-------
-------
3 APPLICATION OF THE UAM TO THE 1995 EMISSION SCENARIOS
In this section we discuss the UAM results for the 1995 Base Case, the 1995 SIP con-
trol strategies, and the 1995 alternative fuel scenarios. Because a photochemical
grid model, such as the UAM, produces large amounts of output, we have limited our
discussion to the primary species of interest, ozone. We present the results for the
1995 emission scenarios in three different forms: (1) tables of predicted region-wide
maximum ozone concentrations; (2) isopleths of predicted daily maximum ozone
concentrations and differences of predicted daily maximum ozone concentrations
between different emission scenarios where appropriate; and (3) isopleths of hourly
ozone concentrations and isopleths of differences in hourly ozone concentrations
where appropriate. The predicted hourly ozone concentrations are presented in the
appendixes in Volume II of this report.
Analyses of future-year alternative emission scenarios should also include the effects
of the emission changes on population exposure, areal extent of exceedances, 6- and
m4°m aver*ge ozone concentrations, and other species (e.g., NO2, PAN, nitric acid,
PM-10, etc.). However, time and resource constraints have limited our discussion
here to how the emission scenarios affect hourly ozone concentrations.
1995 SIP CONTROL STRATEGIES
The UAM results for 1995 base case and type A and type B SIP control strategies are
discussed for three cities: Dallas-Fort Worth, Atlanta, and St. Louis.
Dallas-Fort Worth
1995 Base Case
As seen m Figure 3-1 and Table 3-1, the predicted peak maximum ozone concentra-
tion on 30 August for the Dallas-Fort Worth 1995 base case is 11.6 pphm and occurs
west of Fort Worth. On 31 August the 1995 base case peak ozone concentration is
13.7 and occurs in Dallas. Isopieths of the predicted hourly ozone concentrations for
™6 D<^f-Fort Worth 1995 base case are presented in Appendix B. On both August
30 and 31 there is a lot of spatial variability in the predicted daily maximum ozone
concentrations (Figure 3-1), the predicted ozone concentrations vary by over a factor
of two within a distance of 12 km (3 grid cells).
89116r2 8
23
-------
Time : 200 - 2400 LSI
620 640
NORTH
660 700
Maximum Value » 11.58
Minimum Value » 2.95
SOUTH
FIGURE 3-la. Predicted Daily Maximum, Ozone Concentration (pphm) in Dallas-Fort Worth
on 30 August 1985 for 1995 Base Case Emission Scenario
35 6<
24
-------
Time : 200 - 2400 LSI
620
NORTH
680 700
640 660
Maximum Value » 13.69
Minimum Value * 1.94
720
3700
3660
3630
10
GURE 3-lb.
SOUTH
^^^^^
3640
3620
3600
- 3530
3560
25
-------
TABLE 3-1. Predicted region-wide maximum ozone concentrations for the
base cases and the 1995 SIP control strategies.
Predicted Peak Ozone Concentration (pphm)
August 30 August 31
(a) Dallas-Fort Worth
Emission Scenario
1985 Base Case 13.2 16 4
1995 Base Case 11.6 13.'7
Type A Strategies
30* VOC Reduction 10.0 11.6
60* Percent VOC Reduction 8.9 10!8
Type B Strategies
Scenario 1 (24* VOC and 19* NOX 10.8 13.3
Reductions)
Scenario 2 (24* VOC and 49* NO 12.8 13 4
Reductions)
(b) Atlanta
June 4
Emission Scenario
1985 Base Case 13.2
1995 Base Case 12^5
Type A Strategies
30* VOC Reduction H.g
60* VOC Reduction 11*1
90* VOC Reduction 1
891 16rl 2
26
-------
TABLE 3-1. Concluded.
Predicted Peak Ozone Concentration (pphm)
Type B Strategies
Scenario 1 (18? VOC and 49? NO 10.8
fm
Reductions)
jenario 2 (1i
Reductions)
Scenario 2 (18? VOC and 32? NOV 11.3
A
(c) St. Louis
13 July
Emission Scenario
1976 Base Case 24.4
1995 Base Case 14[5
Type B Strategies
1995 Scenario #1 (24? VOC and
26? NOX reduction) 13.3
1995 Scenario *2 (24? VOC and
38? NOX reduction 13.4
891 16rl 2
27
-------
As seen in Table 3-2, the 1995 base case anthropogenic emission inventory has a
VOC-to-NOx ratio of 2.3 (weekend) to 3.3 (weekday). When biogenic emissions are
included the emission inventory VOC-to-NOx ratio ranges from 5.0 (weekend) to 5.7
(weekday). The 1985 Base Case emission scenario emission inventory VOC-to-NO
ranges ranged from 3.8 to 4.6 (anthropogenic only) and 6.5 to 6.9 (anthropogenic plus
biogenic). The 1985 median measured morning VOC-to-NOx ratio was 11.8
(Lonneman, 1986; Bauges 1986; Chang et al., 1989). There are several reasons why
ambient measurements of VOC-to-NOx ratios are always higher than the ratios in
the emission inventory: (1) a large percentage of the NOX emissions are from eleva-
ted sources which would not be mixed down to the ground during the 6 to 9 a.m.
morning measurement period; (2) the measurements are usually made in the down-
town urban core which is dominated by VOC emissions; and (3) NOX concentrations
are removed from the atmosphere through chemical reactions and deposition faster
then VOC species. The VOC-to-NOx ratio, either measured or in the inventory, is
frequently used to indicate whether VOC emission controls (during low VOC-to-NO
conditions) or NOX emission controls (during high VOC-to-NOx conditions) will be *
more effective for reducing ozone concentrations. However, because the VOC-to-
NOX ratio varies spatially and temporally it is not always a good indicator of emis-
sion control strategies; which is why a model that accounts for these variations, such
as the UAM, is needed to evaluate emission control strategies.
Type A SIP Control Strategies
As seen in Table 3-1 and 3-2, a 30 and 60 percent reduction in the 1995 base case
anthropogenic VOC emissions results in a 13.8 and 23.3 percent reduction in the peak
ozone concentration, respectively. At these fairly low VOC-to-NO ratios in the
inventory (less than 5) VOC emission controls should be more effective at reducing
ozone concentrations then NOX emission controls.
Type B SIP Control Strategies
For the 1995 scenario //I (24 percent reduction in VOC emissions and 19 percent
reduction in NOX emissions) the peak ozone concentration is reduced by 6.9 percent
on 30 August and 2.9 percent on 31 August. Based on the type A SIP control strate-
gies (VOC emission reductions only), it is estimated that the 24 percent reduction in
VOC emissions with no change in NOX emission would result in an approximate 11
percent decrease in the peak ozone concentration. Thus it appears the 19 percent
reduction in NOX emissions hinders some of the benefits for reducing ozone concen-
trations due to the VOC emission reductions.
Isopleths of the daily maximum ozone concentrations for scenario //I are given in
Figure 3-2, whereas deficit enhancement (DE) plots of the differences in daily maxi-
mum ozone concentrations between 1995 scenario //I and the 1995 base case are
89116r2 8 28
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Timt : 200 - 2400 LSI
.gOO 620 640
T\T ^^^^p^^^^^^^^^^W^^T^B^^^W^^^l
660
NORTH
680 700
Maximum Value * 10.81
Minimum Valu« = 2.S2
720
* r,, * } T
740
760
SOUTH
LGURE 3-2a. Predicted Daily Maximum Ozone Concentration (pphm) in Dallas-Fort Worth
on 30 August 1985 for 1995 Scenario#1 Emission Scenario
J720
m 3700
- 36*3
- 3660
S 3640
- 3620
- 3600
- 3530
3560
-------
Tim* : 200 - 2400 LST
000 620 640
660
NORTH
600 700
720
740
Maximum Value » 13.33
Minimum Value * 1.91
720
3700
- 36flO
- 3660
IsiSSSSSS&fesB
/
SOUTH
FIGURE 3-2b. Predicted Daily Maximum Ozone Concentration (pphm) in Dallas-Fort Worth
on 31 August 1985 for 1995 Scenario#1 Emission Scenario
S 3640
- 3620
356C
-------
shown in Figure 3-3. There are regions of increases and decreases in the daily maxi-
mum ozone concentrations in response to the reductions of VOC and NO emissions.
