cr/ra3), a 24-hour level of 0.14 ppm (365 (ig/m3) and a 3-hour
level of 0.50 ppm (1300 jig/m3). - 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.
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 S02 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 SO3 Trends; 1978-87
The long-term trend in ambient S02, 1978 through 1987, is
graphically presented in Figures 3-9 through 3-11. In each
figure, the trend at the HAMS is contrasted with the trend at all
sites. For each of the statistics presented, a steady downward
trend is evident through 1987. Nationally, the annual mean S02,
examined at 347 sites, decreased at a median rate of approximately
4 percent per year; this resulted in an overall change of about
35 percent (Figure 3-9). The subset of 105 NAMS recorded higher
average concentrations but declined at a slightly higher rate of
5 percent per year, with a net change of 41 percent for the 10-year
period.
The annual second highest 24-hour values displayed a similar
improvement between 1978 and 1987, Nationally, among 347 stations
with adequate trend data, the median rate of change was 5 percent
per year, with an overall decline of 40 percent (Figure 3-10).
The 105 NAMS exhibited a 6 percent per year rate of improvement,
for an overall change of 43 percent. The estimated number of
exceedances also showed declines for the NAMS as well as for the
composite of all sites (Figure 3-11). The vast majority of SO2
sites, however, 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. The national composite
estimated number of exceedances decreased 94 percent from 1978 to
1987.
43
-------
0.035
0.030
0.025-
0.020-
0.015-
0.010-
0.005-
CONCENTRAT10N, PPM
0.000
•NMQS
• NAMS SUES (105) • Aj±SrTESj347)__
Figure 3-9.
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
National trend in the composite average of the
annual average sulfur dioxide concentration at both
NAMS and all sites with 95 percent confidence
intervals, 1978-1987.
0.16
0.14
0.12-
0.10-
0.08-
0.06-
0.04-
0.02-
CONCENTRATION, PPM
o.OO
•NAAQS
• NAMS SITES (105) ° AjlSITES_(M7l_
Figure 3-10.
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
National trend in the composite average of the
second-highest 24-hour sulfur dioxide concentration
at both NAMS and all sites with 95 percent
confidence intervals, 1978-1987.
44
-------
ESTIMATED EXCEEDANGES
1.5-
NAMS SITES (105)
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-11.
National trend in the composite average of the
estimated number of exceedances of the 24-hour
sulfur dioxide NAAQS at both NAMS and all sites
with 95 percent confidence intervals, 1978-1987.
45
-------
The statistical significance of these long-term trends is
graphically illustrated in Figures 3-9 to 3-11 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, 1987 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 3-12 and 3-13. 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.
Nationally, sulfur oxide emissions decreased 17 percent from
1978 to 1987 (Figure 3-14 and Table 3-2), reflecting the
installation of flue gas desulfurization controls at 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 oxide emissions from
industrial processes are also significant. Emissions from
industrial processes have declined, primarily as the result of
controls implemented to reduce emissions from nonferrqus smelters
and sulfuric acid manufacturing plants.*
The disparity between the 35 percent improvement in SO2 air
quality and the 17 percent decrease in S02 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 347 trend sites used
in the analysis of average SO2 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 oxide emission decreases comparable
to SO2 air quality improvement. These decreases in sulfur oxide
emissions are due to a combination of energy conservation measures
and the use of cleaner fuels in the residential and commercial
areas.8 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.7 Smelter sources represent a majority of SOX emissions
in the intermountain region of the western U.S. Although one-third
46
-------
0.040
CONCENTRATION, PPM
0.035-
0.030
0.025-
0.020-
0.015-
0.010-
0.005-
0.000
347 SITES
"NAAQS-
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-12. Boxplot comparisons of trends in annual mean sulfur
dioxide concentrations at 347 sites, 1978-1987.
0.25
0.20
0. IS
0.10-
0.05-
CONCENTRATON, PPM
o.oo
347 SITES
-NAAQS-
1 I
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-13.
Boxplot comparisons of trends in second highest
24-hour average sulfur dioxide concentrations at
347 sites, 1978-1987.
47
-------
Table 3-2. National Sulfur Oxide fteission ES!-hates, 197!-IOS?.
[Million rS^.tic f.ori'v'yeai'*
1978 1979
Source Category
1980 1981
1982
1983 1984 1985 1986 1987
Transportation
Fuel Coubustion
Industrial
Processes
Solid Waste
Miscellaneous
Total
o.s
19.5
4.3
0.0
0,0
24.6
0.9
19.5
4,4
0.0
0.0
24.8
C.O
18.7
3.8
0.0
0.0
23.4
O.!1
17.8
3.9
0.0
0,0
22.6
('.':
17,3
3,1
0.0
0.0
21.4
O.S
16.7
.1.3
0.0
0.0
20.7
o.:-:
17.4
7.3
0.0
0.0
21.5
n f*
17,0
..2
0.0
o.o
21.1
(J.<5
16.7
3.1
0.0
0.0
20.7
0.9
16.4
3,1
0.0
0,0
20.4
HOTE: The suas of sub-categories aay not equal total due to rovjidiw
SCL EMISSIONS, 10s METRIC
SOURCE CATEGORY
EU TSAMSPOSTAtlON Hi FUH. COMBUSTION t-3 IHOUJTjIW.l PHOCESSES
0
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-14, National trend in Mill fur icicle emissions, 1978
48
-------
of the trend sites are categorized as source-oriented, the majority
of SO,, emissions are dominated by large point sources. Two-thirds
of all national SOX emissions are generated by electric utilities
(96 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 SO* emitters account for more than 85 percent of all SOX
power plant emissions. These 200 plants account for 61 percent
of all SOX emissions nationally."
Another factor which may account for differences in SO*
emissions and ambient air quality is stack height. The height at
which S02 is released into the atmosphere has been increasing at
industrial sources and power plants.1*'16 This can permit ground
level concentrations to decrease at a faster rate than emissions.
Under these circumstances, concentrations can, in fact, decrease
even if emissions increase.
3.2.2 Recent SO, Trends; 1983-87
Figure 3-15 presents boxplots for the 1983-1987 data using
603 SO2 sites. The 5-year trend shows a 10 percent decline in
average concentrations, indicating that the long term trend has
continued but has been leveling off. Correspondingly, SO2
emissions have decreased only 1 percent over the last 5 years.
Regional changes in composite average S02 concentrations
for the last 3 years, 1985-1987, are shown in Figure 3-16. Most
Regions decreased slightly. Between 1986 and 1987, average
ambient concentrations have declined 3 percent, corresponding to
a l percent decrease in total emissions.
49
-------
0.040
CONCENTRATION, PPM
0.035-
0.030
0.025-
0.020-
0.0)5-
0.010-
0.005-
0.000
603 SITES
•NMQS-
1983
1984
1985
1986
1987
Figure 3-15. Boxplot comparisons of trends in annual mean sulfur
dioxide concentrations at 603 sites, 1983-1987.
CONCENTRATION, PPM
u.uio -
0.014-
0.012-
0.010-
0.008-
0.006-
0.004-
0.002-
<
E
i
^
i
1
if
j
if
ff
/
ft
y
1
7
/
/
/
/
/
/
/
7
*•
i>
f
f
f
f
f
»
s
t
/
/
t
f
f
COMPOSITE AVERAGE
m 1955 • 19S6 D 1987
\
1
/
/
X
t
/
/
/
/
/
/
n
/
/
f
f
/
f
s
7[
/
_
/
/
^
1
/
/
/
/
/
f
X
1
t
7
/
/
/
/
^
^
EPA REGION 1
NO. OF SITES 59
II III IV V VI VII VIII IX X
49 79 92 185 37 21 12 58 11
Figure 3-16.
Regional comparisons of the 1985, 1986, 1987
composite averages of the annual average sulfur
dioxide concentration.
50
-------
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 ppra. This analysis focuses on the 8-hour average results
because the 8-hour standard is generally the more restrictive
limit. In fact, only four exceedances of the CO 1-hour NAAQS were
recorded for the nation during 1987.
Trends sites were selected using the procedures presented in
Section 2.1. This resulted in a data base of 198 sites for the
1978-87 10-year period and a data base of 367 sites for the
1983-87 5-year period. There were 54 NAMS sites included in the
10-year data base and 97 NAMS sites in the 5-year data base. This
almost two-fold 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: 1978-87
The 1978-87 composite national average trend is shown in
Figure 3-17 for the second highest non-overlapping 8-hour CO value
for the 198 long-tern trend sites and the subset of 54 NAMS sites.
During this 10-year period-, the national composite average
decreased by 32 percent, and the subset of NAMS decreased by 30
percent. The median rate of improvement for this time period is
approximately 4 percent per year. After leveling off to no
significant change from 1985 to 1986, the trend resumed downward
in 1987. Long-term improvement was seen in each EPA Region with
median rates of improvement varying from 1 to 7 percent per year.
This same trend is shown in Figure 3-18 by a boxplot presentation
which provides more information on the distribution of ambient CO
levels at the 198 long-term trend sites from year to year. While
there is some year to year fluctuation in certain percentiles, the
general long-term improvement in ambient CO levels is clear.
Figure 3-19 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 improved
91 percent between 1978 and 1987 for the 198 long-term trend sites,
51
-------
12
CONCENTRATION, PPM
10-
8-
6-
4-
2-
0
NAAQS —
NAMS SITES (54) a ALLjrTES_(198)_
—i 1 1 r 1 1 1 1 1 i
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-17.
25
National trend in the composite average of the
second highest nonoverlapping 8-hour average
carbon monoxide concentration at both MAMS and
all sites with 95 percent confidence intervals,
1978-1987.
CONCENTRATION, PPM
20-
15
10
5-
0
198 SITES
^^ **" 7T '*••**.
1 NAAQS
Figure 3-18,
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Boxplot comparisons of trends in second highest
nonoverlapping 8-hour average carbon monoxide
concentrations at 198 sites, 1978-1987.
52
-------
30
EST. 8-HR EXCEEDANCES
20-
10-
NAMS SITES (54) o ALLS(TES^198)_
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-19.
National trend in the composite average of the
estimated number of exceedahces of the 8-hour
carbon monoxide NAAQS, at both HAMS and all
sites with 95 percent confidence intervals,
1978-87.
53
-------
while the subset of 54 NAMS showed a similar 88 percent
improvement. As noted earlier, these percentage improvements for
exceedances are typically much larger than those found for peak
concentrations, such as the annual second maximum. The percentage
change for the second maxima is more likely to reflect the
percentage change in emission levels.
The 10-year 1978-87 trend in national carbon monoxide
emission estimates is shown in Figure 3-20 and in Table 3-3.
These estimates show a 25 percent decrease between 1978 and 1987,
Transportation sources accounted for approximately 74 percent of
the total in 1978 and decreased to 66 percent of total emissions
in 1987. The contribution from highway vehicles decreased 38
percent during the 1978-87 period, despite a 24 percent increase
in vehicle miles of travel. Figure 3-21 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 guality 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. Figure 3-
22 shows 1987 CO levels ordered by population for all MSAs with
populations greater than 500,000. Cities with incomplete, or
missing data, are plotted at the zero concentration level. Studies
are in progress to understand better the differences from one city
to another and the lack of correspondence between CO levels and
city size. 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: 1983-87
This section examines ambient CO trends for the 5-year
period 1983-87. As discussed in section 2.1, this allows the use
of a larger data base, 367 sites versus 198. Figure 3-23 displays
the 5-year ambient CO trend in terms of the second highest
non-overlapping 8-hour averages. These sites showed a 16 percent
54
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improvement between 1983 and 1987. The general patterns are
consistent with the longer term data base and, after no change
between 1985 and 1986, levels resumed their decline by 6 percent
in 1987. Table 3-3 indicates that estimated total CO emissions
decreased 14 percent during this 5-year period and that the
highway vehicle contribution decreased 22 percent. The increase
in CO emissions between 1986 and 1987 is from the increased forest
fire activity in the western states during 1987. In fact,
emissions from transportation sources decreased 5 percent from 1986
to 1987.
Figure 3-24 shows the composite Regional averages for the
1983-87 time period. Eight of the ten Regions havev1987 composite
levels lower than 1986 levels. Increases were observed in Regions
VI and X, however the 1987 levels in Region X were less than in
1985, while the increase in Region VI was small. 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.
55
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Table 3-3. national Carbon Monoxide Mission Estiiates, 1978-1987,
(lillion netric tons/year)
Source Category
Transportation
Fuel Combustion
Industrial
Processes
Solid Haste
Miscellaneous
fotal
1978
61.6
5.8
7.2
2.5
5.7
82.4
1979
56.9
6.6
7.1
2.3
6.5
79.4
1980
53.5
7.3
6.3
2.2
7.6
77.0
1981
52.5
7.5
5.9
2.1
6.4
74.4
1982
50.0
8.0
4.4
2.0
4.9
69.4
1983
49.3
7.9
4.4
1.9
7.7
71.3
1984
47.6
8.1
4.8
1.9
6.3
68.7
1985
45.5
7.2
4.6
2.0
5.3
64.6
1986
42.8
7.2
4.5
1.7
5.0
61.1
1987
40.7
7,2
4.7
1.7
7.1
61.4
DTI: fhe suns of sub-categories lay lot equal total due to rounding.
120
CO EMISSIONS, 106 METRIC TONS/YEAR
100-
80
20
SOURCE CATEGORY
ra TRANSPORTATION
B FUEL
COMBUSTION
M INDUSTRIAL PROCESSES
• SOLID WASTE & MISC
0
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-20,
National trend in emissions of carbon monoxide,
1978-1987.
56
-------
Hwy Emissions, 1CF metric tons/yr
VMT * 109
2000
h 1900
- 1800
h 1700
-1600
r 1500
1400
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-21.
Comparison of trends in total National vehicle
miles traveled and National highway vehicle
emissions, 1978-1987.
concentration, ppm
2,000,000
1,000,000
MSA population
500,000
Figure 3-22.
Carbon monoxide 1987 second-maximum 8-hour
concentrations ordered by MSA population.
57
-------
25
CONCENTRATION, PPM
20-
15-
10-
5-
0
367 SITES
•NAAQS-
1983
1984
1985
1986
1987
Figure 3—23. Boxplot comparisons of trends in second highest
nonoverlapping 8-hour average carbon monoxide
concentrations at 367 sites, 1983-1987.
CONCENTRATION, PPM
[ 1- -
12-
10-
8-
6 -
4-
2 -
0-
COMPOSITE AVERAGE
m 1985 •§ 1986 D 1987
I
I
/
/
/
/
/
t
/
' V
' i
' \
H
M
7
/
/
/>
s
/
f
_
/
/
t
f
VB7,
t
/
/
I
/
/
7
r^
'
M
; i
EPA REGION
r
/
I
'\
\
A
/
/
II 111 IV V VI VII VIII IX X
NO. OF SITES 15 27 47 52 55 27 15 17 85 27
Figure 3-24.
Regional comparisons of the 1985, 1986, 1987
composite averages of the second highest non-
overlapping 8-hour average carbon monoxide
concentration.
58
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3.4 TRENDS IN NITROGEN DIOXIDE
Nitrogen dioxide (NO2), a yellowish brown gas, is present in
urban atmospheres through emissions from two major sources,
transportation and stationary fuel combustion. The major
mechanism for the formation of NO2 in the atmosphere is the
oxidation of the primary air pollutant, nitric oxide. NO2 is
measured using either a continuous monitoring instrument, which
can collect as many as 8760 hourly values a year, or a 24-hour
bubbler, which collects one measurement per 24-hour period. Both
types of data are used to compare annual average concentrations
with the NO2 standard of 0.053 parts per million.
In contrast to previous reports,10'17 the current trends site
selection process excluded bubbler data, because only four of the
nineteen sites meeting the annual data completeness criteria
reported any data in the last 2 years. In fact, only one of the
bubbler sites reported any data in 1987. Thus, these sites were
omitted from the trends data base, because substituting previous
years' levels for missing data would tend to underestimate the
average rate of change. A total of 84 continuous sites were
selected for the 10-year period and 199 continuous sites for the
5-year data base. Fourteen of the long-term trend sites are NAMS,
while 47 NAMS are included in the 1983-87 data base.
3.4.1 Long-term NOj Trends; 1978-87
The composite average long-term trend for the nitrogen
dioxide mean concentrations at the 84 trend sites and the 14 NAMS
sites, is shown in Figure 3-25. Nationally, composite annual
average NOS levels increased from 1978 to 1979, then decreased
through 1983. Following a 3 percent increase in 1984, NO, levels
declined again by 1 percent in 1987. The 1987 composite average
NO, level is 12 percent lower than the 1978 level, indicating an
overall downward trend during this period. Composite mean N0a
levels have remained essentially unchanged since 1984. A similar
trend is seen for the NAMS sites which, for NO,, are located only
in urban areas with populations of 1,000,000 or greater. Although
the composite averages of the NAMS are higher than those of all
sites, they also declined by 12 percent during this period.
In Figure 3-25, 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 1986 and 1987 composite mean N02
levels are not significantly different from one another, but they
are significantly less than the earlier years 1978 and 1979.
