TECHNICAL SUPPORT DOCUMENT FOR AGENCY POLICY
CONCERNING DESIGNATION OF ATTAINMENT,
UNCLASSIFIABLE, AND NONATTAINMENT AREAS
FOR OZONE
U.S. Environmental Protection Agency
Office of Air, Noise and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
January 1979
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TABLE OF CONTENTS
1.0 Introduction 1
2.0 Present designations result in comprehensive
coverage of known volatile organic compound
estimates . 6
3.0 EPA's ozone designations do not prejudice
New Jersey or the Northern states. 15
3.1 New source review requirements in areas
which are presently designated
unclassif iable. 15
3.2 Implementation of emission control
programs in unclassif iable areas. 16
3.3 Monitoring in unclassified areas which may
have a high potential for violating the
Ozone NAAQS.- 17
3.4 Procedures to ensure equity in estimated
control requirements. 18
4.0 Interpretation of the air quality standards for
ozone and attendant uncertainties in the
monitoring area. " 20
4.1 Monitoring requirements. 20
4.1.1 The NAAQS consists of exposure
level and exposure time. 20
4.1.2 Aircraft data cited by the
State of New Jersey. 21
4.2 Geographic area represented by a detected
violation of the NAAQS. . 24
5.0 Chemical and meteorological considerations in
the formation and transport of ozone and its
precursors 26
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5.1 Chemistry of ozone formation and
transport. 26
5.1.1 Chemical stability of ozone. 26
5.1.2 Chemical stability of ozone
precursors. 30
5.2 Meteorology of ozone episodes. 32
6.0 Additional comments submitted by New Jersey.— 36
References
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1.0 INTRODUCTION
On March 3, 1978, the Administrator of the Environmental Protection
Agency (EPA) promulgated air quality designations for all areas of the country
specifying whether the National Ambient Air Quality Standards (NAAQS) required
to have been attained under the 1970 Clean Air Act have been, in fact, at-
tained. The Administrator's designations were required by the 1977 Amendments
to the Clean Air Act, Pub. L. No. 95-95, 91 Stat. 685 (August 7, 1977). Under
Section 107(d) (l)-(2) of the Amendments, each State was required to assess
the air quality within its borders and submit a list to the EPA identifying
those areas in the State which attained the National Ambient Air Quality
Standards, those which had not and those areas which could not be classified.
The Administrator was to review the State's designations and promulgate his
own list with any modifications he deemed necessary. On March 3, 1978, the
Administrator promulgated the designations. 43 Fed. Reg. 8962.
Even though the designations were immediately effective, the EPA solicited
public comments on the designations. On September 11, 12, and October 5, 1978,
the Agency published responses to many of the comments received; in many cases
designations were changed. See 43 Fed. Reg. 40412, 43 Fed. Reg. 40502, and 43
Fed. Reg. 45993. The State of New Jersey submitted comments challenging the
Agency's policy for designating areas as attainment, nonattainment, or un-
classifiable for the ozone standard. This technical support document responds
to each of the technical comments submitted by New Jersey and supports the
Agency's March 3, 1978 policy for ozone designations.
In the March 3, 1978 promulgation, the Administrator determined that, in
the absence of ambient data to the contrary, all urban areas of the country
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(with a population greater than 200,000) and all rural counties with air
quality readings higher than the ozone pollution standard, must be designated
nonattainment areas. The Administrator also determined that without actual
air quality measurements taken from ground level monitors, the available
information is not sufficient to require a nonattainment designation in rural
areas in the Eastern portion of the country and that such areas may be designated
as "unclassifiable" under Section 107(d) (1) (D).
In guidance to the States, the Assistant Administrator for Air, Noise and
Radiation stated that there is scientific evidence that, for many of the areas
in the Eastern portion of the country without ozone monitoring data, ozone
pollution is probably greater than allowed by the national standard. See
40 C.F.R. 50. The Assistant Administrator, therefore, encouraged the Eastern
States to list those areas as nonattainment areas for ozone pollution even
though there is no actual monitoring data showing nonattainment. The State of
New Jersey followed the EPA suggestion and the entire State was designated as
nonattainment for ozone pollution. See 43 Fed. Reg. 9015. In contrast, many
other States did not follow the EPA's suggestion and designated areas in their
States without ozone monitoring data as unclassifiable. Since the Agency
determined that, without actual monitoring data, it is impossible to determine •
for certain that a rural area is nonattainment, the Agency approved the unclassi-
fiable designations. .
12
In comments submitted on the March 3, 1978 promulgation, ' the State of
New Jersey contends that the EPA's suggestion to the States to designate rural
areas without monitoring data as nonattainment should have been a requirement
and that there is sufficient information to find that in all areas east of the
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ississippi River ozone pollution is greater than the national standard allows.
ew Jersey, therefore, argues that all areas in the Eastern half of the country
ust be designated nonattainment under .Section 107(d} (1} (E) of the Act. As
et forth in detail in the section below, the Agency has determined that the
.cientific information relied upon by New Jersey is not definitive enough to
•equire that all areas in the Eastern portion of the country must be designated
lonattainment. Moreover, the Agency's implementation of the nonattainment and
irevention of significant deterioration (PSD) provisions of the 1977 Amendments
should insure that the national standard for ozone pollution is attained and
maintained.
In summary, New Jersey's position is rejected as both unnecessary and
jnsupportable for the following reasons. First, chemical stability of ozone
and its precursors does not allow significant concentrations of ozone to be
transported 1000 miles as suggested by New Jersey. Ambient concentration of
ozone can not persist more than approximately 36 hours unless fresh precursor
emissions occur. Thus, under meteorological conditions prevailing on days
with high ozone, this limits significant transport to less than 300-500 miles.
Since 91 percent of the major stationary sources within 500 miles of Trenton,
New Jersey that cause ozone pollution are situated in areas designated non-
attainment, the designation of additional areas in the Eastern portion of the
country would have little effect on New Jersey's ozone problem. The areas
that affect the State are, for the most part, already designated nonattainment.
Assuming that longer range transport were significant, approximately 79 percent
of major stationary sources within the Eastern U.S. are located in nonattainment
areas. Moreover, the data relied upon by New Jersey, specifically aircraft
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flight data, to argue that all areas in the Eastern portion of the country are
nonattainment does not establish New Jersey's position. There is simply too
poor of a correlation between the aircraft measurements and corresponding
ground level measurements to use aircraft data as a proxy for ground level
moni tors.