The area! extent of decreases in daily maximum ozone concentrations isXlarger than
the region of increases. However, the increases occur at the location of the peak
ozone concentration.
The disbenefits of controlling NOX emissions in Dallas-Fort Worth in 1995 is further
illustrated in the type B SIP control scenario #2 (Figure 3-4 and 3-5). The only dif-
ference between scenario #2 and scenario //I is that scenario #2 has an additional 28
percent reduction in NOX emissions. As seen in Figure 3-4a, the decrease in NO
emissions causes the ozone peak to occur closer to the urban core. The additional
NOX emission reductions also cause the peak ozone concentration in scenario #2 to
be higher than in scenario #1. In fact on 30 August the scenario #2 peak ozone con-
centration (12.S pphm) is higher than the 1995 base case (11.6 pphm) and causes a
violation of the ozone NAAQS.
The disbenefits of the NOX emission reductions in Dallas-Fort Worth is further
emphasized in the DE plots of differences between 1995 scenario #2 and the 1995
base case emission scenarios (Figure 3-5). Maximum increases in daily maximum
ozone concentrations, 5.9 pphm on 30 August and 6.1 pphm on 31 August, are much
larger than the maximum decreases, 2.1 pphm and 2.7 pphm on 30 and 31 August,
respectively.
The fact that 1995 Dallas-Fort Worth shows substantial disbenefits when controlling
NOX emissions is somewhat surprising since Dallas-Fort Worth is considerd a city
with a fairly high measured VOC-to-NOx ratio (11.8), which would indicate that NO
controls may be beneficial. This modeling analysis demonstrates the necessity of X
examining NOX controls for each region separately to determine their benefits or
disbenefits rather than relying on a simplistic representation of a regions charac-
teristic such as the measured VOC-to-NO ratio.
Atlanta
1995 Base Case
The Atlanta 1995 base case predicts a peak ozone concentration of 12.5 pphm (see
Table 3-1 and Figure 3-6) that occurs approximately 20 km to the east of downtown
Atlanta. The presence of several large power plants to the northwest and southeast
of the city of Atlanta are clearly visible in the isopleth of daily maximum ozone con
centrations (Figure 3-6). NOX emissions from the power plants cause an initial sup-
presion of the ozone concentrations at the location of the power plants followed by
higher ozone concentrations further downwind to the east of the power plants.
891 16r2 3
-------
Time : 0 - 2400 1ST
.600 620 640
v,i^i" t::} ,,i\ ""r, i j i
Maximum Value » 16.91
Minimum Value » -8.69
660
700
720
740
* * * 1 « * *
760
.
780
I I I I -5
SOUTH
J72C
370C
36ac
36 6C
364C
362C
360C
56C
FIGURE 3-3a. Differences in Daily Maximum Ozone Concentrations (ppb) between
(scenario^ - base)
-------
Time : 0 - 2400 LSI
NORTH
660 700
Maximum Value
Minimum Value
14.04
-15.24
/ \x
\ -• « / *»
I •' A \\
l V~ t "r~ r~ » t i
SOUTH
:GURE 3-
3b. Differences in Daily Maximum Ozone Concentrations (ppb) between
1995 base case and 1995 scenario#1 emission scenarios (scenario#1
in Dallas-Fort Worth on 31 August 1985.
— base)
3560
-------
Tim* : 200 - 24OO LSI
0 620 640
660
NORTH
680 700
720
Maximum Value » 12.7"
Minimum Value * 2.91
72<
* 37a
~ 36*
- 366<
= 364(
- 362
- 360
- 353
356
SOUTH
FIGURE 3-4a. Predicted Daily Maximum Ozone Concentration (pphm) in Dallas-Fort Worth
on 30 August 1985 for 1995 Scenario#2 Emission Scenario
36
-------
Time : 200 - 2400 LSI
600 620 640
Maximum Vatu* » 13.36
Minimum Valu« « 2.76
720
3700
SOUTH
- 3680
- 3680
= 3640
- 3620
— 3600
- 3530
3580
IGURE 3-4b. Predicted Daily Maximum Ozone Concentration (pphm) in Dallas-Fort Worth
on 31 August 1985 for 1995 Scenario#2 Emission Scenario
-------
Tim. : 0 - 2400 LSI
NORTH
20
10
.
~ ~ ™MftlC?K~.flJS^SS'»
•N
\
\ A
•'*>C^
• —* ^ j»
AOx^
^S
^^•^•^^^^••^^^v ' » *» ^ ^ * ^^»
ZliS&l^',-." -5.^-' X
^of<%/ /
^••---^-::;.V v \
SOUTH
FIGUPE 3-5a. Differences in Daily Maximum Ozone Concentrations (ppb) between
1995 base case and 1995 scenario#2 emission scenarios
in Dallas-Fort Worth on 30 August 1985
Volu« = 59.10
Valu« » -21.4
J72C
370C
362<
40
5 &
- base)
38
-------
Time : 0 - 24OO LSI
1??° 62° 640
•
660
NORTH
680 700
720
740
Maximum Valu*
Minimum Value
760
60.72
-26.80
•*.. *+.^s ... ~«^ { /
. — i^«a^^rv^x-\^. V ^ — ,\
/ v"
• «••••» \
3620
3600
3590
3560
SOUTH
IGURE 3-5b. Differences in Daily Maximum Ozone Concentrations (ppb) between
"5 enar
- base)
-------
Time : 200 - 2400 LST
Maximum Value = 12.49
Minimum Value * 4.01
800
»-« t »ft I { I t I
820
3825
- 3805
- 3785
3765
- 3745
- 3725
3705
- 3685
3665
FIGURE 2-5
Predicted Daily Maximum Ozone Concentration (pohm) in Atlanta
on 4 June 1984 for 1995 Base Case Emission Scenario
40
-------
Type A SIP Control Strategies
A reduction of anthropogenic VOC emissions of 30, 60, and 90 percent from the
Atlanta 1995 base case results in a decrease of the peak ozone concentration of 4.8,
11.2, and 15.2 percent, respectively (Table 3-1 and 3-2). Note that the type A VOC
emission reductions for Dallas-Fort Worth are over twice as effective for reducing
the peak ozone concentration than in Atlanta. This difference is because of the
higher VOC-to-NO ratio in the Atlanta 1995 base case anthropogenic plus biogenic
emission inventory (11.3) than seen for Dallas-Fort Worth (5.7).
Type B SIP Control Strategies
As seen in Table 3-2, the Atlanta 1995 type B SIP control strategies reduce the peak
ozone concentration by 13.6 and 9.6 percent for, respectively, scenario //I (18 per-
cent VOC and 49 percent NOX emission reduction and scenario #2(18 percent VOC
and 32 percent NOX emission reduction). The isopleths of predicted daily maximum
ozone concentrations for the two type B SIP control strategies and differences in
daily maximum ozone concentrations between the two type B SIP control scenarios
and the base case are given in Figures 3-7 through 3-10. Based on the type A SIP
control strategies for Atlanta it is estimated that the 18 percent reduction in VOC
emissions alone would result in an about a three percent reduction in the peak ozone
concentration. Thus it appears that reducing NOX emissions in Atlanta has a bene-
ficial effect on reducing ozone concentrations. As seen in the DE plots (Figure 3-8
and 3-10), the only region where the NOX emission controls results in increases in the
daily maximum ozone concentrations is in the vicinity of the power plants.
St. Louis
1995 Base Case
Isopleths of daily maximum ozone concentrations for the St. Louis 1995 base case are
given in Figure 3-11. The predicted peak ozone concentration for the St. Louis 1995
base case is 14.5 pphm and occurs in north St. Louis. Based on the current policy on
emission controls it is estimated that the peak ozone concentration in 1976 (24.4
pphm) will be reduced by over 40 percent by 1995 (Table 3-1). The VOC-to-NO
ratio in the St. Louis 1995 anthropoegnic emission inventory (3.7) is almost three
times the value in the 1976 inventory (1.3). This is because of substantial reductions
in elevated NOX emissions and the inclusion of many VOC sources in the 1995 inven-
tory (running losses, previously uninventoried sources, etc.) that were not in the 1976
inventory.