Long-term trends in N02 annual average concentrations are also
displayed in Figure 3-26 with the use of boxplots. The
improvement in the composite average between 1979 and 1987 can
59
-------
generally be seen in the upper percentiles until 1984. The lower
percentiles show little change, however.
The trend in the estimated nationwide emissions of nitrogen
oxides (NOB) is similar to the NO2 air quality trend. Table 3-4
shows NOX emissions decreasing from 1978 through 1983 then
increasing in 1984 and 1985. Total 1987 nitrogen oxide emissions
decreased by 8 percent from 1978 levels. Highway vehicle
emissions, the source category likely affecting the majority of
urban N02 sites, decreased by 15 percent during this period. This
decrease in the highway vehicle category is similar to the
long-term decrease in ambient N02 levels of 12 percent. Figure
3-27 shows that the two primary source categories of nitrogen
oxide emissions are fuel combustion and transportation, composing
53 percent and 43 percent, respectively, of total 1987 nitrogen
oxide emissions.
3.4.2 Recent HOa Trends: 1983-87
Figure 3-28 uses the boxplot presentation to display recent
trends in nitrogen dioxide annual mean concentrations for the
years 1983-87. Focusing on the past five years, rather than the
last ten years, more than doubles the number of sites, from 84 to
199, available for the analysis. Although the composite means from
the recent period are 1 to 2 percent higher than the long-term
means, the trends are consistent for the two data bases.
The composite average NO2 level at the 199 trend sites
increased 2 percent from 1983 to 1984 and remained constant during
the last four years. During this same period, nitrogen oxide
emissions increased by 3 percent. Between 1984 and 1987, the NO2
composite average remained constant, while nitrogen oxide highway
vehicle emissions decreased by 3 percent.
Regional trends in the composite average NO2 concentrations
for the years 1985-87 are displayed in Figure 3-29 with bar
graphs. Region X, which did not have any N02 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 of the ten Regions showed small
increases from 1986 to 1987. Only Regions VIII and IX recorded a
decrease in the last 2 years. As discussed in Section 4.0, the
Los Angeles metropolitan area (Region IX) is the only area which
exceeded the NO;, standard during this period.
60
-------
0.06
CONCENTRATION, PPM
0.05-
0.04-
0.03-
0.02-
0.01 -
0.00
•NAAQS-*
i—J-
5 -1—
•*—*--*• i I I—J
I m i -I S-
NAMS SITES (14)
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-25. National trend in the composite average of
nitrogen dioxide concentration at both NAMS
and all sites with 95 percent confidence
intervals, 1978-1987.
CONCENTRATION, PPM
0,07
0.06-
0.05-
0.04-
0.03-
0.02-
0.01 -
0.00
84 SITES
FT
•NMQS
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-26. Boxplot comparisons of trends in annual mean
nitrogen dioxide concentrations at 84 sites,
1978-1987.
61
-------
Table 3-4. National Hitrogen Oxides Eiission Estimates, 1978-1987.
(Million Metric tons/year)
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Source Category
Transportation 9.8 9.6 9.3 9.4 9.0 8.5 8.6 8.8 8.5 8.4
Fuel Coabustion 10.3 10.5 10.1 10.0 9.8 9.6 10.2 10.2 10.0 10.3
Industrial
Processes
Solid Haste
Miscellaneous
.Total
0.7
0.1
0.2
21.1
0.7
0.1
0.2
21.1
0.7
0.1
0.2
20.4
0.6
0.1
0.2
20.4
0.5
0.1
0.1
19.6
0.5
0.1
0,2
19.0
0.6
0.1
0.2
19.7
0.6
0.1
0.1
19.8
0.6
0.1
0.1
19.3
0.6
0.1
0.1
19.5
MOTE; The SUBS of sub-categories Bay not equal total due to rounding.
30
NCL EMISSIONS, 10s METRIC
25-
0
SOURCE CATEGORY
E3 TRANSPORTATION
GH FUEL COMBUSTION
INDUSTRIAL PROCESSES
SOLID WASTE & MISC.
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-27.
National trend in nitrogen oxides emissions, 1978-
1987.
62
-------
0.07
CONCENTRATION, PPM
0.06-
0.05
0.04-
0.03
0.02-
0.01 -
0.00
199 SITES
NAAQS
I
f M
•*-
1
11
•
1983
1984
1985
1986
1987
Figure 3-28. Boxplot comparisons of trends in annual mean
nitrogen dioxide concentrations at 199 sites, 1983-
1987.
CONCENTRATION, PPM
U.U4U -
0.035-
0.030-
0.025-
0.020-
0.015-
0.010-
0.005-
COMPOSfTE AVERAGE
E3 1985 H 1986 E3 1987
EPA REGION
*
,/
**
t
/
/
*>
t
/
/
s
/
/
?
/
—
/
f
X
/
/
f
f
s
/
\
\
!
\
i
,
\
-
/
/
,
/
II .III IV V
' I
/
<•
/
/
'
7
^
/
/
^
/
/
^
^
/
^
x
/
^
f
/
/
f
f
f
j
f
/
/
f
/
s
/
/
/
/
/
*
/
/
VI VII VIII IX
NO. OFSniS 8 13 37 12 29 20 10 8 62
Figure 3-29. Regional comparisons of 1985, 1986, 1987 composite
averages of the annual mean nitrogen dioxide
concentration.
63
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3.5 TRENDS IN OZONE
Ozone (O3) 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 reguirements 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 274 sites being selected for the 1978-87 period and
522 sites qualifying for the 1983-87 5-year data base.
Ninety-eight of the long-term trends sites were NAMS, and 181 NAMS
sites were included 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 improvement in ambient ozone monitoring
networks.
3.5.1 Long-term 03 Trends: 1978-87
Figure 3-30 displays the 10-year composite average trend
for the second highest day during the ozone season for the 274
trends sites and the subset of 98 NAMS sites. Although the 1987
composite average for the 274 trend sites is 16 percent lower than
the 1978 average, this comparison is affected by a calibration
change for ozone measurements that occurred in the 1978-79
period.1* This complication has been discussed in previous reports,
64
-------
as have the reasons that it is difficult to quantify this
effect.7'*'" The stippled portion of Figure 3-30 indicates data
affected by measurements taken before the calibration change.
Considering the data after this calibration change, there was a
9 percent improvement in ozone levels between 1979 and 1987. This
has not been a smooth downward trend, and there has been year-to-
year fluctuation, with 1983 clearly being high. This has been
attributed in part to 1983 meteorological conditions in some areas
of the country that were more conducive to ozone formation.
This same 10-year trend for the annual second highest daily
maximum for the 274 site data base is displayed in Figure 3-31 by
the boxplot presentation. Again, the stippled portion indicates
those years affected by data preceding the calibration change, and
1983 is clearly higher than adjacent years. The 1979, 1980 and
1983 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. Figure 3-
32 depicts the 1978-87 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. The stippled area again
indicates the time period when comparisons would be affected by
the calibration change, so that the 51 percent decrease between
1978 and 1987 incorporates the effect of the calibration change.
Since 1979, the expected number of exceedances decreased 38
percent for the 274 sites and 37 percent for the 98 NAMS. As with
the second maximum, the 1979, 1980 and 1983 values are higher than
the other years in the 1979-87 period.
Table 3-5 and Figure 3-33 display the 1978-87 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 O.,. Total VOC emissions
are estimated to have decreased 17 percent between 1978 and 1987.
Between 1978 and 1987, VOC emissions from highway vehicles are
estimated to have decreased 36 percent, despite a 24 percent
increase in vehicle miles of travel during this time period (see
Figure 3-21). Total VOC emissions declined 17 percent since the
calibration change.
3.5.2 Recent 03 Trends: 1983-87
This section discusses ambient O3 trends for the 5-year time
period 1983-87. Using this period permits the use of a larger
data base of 522 sites, compared to 274 for the 10-year period.
Figure 3-34 uses a boxplot presentation of the annual second
maximum daily value at these 522 sites. The national composite
average decreased 8 percent between 1983 and 1987 while Table 3-5
indicates that total VOC emissions are estimated to have decreased
65
-------
by 4 percent during this period. After declining during the last
4 years, the composite average increased 5 percent from 1986 to
1987. The increase in 1987 ozone levels is likely from the hot,
dry meteorological conditions recorded in much of the Eastern U.S.
during Summer 1987. The most obvious feature of Figure 3-34 is
that 1983 levels were clearly higher than those of the other years.
Previous reports7'9'10 have discussed how these 1983 ozone levels were
influenced that year by meteorological conditions being more
conducive to ozone formation than in the adjacent years.
0.18
O.ti-
0, H
0.12-
0. 10-
0.08
0.06
0.04
0.02
0.00
CONCENTRATION, PPM
NAMS SITES (98) * ALLSrT|Sl27§)_
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-30.
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, 1978-1987.
66
-------
0.30
CONCENTRATION, PPM
0.25-
0.20
0.15-
0.10-
0.05-
0.00
Z74SiTES
IAAQS*
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-31. Boxplot comparisons of trends in annual second
highest: daily maximum 1-hour ozone concentration
at 274 sites, 1978-1987.
NO. OF EXCEEDANCES
Figure 3-32.
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
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, 1978-1987.
67
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Table 3-5. Rational Volatile Organic Coipound Mssion Estiiates, 1978-1987,
(•illion retric tons/year)
1978 1979 1980 1981 1982 1983
Source Category
Transportation 8.7 9.1 7.4 7.2 6.8 6.7
Fuel Conbustion 1.6 1.9 2.2 2.3 2.5 2.6
1984
6.8
2.6
1985 1986
6.4
2.3
6.2
2.3
35
VOC EMISSIONS, 10s METRIC TONS/YEAR
SOURCE CATEGORY
ra TRANSPORTATION
B INDUSTRIAL PROCESSES
FUEL COMBUSTION
SOLID WASTE & MISC
1987
6.0
2.3
Industrial
Processes
Solid Haste
Miscellaneous
9.9
0.8
2.7
9.9
0.7
2.9
9.2
0.6
2.9
8.3
0.6
2.5
7.5
0.6
2.2
7.9
0.6
2.7
8.8
0.6
2.7
8.5
0.6
2.2
8.1
0,6
2.2
8.3
0.6
2.4
TOTAL (23 A 23.5 22.3 21.0 19.7 20.4 21.5 20.1 19.3 19.6
NOTE: Tie sins of sub-categories lay not epal total due to rounding.
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-33,
National trend in emissions of volatile organic
compounds, 1978-1987.
68
-------
0,30
CONCENTRATION, PPM
0.25-
0.20-
0.15
0. 10
0,05-
0.00
522SfTES
1983
1984
1985
1986
1987
Figure 3-34. Boxplot comparisons of trends in annual
second highest daily maximum 1-hour ozone
concentrations at 522 sites, 1983-1987.
Figure 3-35 presents a Regional comparison for 1985, through
1987 of the composite average second highest daily maximum 1-hour
ozone concentration. Again it is worth noting that these 1985-87
values are generally lower than those of 1983. In seven of these
Regions the 1987 values were higher than in 1986. In contrast,
Regions VIII and X recorded the lowest levels of the last 3 years.
Data for 1987 suggest that meteorological conditions may again
have been conducive to ozone formation and may have contributed to
increased ozone levels in the eastern half of the country. 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 (°F) ,x* Figure 3-36 uses the Regional
bar chart format to present the number of days greater than 90° F
in 1985-87 for selected cities in these Regions.20 Although there
is considerable similarity between the patterns for the air quality
data (Figure 3-35) and the patterns for this simple meteorological
indicator, peak ozone levels result from a complex process, as
illustrated by the multi-Region ozone episode described in the
following section.
69
-------
CONCENTRATION, PPM
0. 18-
0. 12-
0.06-
1
r
/
/
S
/
f
'
*•
COMPOSITE AVERAGE
^ 1985 • 1986 O 1987
-i
7
j
I
!
\
^
PJ
/
|
-j
'
/
^
x
/
/
/
/
/
/
/
/
EPA REGION I II III IV V VI VII VIII IX X
NO. OF SITES 27 30 67 77 98 52 28 15 119 9
Figure 3-35.
Regional comparisons of the 1985, 1986, 1987
composite averages of the second-highest daily
1-hour ozone concentrations.
Days > 90° F
ou -
70-
60-
50-
40-
30-
20-
10-
in
_
/
/
/
/
/
f
/
/
/
s
/
/•
,/
1
_
/
/
/
/
'
<<
1
^
fEAR
^ 1985 Hi 198S [Z3 1987
/
/
/
/
/
/
/
/
/
/
/
/
/
' i
'
" 1
' 1
' ^
^ 1
71
/
/
/
/
/
/
/
/
/
/
/
X
/
/
^
/
/
/
,/
^
/
II
Figure 3-36.
Regional comparisons of the number of days greater
than 90°F in 1985, 1986, 1987 for selected cities.
70
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3.5.3 Chronology of a Multi-Regional Ozone Episode, June 17-20,
1987
Because of the recent interest in ozone, a June 1987 multi-
region episode was examined, using the geographic information
system (CIS) ARC/INFO,21 The system was used to generate isopleths
based on the daily maxima of hourly ozone concentrations from all
sites in the northeast and north central areas of the United
States, Data were also obtained from Canadian sites, in Ontario,
during the same time period." The Canadian data helped define the
.isopleths near the Great Lakes. The CIS was used to display the
isopleths as levels of grey shading (Figures 3-37 through 3-40).
These isopleths involve a certain amount of smoothing, so that the
maps provide a simplified overview and are not intended to provide
precise city specific concentrations. The episode begins on
Wednesday, June 17 and ends on Saturday, June 20.
Wednesday, June 17: h strong high pressure system is located
in southeastern Canada, and the whole study area is experiencing
high temperatures from the high 70s to the low 90s, with small
amounts of precipitation in New England. Ozone readings above the
standard are observed in the Chicago and Milwaukee areas and at
one site in Parkersburg, West Virginia (Figure 3-37).
Thursday, June 18; The high pressure system is now over
Pennsylvania, and a strong low pressure system has moved into
southern Canada. No precipitation has been observed in the entire
region. Areas of high ozone concentrations are centered on
Chicago, Milwaukee, northwest Indiana, eastern Ohio, western
Pennsylvania, and central Maryland (Figure 3-38).
Friday, June 19: The high pressure system has moved off the
coast of New Jersey, with high temperatures in the 80s to 90s.
Again, no precipitation has been observed in the entire area. High
ozone concentrations are now observed in eastern Michigan, western
Pennsylvania, and from eastern Pennsylvania through the northeast
corridor (Figure 30-39).
Saturday, June 20: A weak cold front moving into the area
from the northwest has reached Pennsylvania. Precipitation is
observed along this front, and maximum temperatures have reached
the mid-90's to the east of the front. High ozone concentrations
are observed in central New Jersey, with very high concentrations
centered on New York City (Figure 3-40).
These displays indicate an initiation of an episode in the
Chicago-Milwaukee area which is followed by a general eastward
movement ending in New York City. The episode tracks the basic
meteorological events occurring during this period. By Sunday no
elevated readings of ozone are reported, and the episode has ended.
71
-------
MAXIMUM ONI HOUR OZONI FOR JUNI 17, 198?
Ozone Concentrations in ppm
.00-.06
II .07-.12
.13-.16
Figure 3-37.
Isopleths of ozone daily maximum 1-hour
concentrations for June 17, 1987.
72
-------
MAXIMUM ONI HOUR OZONI FOR JUNE IB, 198?
Ozone Concentrations in ppra
r~| .00-.oe
.07-.12
--16
>. 16
Figure 3-38.
Isopleths of ozone daily maximum 1-hour
concentrations for June 18, 1987.
73
-------
MAXIMUM ONI HOUR OZONE FOI JUNE 19, 1987
Ozone Concentrations in ppm
.00-.06 lili -07-.12 Bj .13-.16
>. 16
Figure 3-39.
Isopleths of ozone daily maximum 1-hour
concentrations for June 19, 1987.
74
-------
MAXIMUM ONE HOUR OZONI FOR JUNE 20, 1987
Ozone Concentrations in ppm
00-.06
111 .07-.12
. 1 3 -. I 6
>- 16
Figure 3-40.
Isopleths of ozone daily maximum 1-hour
concentrations for June 20, 1987.
75
-------
3.5.4 Preview of 1988 Ozone Trends
The summer of 1988, with its very hot, dry weather and
stagnant conditions, was highly conducive to peak ozone levels.
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." Preliminary, unvalidated data were reported
to EPA for a subset of peak ozone monitoring sites.
Figure 3-41 provides a Regional overview of how hot the summer
of 1988 was compared to the past 57 years. Nationally, 1988 was
the third hottest summer since 1931. In the north central states,
this was the hottest summer in almost 60 years.24 This single
meteorological indicator, average daily temperature, does not
completely describe the hot, stagnant conditions which occurred
during June in the Southeast and which produced record numbers of
exceedances that month. The observed exceedances of the ozone
standard in these two regions are shown in Figure 3-42 and Figure
3-43, respectively. There are numerous sites with more than 10
exceedances, which is 10 times the allowable average expected
exceedance rate of one per year.