Second, New Jersey is not prejudiced by the EPA's decision to approve
State designations of rural areas without ozone monitoring data as unclassi-
fiable. The Administrator's basic guidance to the States on the criteria the
EPA will apply in determining if nonattainment SIP revisions are approvable
states that, in setting emission reduction levels for sources in nonattainment
areas, the States can assume that the air coming across the State borders
meets the standards. Therefore, a State is required to regulate sources in
the State only to the extent that these sources contribute to pollution. In
other words, a downwind State does not have to overregulate to compensate for
pollution caused by sources in the upwind State. See 43 Fed. Reg. 21673,
21674. It is also not possible for a new source to locate in an unclassifi-
able area and avoid the Act's requirements for nonattainment areas if air
quality in that area is actually nonattainment. The PSD regulations specify
that before a source may receive a permit to construct, the Agency can require
ambient air monitoring for up to one year in the unclassified areas in which
the proposed facility is to be constructed. If the monitoring shows that
ozone levels are above the standards, the area will then be redesignated as a
nonattainment area under Section 107(d), (5)_ and the new source would have to
comply with the Act's requirements for new sources in nonattainment areas.
See 40 C.F.R. 52.21, 43 Fed. Reg. 26403, 26410. In short, the EPA's ozone
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nonattainment designations do not harm existing sources in New Jersey by
requiring that New Jersey overregulate as New Jersey alleges, nor prejudice
New Jersey by permitting the location of new sources in unclassifiable areas.
Finally, the Agency is taking action to determine if the rural areas
designated unclassifiable are actually attainment or nonattainment. The
Assistant Administrator has directed the EPA's Regional Offices to review the
areas designated unclassifiable and determine where there is a high probability
that the ozone standard may be violated. The States may then be required
either to conduct monitoring in the areas or require "reasonably available
control technology" (RACT) on existing sources in the areas. The Agency is
also conducting scientific studies to identify more accurately the area repre-
sented by ozone monitor readings. At present, it is scientifically unclear
just how large a geographic area a monitor reading represents. Until the EPA
studies are completed, it is the EPA policy that ozone monitors will determine
air quality for the entire county where they are located.
Accordingly, the EPA has determined that New Jersey has not submitted
information which requires a change in the EPA designation policy in ozone and
previous designations are affirmed.
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2.0 PRESENT DESIGNATIONS RESULT IN.COMPREHENSIVE COVERAGE OF KNOWN
VOLATILE ORGANIC COMPOUND ESTIMATES
As is explained in Section 5.0. below, ozone pollution is controlled by
reducing emissions of volatile organic compounds (VOC) from stationary sources
and motor vehicle emissions. Evidence compiled from the U.S. EPA's National
Emission Data System (NEDS) establishes that there is only a small fraction of
volatile organic compound (VOC) emissions within 500 miles or more of Trenton
that are not situated in areas designated nonattainment. The small percentage
of VOC emissions within 500 miles of Trenton and located in unclassifiable
areas are unlikely to significantly contribute to New Jersey's ozone problem.
Table 1 sets forth the fraction of total volatile organic emissions
within designated nonattainment areas in each State in the continental
United States and within each EPA Region. The table reflects attainment/non-
attainment designations as of August 1978 and emission data from the EPA's
National Emission Data System (NEDS) as of June 1978. If States in EPA
Regions I-V [i.e., see Table 1)_ are loosely interpreted as the "Eastern part
of the Country," it can be seen that 71 percent of the organic emissions in
the Eastern part of the United States are within designated nonattainment
areas. This inventory includes an aggregate of stationary and motor vehicle
emissions. Since mobile source emissions constitute a significant fraction of
"nonpoint source" emissions and are subject to controls regardless of an
area's attainment status, it is most pertinent to evaluate the fraction of
stationary point source emissions included within designated nonattainment
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TABLE 1. Volatile Organic Compounds (VOC) Emissions in Counties
Designated Honattainment for Ozone: By EPA Region and State
EPA Region/State
Connecticut
Maine
Massachusetts
New Hampshire
Rhode Island
Region II
New Jersey
New York
Region III
VOC Emissions
Unclassified
Counties (TPY)
13,726
9,251
4,475
Delaware
District of Columbia
Maryland
Pennsylvania
Virginia 407,289
West Virginia 169,343
668,915
27,738
64,545
Region rv
Alabama
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
Region V
Illinois
Indiana
Michigan
Minnesota
Ohio
Wisconsin
.Region VI
Arkansas
Louisiana
New Mexico
Oklahoma
Texas
Region VII
Iowa
Kansas
Missouri
Nebraska
Region VIII
Colorado
Montana
North Dakota
South Dakota
Utah
Wyoming
Region IX
Arizona
California
Nevada
Idaho
Oregon
Washington
Regions I-V Totals
National Totals:
2,935,727
346,152
382,858
375,122
297,755
302,411
681,273
282,080
268,076
1,414,799
225,034
460,047
108,859
231,130
106,346
283,383
X, 885,666
217,348
273,898
122,958
273,917
997,545
977,255
305,401
232,721
282,779
156,354
458,089
79,938
109,796
66,849
88,499
41,570
71,437
256,269
82,781
148,364
25,124
563,739
168,276
141,205
254,258
5,033,167
9,174,185
VOC Emissions
Nonattaining Counties
(TPY)
1,393,895
309,563
137,537
682,275
102,120
112,630
2,591,904
985,131
1,606,773
2,045,785
64,052
79,090
467,305
1,228,220
207,118
1,651,580
182,047
558,171
189,699
220,336
72,132
99,215
329,980
4,873,430
1,205,346
318,160
1,219,350
337,748
1,370,662
453,278
2,425,818
38,952
584,172
33,253
168,903
1,600,538
690,081 .
95,153
193,811
337,250
63,867
324,683
212,852
17,827
6,229
87,775
2,659,926
168,902
2,444,671
46,353
370,271
189,919
180,352
12,556,594
19,027.373
% VOC Emissions
in Nonattaining
Counties
11
100
94
100
96
100
100
100
100
75_
70
100
88
100
34
0
3_6_
34
59
34
43
0
10
9
55
Zi
84
41
92
59
93
62
56_
15
68
21
38
62
li
24
45
54
29
li
73
14
9
0
68
0
21
67
94
65
4_0
0
57
41
71
67
Source: National Emissions Data System (NEDS)- June, 1978
7
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In the NEDS data base, a point source is a stationary source which emits
100 tons per year (TRY) or more of any pollutant. For example, if a source
emitted 1 TRY of organics and 100 TRY of sulfur dioxide, it would be classi-
fied as a "point source of organic emissions." Therefore, the term "point
sources" includes a number of stationary sources emitting less than 100 TRY of
organic emissions. Table 2 depicts point source emissions included within
areas designated nonattainment and unclassified for each State and EPA Region.