891 16r2 8
-------
Time : 200 - 2400 LSI
NORTH
680 700 720 740 760
Maximum Value * 10.81
Minimum Value » 4.01
780 800
FIGURE 3-7. Predicted Daily Maximum Ozone Concentration (pohm) in Atlanta
on 4 June 1984 for 1995 Scenano#1 Emission Scenario
- 3685
40
3665
42
-------
Time : 0 - 2400 LSI
^§60 680 700
720
NORTH
740
Maximum Value « 18.56
Minimum Value » -31.08
760
780
800
825
— 3805
;- 3785
h 3765
- 3745
- 3725
^ 3705
?- 3685
665
FIGURE 3-3. Differences m Oa.ly Max,mum Ozone Concentrations (ppo) between
1995 Ease Cose and 1995 Scenario*! Emission Scenarios
,5cer,ano^1 - Base) In Atlanta on 4 June 1984
-------
Time : 200 - 2400 LST
NORTH
680 700 720 740 760
Maximum Value » 11.33
Minimum Value » 4.01
780
800
820
3825
- 3805.
." 3785
3765
- 3745
- 3725
3705
- 3685
3665
FIGURE 3-9. Predictea Daily Maximum Ozane Concentration (pphm) in Atlanta
on 4 June 1984 far 1995 Scenano#2 Emission Scenario
-------
Time : 0 - 2400 LSI
660 680 700
720
760
Maximum Value = 12.40
Minimum Value » -18.15
825
- 3805
- 3785
- 3765
- 3745
- 3725
3705
- 3685
40
665
TGURE 3-10. Differences in Daily Maximum Ozane Concentrations fpob) between
995 Base Case and 1995 3cenario#2 Em.ssion Scenarios
Ucenano#2 - Base) in Atlanta on 4 June 1984.
-------
Time : 200 - 2400 LSI
706 726
NORTH
T
Maximum Value = 14.51
Minimum Value = 9.13
766
SOUTH
FIGURE 3-11. Predated Daiiy Maximum Ozone Concentration (pphm) in St Louis
on 13 July 1976 for 1995 3ase Case Emission Scenario
- 4316
- 4296
- 4276
- 4256
4236
-------
Type B SIP Control Strategies
Isopleths of daily maximum ozone concentrations for St. Louis SIP scenario //I and
differences in daily maximum ozone between scenario #1 and the base case are given
in Figures 3-12 and 3-13, respectively. Similar plots for the 1995 SIP scenario #2 are
given in Figures 3-14 and 3-15. The emission reductions in scenario #1 (24 percent
reduction in VOC emissions and 26 percent reduction in NOX emissions) results in a
8.3 percent reduction in the peak ozone concentration (13.3 pphm) from the base
case (14.5 pphm). Scenario #2 differs from scenario //I in that there is an additional
12 percent reduction in NOX emissions. This additional reduction in NO emissions
results in an increase in the peak ozone concenrations of from 13.3 pphm (scenario
//I) to 13.4 pphm (scenario #2).
Discussion
Despite the fact that the three cities studied have similar measured 1985 median
VOC-to-NOx ratios (9.6 St. Louis, 10.4 Atlanta, and 11.8 Dallas-Fort Worth), the
effects of VOC and NOX emission reductions on the peak ozone concentration are
quite different. Reducing NOX emissions in 1995 Dallas-Fort Worth and St. Louis
results in increases in the peak ozone concentration, whereas, reducing NOX emis-
sions in 1995 Atlanta results in a decrease in the peak ozone concentration. Reduc-
ing VOC emissions always results in a reduction in the peak ozone concentration,
although the VOC reductions in Dallas-Fort Worth are over twice as effective at
reducing the peak ozone concenration than in Atlanta.
1995 ALTERNATIVE FUEL SCENARIOS
The results for the three 1995 alternative fuel scenarios are presented for Dallas-
Fort Worth, St. Louis, and Philadelphia. As noted in Section 2, the three fuel
scenarios (new gas regs, Ml00, CNG) were based on a 20 mph average speed
assumption, which is somewhat lower than speeds used to create the 1985 NAPAP
inventory that was used as a basis for developing the 1995 base case emissions
estimates. Care should be exercised when comparing results between the 1995 base
case and fuel strategies, since exhaust emissions factors increase with decreasing
vehicle speed. The differences in peak ozone between the 1995 base case and fuel
strategies than reported in Tables 3-3a,b might be larger if all 1995 scenarios
utilized identical speed assumptions.
Dallas-Fort Worth
New Regulations for Gas Vehicles
Isopleths of the predicted daily maximum ozone concentrations for the 1995 new reg
gas scenario is given in Figure 3-16. The peak ozone concentration for the 1995 new
39116r2 3
-------
Time : 200 - 2400 LSI
706
NORTH
Maximum Value = 13.27
Minimum Value = 8.99
726
746
20 -
4-316
- 4296
- 4276
- 4256
236
SOUTH
FIGURE 3-12. Predicted Daily Maximum Ozone Concentration (pphm) in St Louis
on 13 July 1976 for 1995 Scenario#1 Emission Scenario '
-------
Time : 0 - 2400 LSI
706
NORTH
726
746
Maximum Value = 3.31
Minimum Value = -18.28
766
SOUTH
- 4316
- 4296
- 4276
- 4256
4236
FIGUBE 3-13. Differences in Daily Maximum Ozone Concentrations (pob) betw^n
1995 base case and 1995 Scenario/? 1 emission scenarios (scenario/? 1 - bcse)
-------
Time : 200 - 2400 LST
706 726
NORTH
Maximum Value = 13.42
Minimum Value = 8.74
746
20-
V)
SOUTH
FIGURE 3-14. Predicted Daily Maximum Ozone Concentration ^ppnrn^ in St i -jis
on 13 July 1976 for 1995 Scenario#2 Emission Scenario " ~^
50
4316
- 4296
- 4276
- 4256
236
-------
Time : 0 - 2400 1ST
706
Maximum Value
Minimum Value
766
4.82
-18.65
SOUTH
FIGURE 3-15. Differences in Daily Maximum Ozone Concentrations (ppb) between
1995 base case and 1995 Scenario#2 emission scenarios fscenario#2
inSrlniu
-------
Time : 200 - 2400 LSI
620 640
NORTH
680 700
Maximum Value
Minimum Value
11.20
2.89
SOUTH
FIGURE 3-16a. Predicted Daily Maximum Ozone Concentration (pphm) in Dallas-Fort Worth
on 30 August 1985 for 1995 New Reg Gas Emission Scenario
- 3600
- 3530
3560
-------
Tim* : 200 - 2400 1ST
620 640
660
NORTH
660 700
Maximum Value » 12.97
Minimum Value * 1.91
720
SOUTH
:CUPE 3-16b. Predicted Daily Maximum Ozone Concentration (pphm) in Dallas-Fort Worth
on 31 August 1985 for 1995 New reg Gas Emission Scenario
3560
-------
reg gas scenario on 30 and 31 August is 11.2 and 13.6 pphm which is a 3 and 5 percent
reduction in the peak ozone concentration from the 1995 base case (Table 3-3). Dif-
ferences in daily maximum ozone concentrations between the 1995 new reg gas and
1995 base case emission scenarios are given in Figure 3-17. Comparisons betwen
these two scenarios should be viewed with caution since there has been adjustments
of emissions in the mobile sector for changes in speed in addition to the implementa-
tion of the proposed new standards for gasoline vehicles. However, the modeling
results do indicate that the maximum difference in daily maximum ozone concentra-
tions due to the new gasoline vehicles regulations would be approximately 1 pphm.
100 Percent Methanol (Ml00)
Use of a 100 percent penetration of methanol powered vehicles in 1995 results in a
decrease in the peak ozone concentration (10.7 and 12.4 pphm) of 4 to 5 percent over
the 1995 new reg gas emission scenario (Table 3-3). The location of the peak ozone
concentration in the 1995 Ml00 emission scenario is the same as seen for the 1995
new reg gas scenario (Figure 3-IS). Decreases in daily maximum ozone concentra-
tions due to the Ml00 vehicles are as high as 1.7 pphm (Figure 3-19).