Meteorological conditions during 1983 were also highly
conducive to ozone formation.* Figure 3-44 presents a boxplot
comparison of 1983 and 1988 ozone levels for the subset of 228
sites with data available for both years. The composite average
of the annual daily maximum 1-hour concentration for 1988 is 5
percent higher than the 1983 value. Except for peak percentiles,
which are lower than those for 1983, the 1988 distribution is
higher, but more compact, than the 1983 distribution. The 95th
percentile level of the 1983 boxplot is lower than that shown in
Figure 3-34, because of the under-representation of southern
California sites in this preliminary data subset of early reporting
sites.
Figure 3-45 shows a preliminary estimate of the trend in the
composite average of the annual daily maximum 1-hour concentration
for the period 1978 through 1988. The 1988 composite average is
14 percent higher than the 1987 level. This estimate is based on
a subset of 272 sites which reported data for both 1987 and 1988.
In order to eliminate any bias from unequal Regional response
rates, the Regional percentage changes were adjusted for the
relative number of sites in the long-term trends data base. This
estimate should be viewed as preliminary, because the 1988 data
have not yet been subjected to the complete quality assurance
process.
76
-------
SUMMER'88 WAS 3RD HOTTEST SINCE 1931
AUG. TEMP
37TH HOTTEST
16TH HOTTEST
11TH HOTTEST
HOTTFST
SEND HOTTEST
14TH HOTTEST
7TH HOTTEST
HOTTEST
Figure 3-41.
Summer '88 was 3rd hottest since 1931. (Source:
USA Todayf September 6, 1988).
77
-------
OZONE
OBSERVED EXCFEDANCES
Figure 3-42.
Ozone exceedances for selected cities in the north
central and northeastern U.S., 1988,
OZONE
OBSERVED EXCEEDANCES
Figure 3-43.
Ozone exceedances for selected cities in the
southeastern U.S., 1988.
78
-------
0.30
CONCENTRATION, PPM
0.25-
0.20-
0.15-
o.to-
0.05-1
0.00
JL
228 SITES
"-NAAQS-
1983
1988
Figure 3-44.
Boxplot comparison of 1983 and 1988 annual second
highest daily maximum 1—hour ozone concentrations
at 228 paired sites.
0.20
0.18
0.16
0. 14
0. 12
0. 10
0.08
0.06
O.04
0.02
0.00
CONCENTRATION, PPM
1 1 1 1 1 1 1 1 T—'—1 I
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988
Figure 3-45.
Preliminary estimate of the national trend in the
composite average of the second highest daily
maximum 1-hour ozone concentration, 1978-1988.
79
-------
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 1987 contributed 37 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 8.6 x 10' and 8.1 x 103 metric tons,
respectively in 1986 and 1987. 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!S 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 1987 unleaded
gasoline sales accounted for 76 percent of the total gasoline
market. Additionally, Pb emissions from stationary sources have
been substantially reduced by control programs oriented toward
attainment of the TSP and Pb ambient standards. Lead emissions in
1987 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 35
percent since the late 70s, In 1987 emissions from solid waste
disposal represent the second largest category of lead emissions.
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: 1978-87
Early trend analyses of ambient Pb data26'27 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." 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.
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 in the 1978 to 1987
80
-------
period. A year was included as "valid" if at least 3 of the 4
quarterly averages were available. For the first time, 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. Nine sites qualified for the 10-year
trend because of the addition of composite data. Sixty additional
sites qualified for the 5-year trend, which will be discussed
later. A total of only 97 urban-oriented sites, representing 27
states, met the data completeness criteria. Twenty-one of these
sites were NAMS, the largest number of lead NAMS sites to qualify
for the 10-year criteria. Thirty-five (36 percent) of the 97 trend
sites were located in the States of California, Ohio and
Pennsylvania? thus these States are over-represented in the sample
of sites satisfying the long-term trend criteria. 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.
The means of the composite maximum quarterly averages and
their respective 95 percent confidence intervals are shown in
Figure 3-46 for both the 97 urban sites and 21 NAMS sites (1978-
1987). There was an 88 percent (1978-87) decrease in the average
for the 97 urban sites. The confidence intervals for these sites
indicate that the 1978-80 averages are significantly different from
the 1981-87 averages. Because of the smaller number (21) of NAMS
sites with 8 years of data, the confidence intervals are wider.
However, the 1986 and 1987 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 1987 are
only slightly higher than the "all sites" average; whereas in the
late 70s the average of the NAMS sites was significantly higher.
Figure 3-47 shows the trend in average lead concentrations for the
urban-oriented sites and for 24 point-source oriented sites which
met the 10-year data completeness criteria. The improvement in
average ambient lead concentrations is even more pronounced at the
point-source oriented sites, reflecting control improvements from
automotive and, of course, industrial sources of lead. In some
cases, the industrial source reductions are because of plant
shutdowns. Figure 3-48 shows boxplot comparisons of the maximum
quarterly average Pb concentrations at the 97 urban-oriented Pb
trend sites (1978-87). This figure shows the dramatic improvement
in ambient Pb concentrations for the entire distribution of trend
sites. As with the composite average concentration since 1978,
most of the percentiles also show a monotonically decreasing
pattern. The 97 urban-oriented sites that qualified for the 1978-
87 period, when compared to the 82 sites for the 1977-86 period
in last year's report," indicate the expansion of the data base in
more recent years.
81
-------
The trend in total lead emissions is shown in Figure 3-49.
Table 3-6 summarizes the Pb emissions data as well. The 1978-87
drop in total Pb emissions was 94 percent. This compares with a
88 percent decrease (1978-87) in ambient Pb noted above. The drop
in Pb consumption and subsequent Pb emissions since 1978 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 1987
amounted to a 62 percent reduction nationwide in total Pb emissions
from 1985 levels. As noted above, unleaded gasoline represented
76 percent of 1987 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.
J
2.2
2
1.8
1.6
1 .4
1.2
1
0.8
0.6
0.4
0.2
0
CONCENTRATION, UG/Jvls
•NAAQS
NAMS SUES (21) a ALL SITES(g7}_
1978 1079 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-46.
National trend in the composite average of the
maximum quarterly average lead concentration
at 97 sites and 21 NAMS sites with 95 percent
confidence intervals, 1978-1987.
82
-------
CONCENTRATION, UG/MS
2.5-
2-
1.5
POINT SOURCE SUES (24) o URBANSlT|S_g7j
Figure 3-47.
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Comparison of national trend in the composite
average of the maximum quarterly average lead
concentrations at urban and point—source oriented
sites, 1978-1987.
2.5
CONCENTRATION,
2-
1.5
1 -
0.5
1
97 SITES
1 1
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-48. Boxplot comparisons of trends in maximum quarterly
average lead concentrations at 97 sites, 1978-1987.
83
-------
Source Category
Transportation
Fuel Coibustion
Industrial
Processes
Solid Haste
Total
Table 3-6. Rational Leid Mssion Estiiates, 1978-1987.
(thousand letric tons/year)
1978 1979 1980 1981 1982 1983 1984 1985 1986 1987
112.4 94.6 59.4 46.4 46.9 40.7 34.7 11.5
6.1 4.9 3.9 2.8 1.7 0.6
5.4 5.2 3.6 3.0 2.7 2.4
4.0 4.0 3.7 3.7 3.1 2.6
127.9 108.7 70.6 55.9 54.4 46.3
34.7
0.5
2.3
2.6
40.1
11.5
0.5
2.3
2.8
21.1
3.5
0.5
1.9
2.7
8.6
3.0
0.5
2.0
2.6
8.1
NOTE: The sins of sub-categories lay not epal total due to rounding.
200
L£AD EMISSIONS, 103 METRIC TONS/YEAR
150-
100-
SOURCE CATEGORY
£22 TRANSPORTATION
BFUEL
COMBUSTION
INDUSTRIAL PROCESSES
SOLID WASTE
50 -
1978 1i79 1980 1981 1982 1983 1984 1985 1986 1987
Figure 3-49. National trend in lead emissions, 1978-1987.
84
-------
3.6.2 Recent Pb Trends: 1983-87
Ambient Pb trends were also studied over the shorter period
1983-87 (Figure 3-50). A total of 394 urban sites in 44 states
met the minimum data requirement of at least 4 out of the 5 years
of data. This larger and more representative set of sites showed
an improvement of 71 percent in average Pb concentrations during
this time period. This corresponds to reductions in total Pb
emissions of 83 percent. 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, Pennsylvania, and Texas.
These states had 35 percent of the 394 sites represented. However,
the percent changes in 1983-87 average Pb concentrations for these
four states were very similar to the percent change at all sites,
thus these contributions of the sites did not bias the national
trends. Indeed, as will be shown later, all sections of the
country are showing declines in average lead concentrations.
It is worth noting that the sites in the 10-year data base also
showed a 71 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 (1983-87), compared with the 10-year, the larger
sample will be used to compare individual yearly averages. The
largest single year drop in average lead concentrations, 42
percent, occurs as expected between 1985 and 1986, because of the
shift from 1.0 grams/gallon of lead in leaded gasoline for the
first half of 1985 to 0.5 grams/gallon of lead in July 1985, and
finally to 0.1 grams of lead/gallon on January 1, 1986. However,
1987 average lead concentrations show the more modest decline of
19 percent from 1986 levels. 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 3-51 shows 1985, 1986 and 1987 composite average Pb
concentrations, by EPA Region. Once again the larger more
representative 5-year data base of 394 sites was used for
comparison. The number of sites varies dramatically by Region from
2 in Region X to 82 in Region V. In all Regions, there is a
substantial difference in average Pb concentrations between 1985
and 1987. 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.
85
-------
2.5
CONCENTRATION,
2-
1 .5
1 -
0.5
0
394 SUES
•NAAQS'
"X....
1983
1984
1985
1986
1987
Figure 3-50
Boxplot comparisons of trends in maximum quarterly
average lead concentrations at 394 sites, 1978-1987.
CONCENTRATION, UG/M*
1.4-
1.2-
1 -
0.8-
0.6-
0.4-
0.2-
COMPOSITE AVERAGE
1985 • 1986 CZD 1987
EPA REGION I II 111 IV V VI VII VIII IX X
NO. OF SITES 40 29 60 47 82 36 31 8 59 2
Figure 3-51. Regional comparison of the 1985, 1986, 1987
composite average of the maximum quarterly
average lead concentration.
86
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3.7 REFERENCES
1. J. W. Tukey, Exploratory Data Analysis, Add!son-Wesley
Publishing Company, Reading,, MA, 1977.
2. B. J, Winer, Statistical Principles in Experimental
Design, McGraw-Hill, NY, 1971.
3. N. L. Johnson and S. Kotz, Discrete Distributions,
Wiley, NY, 1969.
4. R. G. Miller, Jr., Simultaneous Statistical Inference,
Springer-Verlag, NY, 1981.
5. 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.
6. 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.
7. NationaL Air Quality and_Emissions Trends Report, 1984f
EPA-450/4-86-001, U. S. Environmental Protection Agency, Office of
Air Quality Planning and Standards, Research Triangle Park, NC,
April 1986.
8. National Air Pollutant Emission Estimatesf 1940-1987, EPA-
450/4-88-022, U. S. Environmental Protection Agency. Office of Air
Quality Planning and Standards, Research Triangle Park, NC,
January 1989.
9. National Air Quality and Emissions TrendsReport, 1983,
EPA-450/4-84-029, U. S. Environmental Protection Agency, Office of
Air Quality Planning and Standards, Research Triangle Park, NC,
April 1985.
10. National Air Quality and Emissions Trends . Report, JL9_8J5,
EPA-450/4-87-001, U. S. Environmental Protection Agency, Office of
Air Quality Planning and Standards, Research Triangle Park, NC,
February 1987.
11. 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.
87
-------
12. 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,
13. J. Steigerwald, "1987 Total Precipitation Trends Versus
1986 Levels, 5 year Average levels, and Long Term Average Levels",
EPA Contract No. 68-02-4390, PEI Associates, Inc., Durham, NC,
November 30, 1988.
14. 1985 NEDS Data Base, U. S. Environmental Protection Agency,
Research Triangle Park, NC, September 1986.
15. W. M. Koerber, "Trends in SO2 Emissions and Associated
Release Height for Ohio River Valley Power Plants", presented at
the 75th Annual Meeting of the Air Pollution Control Association,
New Orleans, LA, June 1982.
16. Written Communication from C. Bergesen, Utility Data
Institute, Inc., to F. William Brownell, Esq., Hunton and
Williams, Washington, DC, February 21, 1985.
17. National Air Quality and Emissions Trends Report, 1986f
EPA-450/4-88-001, U. S. Environmental Protection Agency, Office of
Air Quality Planning and Standards, Research Triangle Park, NC,
February 1988.
18. Measurement of Ozone in the Atmosphere. 43 FR 26971, June
22, 1978.
19. 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.
20. J. Steigerwald, "Using Publicly Reported Air Quality Index
Data to Provide Updated Trends Information: 1987 Data
Compilations", EPA Contract No. 68-02-4390, PEI Associates, inc.,
Durham, NC, March 1988.
21. ARC/INFO, Environmental Systems Research Institute,
Redlands, CA.
22. Written communication from Thomas Furmanczyk, Environment
Canada, Quebec, Canada to Terence Fitz-Simons, Technical Support
Division, U. S. Environmental Protection Agency, Research Triangle
Park, NC, November 16, 1988.
23. New York Times, July 31, 1988.
88
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24. USA Today. September 6, 1988.
25. National Primary and Secondary Ambient Air Quality
Standards for Lead, 43 FR 46246, October 5, 1978.
,26. R. B. Faoro and T. B. MoMullen, National Trends in Trace
Metals Ambient Air, 1965-1974, EPA-450/1-77-Q03, U. S.
Environmental Protection Agency, Office of Air Quality Planning
and Standards, Research Triangle Park, NC, February 1977.
27. W. Hunt, "Experimental Design in Air Quality Management,"
Andrews Memorial Technical Supplement, American Society for
Quality Control, Milwaukee, WI, 1984.
28. Ambient Air Quality Surveillance, 46 FR 44159, September
3, 1981.
89
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4. AIR QUALITY LEVELS IN METROPOLITAN STATISTICAL AREAS
This section summarizes 1987 air quality levels for each
Metropolitan Statistical Area (MSA) in the United States. Previous
reports have presented air quality data only for those large MSAs
with populations greater than 500,000. This section has been
expanded this year to provide more extensive air quality
information for general air pollution audiences.
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 Figure 4-1 illustrates that, although MSAs
compose only 16 percent of the land area in the U.S., they account
for 77 percent of the population. Table 4-1 displays the
population distribution of the 338 MSAs, based on 1986 population
estimates.*
These summaries are complemented with an estimate of the
number of people living in counties in which pollutant-specific
primary health NAAQS were exceeded by measured air quality in 1987.
These estimates use a single-year interpretation of the NAAQS.
Table 4-2 lists the selected air quality statistics and their
associated NAAQS. Figure 4-2 clearly demonstrates that 03 is the
most pervasive air pollution problem in 1987 for the United States
with an estimated 88.6 million people living in counties which
exceeded the O3 standard. Carbon monoxide follows, with 29.4
million people; PM1D with 21.5 million people; NO2 with 7.5 million
people; Pb with 2.8 million people; and S02 with 1.6 million
people. A total of 102 million persons reside in counties
exceeding at least one air quality standard during 1987. These
estimates are based on available 1980 county population data, thus,
the 7 percent growth in total U.S. population since 1980 is not
reflected in these county 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.
These population estimates are intended to provide a relative
measure of the extent of the effect of 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 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.
90
-------
In the MSA summary table which follows, the air quality
statistics relate to selected pollutant-specific NAAQS listed in
Table 4-2. The population data for each MSA are the 1986
population estimates available from the Bureau of the Census.1
This summary provides the reader with information on how air
quality varied among the nation's metropolitan areas in 1987. The
highest air quality levels measured in each MSA are summarized for
each pollutant monitored in 1987. Individual MSAs are listed to
provide more extensive spatial coverage for large metropolitan
complexes.
The reader is cautioned that this summary is not adequate in
itself to rank _or_ to compare the MSAs according Jbo their air
quality. To rank properly the air pollution severity in different
MSAs, data on population characteristics, daily population
mobility, transportation patterns, industrial composition, emission
inventories, meteorological factors and, most important, the
spatial representativeness of the monitoring sites would also be
needed.
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. Kith 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.
91
-------
TABLE 4-1. Population Distribution of Metropolitan Statistical Areas Based on
1986 Population Estinates
Population Range
Number of HSAs
Total
338
Total Population
< 100,000
100,000 < population < 250,000
250,000 < population < 500,000
500,000 < population < 1,000,000
1,000,000 < population < 2,000,000
population > 2,000,000
27
146
75
46
26
18
2,269,000
23,142,000
25,914,000
32,972,000
38,164,000
64,838,000
187,299,000
METROPOUTAN STATISTICAL AREAS (MSA)
PERCENT OF U.S. UNO AREA
PERCENT OF U.S. POPULATION
Figure 4-1.