Seventy-nine (79) percent of the point source emissions of organic compounds
in the Eastern United States are situated in areas designated nonattainment.
Figure 1 shows that, nationwide, nearly all counties either already have been
designated nonattainment or are not believed to have significant VOC emissions.*
Most relevant to New Jersey's concerns is the fraction of point source
emissions within about 36 hours travel time of New Jersey under meteorological
conditions conducive to high ozone concentrations. As discussed in Section 5.0
below, a parcel of air is not likely to travel more than about 300-500 miles
in a 36 hour period under such atmospheric conditions. Table 3 categorizes
VOC point source emissions within 300-500 miles of Trenton, New Jersey ac-
cording to whether or not the emissions occur within a designated nonattain-
ment area. According to the NEDS inventory, over 95 percent of the point
source emissions in the United States within 300 miles of Trenton (Table 3)
are within areas designated nonattainment. Within 500 miles, greater than
* Since Figure 1 was prepared, the State of Virginia reclassified a number
of counties from "nonattainment" to "unclassifiable." While Figure 1 has
not been modified, the information in Tables 1-4 has been adjusted to
consider the reclassifications.
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TABLE 2. Volatile Organic Compounds (VOC) Point Source Emissions in Counties
Designated Honattainment for Ozone: By EPA Region and State
VOC Point Source VOC Point Source
Emissions Emissions
Total Nonattaining Counties
EPA Region/State
Region I
Connecticut
Maine
Massachusetts
New Hampshire
Rhode Island
Vermont
Region II
New Jersey
New York
Region III
Delaware
District of Columbia
Maryland
Pennsylvania
Virginia
West Virginia
Region IV
Alabama
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
Region V
Illinois
Indiana
Michigan"
Minnesota
Ohio
Wisconsin
Region VI
Arkansas
Louisiana
New Mexico
Oklahoma
Texas
Region -VII
Iowa
Kansas
Missouri
Nebraska
Region -vnr
Colorado
Montana
North Dakota
South Dakota
Utah
Wyoming
Region IX
Arizona
California
Nevada
Region X
Idaho
Oregon
Washington
Heoions I— V Totals
National Totals;
(TPY»
195,394
15,944
49,339
84,177
23,813
17,136
4,985
401,704
275,334
126,370
391,528
13,987
775
131,591
103,505
130,849
10,820
550,878
43,186
28,363
7,451
201,741
37,792
80,989
38,760
112,596
1,108,649
235,009
154,046
220,141
118,608
184,638
196,207
1,878,826
14,070
467,012
40,022
73,075
1,284,647
358,471
62,316
143,585
107,851
44,719
65,576
12,503
18,769
1,984
5,741
8,505
19,074
322,002
11,431
305,371
5,200
76,762
5,241
28,688
42,833
2,643,153
5,349,790
Source: National Emissions Data System
(TPY)
193,081
15,944
47,761
84,177
23,078
17,136
4,985
401,704
275,334
. 126,370
278,985
13,279
775
130,863
103,506
30,919
0
245,041
37,816
15,274
806
94,964
0
5,292
16,955
73,934
966,736
228,790
64,523
215,910
88,110
179,394
190,009
1,286,340
1,643
386,958
246
10,619
886,874
156,603
1,523
96,710
43,877
14,493
22,443
5,631
8,864
343
0
7,605
0
300,315
7,060
289,380
3,875
32,205
0
18 , 015
14,190
2,085.547
3,883,453
(NEDS) - June, 197
% Point Source
Emissions in
Nonattaining
Counties
21
100
97
100
97
100
100
100
100
100
71
95
100
99
100
24
0
44
88
54
11
47
0
7
44
66
21
97
42
98
74
97
97
68
12
83
1
15
69
2
67
41
32
li
45
47
17
0
39
0
11
62
95
75-
11
0
63
33
79
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LEGEND:
HENonattainment or VOC point source emission less than 100 TRY
FIGURE 1. Nonattainment Counties or Counties With VOC Point Source Emissions Less Than 100 TRY
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TABLE 3. Volatile Organic Compounds (VOC) Point Source Emissions Within
Specified Distances of Trenton, New Jersey*
Distance
Emissions in
Nonattainment Counties
Emissions in Attainment
or Unclassified Counties
TOTAL
<_ 300 mi.
880,330
38,972
Within EPA
<_ 400 ml. ^500 ml. Regions I-V
1,045,939 1,210,709 2,085,547
68,662
124,719 562,606
919,302 1,114,601 1,335,428 2,648,153
% VOC Point Source
Emissions Not Within
Designated Nonattainment Areas 4.2
6.2
9.3
21
* Source: NEDS Data Base, June 1978
11
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90 percent of the United States' point source emissions are situated in areas
designated nonattainment (See Figure 2).
New Jersey has questioned the completeness of the data base within the
EPA's NEDS emission data system and therefore implies that the information
presented in Tables 1-3 is misleading. Although States are required to
provide the appropriate information to keep NEDS complete and current, it is
likely that there are omissions in the data base. However such omissions, as
there are, are likely to occur for both designated and unclassified areas and
the percentage values of Tables 1-3 are reasonably accurate. This assumption
is supported by using population data as a surrogate for emissions data. As
Table 4 establishes, 75 percent of the population of EPA Regions I-V live in
areas designated nonattainment. This percentage closely approximates the
corresponding percentages of 71 percent and 79 percent for total and point
source emissions presented in Tables 1 and 2, respectively.
12
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300 mile radius
^
400 mile radius
FIGURE 2. Counties within a specified radius of Trenton, N.J.