100 Percent Compressed Natural Gas (CNG)
Use of 100 percent penetration of CNG vehicles in 1995 results in decreases in the
peak ozone concentration (10.5 and 12.2 pphm) of 6 percent over the 1995 new reg
gas scenario (Table 3-3). Again, the CNG fuels do not effect the location of the peak
ozone concentration (Figure 3-20). There are large regions of ozone reductions due
to the use of the CNG fuel (Figure 3-21). Daily maximum ozone concentrations are
reduced up to 2.4 pphm due to the use of CNG powerd vehicles.
St. Louis
New Regulations for Gas Vehicles
The implemention of the new gas vehicle regulations results in about a i percent
reduction in the peak ozone concentration in 1995 St. Louis (Table 3-3). As seen in
the isopleths of daily maximum ozone concentrations and DE plots with the 1995
base case (Figures 3-22 and 3-23) the predicted ozone concentrations for the 1995
new reg gas emission scenario are almost identical to the 1995 base case. The
maximum difference in the daily maximum ozone concentrations is 0.3 pphm.
100 Percent Methanol (Ml00)
The use of Ml00 vehicles in 1995 St. Louis results in a 1 percent decrease in the peak
ozone concentration over the 1995 new reg gas emission scenario (Figure 3-24). The
-------
Table 3-3a.
Region-wide maximum ozone concentrations (pphm) for
observed, current and 1995 base cases.
Strateav Dallas-Fprt Worth
Auaust 30
"Observed 14.0
"Current base 12.4
21995 base 11.6
Auaust 31
17.
16.
13.
0
4
7
Philadelphia
July 13
20.
23.
18.
5
6
6
St . £jOu
July
22.
24.
14.
13
3
4
5
1 -
2 -
1985, 1979, and 1976 are current base years for Dallas-
Fort Worth, Philadelphia, and St. Louis, respectively.
The 1995 base emissions projections utilized vehicle
speeds based on the NAPAP inventory; these speeds are
generally higher than the 20 mph used in the fuel
strategies in Table 3-3b, below. Care should be taken
when comparing results from this strategy with those
below since a 20 mph assumption would increase the 1995
base emissions.
Table 3-3b.
Region-wide maximum ozone concentrations fpphjin for
1995 fuel strategies.
Strategy Dallas-Fort Worth Philadelphia
Auaust 30 August 31 July 13
New Gas Regs 11.2 13.0 18.2
M10° 10.7 12.4 18.2
CNG 10.5 12.2 18.0
St. Louis
Julv 13
*•* v*-L y + -?
14.3
14.1
13.9
-------
Tim* : 0 - 2400 LST
620 640
660
NORTH
660 700
Maximum Value =* 0.18
Minimum Valu« » -8.20
10
SOUTH
370C
366C
3660
**** ".££!££» f v,f' f* „ % ^jj f f t/f^f I ,f2 m*.f *. * ** * **• ***'$. *?' w * , •"
ff"^£ ??** f s S**f"*£'JS'Z, „,/';£. < "" ' ",/* ' ' f J%* '?"'"£"T^T £****•*? * • '»' ' '"' *T&? tf f'
3640
3620
3600
3580
3360
FIGURE 3-17a. Differences in Daify Maximum Ozone Concentrations (ppb) between
in"D5a,,basS-eporWo^d ^7^1%^"°" ^^ ^^
9616
-------
80
Tim* : 0 - 2400 LST
620 640
s»
| 20
10
^.,.|:,...^^.|_|.^U.}v.^..? ^ ^^J
NORTH
680 700
Maximum Value
Minimum Valu*
760
0.43
-11.80
• fttMX.'tfit^StytntHrftfK*'*' *f'iJ$Sf*
3X/Z?'"
mp "X&'^KCvj
660 680 700 720 740 760
A^&MJM* 44^"'fed~A- A- M* 1-A4.-JL * ~l. *: i *- *, ,*
V-; ~%T-^ii^^^^'l!'^^/;vL'V**-:' .:-£•'.-• , -': r"_7" "•"•','
" * * "*• *• * '**'^y' *"*£/ T "• /ff f* ' *f f "f '**"**"•* "" * ' ff "
,--.,/ji-.^ri^«"/-' -^-./•^j-^^fi-y-.•' "rr',."';2]:-','''?, -*,"s, ,.- '7, ' -cr ' " ..-'
P
.' /'
/ ("
**£**%£?*!£„' *fftfUf'rZ*"fff "**•*•+•#*••' ** * *~f*+rt>*+f
\
.
& !
"\
,A \
^..
N r^ ^
\ ' 'S
A
TT',-""4SZ"£Z^'Z3!ty"JZ'; „ ' C.
10
20
> t >
30
SOUTH
40
'20
3700
3680
3660
3640
3620
3600
3580
3560
IGURE 3-17b. Differences in Daily Maximum Ozone Concentrations (ppb) between
1995 base case and 1995 new reg gas emission scenarios (new reg gas - base)
in Dallas-Fort Worth on 31 August 1985.
-------
Time : 200 - 24OO LSI
4JQO 620 540
660
NORTH
680 700
Maximum Value » 10."
Minimum Value • 2.81
720
740
760
78
87:
10
355
SOUTH
centre
00 Emission Scenario
-Fort Worth
9116
-------
Maximum Value = 12.4-3
Minimum Value » 1.80
Tim« : 200 - 24OO LSI
t* fr*>ftlr'*f, 'ff ' t fM* f fn fff f ft tt S ftt rfr. <. t i
r't- ' " '*' "• •
V v f \ i jXt\>
t * i i i v t t Ai t t i t i
SOUTH
- 3580
3560
CGURE 3-18b.Predicted Doily Maximum Ozone Concentration (pphm) in Dallas-Fort Worth
on 31 August 1985 for 1995 M100 Emission Scenario
-------
Time : 0 - 2400 LSI
,$90
620
30
20
10
640
660
NORTH
6flO 700
Maximum Value » 0.43
Minimum Value * —10.'
*
720
740
» » * f I I f
760
78Q_.
I J i—| 372'
*• V /
> \
—) ...;
*^^ ^^T**""""*™'*™"*"1 ** **»». ^^» • 4 \ /***
.,. ""**•*** ***«^-l ^> ••••••• »* V t* I
-......•^>—"-C^s^^l^^..^ ; >
— -2"*%
•• ••••^ <^.««*
...-- "
366
362
360<
SOUTH
FIGURE 3-19a. Differences in Daily Maximum Ozone Concentrations (ppb) between
1995 new reg gas and 1995 m100 emission scenarios (ml00 - new reg aas)
in Dallas-Fort Worth on 30 August 1985. 9 9 '
60
-------
Tim* : 0 - 2400 LSI
600 620 640
660
NORTH
680 700
Maximum Value
Minimum Value
2.36
-17.26
SOUTH
3560
:OJRE 3-19b.Diggerences in Daily Maximum Ozone Concentrations (ppb) between
1995 new reg gas and 1995 m100 emission scenarios (m100 - new req aas)
in Dallas-Fort Worth on 31 August 1985.
16
-------
Time : 200 - 2400 LSI
620 640
660
NORTH
680 700
Maximum Value » 10.5C
Minimum Value » 2.79
720
740
760
78
§72<
370<
10
SOUTH
35 6C
Ql 1C
-------
Tim* : 200 - 2400 LST
J500 620 640 660
NORTH
680 700
Moximum Valu* * 12.19
Minimum Value » 1.fl1
720 740
760
SOUTH
r20
3700
- 3680
3660
3640
3620
- 3600
- 3530
3560
-------
Tim« : 0 - 2400 LSI
(500 620 640
40i i i JI i-i i i
660
NORTH
680 700
20
10
720
•.•fVSie Se"*" & ~ " "" /
:"• ^.\
• *«— *"
*> '* ^V...——•••«.. ""it i _j, T^~'^'."****" . ^flg. ^ '• N
10
20
SOUTH
Moximum Valua » 0.27
Minimum Valu« » -14.30
740
760
40
"IGURE 3-21a. Differences in Daily Maximum Ozone Concentrations (ppb) between
1995 new reg gas and 1995 cng emission scenarios (cng - new reg gas)
in Dallas-Fort Worth on 30 August 1985.
