Transcript Slide - CMAS

Background Air Quality in the
United States Under Current and
Future Emissions Scenarios
Zachariah Adelman, Meridith Fry, J. Jason West
Department of Environmental Sciences and Engineering
University of North Carolina
Pat Dolwick, Carey Jang
Office of Air Quality Planning and Standards
United States Environmental Protection Agency
Presented at the 10th Annual CMAS Conference
October 24-26, 2011 Chapel Hill, NC
Motivation and Objectives
• Will U.S. background air pollutant concentrations
increase in the future?
• Objectives:
– Gather and process latest IPCC inventories for current and
future year emissions estimates
– Use MOZART-4 to simulate future air quality resulting from
climate change mitigation emissions scenarios
– Estimate background air quality in the U.S. by “zeroing-out”
North American anthropogenic emissions
– Downscale global modeling results to produce boundary
conditions for regional modeling
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Methods and Data
• Chemistry-Transport Model: MOZART-4
• Meteorology: 2005 GEOS-5 1.9°x2.5°
• Emissions Inventory: 2005 and 2030 Representative
Concentration Pathways (RCP)
– RCP8.5 – Business as usual emissions
– RCP4.5 – Best estimate emissions reduction
– RCP2.6 – Maximum emissions reduction
• Zero-out North America (ZONA):
– U.S., Canada, Mexico anthropogenic emissions set to zero
• Includes near-shore (< 50km) shipping, aircraft < 3km, and fertilizer
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Methods and Data
• Emissions processing with
custom IDL and NCL scripts
– Speciate with RCP to
MOZART-4 conversion factors
– Temporalize with RETRO
monthly profiles
– Regrid to GEOS-5 grid
– Merge natural and
anthropogenic sectors and
create MOZART-ready files
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Speciate
Temporalize
Regrid
Merge
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RCP  MOZART-4 Species
MOZART RCP Species
MOZART
RCP Species
CH3OH
0.5*alcohols
C2H2
ethyne
C2H5OH
0.5*alcohols
MEK
0.5*ketones
CH2O
formaldehyde
CH3COCH3 0.5*ketones
C2H6
ethane
HCOOH
0.5*acids
C3H8
propane
CH3COOH
0.5*acids
BIGALK
butanes+pentanes+hexanes
TOLUENE
C2H4
ethene
C3H6
propene
benzene+toluene+xylene+
trimethyl_benzene+other_
aromatics
BIGENE
butane+other_alkenes_and_
alkynes
C10H16
terpenes
ISOP
isoprene
OC1
OC
CB1
BC
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MOZART-4 Simulations
• Simulations using
meteorology for
2005
• July 1 – December
31, 2004 spin-up
• Fixed methane
concentrations
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MOZART
CH4 (ppb)
2005 RCP8.5
1,783
2030 RCP8.5
2,132
2030 RCP4.5
1,830
2030 RCP2.6
1,600
2005 RCP8.5 ZONA
1,783
2030 RCP8.5 ZONA
2,132
2030 RCP4.5 ZONA
1,830
2030 RCP2.6 ZONA
1,600
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Emissions Summaries
Global
US
NOx
NMVOC
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Emissions Summaries
Global
US
BC
OC
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Base Annual Max 8-hr O3 Results
RCP 8.5 2005
RCP 8.5 2030
RCP 4.5 2030
RCP 2.6 2030
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ZONA Annual Max 8-hr O3 Results
RCP 8.5 2005
RCP 8.5 2030
RCP 4.5 2030
RCP 2.6 2030
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8-hr O3 Results
Annual Mean 8-hr O3
RCP8.5 2005
RCP8.5 2030
RCP4.5 2030
RCP2.6 2030
RCP8.5 2005 ZONA
RCP8.5 2030 ZONA
RCP4.5 2030 ZONA
RCP2.6 2030 ZONA
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Annual Max 8-hr O3
Global
US
Global
US
28.8
30.2
29.0
27.3
26.9
28.0
27.4
25.5
42.4
43.1
40.8