13
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TABLE 4. Fraction of Population Within Counties Designated
as Honattainment for the Ozone HAAQS
EPA Region/State
Region I
Connecticut
Maine
Massachusetts
New Hampshire
Rhode Island
Vermont
New Jersey
New York
Region III
Delaware
District of Columbia
Maryland
Pennsylvania
Virginia
West Virginia
Alabama
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
Illinois
Indiana
Michigan
Minnesota
Ohio
Wisconsin
Arkansas
Louisiana
New Mexico
Oklahoma
Texas
Region VII
Iowa
Kansas
Missouri
Nebraska
Region VIII
Colorado
Montana
North Dakota
South Dakota
Utah
Wyoming
Arizona
California
Nevada
Region X
Idaho
Oregon
Washington
Regions I-V Total
Na11onal Totals:
Population
Total
11.203.696
3.031,709
992,048
5,051,203
737,681
946,725
444,330
25.358.904
7,168,164
18.190.740
22.276,794
548,104
756,510
3.922,399
11,793,909
3,511,644
1,744,237
31.854.934
3,444,165
6,789,440
4,589,575
3,218,706
2,216,912
5,082,059
2,590,516
3,923,561
44.057.447
11,113,976
5,193,669
8,875.083
3,804.971
10,652,017
4,417,731
20,381,560
1,923,295
3,641.306
1.061,000
2,559,229
11,196.730
11.230,948
2,824,376
2,246,578
4,676,501
. 1.483,493
5.576.561
2,207,259
694,345
617,761
665,507
1,059,273
332,416
22.212.772
1,770,900
19,953,134
488,738
6,213,12]
712.567
2,091,385
3,409,169
134.751.775
200.366,737
Population
Nonattaining
Counties
11 ,076.942
3,031.709
899,535
5,051,203
703.390
946,725
444,330
25,358,904
7,168,164
18,190,740
18.270,734
385.856
756.510
3,463,395
11 ,793,909
1 ,871 ,064
12,097,122
1 ,271 ,539
4,430,796
1,689,270
1,346,305
499,712
711,945
2.147,555
33,669,423
9,293,771
2,251,436
7,754,871
2,238,944
9,328,650
2,301,751
10,248,022
287,189
2.163,271
315,774
1,010,307
6,471,481
4,582,144
678,992
813.133
2.636.868
453,151
2.560.161
1,651,105
87.367
821 ,689
21 ,332.775
1,319,189
19,596.880
416,706
3,035,989
1,339,875
1 ,696,114
100,473,125
142,232,216
f> Population in
Nonattaining
Counties
2i
100
91
100
95
100
100
100
100
100
82
70
100
88
100
53
38
37
65
37
42
10
27
55
76
84
43
87
59
92
52
50
15
59
30
39
58
41_
24
36
56
31
46
75
13
78
96
74
98
85
49. :
64
50
75
71
Source: 1970 Census of Population
14
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3.0 EPA's OZONE DESIGNATIONS DO NOT PREJUDICE NEW JERSEY
OR THE NORTHEASTERN STATES
3.1 New Source Review Requirements in Areas Which are Presently
Designated Unclassified
In unclassified or attainment areas, prevention of significant
deterioration (PSD) regulations require that all planned major VOC
sources with emissions greater than or equal to 50 tons/year after
control can be required to include in their PSD application up to one
year's worth of continuous air quality monitoring data including monitoring
for ozone levels. If the monitoring shows levels above the ozone standard,
the new source would have to comply with new source requirements for sources
locating in nonattainment areas. Thus, the data collected under the PSD
program will be used to further examine whether an area is meeting the
current ozone standard. See 40 C.F.R. 52.21(e) and (n). Moreover, if the
monitoring data establish that violations exist, the area must be designated
nonattainment and a revision to the State Implementation Plan (SIP) must be
submitted within nine months. If the State fails to submit the revised plan
the sanctions against further industrial growth in the area required by
Section 110(a)(2)(I) will apply. Thus, if New Jersey's allegations
concerning widespread nonattainment of the ozone standard are true, the un-
classifiable designations adopted by some States will not result in competi-
tive advantages for attracting new industry to those States.
If an area is determined to be nonattainment, the new source would
be required to install Lowest Achievable Emission Rate (LAER) control techno
and major existing sources would be required to install RACT. If the area i
determined to be an attainment area, the proposed new source would be requir
to apply best available control technology which is determined on a case-by-
15
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basis. Therefore, in both attainment and nonattainment areas, all new point
sources of emissions of VOC will be controlled.
3.2 Implementation of Emission Control Programs in Unclassifiable Areas
Despite the designation of an area as unclassifiable some VOC emis-
sion controls are required in these areas. Specifically, controls on motor
vehicles and new sources are proceeding within such areas. This fact, together
with the information set forth above establishing that the vast majority of
existing VOC emissions are situated in areas designated nonattainment, supports
the conclusion there will be little environmental impact on New Jersey due to
the EPA's designation of rural areas without monitoring data as unclassifiable.
The Federal Motor Vehicle Control Program plays a vital part in the
strategy to attain the ozone standard everywhere since approximately 40 percent
of the country's VOC emissions result from motor vehicle emissions in both
4
rural and urban areas. That program will result in emission reduction to all
areas of the country regardless of an area's designation and.will be a major
factor, along with controls in urban areas, to insure attainment of the ozone
standard throughout the country.
Further, the area designation, whether nonattainment, attainment or
unclassifiable, does not necessarily in and of itself dictate the applicable
new or existing stationary source control requirements. There are essentially
three reasons for this.
First, because air pollution emissions are transported from one area
to another, the sources that cause or contribute to a NAAQS violation, or
affect an area with clean air may actually be outside the designated nonattainment
16
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or attainment area, respectively. Therefore, the specific control requirements
which a source must meet are not necessarily dependent upon the designation of
the area in which it is located, but rather the designation of the area which
will be impacted by the source's emissions.
Second, many States are choosing to impose requirements over a
broader geographic area than the designated nonattainment area for reasons of
equity, simplicity of administration or added assurance that all sources which
affect the nonattainment area are controlled and are making their revised
emission limitations applicable Statewide.
Finally, Section 107(d). of the Act requires that attainment/non-
attainment designations be made within a very short time period, and that
these are to be composed of air quality control regions Cor portions thereof),
which are often based on State, county, or other political jurisdictional
boundaries. This process is bound to include pockets where the air quality
does not necessarily correspond to the specific designation of the area.
However, these anomalies will be taken into account during the detailed process
of State Implementation Plan development for the given nonattainment area and
in the issuance of individual new source permits which, as already mentioned,
are based upon the source's area of impact rather than its physical location.
3.3 Monitoring in Unclassified Areas which May Have a High Potential
for Violating the Ozone NAAQS
The EPA has encouraged but not required Statewide nonattainment
designations and the development of Statewide controls of volatile organic
compounds. Additionally, the EPA is reviewing and analyzing existing scien-
tific data to determine whether broader nonattainment designations are appropriate.
17
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However, the existing data base may be insufficient to allow for a complete
evaluation.5 Therefore, the EPA Regional Administrators have been requested
by the Assistant Administrator on October 12, 1978 to identify those areas
designated unclassified which do not have monitoring data and have a high
potential to exceed the standards. Once these areas are identified, the EPA
has recommended that the States require, in the 1979 SIP revisions, the appli-
cation of RACT on most major sources of VOC emissions. RACT would be required
for sources with VOC emissions greater than 100 tons/year potential and for
which the EPA has issued a CTG (Control Techniques Guideline) by January 1978.
