Transcript West_9.13.14

Connecting Air Pollution, Climate
Change, and Health
J. Jason West
Dept. of Environmental Sciences and
Engineering
University of North Carolina
Smog Bothers Pedestrians, Los
Angeles (1950s)
Hollywood Citizens News Collection, Los Angeles Public Library
A global picture
How Many People Die From Ambient Air Pollution?
Ozone-related mortality
470,000 (95% CI: 140,000 - 900,000)
PM2.5-related mortality(*)
2.1 million (95% CI: 1.3 - 3.0 million)
(*) PM2.5 calculated as a sum of species (dark blue)
PM2.5 as reported by 4 models (dark green)
Light-colored bars - low-concentration threshold (5.8 µg m-3)
Silva et al. (2013)
5
Global Burden: Ozone-related mortality
Global and regional mortality per year
Regions
Total
deaths
North America
Europe
Former Soviet Union
Middle East
India
East Asia
Southeast Asia
South America
Africa
Australia
34,400
32,800
10,600
16,200
118,000
203,000
33,300
6,970
17,300
469
Deaths
per
million
people (*)
121
96
66
68
212
230
119
38
73
29
472,000
149
Global
Respiratory mortality , deaths yr -1 (1000 km2)-1,
multi-model mean in each grid cell , 14 models
(*) Exposed population (age 30 and older)
Silva et al. (2013)
6
Global Burden: PM2.5-related mortality
Global and regional mortality per year
Regions
North America
Europe
Former Soviet
Union
Middle East
India
East Asia
Southeast Asia
South America
Africa
Australia
Global
Deaths
Total
per
deaths
million
people (*)
43,000
152
154,000
448
128,000
793
88,700
397,000
11,049,000
158,000
16,800
77,500
1,250
371
715
1,191
564
92
327
78
2,110,000
665
CPD+LC mortality , deaths yr -1 (1000 km2)-1,
multi-model mean in each grid cell , 6 models
(*) Exposed population (age 30 and older)
Silva et al. (2013)
7
Global burden of disease of outdoor air pollution
WHO GBD 2010
3.2 million deaths per year
(95% CI:2.8 – 3.6 million)
Lim et al., 2012
Connections Between
Air Pollution and Climate Change
1) Several air pollutants affect climate
- Ozone (O3) is a greenhouse gas (GHG)
- Aerosols scatter and absorb sunlight, and
affect clouds.
2) Changes in climate may affect air quality
(of O3, PM, or other pollutants).
3) Sources of air pollutants and GHGs are
shared – fossil fuel combustion.
4) Climate change may influence demands
for energy, and therefore emissions.
Connections Between
Air Pollution and Climate Change
Sources &
Policies
Emissions
Problems
Air
pollutants
Air
pollution
1
3
GHGs
2
Impacts
Human
Health
Climate
Change
4
Big Question: How can we plan to address air
pollution and climate change in a
coordinated way?
Radiative Forcing 1750-2005
IPCC, 2007
Short-lived and Long-lived GHGs
Ozone Precursors Affect Both Ozone Air
Quality and Climate Forcing
Global
Urban
hn
hn
O3
NO
HO2
NO2
OH
NMVOCs, CO
O3
NO
HO2
NO2
OH
NMVOCs, CO, CH4
Ozone Precursors – Effects on Climate
-20% NOx
-20% NMVOC
-20% CO
Global Warming Potential (GWPH ): RF integrated to time horizon, H,
following 1-year pulse emission: ∫H RFNOx /D emissions / ∫H RFCO2/D emissions
Patterns of GWP100 similar to normalized net RFs
[Fry et al., JGR, 2012]
CO as Kyoto’s Forgotten Gas
Using methods from Fry et al. [2012] and Collins et al. [2013]
4.07 [3.71 to 4.37]
20-yr
GWP
All regional GWP20
within 8.8%
of Global GWP20
O3 + CH4
O3 + SO42-
100-yr
GWP
1.34 [1.26 to 1.44]
All regional GWP100
within 7.5%
of Global GWP100
[Fry et al., ACP, 2013]
Ozone Precursors Affect Both Ozone Air
Quality and Climate Forcing
Global
Urban
hn
hn
O3
NO
HO2
NO2
OH
NMVOCs, CO
O3
NO
HO2
NO2
OH
NMVOCs, CO, CH4
Simulate a 20% Reduction of Global Methane
Annual Average
Change in surface 8-hr.
ozone from a 65 Mton
CH4 yr-1 reduction in
methane emissions, at
steady state (81%
achieved by 2030 if
implemented in 2010).