39.3
30.1
31.6
30.9
29.1
178.1
166.1
142.4
156.1
177.7
165.2
164.9
156.0
170.4
118.9
133.8
138.1
50.1
52.8
51.6
49.3
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Background U.S. mean 8-hr O3
RCP8.5 2005
RCP8.5 2030
RCP4.5 2030
RCP2.6 2030
Annual
Winter
Spring
Summer
Fall
30.1
31.6
30.9
29.1
31.5
33.3
32.6
31.0
32.9 (5.4)
34.4 (5.7)
33.8 (5.6)
31.6 (5.3)
26.5 (5.6)
27.8 (6.0)
27.1 (5.8)
25.4 (5.4)
29.3 (4.8)
30.8 (5.2)
30.2 (5.1)
28.2 (4.6)
Background contribution to U.S. mean 8-hr O3
RCP8.5 2005
RCP8.5 2030
RCP4.5 2030
RCP2.6 2030
Annual
Winter
Spring
Summer
Fall
71%
73%
76%
74%
89%
85%
83%
83%
71%
74%
77%
75%
58%
63%
68%
65%
70%
72%
75%
73%
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U.S. Summer Daily Max 8-hr O3
Frequency Distribution
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Base Annual Max 24-hr non-dust PM2.5* Results
*(SO4, NO3, NH4, SOA, EC, and OC)
RCP 8.5 2005
RCP 8.5 2030
RCP 4.5 2030
RCP 2.6 2030
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ZONA Annual Max 24-hr non-dust PM2.5 Results
RCP 8.5 2005
RCP 8.5 2030
RCP 4.5 2030
RCP 2.6 2030
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PM2.5 Results
Annual Mean 24-hr PM2.5
RCP8.5 2005
RCP8.5 2030
RCP4.5 2030
RCP2.6 2030
RCP8.5 2005 ZONA
RCP8.5 2030 ZONA
RCP4.5 2030 ZONA
RCP2.6 2030 ZONA
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Annual Max 24-hr PM2.5
Global
US
Global
US
1.2
1.1
1.1
1.1
1.1
1.1
1.1
1.0
2.7
1.9
1.8
2.0
0.5
0.5
0.5
0.5
375.3
320.0
238.7
453.3
375.3
319.9
319.8
453.3
79.8
57.2
59.0
66.0
25.7
25.9
25.9
28.2
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Speciated U.S. Annual Max PM2.5
RCP8.5 2005
RCP8.5 2030
RCP4.5 2030
RCP2.6 2030
RCP8.5 2005 ZONA
RCP8.5 2030 ZONA
RCP4.5 2030 ZONA
RCP2.6 2030 ZONA
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SO4
8.4
6.5
2.8
5.0
1.9
2.0
1.9
1.9
NO3
21.9
14.0
16.8
14.8
0.7
0.7
0.9
0.7
16
NH4
25.9
16.6
17.4
18.8
3.1
3.1
3.1
3.1
SOA
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
BC
4.8
1.2
4.1
5.2
1.2
1.2
1.2
1.4
OC
18.7
18.7
17.7
22.0
18.7
18.7
18.7
20.9
Total
79.88
57.24
58.98
65.95
25.66
25.87
25.92
28.18
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CONUS36 CMAQ Annual Max 1-hr O3 BCs
RCP8.5 2005
RCP8.5 2030
S N
E W
S N
E W
S N
E W
S N
E W
RCP4.5 2030
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RCP2.6 2030
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CONUS36 CMAQ Annual Max 1-hr PM2.5 BCs
RCP8.5 2030
S N
E W
S N
E W
S N
E W
RCP4.5 2030
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RCP2.6 2030
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Conclusions
1. These results indicate that only the emissions scenario
that pursued extremely aggressive climate change
mitigation (RCP2.6) lead to reductions in global O3
burden and U.S. background O3 and PM2.5
concentrations.
2. Annual maximum U.S. 8-hr O3 concentrations and
frequency of high (> 70 ppb) 8-hr O3 events are
predicted to decrease in all simulated future emissions
cases, likely due to domestic emission controls
3. Contribution of background to total U.S. O3
concentrations predicted to increase in the future (~25% to annual mean and up to 10% to summer mean):
combination of rise in transported O3 and drop in
domestic O3 production
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Future Work
• Probe MOZART process-level output to
gain a better understanding of the
differences between the RCP results
• Run CMAQ with the downscaled 2005 and
2030 BCs and recalculate U.S.
background concentrations
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