The SIP revisions would have to include a commitment by the State to adopt
additional regulations annually beginning in January 1980 for those sources
for which the EPA has published CTGs in the preceding year. If States do not
comply with this recommendation for their SIP revisions, they may be required
to conduct monitoring for photochemical oxidants in the identified counties
during the next year. If the new monitoring data shows violations of the
ozone standard, the counties will be redesignated as nonattainment areas and a
SIP will be required.
3.4 Procedures to Ensure Equity in Estimated Control Requirements
A major concern expressed by the State of Mew Jersey is that States
which are downwind of unclassifiable areas will have to control emissions more
stringently than would otherwise be necessary. This concern is unfounded.
Procedures developed by the EPA allow States which are downwind of areas not
attaining the ozone NAAQS to "take credit" for controls that would have to be
adopted to attain the standards in upwind States. This provision avoids the
problem of the downwind States having to overregulate to compensate for pol-
lution originating in another State.
18
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The EPA has provided guidance to the States for establishing organic
emission control requirements to meet the oxidant standard in nonattainment
789
areas. ' ' Specifically, the guidance allows a downwind State to assume a
reduced ozone design value prior to calculating control requirements. The
rationale for this guidance is that upwind States are required to meet the air
quality standard for ozone. Therefore, the downwind States may assume that
ozone contributed by upwind sources of precursors will be reduced to levels of
the standard or below. For example, if the second high hourly ozone concentra-
tion recorded in New Jersey during a year is .24 ppm ozone, and ozone trans-
ported into that State from upwind States is estimated to be .14 ppm ozone,
New Jersey would be allowed to reduce the .24 ppm ozone value by an amount
commensurate with the reduction of transport into the State to the ozone
standard. The resulting reduced ozone design value would then be used
to estimate organic emission control requirements in New Jersey. Thus, down-
wind States, such as New Jersey, are allowed to take credit for controls
required in upwind States. The EPA believes that such a procedure eliminates
any inequity attributable to transport of pollution from upwind States.
19
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4JO INTERPRETATION OF THE AIR QUALITY STANDARDS FOR OZONE AND ATTENDANT
UNCERTAINTIES IN THE MONITORING DATA
4.1 Monitoring Requirements
The past National Ambient Air Quality Standard (_NAAQS) for photo-
chemical oxidants was 160 micro.grams per cubic meter (or .08 parts per million
[ppm]) maximum one hour concentration not to be exceeded .more than once per
year. Much of the evidence used by New Jersey to indicate widespread vio-
lations of the NAAQS is based on aircraft data. Determining through aircraft
data whether air quality ozone levels at ground level are being exceeded is
not a straight-forward exercise. In fact, the Agency has determined that, at
present, aircraft data can only be used qualitatively to evaluate air quality
and not to require nonattainment designations for the national standard.
4.1.1 The NAAQS Consists of Exposure Level and Exposure Time
The national ozone standard consists both of an ambient exposure
level and an exposure time. In addition, the standard applies at locations to
which the general public has access. Aircraft data are of short duration and
obviously are not collected at ground level. Moreover, the national ozone
standard was set at or below observed threshold levels corresponding with
adverse effects on health. The standard is designed to provide some factor of
safety in order to protect sensitive members of the population and to protect
against synergistic effects arising from simultaneous exposure to a number of
.pollutants.
Aircraft measurements are of short duration and are spatially
integrated average concentrations observed over short periods. For example,
assuming an aircraft were traveling 120 miles per hour and each ozone reading
20
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represented a five minute integrated average concentration, the recorded ozone
concentration would have been sampled over a ten mile path several hundreds of
feet above the earth's surface. There are scientific uncertainties in relating
such data to the national standard and it can not be claimed, as New Jersey
does, that aircraft recordings of ozone levels higher than the ozone standard
is clear evidence of widespread violations of the standard without having
first documented that such measurements establish that ozone levels at ground
level are exceeding the exposure level stated by the standard for an hour or
more. Such documentation does not exist. While the EPA is examining this
issue at the present time, there is no definitive scientific guidance available.
Moreover, the evidence that is available suggests that aircraft data are a
limited proxy for ground level monitoring data.
4.1.2 Aircraft Data Cited by the State of New Jersey
The aircraft data cited by the State of New Jersey in Reference 2
as supporting .the need for Statewide nonattainment designations are generally
not good indications of ozone concentration levels observed concurrently at or
near the ground. For example, in only 30 percent of the instances in which
ozone concentrations greater than .08 ppm were observed aloft did concurrent
hourly ozone concentrations observed at ground level approximately beneath the
flight track exceed .08 ppm. Using data cited by the State of New Jersey,
Tables 5 and 6 illustrate the difficulties of using aircraft data as an indi-
, 2
cator of ozone concentrations observed at the ground. As shown in Table 5,
12 of the 21 aircraft flights cited by New Jersey indicated ozone concentrations
aloft in excess of .08 ppm. Fewer than half of these indicated a corresponding
concentration of .08 ppm or more at or near the ground.
21
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TABLE 5. Comparability of Aircraft and Ground Level
Data Provided tty ther State of New Jersey
Concentrations
> .08 ppm
Observed
x\ Aloft
Concentratioiisx.
> .08 ppm Observed.
at the Ground x^
Yes
No
Total Number
of
Observations
Fraction of
"Correct"
Indications
YES • NO
5 : 1
7 8
12 , 9
I
5/12 ! 8/9
j
TOTAL
-
— !
i
21
1 3/21
22
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TABLE 6. Comparability of Aircraft and Continuously
Measured Ground Level Data Provided by the State
of New Jersey
\v Concentrations
x. > .08 ppm
^ Observed
X. Aloft
Concentrati ons\v
> .08 ppm Observed^
at the Ground - x^
Yes
No
i
Total Number
of
Observations
i
Fraction of
"Correct
YES .NO TOTAL
3> 1 ! _ -
7 6 1
1 10 ; 7 i 17
i ;
j i
| • |
i i
i
i i
Indications
3/10
6/7
9/17
23
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Table 6 differs from Table 5 in that only flights for which
continuous ground level data are available beneath the flight track are con-
sidered. In these latter comparisons, in only 30 percent of the cases where
ozone concentrations exceeding .0,8 ppm were observed aloft were correspondingly
high concentrations observed with the continuous monitors. It is likely that
a number of these discrepancies can be explained by the presence of local
sinks for ozone near the continuous monitor Ce.g., sources of nitric oxide
emissions) or by the time of day or prevailing meteorological conditions under
which the measurements were made.