Percent of U.S. population and land area within
MSAs, 1986.
92
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fable 4-2. Selected Air Quality Sunary Statistics and Their Associated National AiMent Air
Quality Standards (HAAQS)*
POLLDTAH1
SfAflSHCS
PMHAR! HAiQS
Particulate Matter (PH10)
Sulfur Dioxide (S0a)
Carbon Monoxide (CO)
annual arithmetic xean
annual arithietic lean
second highest 24-hour
average
second highest nonover-
= licrograits per cubic eeter pp« = parts per nillion
*single year interpretation. For a detailed listing of toe KUQS see fable 2-1.
pollutant
215
88.6
Any
NAAQS
101,8
50 ug/i3
0.03 ppi
0.14 ppi
Hitrogen Dioxide (M0a)
Ozone (03)
Lead (Pb)
lapping 8-hour average
annual arithietic Kan
second highest daily
•axiiuB 1-hour average
•axiim quarterly average
9ppi
0.053 pp
0.12 ppa
1.5 ug/i3
20 40 60 80
millions of parsons
100
120
Figure 4-2. Number of persons living in counties with air quality
levels above the primary national ambient air quality
standards in 1987 (based on 1980 population data).
93
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4.1 SUMMARY STATISTICS
In Table 4-3, the air quality levels reported for each
metropolitan area are the highest levels measured from all
available sites within the MSA. 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, S02
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 4-2, with their associated primary NAAQS
concentrations for a single year of data. For example, if an MSA
has three ozone monitors in 1987 with second highest daily hourly
maxima of .15 ppm, .14 ppm and .12 ppm, the highest of these, .15
ppm, would be reported for that MSA for 1987.
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.*1 Most of the maximum quarterly Pb averages are based
on multiple 24-hour measurements.
4.2 MSA AIR QUALITY SUMMARY
In the air quality summary, Table 4-3, the MSAs are listed
alphabetically, with the 1986 population estimate and air quality
statistics for each pollutant. The New York, NY MSA is the
nation's largest metropolitan area with a 1986 population In excess
of 8 million. The smallest MSA is Enid, OK with a population of
63,000. The population groupings and the number of MSAs contained
within each range are listed in Table 4-1. The MSA population
statistics are based on the 1986 Metropolitan statistical Area
estimates.l
Air quality maps of the United States are introduced to 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 88 MSAs within the continental
aA chemical composite measurement can be either a
measurement for an entire month or an entire quarter.
94
-------
U.S. having populations greater than 500,000 are shown. Two large
MSAs, Honolulu, HI and San Juan, PR are not shown. Figures 4-3
through 4-9 appear just before the table summarizing the air
pollution statistics. In each map, a spike is plotted at the city
location on the map surface. This represents the highest
pollutant concentration recorded in 1987, 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.
95
-------
The nap for PM10 shows the 1987 maximum annual arithmetic means
in metropolitan areas greater than 500,000 population.
Concentrations above the level of the PM10 standard of 50 ug/m3 are
found in eleven of these metropolitan areas (Figure 4-3).
PM10
ANNUAL ARITHMETIC MEAN
Figure 4-3.
United States nap of the highest annual arithmetic
mean PHta concentration by MSA, 1987.
96
-------
The map for sulfur dioxide shows maximum annual mean
concentrations in 1987. Among these large metropolitan areas, the
higher concentrations are found in the heavily populated Midwest
and Northeast. All these large urban areas have ambient air
quality concentrations lower than the current annual standard of
80 ug/m3 (.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 4-4).
SULFUR DIOXIDE
ANNUAL ARITHMETIC MEAN
Figure 4-4.
United States map of the highest annual arithmetic
mean sulfur dioxide concentration by MSA, 1987.
97
-------
The map for sulfur dioxide shows the highest second highest
maximum 24-hour average sulfur dioxide concentration by MSA in
1987. The highest concentration in a large urban area is found
at a site in Pittsburgh, PA which is impacted by major SO, sources.
All other major urban areas have ambient concentrations below the
24-hour NAAQS of 0,14 parts per million (Figure 4-5).
SULFUR DIOXIDE
2ND MAX 24-HR AVG
Figure 4-5,
United States map of the highest second maximum
24-hour average sulfur dioxide concentration by MSA,
1987.
98
-------
The map for carbon monoxide shows peak metropolitan are
concentrations in terms of the second highest annual 8-hour value
recorded in 1987. The east-west profile indicates that about a
third of these urban areas in all geographic regions have air
quality at or exceeding the 9 ppm level of the standard. While
highest concentration recorded in 1987 is found in New York, NY,
twenty-one of these large metropolitan areas exceeded the 8-hour
CO NAAQS in 1987 (Figure 4-6).
CARBON MONOXIDE
2ND MAX 8-HR AVG
Figure 4-6.
United States map of the highest second maximum
nonoverlapping 8-hour average carbon monoxide
concentration by MSA, 1987.
99
-------
The map for nitrogen dioxide displays the maximum annual mean
measured in the nation's largest metropolitan areas during 1987,
Los Angeles, California, with an annual NO, mean of 0.055 ppm is
the only area in the country exceeding the NO2 air quality
standard of .053 ppm (Figure 4-7).
NITROGEN DIOXIDE
ANNUAL ARITHMETIC MEAN
Figure 4-7.
United States map of the highest annual arithmetic
mean nitrogen dioxide concentration by MSA, 1987.
100
-------
The ozone map shows the second highest daily maximum 1-hour
concentration in the 88 largest metropolitan areas in the
Continental U.S. As shown, about 60 percent of these areas (52
MSAs) did not meet the 0.12 ppn standard in 1987. 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 4-8).
OZONE
2ND DAILY MAX 1-HR AVG
Figure 4-8.
Onited States nap of the highest second daily
maximum 1-hour average ozone concentration by MSA,
1987.
101
-------
The map for Pb displays maximum quarterly average
concentrations in the nation's largest metropolitan areas.
Exceedances of the Pb NAAQS are found in the vicinity of nonferrous
smelters or other point sources of lead in three large cities.
Because of the switch to unleaded gasoline, other areas, primarily
affected by automotive lead emissions, show levels below the
current standard of 1.5 ug/m3 (Figure 4-9).
LEAD
MAX QUARTERLY MEAN
Figure 4-9.
United States map of the highest maximum quarterly
average lead concentration by MSA, 1987.
102
-------
4.3 REFERENCES
1. Statistical Abstract of the United States. 1988. U. S.
Department of Commerce, U. S. Bureau of the Census, Appendix II.
103
-------
TABLE 4-3.
1987 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
ABILENE, TX
AGUADILLA, PR
AKRON, OH
ALBANY, GA
ALBANY-SCHENECTADY-TROY, NY
ALBUQUERQUE, NM
ALEXANDRIA, LA
ALLENTOHN-BETHLEHEM, PA-NJ
ALTOONA, PA
AMARILLO, TX
ANAHEIM-SANTA ANA, CA
ANCHORAGE, AK
ANDERSON, IN
ANDERSON, SC
ANN ARBOR, MI
ANNISTON, AL
APPLETON-OSHKOSH-NEENftH, MI
ARECIBQ, 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 ROUSE, LA
BATTLE CREEK, MI
BEAUMONT-PORT ARTHUR, TX
BEAVER COUNTY, PA
BELLINGHAM, HA
BENTON HARBOR, HI
BERGEN-PASSAIC, NJ
1986
POPULATION
2
2
2
1
126
156
645
117
844
47*
140
657
132
195
,167
235
133
141
266
1Z4
307
170
170
141
,561
297
390
345
726
494
,280
S3
546
137
376
193
114
164
,298
,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
(UBM)
ND
ND
33
ND
34-
33
ND
33
29
18
SO
31
ND
ND
ND
ND
ND
ND
31
ND
46
44
23
ND
25
64
43
IN
31
33
ND
ND
45
ND
42
S02
AM
(PPM)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ND
ND
.017
NO
.010
ND
ND
.012
.010
ND
.005
ND
ND
ND
.007
ND
IN
ND
ND
ND
.008
.004
ND
ND
.001
.006
.012
IN
.007
ND
.010
.012
.008
ND
.011
S02
24-HR
IPPMI
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ND
ND
.057
ND
.047
ND
ND
.035
.051
ND
.015
ND
ND
ND
.065
ND
.056
ND
ND
ND
.050
.016
ND
ND
.009
.016
.045
.037
.030
ND
.058
.050
.025
ND
.038
CO
8HR
(PPM)
ND
ND
5
ND
8
16
ND
5
ND
ND
10
12
ND
ND
ND
ND
ND
ND
ND
ND
6
ND
ND
ND
ND
7
9
ND
5
ND
4
3
ND
ND
8
N02
AM
(PPM)
ND
ND
ND
ND
ND
0.018
ND
0.019
ND
ND
0.042
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.028
ND
ND
ND
ND
0.029
0.035
ND
0.023
ND
IN
0.021
ND
ND
0.036
OZONE
2ND DMX
(PPM)
ND
ND
0.13
ND
0.10
0.10
ND
0.13
0.13
ND
0.24
ND
ND
ND
O.U
ND
0.10
ND
0.09
ND
0.17
0.14
ND
0.10
0.10
0.16
0.17
ND
0.16
NO
0.13
0.11
ND
ND
0.17
PS
QMAX
(UGH)
ND
ND
0.16
ND
0.08
0.10
ND
0.76
ND
0.03
ND
0.13
ND
0.06
ND
ND
ND
ND
ND
ND
0.08
0.06
0.03
0.11
o.oa
0.13
0.13
0.07
0.14
ND
0.04
0.24
ND
ND
0.13
TSP = HIGHEST
PM10 = HIGHEST
S02 =
CO
N02
03
PB
HIGHEST
HIGHEST
= HIGHEST
= HIGHEST
= HIGHEST
= HIGHEST
GEOMETRIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND MAXIMUM 24-HOUR CONCENTRATION
SECOND MAXIMUM NONOVERLAPPING 8-HOUR CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION
QUARTERLY MAXIMUM CONCENTRATION
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
-------
TABLE 4-3.
1987 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
O
O1
METROPOLITAN STATISTICAL AREA
BILLINGS, MT
BILQXI-GULFPORT, MS
BINGHAMTON, NY
BIRMINGHAM, AL
BISMARK, ND
BLODMINGTON> IN
BLOQMIN6TON-NORMAL, IL
BOISE CITY, ID
BOSTON, MA
BQULDER-LONSMONT, CO
BRAOENTON, PL
BRAZORIA, TX
BREMERTON, HA
BRIDGEPORT-MILFORD, CT
BRISTOL, CT
BROCKTON, MA
BROKNSVILLE-HARLINGEN, TX
BRYAN-COLLEGE STATION, TX
BUFFALO, NY
BURLINGTON, NC
BURLINGTON, VT
CAGUAS, PR
CANTON, OK
CASPER, MY
CEDAR RAPIDS, IA
CHAMPAIGN-URBANA-RANTOUL, IL
CHARLESTON, SC
CHARLESTON, NV
CHARLOTTE-6ASTONIA-ROCK HILL, NC-SC
CHARLOTTESVILLE, VA
CHATTANOOGA, TN-GA
CHEYENNE, NY
CHICAGO, IL
CHICO, CA
CINCINNATI, OH-KY-IN
1986
POPULATION
120,000
204,000
262,000
911,000
86,000
102,000
123,000
194,000
2,824,000
214,000
177,000
189,000
169,000
444,000
76,000
168,000
257,000
121,000
965,000
102,000
125,000
275,000
400,000
71,000
169,000
171,000
486 , 000
266,000
1,065)000
121,000
426,000
75,000
6,186,000
167,000
1,419,000
PM10
AH
(UGH)
IN
ND
ND
52
23
ND
ND
48
39
40
ND
ND
ND
31
ND
ND
ND
ND
31
ND
SO
ND
ND
29
39
ND
30
37
34
ND
45
30
45
48
43
S02
AM
«PPMJ
0.024
0.007
NO
IN
ND
ND
ND
ND
0.017
ND
ND
ND
ND
0.013
ND
ND
ND
ND
0.013
ND
0.006
ND
0.010
ND
0.010
0.005
0.005
0.009
ND
ND
ND
ND
0.011
ND
0.018
SO2
24-HR
tPPM)
0.099
0.045
ND
0.018
ND
ND
ND
ND
0.049
ND
ND
ND
ND
0.045
ND
ND
ND
ND
0.068
ND
0.018
ND
0.04S
ND
0.071
0.021
0.042
0.035
ND
ND
ND
ND
0.053
ND
0.076
CO
8HR
(PPM)
ND
ND
ND
8
ND
ND
ND
8
7
9
ND
ND
9
5
ND
ND
ND
ND
S
ND
5
ND
4
ND
3
NO
5
5
8
ND
ND
ND
9
8
6
N02
AM
(PPM)
ND
ND
ND
ND
ND
ND
ND
ND
J.038
ND
ND
ND
ND
0.026
ND
ND
ND
ND
0.025
ND
0.019
ND
ND
ND
0.025
ND
ND
0.021
ND
ND
NO
ND
0.043
0.017
0.033
OZONE
2ND DHX
(PPM)
ND
ND
ND
0.14
ND
ND
ND
ND
0.14
0.12
ND
ND
ND
0.17
ND
0.12
ND
ND
0.13
ND
0.09
ND
0.12
ND
0.10
0.10
0.10
0.11
0.14
ND
0.12
ND
0.16
0.10
0.15
PB
QMAX
(UGM)
ND
ND
ND
3.04
ND
0.03
ND
0.16
0.12
ND
ND
ND
ND
0.13
0.06
ND
0.04
ND
0.11
ND
ND
ND
NO
ND
ND
ND
0.05
0.06
0.07
ND
ND
ND
0.18
0.03
0.11
(1)
GEOMETRIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND MAXIMUM 24-HOUR CONCENTRATION
SECOND MAXIMUM NONOVERLAPPING 8-HOUR CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION
QUARTERLY MAXIMUM CONCENTRATION
= INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
TSP
PM10
S02
CO
NO 2
03
PB
ND
IN
= HIGHEST
= HIGHEST
= HIGHEST
HIGHEST
= HIGHEST
= HIGHEST
= HIGHEST
= HIGHEST
= INDICATI
= INDICATI
(1) IMPACT FROM INDUSTRIAL PB SOURCE IN LEEDS, AL. THE
1987 PB LEVEL AT THE HIGHEST POPULATION ORIENTED SITE
IN BIRMINGHAM, AL IS 0.21 UG/M3.
UGM = UNITS ARE MICROGRAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
-------
TABLE 4-3.
1987 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
CLARKSVILLE-HQPKINSVILLE, TN-KY
CLEVELAND, OH
COLORADO SPRINGS. CO
COLUMBIA, MO
COLUMBIA, SC
COLUMBUS, GA-AL
COLUMBUS, OH
CORPUS CHRISTI, TX
CUMBERLAND, MD-NV
DALLAS, TX
DANBURY, CT
DANVILLE, VA
DAVENPORT-ROCK 1SLANO-MOLINE, IA-IL
DAYTON-SPRINGFIELD, OH
DAYTONA BEACH, FL
DECATUR, IL
DENVER, CO
DES MOINES, IA
DETROIT, MI
DOTHAN, AL
DUBUQUE, IA
OULUTH, MN-HI
EAU CLAIRE, HI
EL PASO, TX
ELKHART-GOSHEN, IN
ELMIRA, NY
ENID, OK
ERIE, PA
EUGENE-SPRINGFIELD, OR
EVANSVILLE, IN-KY
FALL RIVER, MA-RI
FARGO-MOORHEAD, ND-KN
FAYETTEVILLE, NC
FAYETTEVILLE-SPRINGDALE, AR
FITCHBURG-LEOMINSTER, MA
1986
POPULATION
154,000
1,850,000
380,000
106,000
445,000
251,000
1,299,000
363,000
102,000
2,401,000
186,000
110,000
371,000
934,000
321,000
127,000
1,633,000
381,000
4,335,000
130,000
91,000
244,000
137,000
561,000
146,000
91,000
63,000
279,000
263,000
281,000
158,000
145,000
259,000
107,000
96,000
PM10
AM
(UGM)
ND
51
28
IN
36
ND
40
33
ND
29
ND
ND
30
48
ND
40
46
40
_-, .« t
ND *
ND
28
ND
54
ND
ND
ND
31
43
ND
NO
20
32
ND
ND
S02
AM
(PPM)
0.005
0.016
ND
ND
IN
ND
0.009
0.003
0.012
0.004
0.008
ND
0.004
0.007
0.002
0.013
0.009
ND
0.01S
ND
0.005
0.004
ND
0.018
ND
0.005
ND
0.013
ND
0.017
0.010
ND
ND
NO
NO
502
24-HR
(PPM)
0.040
0.076
ND
ND
0.011
ND
0.032
0.018
0.047
0.017
0.035
ND
0.018
0.031
0.009
0.081
0.025
ND
0.062
NO
0.026
0.013
ND
0.070
ND
0.029
ND
0.045
ND
0.079
0.053
ND
ND
ND
ND
CO
BHR
(PPM1
ND
7
9
ND
7
ND
6
ND
5
5
ND
ND
5
6
ND
ND
16
6
9
ND
7
9
ND
15
ND
ND
ND
5
7
3
ND
ND
ND
ND
ND
N02
AM
(PPM)
ND
O.O31
ND
ND
ND
ND
ND
ND
ND
0.023
ND
ND
ND
ND
ND
ND
0.041
ND
0.023
ND
ND
ND
ND
0.023
ND
ND
ND
0.016
ND
0.021
ND
ND
ND
ND
ND
OZONE
2ND DMX
(PPM)
ND
0.13
0.10
ND
0.12
0.12
0.12
0.14
0.09
0.15
0.15
ND
0.10
0.12
ND
0.10
0.12
0.05
0.13
ND
ND
ND
ND
0.17
ND
0.10
ND
0.11
0.11
0.12
ND
ND
ND
ND
ND
PB
QMAX
(UGM)
ND
0.43
0.00
ND
0.08
ND
0.10
0.09
ND
1.27
0.10
ND
0.03
0.09
ND
0.09
0.15
0.02
0.14
ND
ND
0.09
ND
1.38
ND
ND
ND
ND
0.08
ND
ND
ND
ND
ND
ND
(1)
(2)
GEOMETRIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND MAXIMUM 24-HOUR CONCENTRATION
SECOND MAXIMUM NONOVERLAPPING 8-HOUR CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION
QUARTERLY MAXIMUM CONCENTRATION
= INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
TSP
PM10
S02
CO
N02
03
PB
ND
IN
=
a
=
=
=
=
=
=
=
HIGHEST
HIGHEST
HIGHEST
HIGHEST
HIGHEST
HIGHEST
HIGHEST
HIGHEST
INDICATI
INDICATI
(13 IMPACT FROM PB RECLAMATION PLANT IN FRISCO, TX. THE
1987 PB LEVEL AT THE HIGHEST POPULATION ORIENTED SITE
IN DALLAS, TX IS 0.47 UG/M3.