§720
3700
3680
3660
3640
3620
3600
3580
3560
-------
Time : 0 - 240O LSI
600 620 640
660
20
10
NORTH
660 700
Maximum Value = 3.20
Minimum Value » -23.92
720
740
,.,, ~.~ „.';.',•; ,", z,zss*yt'j^', : , ' " • ~. -.• - /*
. r,M*,,'",', • •• ,-„,", ,••„„:..,•/"••„', • •• • „,.,,.•,• •• ' '':',:
\ \ t:>'^^^r-"r-'f \ t t '>">' t^r"«'-r t
10
20
30
SOUTH
760
40
IGURE 3-21b. Diggerences in Daily Maximum Ozone Concentrations (ppb) between
1995 new reg gas and 1995 cng emission scenarios (cng - new reg gas)
in Dallas-Fort Worth on 31 August 1985.
78(
'20
3700
3680
3660
3640
3620
3600
3530
3560
-------
Time : 200 - 2400 LSI
NORTH
706
726
74-6
Maximum Value = 14.25
Minimum Value = 9.13
766
V)
u
SOUTH
FIGURE 3-22. Predicted Daily Maximum Ozone Concentration (pphm) in St. Louis
on 13 Juiy 1976 for 1995 New Reg Gas Emission Scenario
66
- 4316
- 4296
- 4276
- 4256
4236
39116
-------
NORTH
Maximum Value = 0.05
Minimum Value = -2.62
766
4316
SOUTH
- 4296
4276
4256
4236
-------
Time : 200 - 2400 1ST
706 726
NORTH
746
Maximum Value = 14.08
Minimum Value = 9.13
766
SOUTH
FIGURE 3-24. Predicted Daily Maximum Ozane Concentration (pohm) in St. Louis
on 13 July 1976 for 1995 M100 Emission Scenario
-4316
- 4296
- 4276
- 4256
4236
-------
predicted ozone concentrations for the 1995 M100 emissions scenario are very simi-
lar to the 1995 new reg.gas emission scenario (Figure 3-25) with a maximum decrease
in daily maximum ozone concentrations of 0.4 pphm.
100 Percent Compressed Natural Gas (CNG)
Use of CNG fuel results in larger decreases in ozone concentrations over the 1995
new reg gas scenario than exhibited by the Ml00 fuel scenarios. The peak ozone
concentration is reduced by 3 percent (Table 3-3 and Figure 3-26) and the maximum
decrease in daily maximum ozone concentrations is 0.6 pphm (Figure 3-27).
Philadelphia
For the Philadelphia 1995 emission scenarios initial and boundary conditions were
adjusted based on observed changes in national emission trends from 1979 to 1985
and projected changes in emissions taken from the 1985 and 1995 base case emission
scenarios. Initial and boundary conditions in 1995 for the other cities were not modi-
^ "Clean" ValU6S W ; M°rris Myers' and Carr
1995 Base Case
Isopleths of daily maximum ozone concentrations for the Philadelphia 1995 Base
Case is given in Figure 3-28. The peak predicted ozone concentration is 18.6 pphm
and occurs approximately 10 km to the north of downtown Philadelphia. The 1979
Base Case predicted a peak ozone concentration of 25.6 pphm. Since there is consid
erable increase in VOC emissions (79 percent) and NOX emissions (29 percent)
between the 1979 and 1995 base case emission inventories, the reduction in the peak
Th°nfQo°,nKentratl0n mUSt be due t0 the reduction in initial and boundary conditions.
The 1995 base case emission inventory has higher emissions than the 1979 base case
due to the inclusion of many previously uninventoried sources. Thus despite these
^Jtfr5' °n national emission trends and projections it is projected that VOC
and NOX emissions will go down between 1979 and 1995.
New Regulations for Gas Vehicles
Isopleths of daily maximum oozne concentrations for the 1995 new reg gas emission
scenario are given in Figure 3-29. Differences between the 1995 new reg gas and
1995 base case emission scenarios are given in Figure 3-30. The new gasoline vehicle
regulations is estimated to reduce the peak ozone concentrations by approximtaely 2
percent. The maximum reduction in the daily maximum ozone conLEaXTX-
mated to be around 0.5 pphm. Again, because of the differences in speed used in the
39116r2 8
-------
Time : 0 - 2400 LSI
706
726
NORTH
746
Maximum Value = 0.22
Minimum Value = -3.74
766
-4316
- 4296
- 4276
- 4256
4236
SOUTH
FIGURE 3-25. Differences in Dailv Maximum Ozone Concentrations (pob) between
1995 new reg .gas and 1995 M100 emission scenarios (M100 - new reg gas;
in St. Louis on 13 July 1976.
39116
70
-------
Time : 200 - 2400 1ST
706 726
3"26
NORTH
746
Maximum Value = 13.92
Minimum Value = 9.13
766
SOUTH
4316
4296
4276
4256
4236
-------
Time : 0 - 2400 LSI
706
u
NORTH
726
746
Maximum Value = 0.09
Minimum Value = -6.55
766
SOUTH
-4-316
- 4-296
- 4-276
- 4256
4236
FIGURE 3-27. Differences in Daily Maximum Ozone Concentrations (ppo) between
1995 new reg gas and 1995 CNG emission scenarios ( CNG - new rea aas)
in St. Louis on 13 July 1976.
72
0 AT 1 P
-------
Time : 200 - 2400 LSI
387 407 427
447
NORTH
467 487
Maximum Valu* « 18.56
Minimum Valu« = 7.74
507
527
547
587
'*r 4500
C 4480
- 4480
4440
- 4420
- 4400
- 4380
- 4360
4340
SOUTH
FIGURE 3-28. Predicted Daily Maximum Ozone Concentration (pphm) in Philadelphia
on 13 July 1979 for 1995 Base Case Emission Scenario
-------
Tim« : 200 - 2400 LSI
387 407 427
447
NORTH
467 467
Maximum Value » 18.19
Minimum Valu« » 7.68
507
527
547
567
- 4500
r 4480
*• 4460
4440
- 4420
- 4400
- 4380
- 4360
4340
SOUTH
FIGURE 3-29. Predicted Daily Maximum Ozone Concentration (pphm) in Philadelphia
on 13 July 1979 ior 1995 New Reg Gas Emission Scenario
-------
Tim* : 0 - 2400 LSI
387 407 427
447
NORTH
467 487
Maximum Valiw » 0.67
Minimum Valu« « -4.80
507
527
547
SOUTH
567
- 4500
C 4480
- 4460
4440
- 4420
- 4400
- 4380
- 4360
4340
FIGURE 3-30.Differences in Daily Maximum Ozone Concentrations (ppb) between
1995 base case and 1995 new reg gas emission scenarios (new req aas
in Philadelphia on 13 July 1979.
- base)
-------
development of the 1995 base case and 1995 alternative fuel scenarios, care should
be taken in the interpretation of these results,.
100 Percent Methanol (Ml00)
The use of 100 percent penetration of MiOO powered vehicles in 1995 Philadelphia
has almost no effect on ozone concentrations when compared to the 1995 new reg
gas emission scenario (Table 3-3 and Figure 3-31 and 3-32). As seen in the DE plot
(Figure 3-32) the maximum increase and decrease in daily maximum ozone concen-
trations due to the MIOO fuel is 0.1 and 0.3 pphm, respectively. The lack of any
effect of the MIOO vehicles in Philadelphia is due to several factors including the
large amount of transported pollutants (initial and boundary conditions) in the region
and the large amount of VOC emissions from nonmobile sources in the region.
100 Percent Compressed Natural Gas (CNG)
There is a slight reduction in the peak ozone concentration (1 percent) when CNG
fueled vehicles are used in Philadlephia (Table 3-3 and Figure 3-33). Daily maximum
ozone concentrations for the 1995 CNG emission scenario decrease by as much as 0.5
pphm when compared to the 1995 new regulations for gas vehicles emission scenario
(Figure 3-34). Due to the large influence of transport and other nonmobile emission
sources in the Philadelphia region the alternative fuels do not have as big of an
effect on urban ozone concentrations as seen in Dallas-Fort Worth and St. Louis.