Regardless, the conditions under which ozone concentrations
measured aloft are good indicators of concentrations at ground level have not
been scientifically established. The EPA is studying the question at present
but until those studies are completed, the EPA will only use aircraft data to
make qualitative assessments of air quality. Accordingly, aircraft measure-
ments were used by the EPA as one reason for encouraging States in the Eastern
portion of the country to make Statewide nonattainment designations for ozone
pollution. However, the Agency does not believe that aircraft data constitute
sufficient bases for mandatory Statewide nonattainment designations.
4.2 Geographic Area Represented by a Detected Violation of the NAAQS
There is considerable uncertainty over the geographic area repre-
sented by a recorded violation of the ozone standard at an individual ground
level monitor. As Reference 11 suggests, the area represented by an ozone
monitor depends on the site characteristics (e.g., the environment immediately
surrounding the monitor}. However, unlike CO and TSP for which observed
violations frequently appear to be the result of localized problems, violations
24
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of the ozone standard appear to be more widespread. Consequently, the Agency
has strongly suggested that designated nonattainment areas for the ozone
standard be at least as large as a county. In most cases, a county represents
the smallest geographical or jurisdictional boundary for which most control
programs will be centered. .As the EPA develops more scientific guidance on
the area represented by specific ozone monitors, designation areas will be
modified as appropriate.
.25
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5.0 CHEMICAL AND METEOROLOGICAL CONSIDERATIONS IN THE FORMATION AND
TRANSPORT OF OZONE AND ITS PRECURSORS
Ozone (03) is a "secondary pollutant" which is a pollutant not emitted
directly by a source of pollution. Instead, secondary pollutants arise from
chemical reactions among other pollutants (_i.e., precursors 1 which themselves
may or may not be directly emitted by sources. Because ozone is a secondary
pollutant, highest concentrations do not necessarily occur in the immediate
vicinity of the sources which emit the precursors. For a significant amount
of ozone to be formed, two conditions must occur. First, organic precursors
and oxides of nitrogen (NO ) must both be present in sufficient concentrations;
and second, ultraviolet radiation from sunlight must be sufficient to enable
photodissociation of nitrogen dioxide (_N021 to sustain the sequence of reactions
leading to ozone formation. Because the chemical lifetimes of ozone and most
of its precursors appear to be limited, and because of the impact of continual
dilution, there are geographical limits to significant transport of ozone
unless high concentrations can be sustained by interaction with fresh precursor
emissions.
5.1 Chemistry of Ozone Formation and Transport
5.1.1 Chemical Stability of Ozone
The chemical stability of ozone and its precursors is important
in estimating geographical distances of significant of ozone transport. If
these pollutants decay away to negligible amounts within a few hours, their
impact at remote locations will be small. If, on the other hand, they are
chemically stable, then under adverse meteorological conditions their impact
could be significant at remote sites.
26
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The bulk of available evidence suggests that in the absence
of fresh precursor emissions, the lifetime of ozone in the atmosphere is
limited.14'19'20'36 The chemical stability of ozone and other pollutants is
frequently expressed in terms of their half lives (j-e., the time it would take
a pollutant to decay to one half of its original concentration).. The lifetime
of ozone in the atmosphere depends on the extent to which prevailing meteoro-
logical conditions enable the ozone to come into contact with scavengers and
the earth's surface. Scavengers such as airborne aerosols, some naturally
emitted organic pollutants (e.g., terpenes). and nitric oxide (NO) as well as
surface deposition all act to limit the lifetime of ozone in the atmosphere.
In the absence of fresh precursor emissions, it is unlikely that significant
concentrations of ozone can persist near the earth's surface for greater than
about 36 hours. Therefore, emissions from sources within 36 hours of New Jersey
would be most likely to impact on ozone levels in New Jersey. As discussed
above, within 36 hours travel time of New Jersey, almost all sources of pol-
lution causing ozone are situated in areas designated nonattainment.
The 36 hour transport estimate is based on available infor-
mation on the stability of ozone under different conditions. It has been
12 13
clearly demonstrated that ozone trapped aloft overnight is quite stable. '
Ozone which is transported over water also appears to have a long lifetime of
several days. ' »I5>' >ia Trajectories-over water could therefore present a
special case in which transport from very remote sources could be significant.
For example, it has been demonstrated that ozone transport from the Northeastern
18
U.S. impacts on the coast of Virginia. A review of rural diurnal ozone
14 19
concentration patterns reported in several field studies ' suggests that
27
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the half life of ozone in rural areas near the earth's surface at night is in
the order of 5-12 hours. Nighttime half life of ozone within an urban plume
14 19
near the earth's surface appears to be about 2-3 hours. '
It is much more difficult to determine daytime half life of
ozone over land because fresh ozone is being synthesized as new precursor
emissions are injected into the air parcel. Thus, data reflecting the buildup
of ozone during the day may be the result of new ozone being synthesized more
rapidly than the depletion of "aged ozone" resulting from remote sources.
However, recent modeling of the stability of ozone to simulate daytime con-
ditions in a mixture of carbon monoxide, methane and water vapor exposed to
sunlight suggests that the daytime half life of ozone in such a system is 5-
20
7 hours. Such a mixture consists of naturally occurring stable compounds.
As such, there is likely to be slower destruction of ozone under such conditions.
Therefore, the modeling exercise suggests that daytime half life of ozone over
land is likely to be less than seven hours.
By combining the estimated daytime and nighttime half lives of
ozone, the EPA estimates that 36 hours after a significant amount of ozone is
formed, only 25 percent remains in the atmosphere (see Table 7)_. Furthermore,
the 36 hour estimate is a conservative one for several reasons. The estimate
ignores any impact of dilution, assumes ozone does not decay at all overnight,
assumes the daytime half life of ozone is six hours, and assumes transport
begins at 6:00 p.m. — the most conservative possible assumption in this
scenario.
28
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TABLE 7. SCENARIO ILLUSTRATING OZONE TRANSPORT
Elapsed
Time, hr
0
6
12
18
24
30
36
Day
1
1
2
2
2
2
3
Time of
Day
6 p.m.
Midnight
6 a.m.
Noon
6 p.m.
Midnight
6 a.m.
Percent of
Initial Ozone
Remaining
100
100
100
50
25
25
25
Ozone
Concentration, ppm
.16
.16
.16
.08
.04
.04
.04
29
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5.1.2 Chemical Stability of Ozone Precursors
There are two classes of ozone precursors: volatile organic
compounds (VOC) and oxides of nitrogen (NO ). There is information which
A
implies that long range transport of N0x is not significant.14'15'19'21'22'23
There is greater uncertainty about the transport of volatile organic pre-
cursors; however, the available information suggests that the half lives of
24 25
most volatile organic compounds are less than 24 hours. '
Theoretical and limited monitoring data suggest rapid daytime
p£ pc pc
decay of most volatile organic compounds during the summer months. ''
Organic compounds appear to be somewhat more persistent at night. Low con-
centrations of slow reacting compounds could survive for several days; how-
ever, modeling studies suggest that these low concentrations do not contribute
significantly to ambient ozone concentrations, particularly when compared with
23
fresh precursor emissions.