(2) IMPACT FROM PB SMELTER, THE 1987 PB LEVEL AT THE HIGHEST
POPULATION ORIENTED SITE IN EL PASO, TX 0.40 UG/M3.
UGM = UNITS ARE MICROGRAHS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
-------
TABLE 4-3, 1987 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOQK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY HSA
H"
O
METROPOLITAN STATISTICAL AREA
FLINT, MI
FLORENCE, AL
FLORENCE* SC
FORT COLLINS, CO
FORT LAUDERDALE-HOLLYNOOD-POMPANO BE
FORT MYERS-CAPE CORAL, FL
FORT PIERCE, FL
FORT SMITH, AR-OK
FORT HALTON BEACH, FL
FORT NAYNE, IN
FORT NORTH-ARLINGTON, 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, HT
GREELEY, CO
GREEN BAY, MI
GREENSBORO-NINSTON SALEM-HIBH POINT,
GREENVILLE-SPARTANBURG, SC
HAGERSTOHN, MD
HAMILTON-MIDDLETOHN, OH
HARRISBURG-LEBANON-CARLISLE, PA
HARTFORD, CT
HICKORY, NC
HONOLULU, HI
HOUMA-THIBODAUX, LA
HOUSTON, TX
HUNTIN6TON-ASHLAND, WV-KY-OH
HUNTSVILLE, AL
INDIANAPOLIS, IN
1986
POPULATION
425,000
138,000
116,000
175,000
1,142,000
279,000
206,000
176,000
141,000
356,000
1,254,000
538,000
102,000
200,000
215,000
615,000
112,000
69,000
649,000
79,000
135,000
187,000
899,000
606,000
114,000
271,000
577,000
739,000
218,000
817,000
189,000
3,231,000
328,000
234,000
1,213,000
PM10
AH
(UGH)
IN
ND
NO
30
28
ND
ND
NO
ND
38
28
63
44
ND
27
64
ND
24
IN
26
31
40
40
36
ND
45
29
35
ND
22
ND
41
49
ND
47
S02
AM
(PPM)
0.005
0,007
ND
ND
ND
ND
ND
ND
ND
0.005
0.002
0,002
ND
0.002
0,006
0.012
0,006
ND
0.006
ND
ND
0.007
0.008
ND
ND
IN
0.009
0.010
0.003
0.001
ND
0.009
0,015
ND
0.016
SO2
24-HR
(PPM)
0.020
0.071
ND
ND
ND
NO
ND
ND
ND
0.018
0.010
0.010
ND
0.009
0.053
0.051
0.029
ND
0.054
ND
ND
0.050
0.028
ND
ND
0.029
0.031
O.OS4
0.016
0.005
NO
0.031
0,067
ND
0,067
CO
8HR
IPPM)
ND
ND
ND
13
6
ND
ND
ND
ND
ND
6
11
ND
ND
ND
5
ND
ND
5
11
11
ND
7
ND
ND
ND
7
11
ND
4
ND
9
5
ND
7
N02
AM
(PPM)
ND
ND
ND
ND
ND
ND
ND
NO
ND
0.009
0.015
0.030
ND
ND
ND
ND
ND
NO
NO
ND
ND
ND
0.018
ND
ND
ND -
0.022
0.020
NO
ND
ND
0.030
0.016
ND
0,023
OZONE
2ND DMX
(PPM)
o;i2
ND
ND
0.08
0.10
ND
ND
ND
NO
0.11
0.14
0.17
ND
ND
0.13
0.16
ND
ND
0.14
ND
0.09
0.11
0.11
0.11
NO
0.10
0.13
0.14
0.10
0.04
ND
o.ia
0.14
0.11
0.12
PB
QMAX
CUGM)
0.05
ND
ND
ND
0.04
ND
ND
ND
ND
ND
0,12
0.10
ND
ND
0.08
2.56
NO
NO
0.19
ND
ND
ND
ND
0.11
ND
ND
ND
0.11
HB '
0.00
ND
0.12
0.11
ND
1.15
(1)
(2)
TSP = HIGHEST
PM10 = HIGHEST
S02 = HIGHEST
HIGHEST
CO
N02
03
PB
= HIGHEST
= HIGHEST
= HIGHEST
E HIGHEST
GEOMETRIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND MAXIMUM 24-HOUR CONCENTRATION
SECOND MAXIMUM NONOVERLAPPING 8-HOUR CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION
QUARTERLY MAXIMUM CONCENTRATION
ND = INDICATES DATA NOT AVAILABLE
IN = INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
(1) IMPACT FROM PB BATTERY PLANT IN HAMMOND, IN, THE
1987 PB LEVEL AT THE HIGHEST POPULATION ORIENTED SITE
IN GARY, IN IS 0.20 UG/M3,
(2) IMPACT FROM PB BATTERV PLANT. THE 1987 PB LEVEL
AT THE HIGHEST POPULATION ORIENTED SITE
IN INDIANAPOLIS, IN IS 0.13 UG/M3.
UGM = UNITS ARE MICROGRAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
-------
TABLE 4-3.
1987 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
H>
O
00
METROPOLITAN STATISTICAL ARIA
IOHA CITY, IA
JACKSON, MI
JACKSON, MS
JACKSON, TN
JACKSONVILLE, FL
JACKSONVILLE, NC
JANESVILLE-BELOIT, HI
JERSEY CITY, NJ
JOHNSON CITY-K1NSSPORT-BRISTOL, TN-V
JOHNSTOWN, PA
JOLIET, IL
JOPLIN, MO
KALAMAZOO, MI
KANKAKEE, IL
KANSAS CITY, MO-KS
KENOSHA, HI
KXLLEN-TEMPLE, TX
KNOXVILLE, TN
KOKOMO, IN
LA CROSSE, MI
LAFAYETTE, LA
LAFAYETTE-WEST LAFAYETTE, IN
LAKE CHARLES, LA
LAKE COUNTY, IL
LAKELAND-HINTER HAVEN, FL
LANCASTER, PA
LANSING-EAST LANSING, MI
LAREDO, TX
LAS CRUCES, MM
LAS VESAS, NV
LAHRENCE, KS
LAHRENCE-HAVERHILL, MA-NH
LAMTON, OK
LEWISTON-AUBURN, ME
LEXIN6TDN-FAYETTE, KY
1986
POPULATION
85,000
144,000
392,000
78,000
853,000
127,000
138,000
553,000
443,000
254,000
370,000
133,000
218,000
98,000
1,518,000
120,000
234,000
591,000
101,000
94,000
218,000
124,000
173,000
480,000
377,000
394,000
425,000
121,000
123,000
569,000
73,000
368,000
121,000
85,000
332,000
PM10
AM
(UGM)
ND
ND
32
36
34
ND
34
37
40
ND
34
ND
ND
ND
75
ND
ND
42
ND
ND
ND
40
ND
ND
ND
ND
24
ND
37
43
ND
IN
ND
ND
ND
S02
AM
(PPM)
ND
ND
ND
ND
0.008
ND
0.004
0.014
0.012
0.016
ND
NO
NO
ND
0.011
0.007
ND
0.012
ND
ND
ND
0.006
0.002
ND
0.004
0.007
0.006
ND
0.017
ND
ND
0.010
0.006
0.009
0.007
SO2
24-HR
(PPM)
ND
ND
x ND
ND
0.087
ND
0.023
0.041
0.064
0.065
ND
ND
ND
ND
0.047
0.037
ND
0.041
ND
ND
ND
0.028
0.007
ND
0.019
0.027
0.023
ND
0.071
ND
ND
0.045
0.023
0.034
0.031
CO
8HR
(PPM>
ND
ND
4
ND
7
NO
ND
8
5
6
ND
ND
ND
ND
8
ND
ND
ND
ND
ND
ND
2
ND
ND
ND
3
ND
ND
8
12
ND
ND
ND
ND
6
N02
AM
(PPM)
ND
ND
ND
ND
0.018
ND
0.012
0.031
0.020
0.020
ND
ND
ND
ND
0.019
0.022
ND
ND
ND
ND
ND
0.009
ND
ND
ND
0.019
ND
ND
ND
0.028
ND
ND
ND
ND
0.017
OZONE
2ND DMX
(PPM)
0.09
ND
0.09
ND
0.12
ND
0.10
0.16
0.10
0.12
0.11
ND
ND
ND
0.12
0.18
ND
0.12
ND
0.09
0.11
ND
0.13
0.16
ND
0.12
0.11
ND
0.12
0.11
ND
0.13
ND
ND
0.11
PB
UMAX
(UGM)
ND
ND
0.12
ND
0.13
NO
ND
0.10
0.00
O.S2
0.03
ND
0.06
ND
0.08
ND
ND
ND
NO
ND
ND
0.03
ND
ND
ND
0.09
0.04
0.04
0.44
ND
ND
ND
ND
0.08
ND
TSP = HIGHEST GEOMETRIC MEAN CONCENTRATION
PH10 = HIGHEST ARITHMETIC MEAN CONCENTRATION
S02 = HIGHEST ARITHMETIC MEAN CONCENTRATION
HIGHEST SECOND MAXIMUM 24-HOUR CONCENTRATION
CO = HIGHEST SECOND MAXIMUM NONOVERLAPPIN6 8-HOUR CONCENTRATION
N02 = HIGHEST ARITHMETIC MEAN CONCENTRATION
O3 = HIGHEST SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION
PB = HIGHEST QUARTERLY MAXIMUM CONCENTRATION
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
-------
TABLE 4-3.
1987 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBQOK.
PEAK STATISTICS FDR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
LIMA. OH
LINCOLN, NE
LITTLE ROCK-NORTH LITTLE ROCK, AR
LON6VIEH-MARSHALL, TX
LORAIN-ELYRIA, OH
LOS ANBELES-LONS BEACH, CA
LOUISVILLE, KY-IN
LOWELL, MA-NH
LUBBOCK, TX
LYNCHBURG, VA
HACON-HARNER ROBINS, GA
MADISON, HI
HANCHESTER, NH
MANSFIELD, OH
MAYA6UEZ, PR
HCALLEN-EDINSURG-MISSION, TX
MEDFORD, OR
MELBOURNE-TITUSVILLE-PALM BAY, FL
MEMPHIS, TN-AR-MS
MERCED, CA
MIAMI-HIALEAH, FL
MIDDLESEX-SOHERSET-HUNTERDON, NJ
MIDDLETOWN, CT
MIDLAND, TX
MILWAUKEE, HI
MINNEAPOLIS-ST. PAUL, MN-HI
MOBILE, AL
MODESTO, CA
MONMQIJTH-OCIAN, NJ
MONROE, LA
MONTGOMERY, AL
MU1CIE, IN
MUSKE60N, MI
NAPLES, FL
NASHUA, NH
1986
POPULATION
154,000
£06,000
506,000
170,000
271,000
8,296,000
f 63, 000
254,000
225,000
144,000
282,000
345,000
145,000
129,000
210,000
366,000
140,000
361,000
959,000
164,000
1,770,000
950,000
84,000
111,000
1,280,000
2,295,000
470,000
317,000
935,000
146,000
299,000
121,000
159,000
121,000
163,000
PM10
AM
(UGM)
ND
NO
31
ND
38
68
43
ND
34
ND
ND
ND
IN
ND
ND
ND
B2
ND
35
44
38
ND
ND
ND
40
41
48
44
ND
ND
28
ND
ND
ND
ND
S02
AM
(PPM)
0.006
ND
0.002
: ND
b.oii
0,006
0,011
ND
ND
ND
ND
0.004
0.009
0.009
ND
ND
ND
ND
0.014
ND
0,002
0.011
ND
ND
0.006
0.017
0,009
0,003
ND
0,006
ND
ND
0.005
ND
0.008
S02
24-HR
(PPM)
0.029
ND
0.006
ND
0.041
0.021
0.067
ND
ND
ND
ND
0.016
0.040
0.035
ND
ND
ND
ND
0.067
ND
0.008
0.035
ND
ND
0.027
0.090
0.052
0.010
ND
0.025
ND
ND
O.OE1
ND
0.034
CO
8HR
(PPMJ
NO
8
ND
ND
ND
17
7
ND
ND
ND
ND
S
10
ND
ND
NO
10
ND
11
ND
8
5
ND
ND
S
13
ND
9
6
ND
ND
ND
4
ND
9
N02
AM
(PPM)
ND
ND
0.009
IN
ND
0.055
0.032
ND
ND
ND
ND
ND
0.020
ND
ND
ND
ND
ND
IN
ND
0.012
0.027
ND
ND
0.027
0.020
ND
0.024
ND
ND
ND
ND
ND
ND
ND
OZONi
2ND DMX
(PPM)
0.10
0.06
0,12
0.12
0.09
0.32
0.13 .
ND
ND
ND
ND
0.10
0,10
ND
ND
ND
0.09
ND
0.13
ND
0.15
0.19
0.17
ND
0.18
0.11
0.11
0.15
ND
0.10
0.14
ND
0.18
ND
0.10
PB
QMAX
(UGM)
ND
ND
0.21
ND
ND
0.27
0.10
0.09
0.08
ND
ND
ND
0.06
ND
ND
0.03
0.07
ND
0.33
ND
0.15
0.17
0.07
ND
0.16
1.51
ND
ND
ND
ND
ND
ND
0.04
ND
0.05
(1)
TSP = HIGHEST GEOMETRIC MEAN CONCENTRATION
PM10 = HIGHEST ARITHMETIC MEAN CONCENTRATION
S02 = HIGHEST ARITHMETIC MEAN CONCENTRATION
HIGHEST SECOND MAXIMUM 24-HOUP CONCENTRATION
CO * HIGHEST SECOND MAXIMUH NONOVERLAPPINB 8-HOUR CONCENTRATION
N02 = HIGHEST ARITHMETIC MEAN CONCENTRATION
03 = HIGHEST SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION
PB = HIGHEST QUARTERLY MAXIMUM CONCENTRATION
ND = INDICATES DATA NOT AVAILABLE
IN = INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
(1) IMPACT FROM PB POINT SOURCE IN EAGAN, MM. THE 1987 PB
LEVEL AT THE HIGHEST POPULATION ORIENTED SITE IN
MINNEAPOLIS, UN IS 0.08 US/M3.
USM = UNITS ARE MICRQGRAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
-------
TABLE 4-3.