Discussion
The calculation of the effects of alternative fuels on urban ozone concentrations in
1995 is highly dependent on the mix of the emissions inventories. Current emission
control policy is focusing on reducing VOC emissions from the transportation sec-
tor. Thus it is projected that by 1995 there will be a substantial reduction in mobile
source VOC emissions. However due to growth in the region current emission projec-
tion factors estimate that VOC emissions from other nonmobile sources will
increase. The net result is that it is estimated that the influence of mobile source
emissions will be substantially lower than it is currently. For example, as seen in
Table 2-1, it is estimated that the contribution of mobile sources to the total anthro-
pogenic VOC emission inventory in Dallas-Fort Worth will almost be halved when
comparing the 1985 (64 percent) to the 1995 (38 percent) base case inventories.
The results on alternative fuels presented here raise several important issues:
1. Are current future year mobile source emission reduction estimates
overly optimistic in the amount of emission reductions;
891 16r2 8
76
-------
Time : 200 - 2400 LSI
387 407 427
447
NORTH
467 487
Maximum Value * 18.17
Minimum Value » 7.69
507
527
547
567
45 OO
C 4480
- 4460
4440
.-? 4420
- 4400
r" 4380
- 4360
4340
SOUTH
FIGURE 3-31. Predicted Daily Maximum Ozone Concentration (pphm) in Philadelphia
on 13 July 1979 for 1995 M100 Emission Scenario
-------
Tim« : 0 - 2400 LSI
387 407 427
447
NORTH
467 487
Maximum Valtw * 1.10
Minimum Volua * -2.69
507
527
54-7
567
- 4500
C 4480
- 4460
4440
- 4420
- 4400
- 4380
- 4360
4340
SOUTH
FIGUPE 3-32. Differences in Daily Maximum Ozone Concentrations (ppb) between
1995 New Reg Gas and 1995 M100 emission scenarios (Ml00 - new rea aas}
in Philadelphia on 13 July 1979.
78
9116
-------
387
es
Tim* : 200 - 24OO LSI
407 427
447
NORTH
467 467
Maximum Value » 17.95
Minimum Value * 7.67
507
527
547
SOUTH
FIGURE 3-33. Predicted Daily Maximum Ozone Concentration (pphm) in Philadelphia
on 13 July 1979 for 1995 CNG Emission Scenario
587
- 4500
C 4460
- 4460
4440
- 4420
- 4400
- 4380
- 4360
4340
-------
Time : 0 - 2400 LSI
387 407 427
447
NORTH
467 467
Maximum Value » 0.32
Minimum Value » -5.21
507
527
547
567
- 4500
c 4480
*• 4460
* 4440
- 4420
- 4400
- 4380
- 4360
4340
SOUTH
FIGURE 3-34.Differences in Daily Maximum Ozone Concentrations (ppb) between
Dt,N!W, Ru6g GOS °nd 1995 CNG emission scenarios (cng - new req gas)
in Philadelphia on 13 July 1979 y y '
-------
2. Are the emission projections for the other source categories over- or
underestimates of actual values; and
3. Given that the current emission projections are correct, then the ozone
attainment policy needs to consider reductions in VOC (and possibly NOX
for some regions) emissions from sources outside the mobile sector.
391 16r2 8
-------
-------
RESULTS FOR THE EKMA MODELING
One of the initial goals of the EPA Five Cities UAM Study was to compare VOC
emission control reductions needed to reach attainment of the ozone NAAQS calcu-
lated by the Empirical Kinetics Modeling Approach (EKMA) and the UAM. However,
because of fundamental differences in model formulation and how the EKMA and
UAM are used, this comparison is not possible. Given an observed VOC-to-NOx
ratio, an observed peak ozone concentration, and a spatially averged emission inven-
tory the EKMA calculates the percentage of VOC emissions that needs to be reduced
to reach attainment of the ozone NAAQS for a historical ozone episode (i.e. "design
day"). Procedues for using the UAM usually involve a comprehensive model perfor-
mance evaluation followed by the evaluation of how future year emission control
strategies will effect urban ozone concentrations.
In this section we discuss the application of the EKMA to five cities: Dallas,
Atlanta, Philadelphia, St. Louis, and New York. The EKMA analysis was performed
by EPA/OAQPS using best estimates of model input data. The EKMA modeling was
performed for the "design day" from 1983 to 1985, except for New York where a day
with a slightly lower ozone concentration was used. Much of the EKMA modeling
inputs were "generic" in nature, i.e. modeling inputs were based on analysis of
observed data from the city in question rather then representing conditions for a
given episode. The source of the key EKMA inputs are listed as follows:
EKMA INPUT SOURCE
Emissions 1985 NAPAP Emission Inventory
(Zimmerman et al., 1989)
Day Design day from 1983 to 1985
Ozone aloft From AIRS data base
Initial NMOC and NOX Based on measurments using data from
1984 to 1986 (Bauges, 1986)
Initial CO Based on guidance for running EKMA
NMOC/NOX ratio From 1984 to 1986 measurement studies
(Bauges, 1986)
39116r2 10
-------
Hourly temperatures Local climatologicai summaries
Relative humidity Local climatoligical summaries
The EKMA calculations were first performed in the CALC mode to make sure that
the predicted peak ozone concentrations was within 30 percent of the design value.
The model was then exercised in the EKMA mode to calculate the amount of VOC
emissions reductions needed to reduce the design value to the ozone NAAQS. Note
that NOX emission reductions and biogenic emissions were not included in the anal-
ysis.
Table 4-1 lists the VOC emission reduction amounts required to reach attainment of
the ozone NAAQS for the five cities as calculated by EKMA. As noted previously, it
is impossible to compare these results with those produced by the UAM due to dif-
ferences in the days studied, differences in the base emission inventories (1995 for
UAM and 1985 for EKMA), lack of including biogenic emissions in the EKMA anal-
ysis, and inherent differences in model formulations and procedures for using the two
models.
89116r2 10
-------
TABLE 4-1. Results of the EKMA modeling for five cities.
(Biogenic emissions were not included in these analysis.)
Percent VOC Emission Reductions
Needed to Reach Attainment
City Date Modeled of the Ozone NAAQS
Dallas 27 June 1981 52
Atlanta 14 July 1983 55
Philadelphia 13 August 1985 25
St. Louis 26 August 1983 65
New York 13 June 1984 68
89116rl 2
34
-------
-------
References
ARB. 1989. "Definition of a Low-Emission Motor Vehicle in Compliance With the
• c^1? °f Health Snd ^^ SeCtion 39037-05 (Assembly Bill 234, Leonard,
1987. California Air Resources Board, Mobile Source Division, El Monte,
California. *
Baugues, K. 1986. A Review of NMOC/N
-------
Lonneman, W. 1986. "Comparison of 0600-0900 AM Hydrocarbon Composition
Obtained from 29 Cities." Proceedings of the 1986 EPA/APCA Symposium on
Measurements of Toxic Air Pollutants, APCA Publication VIP-7 and EPA
600/9-86-013, pp. 419-430.
Morris, R. E., T. C. Myers, E. L. Carr, and M. C. Causley. 1989c. "Urban Airshed
Model Study of Five Cities. Demonstration of Low-Cost Application of the
Model to the City of Atlanta and the Dallas-Fort Worth Metroplex Regions."
Systems Applications, Inc., San Rafael, California (SYSAPP-89/122).
Morris, R. E., T. C. Myers, M. C. Causley, and L. Gardner. 1989b. "Low-Cost Appli-
cation of the Urban Airshed Model to Atlanta and Evaluation of the Effects of
Biogenic Emissions on Emission Control Strategies." Systems Applications,
Inc., San Rafael, California.
Morris, R. E., T. C. Myers, H. Hogo, L. R. Chinkin, L. A. Gardner, and R. G.
Johnson. 1989a. "A Low-Cost Application of the Urban Airshed Model to the
New York Metropolitan Area and the City of St. Louis." Systems Applications,
Inc., San Rafael, California (SYSAPP-89/038).
OTA. 1988a. "Urban Ozone and the Clean Air Act: Problems and Proposals for
Change." Office of Technology Assessment, Washington, D.C.
OTA. 1988b. "Ozone and the Clean Air Act: Summary of OTA Workshop with State
and Local Air Pollution Control Agency Officials." Office of Technology
Assessment, Washington, D.C.