Numerous field studies of urban plumes have failed to detect
elevated levels of reactive pollutants greater than one travel day away from
14 20 23 26 27
the source of emission. '''' In studies described in Reference 25,
organic pollutants and ozone were sampled at a site approximately 100 km from
St. Louis. When the urban plume impacted the site during the day, elevated
ozone was observed, but organic pollutants (with the exception of nonreactive
halogenated compounds^ were not above background levels. At night however,
organic pollutants were found to be higher than background levels and ozone
was depressed. Occasionally, transport from a city (Chicago), about 270 km
away could be detected using halogenated compounds as tracers. No significant
buildup in organic pollutants or in ozone could be detected in these-cases.
30
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These observations are consistent with the theoretical findings
summarized in Reference 25 which suggest that rapid decay of most organic
compounds occurs during summer days (the ozone pollution season), with the
decay being slower at night. Half lives of most volatile organic compounds
are probably less than 24 hours. See References 24, 25, 26 and 36. Additional
support comes from monitoring studies conducted in rural, remote areas in
20
which ambient levels of organic compounds are typically .10 ppmC or less.
Such data could be presumed to be a conservative representation of cases where
the monitoring site is not impacted upon by significant sources within a day
or two of travel time.
Several simulations have been conducted with chemical kinetics
models to estimate the impact of organic precursors transported from afar as
23
compared with emissions of fresh precursors. In scenarios in which concentra-
tions of VOC of .10 ppmC (about the level seen at remote sites), were added to
the model, negligible impacts on peak ozone concentrations (y .006 ppm) were
typically observed.
To summarize, most organic precursors decay or are diluted to
very low concentrations before they are transported over great distances. The
modeling exercises imply that these low levels are not significant in ozone
formation far downwind when compared to the impact of locally generated pre-
cursors. In short, because of dilution and instability of most precursors,
long range transport of ozone precursors does not appear to significantly
contribute to local ozone concentrations in the urban areas of the Northeast.
In addition, unless long range transport of ozone is supplemented by more
locally emitted precursors (which, as shown earlier, are subject to controls
31
-------
in the case of New Jersey), the chemical lifetime of ozone, as a rule, is
insufficient to sustain high concentrations for more than about 36 hours.
5.2 Meteorology of Ozone Episodes
Ozone episodes are typically characterized by light and variable
winds. Since pollutants are borne by the winds, the distances over which
transport of pollutants is significant is limited to 3QO-500 miles which is
the distance pollutants could travel within about 36 hours with light and
variable winds. This information suggests that New Jersey's concerns about
significant adverse environmental impacts from ozone generated from unregu-
lated sources more than about 500 miles away from New Jersey is unwarranted.
As New Jersey has commented, highest concentrations of ozone in the
Midwest appear to occur in the presence of stagnating or, more generally,
slow-moving high pressure systems. Highest ozone concentrations within such
high pressure systems usually occur in the western or back side. In general,
:emperatures are warmer on the back side of the system, and it is possible
bhat air within that sector may have been within the system somewhat longer
than air further east. However, simply analyzing the movement of weather
systems from the Midwest to the East does not establish that pollution gener-
ated in the Midwest is transported to the East.
As several investigators have pointed out, pollutants are trans-
14 28
ported by the wind, not by the weather system. ' Therefore, while a parcel
of air may remain within the same weather system for up to a few days, it is
not correct to think of a high pressure system as a self-contained mass of air
which migrates intact toward the East Coast from points west or south. Rather,
32
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it is more accurate to compare air parcel trajectories during high ozone
weather conditions with trajectories observed on other days. Comparisons of
this nature have been done at rural and urban sites in the Midwest and the
South (see References 14 and 19)_. Such comparisons show that, over a 36-hour
period, the area covered by an air parcel in the lowest 300 meters of the
atmosphere is generally rather limited (usually < 300 miles), on days observing
high ozone.
There are several factors associated with transport and buildup of
ozone that make it unlikely that ozone transport over extended distances
(greater than 300-500 miles) is significant. These factors are the following:
1. High ozone buildup generally occurs in high pressure
systems migrating from west to east. However, pollutants emitted into such
systems do not move with the system itself but are transported by the wind
circulating about the system. Hence, an air parcel into which ozone or pre-
cursors are injected will usually take a more circuitous route than the
system itself.
2. There is no assurance that an air parcel will remain
within a high pressure system over an extended travel distance. Parcels do
not travel within such systems indefinitely but exit or "spin off" within
hours or days and are replaced by other parcels entering the system. It has
been estimated that the range for retention of an air parcel within a slow
moving high pressure system depends on the speed with which the system mi-
grates across the country and varies from less than one to as many as six
19
days. Therefore, as travel distance increases, it becomes less probable
that a specific air parcel in a high pressure system will stay in that system.
33
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3. Ozone buildup is associated with relatively light and
variable winds. Assuming that in such a system the transport wind averages
ten miles per hour or less, an air parcel would travel at most only 200-300
miles over a day's time. At this wind speed it would take three-to-five days
or more to traverse more than 1,000 miles. The chemical instability of ozone
would make survival of ozone over such long distances highly improbable. If
wind speeds were much greater, dilution would be correspondingly greater and
ozone concentration buildup would be unlikely. Therefore, the limit for
significant contribution of precursor sources to ozone concentration is probably
no more than about 300-500 miles. Beyond those distances, the relative contri-
bution would decline considerably. It would be difficult to determine a
precise distance beyond which contribution becomes negligible. However,
significant transport from remote precursor source areas as far as 1,000 miles
away appears to be highly unlikely.
In short, there are numerous studies14'15'19'21'22'23 which have
demonstrated that precursor and ozone transport over tens to a few hundred
miles is important to the buildup of high ozone concentrations. The EPA
participated in some of these studies and acknowledges that such transport and
subsequent impact does occur. However, the EPA differs with New Jersey on the
range over which significant transport and impact may occur. Supporting
i? ?Q "*r\ "31 i? n
technical studies1^'""30"31 »•»*»•" submitted by New Jersey, which have been
conducted by the Interstate Sanitation Commission (.ISC), argue that significant
transport on some occasions from source areas as far as the Texas-Louisiana
Gulf Coast and parts of the Midwest can impact on New Jersey. Some of these
areas represent a transport distance of over 1,000 miles.