1987 HETROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
NASHVILLE, TN
NASSAU-SUFFOLK, NY
NEH BEDFORD, MA
NEH BRITAIN, CT
NEN HAVEN-MERIDEN, CT
NEW LONDON-NORWICH, CT-RI
NEK ORLEANS, LA
NEH YORK, NY
NEWARK, NJ
NIAGARA FALLS, NY
NORFOLK-VIRGINIA BEACH-NEHPORT NEWS,
NORNALK, CT
OAKLAND, CA
OCALA, FL
ODESSA, TX
OKLAHOMA CITY, OK
OLYMPIA, HA
OMAHA, NE-IA
ORANGE COUNTY, NY
ORLANDO, FL
OHENSBORO, KY
OXNARD-VENTURA, CA
PANAMA CITY, FL
PARKERBURG-MARIiTTA, HV-OH
PASCASOULA, MS
PAWTUCKET-NOONSOCKET-ATTLEBORO, RI-M
PENSACOLA, FL
PEORIA, IL
PHILADELPHIA, PA-NJ
PHOENIX, AZ
PINE BLUFF, AR
PITTSBURGH, PA
PITTSFIELD, MA
PONCE, PR
PORTLAND, HE
1986
POPULATION
931,000
2,635,000
170,000
144,000
512,000
260,000
1,334,000
8,473,000
1,889,000
217,000
1,309,000
128,000
1,934,000
171,000
133,000
983,000
147,000
614,000
282,000
898,000
88,000
611,000
122,000
156,000
128,000
317,000
337,000
340,000
4,826,000
1,900,000
90,000
2,123,000
81,000
235,000
206,000
PM10
AM
(UGH)
47
ND
ND
ND
58
ND
37
42
39
ND
38
ND
30
ND
22
31
NO
38
ND
ND
ND
35
ND
ND
ND
30
ND
ND
42
ND
ND
45
ND
ND
31
S02
AM
(PPM)
0.012
0,011
ND
0.010
0,015
0,007
0,003
0,020
0.013
0.012
0.007
0.009
0.002
ND
ND
0.005
ND
IN
ND
0.002
0,008
0.001
ND
0,017
0,006
0.012
0.010
0.009
0.015
0,001
ND
0,025
ND
ND
0.012
S02
24-HR
IPPM)
0,043
0,049
ND
0.045
0.068
0.029
0.012
0.076
0.053
0,052
0,027
0,049
0.013
ND
ND
0.012
ND
0.006
ND
0.008
0.033
0.010
ND
0.070
0.012
0.050
0.086
0.062
0.074
0.010
ND
0.155
ND
ND
0.042
CO
8HR
(PPM)
9
10
ND
ND
8
ND
7
20
9
5
9
NO
5
NO
ND
11
ND
8
ND
6
4
5
ND
ND
ND
ND
ND
7
9
13
NO
9
ND
ND
6
N02
AM
(PPM)
ND
0.032
ND
ND
0.028
ND
0.026
0.043
0.042
ND
0.019
ND
0.025
ND
ND
0.019
ND
NO
ND
ND
0.015
O.OZ2
ND
ND
ND
ND
ND
ND
0.043
ND
ND
0.032
ND
ND
ND
OZONE
2ND DMX
(PPM)
0.14
0.17
0.12
ND
0.16
0.16
0.12
0.18
0.18
0.13
0.13
ND
0.15
ND
ND
0.11
ND
0.09
NO
0.11
0.11
0.17
ND
0.15
0.11
ND
0.12
0.12
0.18
0.12
ND
0.19
ND
ND
0.14
PB
QMAX
(UGM)
1.50 (1)
0.07
ND
0.06
0.22
0.06
0.10
0.14
0,58
ND
0.10
0.06
0.33
ND
0.00
0,09
ND
1,20 (2)
1,68 (3)
ND
0.11
0.05
ND
0.08
ND
ND
ND
0.04
1,52 (4)
0.27
ND
0.10
ND
ND
0,06
TSP = HIGHEST
PM10 = HIGHEST
S02 = HIGHEST
HIGHEST
CO = HIGHEST
NQ2 = HIGHEST
03 = HIGHEST
PB = HIGHEST
ND
IN
GEOMETRIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND MAXIMUM 24-HOUR CONCENTRATION
SECOND MAXIMUM NONOVERLAPPING 8-HOUR CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION
(iUARTERLY MAXIMUM CONCENTRATION
= INDICATES DATA NOT AVAILABLE
= INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
UGM = UNITS ARE MICROSRAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
(1) IMPACT FROM PB POINT SOURCE IN HILLIAMSON COUNTY. THE
1987 PB LEVEL AT THE HIGHEST POPULATION ORIENTED SITE
IN NASHVILLE, TN IS 0.1S UG/M5.
tZl IMPACT FROM PB POINT SOURCE IN OMAHA, NE. THE 1987
PB LEVEL AT THE HIGHEST POPULATION ORIENTED SITE
IN OMAHA, NE IS 0.40 UG/M3.
(3) IMPACT FROM PB POINT SOURCE IN ORANGE COUNTY, NY. THE
1987 PB LEVEL AT THE HIGHEST POPULATION ORIENTED SITE
IN NEH YORK, NY IS 0.18 UG/M3.
(4) IMPACT FROM PB BATTERY RECLAMATION PLANT. THE 1987
PB LEVEL AT THE HI6HEST POPULATION ORIENTED SITE
IN PHILADELPHIA, PA IS 0.14 UG/J13.
-------
TABLE 4-5.
1987 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS iY BSA
METROPOLITAN STATISTICAL AREA
PORTLAND, 0R-HA
PORTSMOUTH-DOVER-ROCHESTER, NH-ME
POUGHKEEPSIE, NY
PROVIDENCE, RI
PRQVO-OREM, UT
PUEBLO, CO
RACINE, HI
RALEIGH-DURHAM, NC
RAPID CITY, SO
READING, PA
REDDING, CA
RENO, NV
RICHLAND-KENNEHICK-PASCO, HA
RICHMOND-PETERSBURG, VA
RIVERSIDE-SAN BERNARDINO, CA
ROANOKf, VA
ROCHESTER, MN
ROCHESTER, NY
ROCKFORD, IL
SACRAMENTO, CA
SASINAN-BAY CITY-HIDLAND, HI
ST. CLOUD, MN
ST. JOSEPH, MO
ST. LOUIS, HO-IL
SAL1M, OR
SALEM-GLOUCESTER, MA
SALINAS-SEASIDE-MONTEREY, CA
SALT LAKE CITY-OGDEN, UT
SAN ANBELO, TX
SAN ANTONIO, TX
SAN DIEGO, CA
SAN FRANCISCO, CA
SAN JOSE, CA
SAN JUAN, PR
SANTA BARBARA-SANTA MARIA-LOMPOC, CA
1986
POPULATION
1,153,000
, 215,000
257,000
634,000
£41,000
127,000
172,000
651,000
77,000
321,000
133,000
225,000
150,000
810,000
2,001,000
225,000
98,000
980,000
280 ,000
1,291,000
404,000
175,000
86,000
2,438,000
262,000
259,000
340,000
1,041,000
98,000
1,276,000
2,201,000
1,588,000
1 ,402 ,000
1,541,000
339,000
PM10
AH
I UGM)
48
NO
ND
31
39
ND
29
37
35
ND
32
61
27
31
90
37
28
24
ND
39
42
30
41
70
ND
ND
25
53
ND
35
38
30
44
39
30
S02
AH
(PPN)
0.006
0.005
0.009
0.016
NO
ND
0.005
ND
ND
0.014
ND
NO
ND
0.007
0.003
0.004
0.003
0.013
NO
ND
0.007
IN
NO
0.020
ND
ND
0.001
0.012
ND
0.001
0.005
0.002
ND
IN
0.003
S02
24-HR
(PPM)
0.018
0.025
0.050
0.052
ND
ND
0.021
ND
ND
0.047
ND
ND
ND
0.031
0.008
0.023
0.032
0.052
ND
ND
0.068
0.005
ND
0.092
ND
ND
0.003
0.102
ND
0.005
0.018
0.010
ND
0.029
0.012
CO
8HR
(PPM)
9
ND
ND
8
13
ND
7
10
ND
5
2
9
ND
a
7
2
9
4
8
13
3
7
ND
11
8
ND
2
10
ND
7
8
9
7
5
7
N02
AM
CPPM)
0.019
ND
ND
0.025
0.024
ND
ND
ND
ND
0.025
0.016
IN
ND
0.026
0.047
0.016
NO
ND
ND
0.022
ND
ND
ND
0.029
ND
ND
0.013
0.032
ND
ND
0.032
0.024
0.031
ND
0.025
OZONE
2ND DMX
(PPM)
0.11
0.13
0.10
0.16
0.10
NO
0.18
0.13
ND
0.12
0.13
0.08
ND
0.14
0.27
0.11
ND
0.12
0.09
0.16
ND
ND
ND
0-17
ND
ND
0.09
0.11
ND
0.12
0.18
0.10
0.1S
0.09
0.13
PB
WAX
(UGM)
0.28
0.06
ND
0.14
0.13
0.05
ND
ND
ND
0.43
ND
NO
ND
ND
ND
ND
ND
0.12
0.05
0.09
0.06
ND
ND
3.46
0.08
NO
0.05
0.18
ND
0.15
0.16
0.16
0.26
0.24
0.08
(1)
TSP = HIGHEST GEOMETRIC MEAN CONCENTRATION
PM10 = HIGHEST ARITHMETIC MEAN CONCENTRATION
SO2 = HIGHEST ARITHMETIC MEAN CONCENTRATION
HIGHEST SECOND MAXIMUM 24-HOUR CONCENTRATION
CO = HIGHEST SECOND MAXIMUM NQNOVERLAPPINB 8-HOUR CONCENTRATION
N02 = HIGHEST ARITHMETIC MEAN CONCENTRATION
03 a HIGHEST SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION
PB = HIGHEST QUARTERLY MAXIMUM CONCENTRATION
ND a INDICATES DATA NOT AVAILABLE
IN = INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
(1J IMPACT FROM PB POINT SOURCE IN HERCULANEUM, MO. THE
1987 PB LEVEL AT THE HIGHEST POPULATION ORIENTED SITE
IN ST. LOUIS, MO IS 0.21 UG/M3.
UGM = UNITS ARE MICROGRAMS PER CUBIC METER
PPN = UNITS ARE PARTS PER MILLION
-------
TABLE 4-3.
1987 METROPOLITAN STATISTICAL AREA AIR QUALITY FACTBQQK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
SANTA CRUZ, CA
SANTA FE, NH
SANTA ROSA-PETALUMA, CA
SARASQTA, FL
SAVANNAH, GA
SCRANTON-HILKES-BARRE, PA
SEATTLE, WA
SHARON, PA
SHEBOYGAN, NI
SHERMAN-DENISON, TX
SHREVEPORT, LA
SIOUX CITY, IA-NE
SIOUX FALLS, 3D
SOUTH BENO-MISHAWAKA, IN
SPOKANE, HA
SPRINGFIELD, IL
SPRINGFIELD, MO
SPRINGFIELD, MA
STAMFORD, CT
STATE COLLEGE, PA
STEUBENVILLE-WEIRTON, OH-NV
STOCKTON, CA
SYRACUSE, NY
TACOMA, WA
TALLAHASSEE, FL
TAMPA-ST. PETEHSBURG-CLEARNATER, FL
TERRE HAUTE, IN
TEXARKANA, TX-AR
TOLEDO, OK
TOPEKA, KS
TRENTON, NJ
TUCSON, AZ
TULSA, OK
TUSCALOOSA, AL
TYLER, TX
1986
POPULATION
218,000
106,000
344,000
248,000
240,000
726,000
1,751,000
124,000
103,000
98,000
365,000
116,000
123,000
241,000
357,000
191,000
518,000
Z25,000
195,000
115,000
155,000
433,000
649,000
533,000
218,000
1,914,000
134,000
120,000
611,600
161,000
321,000
602,000
734,000
141,000
152,000
PM10
AM
(UGM)
30
NO
27
NO
38
29
46
m
ND
NO
31
IN
23
32
S9
ND
27
32
ND
ND
69
49
49
48
NO
35
42
NO
30
ND
31
38
33
ND
ND
S02
AM
(PPM)
ND
ND
ND
0.002
0,002
0,011
0,013
0.009
0.004
ND
0.003
ND
ND
0.008
ND
0.008
0.010
0,012
0,011
ND
0,033
0.004
0.005
0.008
ND
0.010
0.010
ND
0.009
ND
O.OOS
0.003
0.010
ND
ND
S02
24-HR
(PPM)
ND
ND
ND
0.008
0.010
0.050
0.034
0.037
0.023
ND
0.010
ND
ND
0.030
ND
0.039
0.131
0.053
0.042
ND
0.157
0.016
0.020
0.035
ND
0.046
0.035
ND
0.044
ND
0.041
0.013
0.085
ND
ND
CO
BHR
(PPM)
ND
4
4
ND
ND
6
10
ND
ND
ND
ND
ND
ND
4
19
5
8
9
6
ND
19
6
10
15
ND
6
NO
ND
5
ND
6
7
7
ND
ND
N02
AM
(PPM)
ND
ND
0.016
ND
NO
o.ozo
IN
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.003
0.022
ND
NO
0.020
0.025
ND
ND
ND
0.024
IN
ND
ND
ND
ND
0.019
0.015
ND
ND
OZONE
2ND DMX
(PPM)
0.09
ND
0.10
0.08
ND
0,12
0.09
0.12
0.20
ND
0.11
ND
ND
0.12
ND
0.10
0.09
0.12
0.17
ND
0.10
0.12
0.11
0.10
0.08
0.16
0.11
ND
0.12
ND
0.16
0.09
0.12
ND
ND
PB
QMAX
(USMJ
ND
ND
O.OS
ND
ND
ND
0.43
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.16
0.10
ND
0.17
0.07
0.07
0.09
ND
ND
ND
ND
0.65
0.05
ND
0.10
0.33
ND
0.05
TSP = HIGHEST
PM10 = HIGHEST
SOZ = HIGHEST
HIGHEST
CO
N02
03
HIGHEST
HIGHEST
HIGHEST
HIGHEST
GEOMETRIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND MAXIMUM 24-HOUR CONCENTRATION
SECOND MAXIMUM NONOVERLAPPING 8-HOUR CONCENTRATION
ARITHMETIC MEAN CONCENTRATION
SECOND DAILY HAXIMUM 1-HOUR CONCENTRATION
QUARTERLY MAXIMUM CONCENTRATION
ND = INDICATES DATA NOT AVAILABLE
IN = INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
USM = UNITS ARE MICROGRAMS PER CUBIC KETER
PPM = UNITS ARE PARTS PER MILLION
-------
TABLE 4-3.
1987 METROPOLITAN STATISTICAL AREA AIR 9UALITY FACTBOOK
PEAK STATISTICS FOR SELECTED POLLUTANTS BY MSA
METROPOLITAN STATISTICAL AREA
UTICA-ROME, NY
VALLEJO-FAIRFIELD-NAPA, CA
VANCOUVER, HA
VICTORIA, TX
VINELAND-MILLVILE-BRIDGETON, NJ
VISALIA-TULARE-PORTERVILLE, CA
HACO, TX
HASHINGTQN, DC-MD-VA
HATERBURY, CT
HATERLOO-CEDAR FALLS, XA
HAUSAU, HI
HEST PALM BEACH-BOCA RATON-DELRAY BE
WHEELING, WV-OH
WICHITA, KS
HICHITA FALLS, TX
HILLIAMSPORT, PA
HILMINGTON, DE-NJ-MD
HILMINGTON, NC
WORCESTER, MA
YAKIMA, HA
YORK, PA
YOUNSSTOHN-HARRiN, OH
YUBA CITY, CA
1986
POPULATION
315,000
392,000
211,000
76,000
135,000
287,000
168,000
3,563,000
212,000
152,000
112,000
756,000
175,000
470,000
127,000
116,000
551,000
114,000
408,000
183,000
398,000
510,000
114,000
PM10
AM
CUGMJ
ND
33
ND
ND
. ND
61
NO
39
33
ND
ND
ND
30
27
ND
ND
34
IN
29
78
28
31
40
S02
AH
(PPM)
NO
0.002
ND
ND
0.007
0.003
NO
0,014
0.012
ND
0.008
0.001
0.021
NO
ND
0,006
0.016
ND
0.009
ND
0,008
0.010
ND
S02
24-HR
(PPM)
ND
0.011
ND
ND
0.038
0.020
ND
0.051
0.059
ND
0.067
0.005
0.082
ND
Nn
0.026
0.052
ND
0,039
ND
0.032
0.043
ND
CO
8HR
(PPM)
ND
6
12
ND
ND
6
ND
11
ND
ND
ND
4
6
9
ND
ND
5
NO
7
11
5
4
ND
NOZ
AM
tPPM)
ND
0.018
ND
ND
ND
0.019
ND
0.031
ND
ND
ND
0.012
0.019
ND
ND
ND
0.032
ND
0.034
ND
0.025
ND
ND
OZONE
2ND DMX
(PPMJ
0.11
0.12
ND
ND
0.14
0.15
ND
0.16
ND
ND
0.09
0.09
0.12
0.10
ND
0.09
0.15
ND
0.11
ND
0.12
0.11
0.11
PB
QMAX
IUSM)
ND
0.13
ND
ND
ND
0.03
0.03
0.10
0.14
ND
ND
ND
0.06
0.04
0.03
ND
0.10
ND
0,06
ND
ND
ND
ND
PM10 = HIGHEST ARITHMETIC MEAN CONCENTRATION
SOZ = HIGHEST ARITHMETIC MiAN CONCENTRATION
HIGHEST SECOND MAXIMUM 24-HOUR CONCENTRATION
CO = HIGHEST SECOND MAXIMUM NONOVERLAPPIN6 6-HOUR CONCENTRATION
N02 = HIGHEST ARITHMETIC MEAN CONCENTRATION
03 = HIGHEST SECOND DAILY MAXIMUM 1-HOUR CONCENTRATION
PB = HIGHEST QUARTERLY MAXIMUM CONCENTRATION
ND - INDICATES DATA NOT AVAILABLE
IN = INDICATES INSUFFICIENT DATA TO CALCULATE SUMMARY STATISTIC
UGM = UNITS ARE MICR06RAMS PER CUBIC METER
PPM = UNITS ARE PARTS PER MILLION
-------
114
-------
5. TRENDS ANALYSES FOR FOURTEEN METROPOLITAN STATISTICAL AREAS
This chapter presents trends and analyses in ambient air
quality for the period 1983 through 1987 in 14 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-CT CMSA contains 12 MSAs which are listed
separately in Section 4. There are 21 metropolitan complexes
designated as CMSAs, 9 of which have been selected for trends
analysis. The areas included in these analyses are Atlanta, GA
MSA; Baltimore, MD MSA; Boston-Lawrence-Salera, MA-NH CMSA; Chicago-
Gary-Lake County, IL-IN-WI CMSA; Denver, CO MSA; 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-CT CMSA,- Philadelphia-Wilmington-Trenton, PA-DE-MD-NJ CMSA;
Phoenix, AZ MSA; Portland-Vancouver, OR-WA CMSA; Seattle-Tacoma,
WA CMSA; and St. Louis, MO-IL MSA. These areas have been selected
because they are among the largest cities in each of the EPA
Regions.