OTA. 1988c. "Ozone and the Clean Air Act: A Summary of OTA Workshops on
Congressional Options to Address Nonattainment of the Ozone Standard."
Office of Technology Assessment, Washington, D.C.
Pechan and Assoc. 1988. "National Assessment of VOC, CO, and NO Controls,
Emissions, and Costs." E. H. Pechan <5c Associates, Inc., Springfield, Virginia.
Rao, S. T. 1987. Application of the Urban Airshed Model to the New York Metro-
politan Area. U.S. Environmental Protection Agency (EPA-450/4-87-011).
SAL 1989. "User's Manual for Preparing Emission Files for Use in the Urban Airshed
Model." Systems Applications, Inc., San Rafael, California (SYSAPP-89/114).
Schere, K. L., and 3. H. Shreffler. 1982. Final Evaluation of Urban-Scale Photo-
chemical Air Quality Simulation Models. U.S. Environmental Protection
Agency (EPA-600/3-82-094).
Science. 1988. Rural and urban ozone. Editorial in Science, 241(4873): 1569.
39 I16r L 9
86
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Seinfeld, J. H. 1988a. Ozone air quality models. A critical review. J. Air Pollut.
Control Assoc.. 38(5):616.
Seinfeld, J. H. 1988b. Closing remarks. 3. Air Pollut. Control Assoc..38(8); 1136-
1137.
Smolarkiewicz, P. K. 1983. A simple positive definite advection scheme with small
implicit diffusion. Monthly Weather Review. 111:479-486.
Zimmerman, D., W. Tax, M. Smith, J. Demmy, and R. Battye. 1988. Anthropogenic
Emissions Data for the 1983 NAPAP Inventory. U.S. Environmental Protection
Agency (EPA-600/7-88-022).
891 16rl 9
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Appendix A
MEMORANDUM OF IS SEPTEMBER 1989 FROM EPA/OMS TO
EPA/OPPE DESCRIBING PROCEDURES TO BE USED FOR
DEVELOPING THE 1995 NEW REGULATION GAS VEHICLE,
1995 100 PERCENT METHANOL (M100) VEHICLE, AND 1995
100 PERCENT COMPRESSED NATURAL GAS (CNG) VEHICLE
SCENARIOS
89 1 16r2 1
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
ANN ARBOR. MICHIGAN 48105
.c
18 MB
MEMORANDUM
OFFICE OF
AIR AND RADIATION
SUBJECT: Emission Factors- for SAI Runs with CNG and Neat
Methanol
FROM: Phil Lorang, Chief
Technical Support Staff
TO: Gene Durman, Chief
Air Economics Branch (PM-221)
THRU: Charles L. Gray, Jr., Director
Emission Control Technology Division
Recently, John Chamberlin, Robin Miles-McLean, and Dwight
Atkinson called to ask for emission factor input for some SAI
runs you are planning for Dallas, Philadelphia, and St. Louis
using CNG and neat methanol vehicles (which would be LDVs and
LDTs under the President's proposal).
We understand that the 1985 NAPAP inventory and source
category growth factors to 1995 provided by Pechan are being
used. For motor vehicle emissions excluding refueling, SAI in
effect recovers 1985 VMT by dividing the 1985 tons by a 1985
emission factor. SAI then multiplies the VMT by the Pechan
growth factor and the scenario-specific 1995 emission factor to
obtain the 1995 motor vehicle tons. The vehicle categories are
LDGV, LDGT, HDGV, and "HDD" (which in Pechan1 s treatment is
really the aggregate of LDDV, LDDT, and HDDV), and tons and VMT
are distinct for three road types in each county. Emission
factors are for the day as a whole, not hour-by-hour.
As you and the other involved EPA staff know, the 1985
NAPAP inventory has a speed problem, towards overestimating
average speed and underestimating exhaust emissions. I
recommend we assume that all VMT in 1995 occurs at 20 mph.
(The 1985 emission factors used to recover 1985 VMT should
continue to be based on the speeds assumed for the 1985 NAPAP
-------
-2-
inventory.) This simple treatment does not interfere with the
gasoline versus methanol versus CNG comparison. It does mean
that none of these three cases should be compared to any
previous run based on the stock NAPAP inventory approach.
With this speed assumption, providing the required motor
vehicle inputs is fairly easy, given the head start from our
work with OAQPS and Pechan. Gasoline emission factors have
been prepared for each of the three cities, with the minimum
.and maximum temperatures and the gasoline RVP for each city
used as input. For each city, separate tables have been
prepared for gasoline-fueled light-duty vehicles and light-duty
trucks. SAI provided us with the minimum and maximum
temperatures for Dallas, Philadelphia, and St. Louis as
inputs.
Tables 1 through 6 give LDGV and LDGT emission factors for
the gasoline cases. For both LDV and LDT the standards
proposed by the President for his Clean Air Act revisions sent
to Congress are assumed. MOBILE4 was run out to steady state
using these standards and the temperature ranges SAI provided
as input. An RVP of 9.0 psi is assumed for all three cities-
data for a 7.8 psi RVP fuel are also given in Philadelphia and
St. Louis since the lower RVP fuels may be used there.
The evaporative and running loss emissions have been
"corrected" to account for improvements in the test procedure
that would reduce excess evaporative emissions. This involved
a comparison of the standard MOBILE4 output (called A) with an
output eliminating tampering and fuel switching (called B) and
a rough estimate (0.11 g/mile, called C) of what evaporative
emissions would be under the best system. The percent
reduction to apply to the standard MOBILE4 output (A) to get
the final evaporative and running loss estimates given in the
tables were obtained by the following formulas:
Evaporative % reduction = 70% (B-O/A
Running loss % reduction = 80% (B/A)
The hydrocarbon speciation for the gasoline cases should
be as given in my previous memos and notes, which are attached
and referenced in the tables.
The emission factors for the vehicles optimized for 100%
methanol (Tables 7 and 8) were taken from the latest version of
the draft special report, at one time titled "Clean,
Alternative Fuels - The President's Proposal." For evaporative
and running loss emissions, the emission factors in the soecial
report are taken directly, and not adjusted for temperature
Evaporative and running loss emissions from M100 vehicles are
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-3-
expected to be very insensitive to local temperatures because
of the relatively high boiling point of M100. To estimate the
NMHC, methanol, and formaldehyde emission factors for M100
trucks, the M100 vehicle emission factors were adjusted by
applying the ratios of LDT to LDV hydrocarbon emission factors
obtained in the special MOBILE4 run. This accounts for
presumably higher exhaust standards, larger fuel tank volumes,
and lesser heating of the fuel tank.
The hydrocarbon speciation for the MlOO vehicles and
trucks (excluding methanol and formaldehyde which are explicit
in Tables 7 and 8) should be that given in the attached report
prepared by the California Air Resources Board titled,
"Definition of a Low-Emission Motor Vehicle in Compliance with
the Mandates of Health and Safety Code Section 39037 05
(Assembly Bill 234, Leonard, 1987)." However, you should
probably assume that the reported number for butane is about
50% butane and 50% butadiene. EPA ORD has some preliminary
detailed speciation data for a methanol fueled vehicle; ORD
personnel (Peter Gabele) indicate that these data are
consistent with the California results.
The NMHC emission factors for the CNG vehicles are based
on test data discussed in the attached 1989 paper titled,
"Motor Vehicle Emission Characteristics and Air Quality Impacts
of Methanol and Compressed Natural Gas" by Jeff Alson, Jon
Adler, and Tom Baines. The NMHC emission factor is an average
of those for the dedicated and dual-fueled vehicles. This
approach was used as a way to try to account for in-use
deterioration from an optimized CNG vehicle. We are assuming,
as stated in the EPA Guidance Document, that there are no
evaporative emissions (and thus no running loss or refueling
losses) from CNG vehicles. The formaldehyde emission factor
was calculated by applying the formaldehyde fraction found in
the attached CARS report to the NMHC exhaust emission factor.
The same procedure used for MlOO was used to estimate emission
factors for CNG trucks.