34
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The 'EPA is not able to accept the conclusions reached by these
studies. Much of the bases for the ISC analyses are trajectory estimates
which indicate the probable flow of air and buildup of ozone observed in the
general area of the trajectory over a period of days. Such analyses do not
establish transport distances since the air flow does not necessarily demon-
strate that a reactive pollutant like ozone can survive for a period of time
required for travel over such a great distance. The ISC studies contain some
questionable assumptions in their attempts to justify very long distance
transport at sustained high ozone levels. In multiday transport cases, they
assumed that ozone is regenerated on the day(js)_ after initial formation even
without addition of new precursors. The ISC authors rely on smog chamber
studies that were subject to chamber wall interferences. In shorter duration
transport over long distances, they assumed mean transport wind speeds on the
order of 45 miles per hour which would cause considerable dilution of pre-
cursor injections into an air mass as well as considerable dilution of ozone
or precursors within an air mass. Regardless of the validity of these assump-
tions, it is very difficult to conclusively demonstrate very long range trans-
port toward the Northeast because of the ambiguities introduced by considerable
potential for fresh precursor emissions along the way.
35
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6.0 ADDITIONAL COMMENTS SUBMITTED BY NEW JERSEY
New Jersey has also commented that the EPA did not use certain data
available to it in making the designations. Specifically, New Jersey has
alleged that certain rural monitoring data were excluded in designating non-
attainment areas. The air quality data base utilized by the Agency is the
most complete one which was available at the time of the designations. In an
effort to ensure that erroneous designations based on faulty data were not
made, only those data collected using appropriate quality assurance procedures
were used to make nonattainment designations.
In addition to regularly reported data, rural data collected by the EPA
in special field studies or additional data certified as valid by the EPA
Regional Offices were used to make designations. In addition the EPA, through
a contract study, reviewed privately collected ozone data at rural sites in
the Western United States for assessing ambient ozone levels. After completion
of the contract study, the EPA Regional Offices were contacted to determine
whether specific privately collected data were considered valid. Only those
data in the report which the appropriate Regional Office could assert were
valid were included in SAROAD (j.e., the EPA's computerized air quality data
base).
36
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References Cited
1. Letter from Rocco D. Ricci to Douglas M. Costle, dated April 28, 1978
with attachments.
2. Letter from Paul D. Arbesman to Ronald C. Hausmann, dated July 7, 1978
with attachments.
3. 38 FR 20, 834-20,835, paragraph 51.7 (August 3, 1973).
4. U.S. EPA, MDAD, National Air Quality, Monitoring and Emission Trends
Report. 1977, EPA-450/2-78-052 (December 1978).~
5. Letter from Ronald C. Hausmann to Richard M. Hluchan, dated September 15, 1978
with attachments.
6. Letter from David G. Hawkins to EPA Regional Administrators, Regions I-X
dated October 7, 1977, subject: Mailed letter reporting States designation
of attainment status, with attachment.
7. U.S. EPA, Workshops on Requirements for Nonattainment Area Plans—Compilation
of Presentations (Revised Edition), April 1978.
8. U.S. EPA, Office of Air Quality Planning and Standards, Uses, Limitations
and Technical Basis of Procedures for Quantifying Relationships between
Photochemical Oxidants and Precursors. EPA-450/2-77-021a (November 1977).
9. Memorandum from Richard G. Rhoads to Director, Air and Hazardous Materials
Division, Region I, III-X and Director Environmental Programs Division,
Region II, subject: "Clarification of Attainment/Nonattainment Evaluation
Guidance," dated August 16, 1978 with enclosure.
10. Federal Register 36 No. 228, paragraph 50.9, (November 23, 1971), page 22,335.
11. Ludwig, F. L., et_al_., Site Selection for the Monitoring of Photochemical
Air Pollutants. EPA-50/3-78-013 (April 1978).
12. Wolff, G. T. and P. J. Lioy, "Ozone Concentration Patterns Associated With
the July 1977 Eastern U.S. Heat Wave." Presented at 71st Annual Meeting
APCA, Paper #78-30.4, Houston, Texas (June 1978).
13. Decker, C. E., J. E. Sickles, II, W. D. Bach, F. M. Vukovich, and
J. J. B. Worth, Project Da Vinci II: Data Analysis and Interpretation,
EPA-450/3-78-028 (June 1978).
14. Decker, C. E., et al., Formation and Transport of Oxidants Along Gulf Coast
and in Northern United States, EPA-450/3-76-033 (August 1976).
15. Spicer, C. W., et al., The Transport of Oxidant Beyond Urban Areas
EPA-600/3-76-018~TFebruary 1976).
-------
16. Cox, R. A., A. E. J. Eggleton, R. G. Derwent, J. E. Lovelock and
D. H. Pack, "Long-Range Transport of Photochemical Ozone in Northwestern
Europe," Nature 225 (No. 55404)., pages 118-121 (1975).
17. DeMarrais, G. A.., The Ozone Problem in the Norfolk, Virginia Area,
EPA-600/4-78-006 (January 1978).
18. Salop, J. and G. F. Maier, "A Study of Ozone Levels in a Maritime and
Land Environment," J. Air Pollution Control Association 28 (December 1978).
19. Research Triangle Institute, Investigation of Rural Oxidant Levels as
Related to Urban Hydrocarbon Control Strategies, EPA-450/3-75-036
(March 1975).. :
20. Bufalini, J. J. and W. A. Lonneman, "Ozone Formation from Rural Hydrocarbons,"
paper presented at CRC Air Pollution Symposium, New Orleans, Louisiana
(May 1978)..
21. U.S. EPA, Office of Air Quality Planning and Standards, Effectiveness of
Organic Emission Control Programs as a Function of Geographic Location
(April 1977)..
22. Westberg, H., et al., Studies of Oxidant Transport Beyond Urban Areas,
final report. EPA Contract No. 68-02-2239, Washington State University
(1977).
23. U.S. EPA, Office of Air Quality Planning and Standards, Procedures for
Quantifying Relationships between Photochemical Oxidants and Precursors:
Supporting Documentation, EPA-450/2-77-021 b (February 1978). ~
24. Pitts, J. N. Jr., A. M. Winer, K. R. Darnall, A. C. Lloyd and G. J. Doyle,
"Hydrocarbon Reactivity and the Role of Hydrocarbons, Oxides of Nitrogen,
and Aged Smog in the Production of Photochemical Oxidants,"
EPA-600/3-77-001b, page 687 (January 1977)..
25. Altshuller, A. P., "Formation and Removal of S02 and Oxidants from the
Atmosphere," Fate of Pollutants in the Air and Water Environment. Part H,
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