Where sufficient data were available, trends in these areas
are presented for the NAAQS pollutants TSP, S02, CO, NO2, O3, and
Pb. Also, the CMSA/MSA areas are grouped into five broad
geographic areas: East, Midwest, South, Southwest, 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 Aeroraetric Information
Retrieval System (AIRS), with additional limited data taken from
State annual reports. This section employs the same data
completeness and historical continuity criteria as the 5-year
trends analyses in Section 3. That is, only those monitoring sites
meeting the historical continuity criterion of 4 out of 5 years of
"complete" data for the years 1983 through 1987 were selected for
the trends analyses. Each year with data had to satisfy an annual
data completeness criterion, also. 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 had to satisfy the
criterion of at least six samples per quarter in at least 3 of the
115
-------
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.
Because this chapter only includes sites with sufficient data
for trends, it is possible that an area will be violating a NAAQS
but the trend graph will show 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 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 4 out of 5 years) reported data not meeting the NAAQS.
In 1988, IPA proposed that the St. Louis area be designated
nonattainment. It is possible that 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 1983
through 1987, complementing the 5-year national trends analyses in
Chapter 3. The national trends analyses also produce a 10-year
trend (1978 to 1987). However, only the 5-year trend is presented
in this chapter.
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 ofthe United States prepared
by the U. S. Bureau of Census.1 Before this year, sites within the
urbanized areas of the 14 major cities were used to compile the
trends. Since a CMSA/MSA is larger than an urbanized area,
additional monitors from outlying areas are included in the trends
analyses. Because these 'additional monitors are located farther
from the core urbanized area, the overall effect for most cities
is a lowering of the average and the minimum concentrations. In
one case, expanding the area added point source oriented monitoring
sites which increased the average concentration. Accordingly,
comparisons to past reports should be avoided or done with caution
because of these changes in the types and number of sampling sites.
Figure 5-1 shows the plotting convention used in trends
analyses. For 1983 through 1987, 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
concentration (which includes one or more interpolated values)
exceeds the measured maximum value or is less than the measured
116
-------
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 14 cities.
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 taken into consideration.
117
-------
A 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 Ranges Used
In CMSA/MSA Area Trend Analysis.
TABLE 5-1. AIR QUALITY TREND STATISTICS AND THEIR
ASSOCIATED NATIONAL AMBIENT AIR QUALITY STANDARDS (NAAQS)*
PRIMARY NAAQS
POLLUTANT _ TREND STATISTICS _ CONCENTRATION
Total Suspended annual geometric mean 75 n,g/m3
Particulate**
Sulfur Dioxide annual arithmetic mean 0.03 ppm
(80
Carbon Monoxide second highest nonover- 9 ppm
lapping 8-hour average (10
Nitrogen Dioxide annual arithmetic mean 0.053 ppm
(100
Ozone second highest daily 0.12 ppm
maximum 1-hour average (235
Lead maximum quarterly average 1.5
= micrograms per cubic meter
ppm = parts per million
* See Table 2-1 for a more detailed description of NAAQS
** Replaced by PM10 on July 1, 1987 (see Chapter 3.1)
118
-------
5.1 AIR QUALITY TRENDS FOR FIVE GEOGRAPHICAL AREAS
Figures 5-2 through 5-15 show the CMSA/MSA area trends 1983
through 1987 for the six NAAQS pollutants. Table 5-2 presents a
pollutant-specific summary of the overall concentration changes
in each of the 14 areas. These areas are grouped into five
geographic areas: East, Midwest, South, Southwest, and
Northwest.
East - Boston, New York, Baltimore, Philadelphia
Midwest - Chicago, Detroit, St. Louis
South - Atlanta, Houston
Southwest - Denver, Los Angeles, Phoenix
Northwest - Portland, Seattle
Composite geographic area averages of the 5-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.
Table 5.2 Percent Change in iir Quality frend Statistics 1983 Through 1987
National
- 1
Pb SJ2 CO »2
-70 - 9 -16 + 2
East
Midwest
South
Southwest
Northtrest
Beighted
Boston
He» York
Philadelphia
Baltimore
Detroit
Chicago
St. Louis
Atlanta
Houston
Denver
Phoenix
Los Angeles
Portland
Seattle
Averaaed
+ 9
+ 1
- 3
- 6
- 1
- 8
+12
+10
-21
-11
+12
+12
+19
+24
0
-74
-61°
-62"
-81
-73
-70
-33C
-85
-82
-76
-75
-59
-67
-31
-66
+ 0
-10
- 9
-14
-15
-15
-21
-19
-21
-30
-
-26
-
-14
-16
-38
-25
-13
-33
- 6
-37
+ 2
-27
- 5
-21
-13
-17
-24
- 2
-19
+33
- 3
- 3
+13
_
+ 4
- 5
+14
0
- 9
-
- 3
-
—
0
- 8
-15
- 9
-5
- 9
- 8
- 7
- 2
-25
•12
-16
-19
+ 3
+13
-12
"Source oriented sites decreased 4 percent, and traffic oriented sites decreased 81 percent.
"Source oriented site decreased 67 percent, and traffic oriented sites decreased 59 percent.
cSouree oriented sites decreased 31 percent, and traffic oriented sites decreased 44 percent.
''Weighted by number of wnitors in each city for coiparison to national aferage.
119
-------
ANNUAL GEOMETRIC MEAN (/irj/mj)
ANNUAL ,VIAX QUARTERLY MFAN (^.g/
ANNUAL ARITHMETIC AVERAGE
1 UU
80
60
40
20
0
12 SITES
NAAOS
,
(
w— — — <
r~
>— v__j
1983 1984 1985 1986
rx>
o
TSP
. — •<
i
1987
1.5
1.0
0.5
0.0
3 SITES
NAAOS
J— ]
F~
, -
^
£~
1983 1984 1985 1986
YEAR
ANNUAL SECOND DAILY MAX 1 -
0.16
0.12
0.08
0.04
n nn
5 SI
NAAOS_
TFS
-^
H «
J
3- 1
-^
r~
HR
Pb
— *
B=
19B7
YEAR
U,U
ANNUAL SECOND MAXIMUM 8-KR AVG. (ppm)
5 SITES CO
— i—
NAAOS *V -i- T
-
1983 1984 1985 1986 1987
YEAR
1S83 1984 1985 1986 19S7
YEAR
1983 1984 1985 1986 I9£7
YEAR
Figure 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. 1983-1987.
-------
ANNUAL GEOMETRIC MEAN
100
80
60
40
20
ANNUAL MAX QUARTERLY MEAN {ju-g/rn3}
53 SITES
NAAQS
TSP
1983 1984 1985 1986 1987
YEAR
3 SOURCE SITES
17 TRAFFIC SITES
0,5 -
0.0
1983 1984 1985 1986 1987
YEAR
0,04
0,03
0.02
0,01
0.00
ANNUAL ARITHMETIC AVERAGE (ppm)
28 SITES
NAAOS
SO,
1983 1984 1985 1986 1987
YEAR
0.30
0.24 -
0.18 -
0.12
0,06 •
0,00
ANNUAL SECOND DAILY MAX 1 - HR (ppm)
ANNUAL ARITHMETIC AVERAGE (ppm)
1983 1984 1985 1986 1987
YEAR
0.06
0.05
0.04
0.03
0.02
0.01
0.00
10 SITES
NAAOS
NO,
20.
ANNUAL SECOND MAXIMUM 8-HR AVG. (ppm)
1983 1984 1985 1986 1987
YEAR
15.0 •
10.0
1983 1984 1985 1986 198?
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, 1983-1987.
-------
100
ANNUAL GEOMETRIC MEAN
ro
ro
0.25
1983 1984 1985 1986 1987
YEAR
ANNUAL SECOND DAILY MAX 1-HR (ppm)
8 SITES
O
0.20
0.15
0.10
0.05
0.00
1983 1984 1985 1986 1987
YEAR
2-0
1.5
1.0
0.5
O,0
ANNUAL MAX QUARTERLY MEAN
6 SITES
NAAOS
Pb
1983 1984 1985 19S6 1987
YEAR
ANNUAL ARITHMETIC AVERAGE (ppm)
0 06
0.05
0.04
0.03
0.02
0.01
n nn
3 SITES NO 2
.
NAAQS
-
t-f-j. | I
-
,1111
0.04
0.03
0.02
0.01
0.00
ANNUAL ARITHMETIC AVERAGE (ppm)
5 SITES
NAAOS
SO,
1983 1984 1985 1986 1987
YEAR
'ANNUAL SECOND MAXIMUM B-HR AVG. (ppm)
YEAR
1983 1984 1985 1986 1987
YEAR
Figure 5-4. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics
for the Baltimore. MD Metropolitan Statistical Area, 1983-1987.
-------
100
80 •,
60
40 -
20 •
ANNUAL GEOMETRIC MEAN (pg/m3)
ANNUAL MAX QUARTERLY MEAN (ft,q/m3)
ANNUAL ARITHMETIC AVERAGE (ppm)
0.25
0.20 •
0.15 •
0.10
0.05
0.00
35 SITES
NAAOS
j — -(
I — — , _j
i— _1_ —
TSP
1983 1984 1985 1986
YEAR
ANNUAL SECOND DAILY MAX 1-
15 SITES
(
NAAOS
^
^^
^—.
»— i
*
r-
'
• — «
i
4 o
3.0
2.0
1.0
i auurs^t an c.
""d
O
-
NAAQS
-j-
-^ "iT~*~~-ii <
u
i —
19B7 1983 1984 1985 1986
YEAR
HR (ppm) ANNUAL ARITHMETIC AVERAGE
°3
^
I
006
O.OS
0.04
O.O3
0.02
0.01
A AA
7 SITES
.
NAAQS
T T
11 " — ~-~J,
' rr"
•
"
y
I-
1
Pb
~~<
*r
T
0.02
0.01
20 SITES SO o
NAAQS
-
<
\ «
1
•*• rm
h- — «
_ _
— __
' ""
J—
1987 1983 1984 1985 1986 1987
YEAR
(ppm) ANNUAL SECOND MAXIMUM 8-HR AVG. (ppm)
NO2
__— j
•
10.0
a.o
6.0
4.0
7 O
A A
14 SITES CO
-
NAAOS
-
(
_|
^
\
T(
>. — -*
_L _i_
-j-
>-— -^.
i t i i_ i
1983 1984 1985 1986 1987
YEAR
1983 1984 1985 198S 1987
YEAR
1983 1984 1985 1986 198"?
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. 1983-1987.
-------
ANNUAL GEOMETRIC MEAN
ANNUAL MAX QUARTERLY MEAN
ANNUAL ARITHMETIC AVERAGE (ppm)
100
60
60
40
20
0
ro
4*
0.25
0.20
0.15
0,10
0.05
n nn
S SITES TSP
NAAOS
c^^k^-tK^ '
' '""•
1983 1984 1985 1986 19B7
YEAR
ANNUAL SECOND DAILY MAX 1-HR {ppm)
2 SITES OT
'V -r -S
' ^xr -Tf^t
3L 31
NAAQ5
z.u
.5
1.0
0.5
.0
0 06
0.05
0.04
0.03
0.02
0.01
n An
' 1 SITE ' Pb
NAAOS
•
^^^_
19S3 1984 1985 1986 1§87
YEAR
ANNUAL ARITHMETIC AVERAGE (ppm)
2 SITES NO 2
NAAPS
.
.
T T JLJT
T o I-H* f
A- o- _j_ J_
•
U.UT-
,OJ>
0.02
0.01
.00
IZ.u
10.0
8.0
6.0
4.0
2.0
A n
1 SITE SO 2
NAAQS.
ft— — , ^ „, . _ O ^,.
O O • "^^»«n
1983 1984 1985 1986 1987
YEAR
ANNUAL SECOND MAXIMUM 8-HR AVC. (ppm)
1 SITE CO
NAA£?
a%Xsx^
^"X.
^\^^^~~& o
1SS3 1984 1985 1986 1987
YEAR
1983 1984 1985 1986 1987
YEAR
1983 1984 1985 1986 1987
YEAR
Figure 5-6. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics
for the Atlanta. GA Metropolitan Statistical Area, 1983-1987.
-------
120
100
80
60
40
20
ANNUAL GEOMETRIC MEAN (jj.g/m3)
76 SITES
NAAQS
TSP
ro
CD
1983 1984 1985 1986 1987
YEAR
. ANNUAL SECOND DAILY MAX 1-HR (ppm)
0.20 -
0.15 •
0,10 -
0.05 -
0.00
3.5
3.0
2,5
2,0
1.5
1.0
0.5
0.0
ANNUAL MAX QUARTERLY MEAN (fj,q/m*)
35 SITES
Pb
NAAQS
1983 1984 19B5 1986 1987
'TEAR
ANNUAL ARITHMETIC AVERAGE (ppm)
1983 1984 1985 1986 1987
YEAR
0.06
0,05
0.04
0,03
0.02
0,01
0.00
8 SITES
NAAQS
NO,
0.04
0,03
0.02
0.01
0.00
ANNUAL ARITHMETIC AVERAGE (ppm)
22 SITES
NAAOS
SO,
1983 1984 19B5 1986 1987
YEAR
ANNUAL SECOND MAXIMUM 8-HR AVG. (ppm)
1883 1964 1985 ' 1986 1987
YEAR
1983 1984 1985 1986 1987
YEAR
Figure 5-/. Air Quality Trends in the Composite Mean and Rarge of Pollutant-Specific Statistics
for the Chicago - Gary — Lake County, IL —IN-WI Consolidated Metropolitan Statistical Area, 1983-1987.
-------
ANNUAL GEOMETRIC MEAN
125
100
75
50
25
31 SITES
TSP
NAAOS
no
CTi
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
1983 1984 1985 1986 1987
YEAR
ANNUAL SECOND DAILY MAX 1-HR (ppm)
1983 1984 1985 1986 1987
YEAR
2.0
1.5
1.0
0.5
0.0
ANNUAL MAX QUARTERLY MEAN
4 SITES
NAAOS
Pb
1983 1984- 1985 1986 198?
YEAR
NO-
INSUFFICIENT DATA
0.04
0.03
0.02
0.01
0.00
15,0
12,0
9,0
6.0
3.0
0.0
ANNUAL ARITHMETIC AVERAGE (ppm)
9 SITES
NAAOS
SO
1983 1984 1985 1986 1987
YEAR
ANNUAL SECOND MAXIMUM 8-HR AVG. (ppm)
7 SITES
CO
1983 1984 1985 1986 1937
YEAR
Figure 5-8. Air Quality Trends in the Composite Mean and Range of Pollutant—Specific Statistics
for the Detroit - Ann Arbor. Ml Consolidated Metropolitan Statistical Area, 1983-1987,
-------
ANNUM. GEOMETRIC MEAN
ANNUAL MAX QUARTERLY MEAN
ANNUAL ARITHMETIC AVERAGE (ppm)
100
75
50
25
0
32 S
NAAQS
(
TES'
k--.
^-,
1983 1984 1985 1986
0.35
0.30
O.Z5
0.20
0.15
0.10
0.05
n nn
YEAR
ANNUAL SECOND DAILY MAX
9 Sll
c
NAAQS
FES
k
-^
~^^_
H
TSP
)
1987
Z.U
1.5
1.0
0.5
0,0
2 STES
NAAOS
Pb
'-*-~
1983 1984 1985 1986
1987
YEAR
1-
HR
(ppm)
03
*
!