The NMHC speciation for the CNG vehicles and trucks should
be as given in the CARB report. Total HC emissions for CNG
vehicles consist of about 90% methane and 10% NMHC; you may
need to include this methane fraction in your runs. By
contrast, methane levels for gasoline vehicles are about 10% of
the total hydrocarbon levels. The methane levels for the 100%
methanol vehicles are about 50% of the total hydrocarbon levels.
CO emissions from the MlOO CNG vehicles and trucks are
assumed to be the same as the gasoline case. (With a 0.2 NOx
standard and without a lower CO standard for CNG, we should not
count on a CO reduction under summer conditions.) For NOx
emissions, it is assumed that gasoline, MlOO, and CNG vehicles
-------
a
-4.
and trucks emit equal NOx. Even though available data show
tendency towards an increase in NOx for CNG, we are assuming
that the CNG vehicles and trucks will be modified to meet the
Administration Bill's NOx standards.
Emission factors for uncontrolled refueling emissions are
fifij611 inn^hei tab^ For the gasoline case, you should assume
66% control (74% per station; 10,000 gallons/month
exemptions). For the M100 case, you can incorporate some
temperature dependence by assuming 24% as much methanol as
there is NMHC in the controlled 9 psi gasoline case. This is
about 91% control of the mass. For the CNG case, you should
assume no refueling emissions.
We strongly recommend that SAI be required to account for
reduction in VOC emissions from production, storage, and
transfer of gasoline. Jim Wilson's letter on this subject
would be the starting point. Inventory categories will have to
be matched up. The M100:gasoline ratio from the refueling
category could be used to adjust other transfer and storage
categories. It will be important to be aware of whether the
gasoline inventories already represent some control or not.
_ You should assume that LDDV, LDDT, HDGV, and HDDV
emissions are the same in all scenarios. None is affected by
the Administration bill, so standard MOBILE4 applies. SAI and
Pechan should coordinate on the treatment of diesel vehicles
Diesel vehicles are not sensitive to temperature so all three
cities will use the same emission factors.
I hope this information is helpful to you. if you or the
SAI personnel have further questions, please call either Joe
Somers (FTS 374-8321, commercial 313-668-4321) or me (FTS
374-8374, commercial 313-668-4374).
Attachments
cc: Richard D. Scheffe
Ken Knapp
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Table 1
Projected In-Use Emissions For
Light-Duty Gasoline Vehicles (grams per mile)
Dallas (T min. 77°, T max. 102°)
Type of
Emission
Exhaust
Evap
Running
Losses
Uncontrolled
Refueling
7.8 psi RVP
NMHC CO NOx
0.45 5.56 0.71
0.184
0.154
0.17
9 . 0 psi
NMHC " CO
0.50 7.36
0.26
0.39
0.20
RVP
NOx
0. 73
Gasoline NMHC speciation guidance provided in the August 23,
August 30, and September 2, 1988 memos from Phil Lorang to Ralph
Morris, and a September 1, 1988 memo from Phil Lorang to Gene
Durman.
Exhaust emission factors calculated at an average speed of 20
mph.
66% control of these refueling emissions should be assumed.
-------
Table 2
Projected In-Use Emissions For
Light-Duty Gasoline Vehicles (grams per mile)
Philadelphia (T min. 72°, T max. 92°)
Type of
Emission
Exhaust
Evap
Running Losses
NMHC
0.53
0.187
0.136
9.0 psi ~RVP
CO
7.90
NOx
0.72
Uncontrolled
Refueling 0.20
Gasoline NMHC speciation guidance provided in the August 23,
August 30, and September 13, 1988 memos from Phil Lorang to
Ralph Morris, and a September 7, 1988 memo from Phil Lorang to
Gene Durman.
Exhaust emission factors calculated at an average speed of 20
mph.
66% control of these refueling emissions should be assumed.
-------
Projected In-Use Emissions For Light-Duty
Gasoline Vehicles (grams per mile)
St. Louis (T min. 68°, T max. 92°)
Type of
Emission
Exhaust
Evap
Running
Losses
7.8 psi RVP
NMHC CO NOx
0.52 7.78 0.72
0.163
0.086
9.0 psi RVP
NMHC CO NOx
0. 52 7. 78 0 . 72
0. 183
0.142
Uncontrolled
Refueling
0.17
0.20
Gasoline NMHC speciation guidance provided in the August 23,
August 30, and September 2, 1988 memos from Phil Lorang to
Ralph Morris, and a September 1, 1988 memo from Phil Lorang to
Gene Durman.
Exhaust emission factors calculated at an average speed of 20
mph.
66% control of these refueling emissions should be assumed.
-------
Table 4
Projected In-Use Emissions For Light-Duty
Gasoline Trucks (grams per mile)
Dallas (T min. 77°, T max. 102°)
Type of
Emission
Exhaust
Evap
Running
Losses
7.8 psi RVP
NMHC CO NOx '
0.53 4.89 l.ll
0.211
0.142
9.0 psi RVP
NMHC CO NOx
0.63 6.68 1.13
0.278
0.322
Uncontrolled
Refueling 0.23 0.26
Gasoline NMHC speciation guidance provided in the August 23,
August 30, and September 2, 1988 memos from Phil Lorang to
Ralph Morris, and a September 7, 1988 memo from Phil Lorang to
Gene Durman.
Exhaust emission factors calculated at an average speed of 20
mph.
66% control of these refueling emissions should be assumed.
-------
Table 5
Projected In-Use Emissions For Light-Duty
Gasoline Trucks (grams per mile)
(Philadelphia (T min. 72°, T max. 102°)
Type of
Emission
Exhaust
Evap
Running Losses
9.0
NMHC
0.64
0.201
0.136
psi RVP
CO
7,84
NOx
1. 12
Uncontrolled
Refueling 0.26
Gasoline NMHC speciation guidance provided in the August 23,
August 30, and September 2, 1988 memos from Phil Lorang to
Ralph Morris, and a September 7, 1988 memo from Phil Lorang to
Gene Durman.
Exhaust emission factors calculated at an average speed of 20
mph.
66% control of these refueling emissions should be assumed.
-------
Table 6
Projected In-Use Emissions For Light-Duty
Gasoline Trucks (grams per mile)
St Louis *(T min. 68°. T max. 92°)
Type of
Emission
Exhaust
Evap
Running
Loss
Uncontrolled
refueling
7.8 psi RVP
NMHC CO ttOx
0.64 7.13 1.12
0.173
0.082
0.23
9 . 0 psi
NMHC CO
0.64 7.13
0.214
0.134
0.26
RVP
NOx
1 . 12
Gasoline NMHC speciation guidance provided in the August 23,
August 30, and September 2, 1988 memos from Phil Lorang to
Ralph Morris, and a September 7, 1988 memo from Phil Lorang to
Gene Durman.
Exhaust emission factors calculated at an average speed of 20
mph.
66% control of these refueling emissions should be assumed.
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TECHNICAL REPORT DATA
fflease read Instructions on the reverse before completing)
EPA 450/4-90-006F
3. RECIPIENT'S ACCESSION NO.
T.TLEANDSUBT.TLE URBAN AIRSHED MODEL STUDIES OF FIVE
CITIES - Low-Cost Application'of the Model to Future-Year
SIP Control and Alternative Fuel Strategies for Dallas-
Fort Worth, Atlanta, Philadelphia, and St. Louis(Vol 1)
5. REPORT DATE
April 1990
». PERFORMING ORGANIZATION CODE
Ralph E. Morris, Marianne C. Causley, Julie L. Fieber,
LuAnn Gardner, Thomas C. Myers
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Systems Applications, Inc.
101 Lucas Valley Road
San Rafael, CA 94903
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
2i SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Philadelhi
Po?senH,^ban Airshed Model results on alternative fuel and State
strategies for Atlanta, Dallas-Fort Worth, St. Louis and
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Ozone
i Urban Airshed Model
! Photochemistry
| Control Strategy
Alternative Fuels
18. DISTRIBUTION STATEMENT
b.lDENTIFIERS/OPEN ENDED TERMS
19. SECURITY CLASS (This Report)
20. SECURITY CLASS (This page)
EPA Form 2220-1 (R«v. 4-77) PREVIOUS EDITION is OBSOLETE
c. COSATI Field/Group
21. NO. OF PAGES
88
22. PRICE
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