ANNUAL ARITHMETIC AVERAGE
0.06
0.05
0.04
0.03
0.02
0.01
n no
5 SITES
NAAQS
(
( m i
T ~*
i
#— "• '
i —
U.U4
0.03
0.02
0.01
0.00
11 SITES SO 2
NAAQ§
m
1983 1984 1985 1986 1987
YEAR
(ppm)
N02
)
12.0
10.0
8.0
6.0
4.0
2.0
n n
ANNUAL SECOND MAXIMUM B-HR AVG. (pprn)
4 SITES CO
NAAQ$T"
T >»^^
(k\ f^^^"
-
1983 1984 1985 1986 1987
YEAR
1983 1984 19BS 1986
YEAR
1987
1983 1984 1985 1986
YEAR
1987
I
(J
Figure 5-9. Air Quality Trends in the Composite Me,an and Range of Pollutant-Specific Statistics
for the Houston - Galveston - Brozoria, TX Consolidated Metropolitan Statistical Area, 1983-1987.
-------
180
ANNUAL GEOMETRIC MEAN Qug/m3)
26 SITES
150
120
TSP
NA4QS
60
30
C3
0-25
0.20
0.15
0.10,
0.05
1983 1984 1985 1986 1987
YEAR
ANNUAL SECOND DAILY MAX 1-HR (ppm)
is SITES
O
0.00
a.o
5.0
4.0
2.0
0.0
ANNUAL MAX QUARTERLY MEAN
(
-
NAAGS...
ffl-
5 SOURCE SITES
8 TRAFFIC SITES Pb
]
I
(
I
U
r
_ _"3T
-i-
''•( |
1983 1984 1985 1986 1987
YEAR
ANNUAL ARITHMETIC AVERAGE (ppm)
1983 1984 1985 1986 1987
YEAR
0 06
0.05
0.04
0.03
0.02
0.01
n nn
8 SI
.
NAAQS
-
-
(
.
FES
)• . _ — ,
i j
i 1
N02
( U
19B3 1984 1985 1986 198?
YEAR
0.04
0.03
0.02
0.01
0.00
12.0
10,0
8.0
6.0
4.0
2.0
O.C
ANNUAL ARITHMETIC AVERAGE (pprn)
11 SITES
NAAOS
SO,
1983 1984 1985 19B6 1987 .
YEAR
ANNUAL SECOND MAXIMUM 8-HR AVG. (ppm)
6 SITES
NAAQS
CO
1983 1984 1985 1986 1967
YEAR
Figure 5—10. Air Quality Trends in the Composite Mean and Range of Pollutant—Specific Statistics
for the St. Louis, MO-JL Metropolitan Statistical Area, 1933-1987.
-------
ANNUAL GEOMETRIC MEAN (jig/mj)
ANNUAL MAX QUARTERLY MEAN
ANNUAL ARITHMETIC AVERAGE (ppm)
nou
150
120
90
60
30
0
~4
11 S
NAAOS*
TES
r--'
^-1
k^'«
••••^^
h—
~4_
1983 1984 1985 1986
TSP
— H
1
1987
B YEAR
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
ft Oft
ANNUAL SECOND DAILY MAX 1-
7 SI"
1
NAAQS
res
\ 1
\
-
^ ~
"1
L J
•
•
.
•
S
-/
^-U
L
HR
z.u
1,5
1.0
0,5
0.0
4 SITES
Pb
^S,
^
1983 1984 1985 1986
1987
YEAR
(ppm)
°3
__
iq
j
i
ANNUAL ARITHMETIC AVERAGE
0.06
0.05
0.04
0.03
0.02
0.01
ft on
3 SITES
NAAftS.
-p
JL _L
, 1
*>
i-~
U.U*
0.03
0.02
0.01
0.00
2 SITES SO 9
NAAQS
1^ T
X^^i^^r x -5"
_i_ i A
1983 1984 1985 1986 1987
YEAR
(ppm)
NO2
1
^ ^1
^N 1 j r—-"-"~' ^~««%^
NAAOS
-J-
YEAR
1983 1984 1985 19B6 1987
YEAR
1983 1984 1985 1986 1987
YEAR
Figure 5-11. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics
for the Denver - Boulder, CO Consolidated Metropolitan Statistical Area, 1983-1987.
-------
150
ANNUAL GEOMETRIC MEAN
ANNUAL MAX QUARTERLY MEAN
28 SITES
120
90
NAAOS
50
30
TSP
CO
o
0,50
1983 1984 1985 1986 1987
YEAR
ANNUAL SECOND DAILY MAX 1-HR (ppm)
35 SITES
O
0.40
0.30
0.20
0.10
0.00
1983 1984 1985 1986 1987
YEAR
O.5 •
0.0
1983 1984 1S85 1986 1987
YEAR
ANNUAL ARITHMETIC AVERAGE (ppm)
0.06
0.05
0.04
0.03
0.02
0.01
0.00
24 SITES
NAAOS
NO,
1983 1984 1985 19B6 1987
YEAR
0.04
0.03
0,02
0.01
0.00
30.0
25,0
20,0
15,0
10.0
5.0
0.0
ANNUAL ARITHMETIC AVERAGE (pprn)
18 SITES
NAAOS
SO,
1983 1984 1985 1986 1987
YEAR
ANNUAL SECOND MAXIMUM S-HR AVG. (pprn)
23 SITES
NAAOS
CO
1983 1984 1985 1986 198?
YEAR
Figure 5-12, Air Quality Trends In the Composite Mean and Range of Pollutant-Specific Statistics
for the Los Angeles - Anaheim - Riverside, CA Consolidated Metropolitan Statistical Area, 1983-1987.
-------
250
200 •
150 -
ANNUAL GEOMETRIC MEAN
100
1983 1984 1985 1986 1987
YEAR
2,0
1.5
1.0
0.5
0.0
ANNUAL MAX QUARTERLY MEAN
1 SITE
Pb
19B3 1984 1985 1986 19B7
YEAR
SO
INSUFFICIENT DATA
ANNUAL SECOND DAILY MAX 1-HR (ppm)
6 SITES
0.1S
0.12
NAAQS,
0.08
0,04
0,00
o
1983 1984 1985 19B6 1987
YEAR
INSUFFICIENT DATA
NO,
25.0
20.0
15.0
10.0
5.0
0.0
ANNUAL SECOND MAXIMUM 8-HR AVG. (ppm)
9 SITES
CO
NAAQS (
1983 1984 1985 1986 1987
YEAR
Figure 5-13. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics
for the Phoenix, AZ Metropolitan Statistical Area, 1983-1987.
-------
150
120
90
ANNUAL GEOMETRIC MEAN
16 SITES
TSP
to
1983 1984 1985 1986 1987
YEAR
2.0
1.5
1.0
0.5
0.0
ANNUAL MAX QUARTERLY MEAN
1 SITE
Pb
NAAQS..
1983 19S4 1985 1986 1987
YEAR
SO,
INSUFFICIENT DATA
0.1
0.15
0.12
0.09 •
0.06
0.03
0,00
ANNUAL SECOND DAILY MAX 1-HR (ppm)
ANNUAL SECOND MAXIMUM 8-HR AVG. (ppm)
INSUFFICIENT DATA
NO,
1983 1984 1985 1986 1987
YEAR
1983 1984 1985 1986 1987
YEAR
Figure 5-14. Air Quality Trends in the Composite Mean and Range of Pollutant—Specific Statistics
for the Portland - Vancouver. OR-WA Consolidated Metropolitan Statistical Area, 1983- 1987.
-------
100
80
60
40
20
ANNUAL GEOMETRIC MEAN
25 SITES
NAAOS
TSP
CO
CO
0.15
0.12
o.os
0,04
0.00
1983 1984 1985 1986 1987
YEAR
ANNUAL SECOND DAILY MAX 1-HR (ppm)
5 SITES
NAAOS
1983 1984 1985 1986 198?
YEAR
2,0
1.5
1.0
0.5
0.0
ANNUAL MAX QUARTERLY MEAN
3 SITES
NAAGS.
Pb
1983 1984 1985 1986 1987
YEAR
NO,
INSUFFICIENT DATA
0.04
0.03
0.02
0,01
0.00
ANNUAL ARITHMETIC AVERAGE (ppm)
4 SITES
SO.
1983 1984 1985 1988 1987
YEAR
ANNUAL SECOND MAXIMUM 8-HR AVG. (ppm)
6.0
3.0 -
0.0
1983 1984 1985 1986 1987
YEAR
Figure 5-15. Air Quality Trends in the Composite Mean and Range of Pollutant-Specific Statistics
for the Seattle - Tccoma. WA Metropolitan Statisticci Area, 1983-195".
-------
5.1.1 ISP Trends
The 14-city weighted average shows no change over the 5-year
period. Similarly, the national 5-year trend shows a slight
decrease of 1 percent in average concentrations. Among specific
geographic areas, the South exhibited the greatest decrease, 6
percent, and the East had no change. Reversing the national trend,
the Midwest had a 1 percent increase, the Southwest had a 4 percent
increase, and the Northwest showed a sizeable increase, 21 percent,
over the last 5 years. The Northwest, showed increases in 3 of the
last 5 years and are in the midst of a drier than normal period.
Although the 14 city weighted average was within 1 percent of the
national trend, the individual cities ranged from a 21 percent
decrease in Houston to a 24 percent increase in Seattle. The
decrease in Houston is attributed to their converting most
industrial boilers from oil to gas in the early 1980s and to the
shutdown of a major TSP source. Also, the economic slowdown has
resulted in a decrease in construction projects. In the Northwest,
particularly in Seattle, the years 1985 and 1987 were drier than
normal and seem to be the prime contributor to the increasing
trend. Also, there has been an increase in forest fires over the
past few years, especially in the West, which has contributed to
increased particulate concentrations.
5.1.2 Pb Trends
The national trend for lead shows a 70 percent decrease, while
the 14-city weighted average shows a 66 percent improvement. The
South has the largest decrease, an average of 83 percent, followed
by the East and Southwest with 70 percent each, the Midwest with
59 percent and the Northwest with a 49 percent decrease.
Individual cities with improvements substantially less than the
national average are St. Louis, with a 33 percent decrease and
Seattle with a 31 percent decrease. In St. Louis the lower drop
is attributed to the relatively high point source-oriented lead
sites which showed a smaller decrease than the automobile oriented
sites. When the trend was restricted to roadway oriented sites,
the decrease was 44 percent. In Seattle, only three sites met the
trends selection criteria, and one of them was source-oriented and
located near a toxic waste site which emitted lead.
The trend graphs for New York show that the lead standard was
exceeded for a source oriented site. The site is in Orange County,
New York which is outside of the New York MSA, but was included in
the New York CMSA. Because of less stringent criteria for the
trends graphs than for the Section 4 MSA air quality levels, which
are based on the AIRS data completeness criteria of 12 observations
per quarter, the maximum quarterly average plotted for 1987 in
Figure 5-3 is from a different quarter than that shown in Section
4.0.
134
-------
5.1.3 SO2 Trends
The weighted average of the 12 cities with data yielded a 16
percent reduction in SOZ levels compared to the 9 percent national
average improvement. The cities displayed air quality results
ranging from 30 percent improvement in Denver to no change in
Boston. The average concentrations for Boston correlate very
closely with the emission trends for the area. The last had the
smallest decrease, 8 percent, and the Northwest, Midwest and South
had respective decreases of 14, 17, and 20 percent. The Southwest
had the largest decrease of all, at 28 percent.
In general, the areas which show a greater decrease than the
national average are in the Sun Belt and energy producing areas of
the country rather than in the industrialized northeastern portion
of the country. The recent downturn in the oil producing/refining
industry and the reduction in the primary and secondary metal
smelting processes could account for these areas all having a
greater than the national average decrease for SO2 levels.
5.1.4 CO Trends
The national downward CO trend of 16 percent was closely
reflected by the 14-city weighted average downward trend of 19
percent. Almost all of the 14 cities had a decreasing trend with
St. Louis as the lone exception, showing an increase of 2 percent.
The slight increase in St. Louis is a result of two sites which
showed an increase in the 1983 through 1987 period which
overshadowed the decrease over the 1983 through 1987 time period
of the other 4 sites used in the trend analysis. The bulk of the
change came from a rural site located next to the parking area for
a community college. The CO levels recorded -at this site are all
well below the standard and the 1986 through 1987 increase is
probably attributable to a change in parking patterns at the
community college. It should be noted that none of these St. Louis
trend sites exceeded the CO standard, although a new site did
exceed the NAAQS. The improvement in the CO air quality ranged
from 2 percent for Seattle to 38 percent for Boston. Regionally,
the last exhibited the greatest downward trend of 27 percent, while
the rest of the geographical regions all had trends similar to the
national average.
5.1.5 M0a
The national trend for NO2 was a 2 percent air quality
degradation over the last 5 years. The 14-cities weighted average
showed no change over the last 5 years. The individual cities were
mixed with four showing an increasing trend, five showing a
decreasing trend, one showing no change and four cities failed to
have an NO2 monitor meet the selection criteria for the calculation
of a 5-year trend. On a regional basis, the East had the greatest
deterioration of NOS levels, with a 10 percent increase, followed
135
-------
by the South, with a 7 percent increase. The Midwest had a less
than 1 percent improvement, and the Southwest showed the greatest
improvement, with a 6 percent decrease in NO2 concentrations. The
Northwest was not included in the trend analysis because none of
the NOZ monitors met the selection criteria,
The degradation in the East is primarily driven by a 33
percent increase in Boston and, to a lesser extent, by a 13 percent
increase in Baltimore. Both these trends are primarily caused by
one site in each city in 1983 which records a lower than typical
value. The increase in the trend at that particular site in Boston
is by itself, 46 percent. If 1984 is used as the base year and the
most recent 4 year trend is calculated, the trend in Boston changes
from +33 percent to -3 percent. Similarly, the Baltimore trend
changes from +13 percent to +4 percent. The only other city with
a large increase is Atlanta, which appears to be a steady
incremental increase over the last 5 years. The trend is based
upon only two monitors, each one well below the standard and among
the lowest in the 14-city trend section.
5.1.6 03
The national trend for 1983 through 1987 showed an improvement
of B percent, while the 14-city weighted average showed an
improvement of 12 percent from 1983 through 1987. This compares
with a 7 percent improvement reported in last year's trends report,2
based on the 1982 through 1986 period. This apparent improvement
in the consecutive 5-year trends is explained by the fact that the
base year of the most recent trend, 1983, was by far the worst year
for ozone levels during the trend periods. Based upon preliminary
1988 ozone data, a 5-year comparison between 1984 and 1988 could
show a reversal in some areas. For the 1983-87 period, the
Southwest region had a 16 percent improvement in ozone levels, the
South improved 14 percent, the East 9 percent, and the Midwest 8
percent. The Northwest region was the only area in which 1983 (the
base year for the 5-year trend) was not the highest year. In
fact, the West in 1983 had lower concentrations than in 1982.
Consequently, the Northwest showed an 8 percent increasing trend
over the past 5 years.
136
-------
5.2 REFERENCES
1. Statistical Abstract of the United States. 108th Edition, U.
S. Bureau of the Census, Washington, DC, December 1987.
2. National &ir__Quality and Emissions Trends Report, 1986,, EPA-
450/4-88-001, U.S. Environmental Protection Agency, Research
Triangle Park, NC 27711, February 1988.
87011
137
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
FPA dBO/4-aQ-nOl
2.
3, RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
S. REPORT DATE
National Air Quality and Emissions Trends
Report, 1987
6. PERFORMING ORGANIZATION CODE
7. AUTHORISI T< curra]lf j. paoro/ f. pitz-siions, H. Frank
W. Freas, W. F. Hunt, Jr., S. Kiibrough, S. Sleva,
H. Berg. E. Hanks. D. Lutz. G. Hanire, S G. Porosz
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Bnvironiental Protection Agency
Office of Air and ladiation
Office of Air Quality Planning and Standards
Hesearch Triangle Park, HC 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
1 5. 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 1978 through 1987 for total suspended particulate, sulfur
dioxide, carbon monoxide, nitrogen dioxide, ozone and lead. Air
pollution trends were also examined for the 5-year period (1983-
87). 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 (NAME) 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 1987.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b. IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution Trends Air Pollition
liission Trends
Carbon Monoxide
nitrogen Dioxide
Ozone
Sulfur Dioxide
Metropolitan
Statistical Area (HSA)
Air Quality Standards
National Air Monitoring
Stations (HAMS)
total Suspended Participates
1B DISTRIBUTION. STATEMENT
19. SECURITY CLASS (ThisReportj
21. NO. OF PAGES
Release Unlimited
"JO. SECURITY CLASS (This page?
22, PRICE
EPA Fotm 222C-1 'Re-. 4-77)
PfcEV'OUS EC I T 10?,- '£ C£5O UETE
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