Jun-Jul-Aug
Global annual average ozone (ppb)
2000
A2 2030
∆O3
24-hr.
29.1
33.6
-0.82
8-hr. daily max.
31.8
37.1
-0.87
8-hr. populationweighted
49.4
61.7
-1.16
A2 Anthrop. emissions 2000-2030:
CH4 +48%, NOX +70%
2030 Avoided Premature Deaths
20% Global Methane Emissions Reduction
Total 2030 avoided deaths: 30,200
West et al. (2006) PNAS
Comparing Monetized Health Benefits
with Control Costs
 ~10% of anthropogenic methane emissions can be
reduced at a cost-savings.
 Marginal cost of reducing 65 Mton CH4 yr-1 (20%) is
~$100 per ton CH4 (total cost is negative, IEA (2003)).
 Marginal cost-effectiveness is $420,000 per avoided
death for the 20% reduction.
 Benefit is ~$240 per ton methane reduced (~$12 per ton
CO2 equivalent) when deaths are valued at $1 million
each.
 Health benefits can exceed the costs of the 20%
methane reduction.
 Methane mitigation can be a cost-effective tool for
global and decadal ozone management. West et al. (2006) PNAS
Shindell et al., Science, 2012
Co-benefits - Background
Reducing GHG emissions also reduces co-emitted
air pollutants
- Air quality and health co-benefits shown to be substantial
compared to GHG abatement costs.
“$2-175 / ton CO2 … all studies agree that monetized health
benefits make up a substantial fraction of mitigation costs.”
IPCC AR4
“$2-196 / ton CO2, and the highest co-benefits found in
developing countries. These values, although of a similar order
of magnitude to abatement cost estimates, are only rarely
included in integrated assessments of climate policy.” Nemet et
al. (2010)
- Most studies have focused locally or regionally.
- Tend not to analyze future scenarios.
- None has been global, using an atmospheric model.
Co-benefits of GHG Mitigation for Air
Quality
1) Immediate and Local
Air
pollutants
Air
pollution
Sources &
Policies
Human
Health
GHGs
Climate
Change
2) Long-Term and Global
Objective: Analyze global co-benefits for air
quality and human health via both
mechanisms, in scenarios to 2100.
Results – PM2.5 Concentration
Global PM2.5 (μg m-3)
38
36
34
32
30
28
2000
REF
RCP4.5
eREFm45
e45m85
2020
2040
Year
2060
2080
Global population-weighted, annual average PM2.5
2100
Results – PM2.5 Concentration
Annual average PM2.5
Total change
RCP4.5 - REF
2050
2100
Meteorology
eREFm45 - REF
Emissions
RCP4.5 – eREFm45
Results – Ozone Concentration
62
60
Global O3 (ppb)
58
56
54
52
50
48
46
44
2000
REF
RCP4.5
eREFm45
e45m85
2020
2040
Year
2060
Global population-weighted,
max. 6 month average of 1 hr. daily max ozone
2080
2100
Results – Ozone Concentration
Max. 6 month average of 1 hr. daily max ozone
Total change
RCP4.5 - REF
Meteorology
eREFm45 - REF
Total co-benefit
#2 Meteorology
Emissions
RCP4.5 - eREFm45
2050
2100
#1 Emissions
Mortality (Millions yr-1)
Results – Global Premature Mortality
1
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
2000
Global
Projection of global
population and
baseline mortality
rates from
International Futures.
O3 REF
O3 RCP4.5
PM2.5 REF
PM2.5 RCP4.5
2020
2040
2060
Year
PM2.5 co-benefits
(CPD + lung cancer mortality)
2030: 0.4±0.2
2050: 1.1±0.5
2100: 1.5±0.6
2080
2100
Ozone co-benefits
(respiratory mortality)
2030: 0.09±0.06
2050: 0.2±0.1
2100: 0.7±0.05
Results – Global Premature Mortality
Results – Valuation of Avoided
Mortality
Red: High valuation (2030 global mean $3.6 million)
Blue: Low valuation (2030 global mean $1.2 million)
Green: Median and range of global C price (13 models)
Monetized Co-benefits
• Global average: $50-380 / ton CO2
• US and Western Europe: $30-600 / ton CO2
• China: $70-840 / ton CO2
• India: -$20-400 / ton CO2
• Higher than previous estimates: $2-196 / ton CO2
- Use future scenarios where population,
susceptibility to air pollution, and economies grow.
- Account for chronic mortality influences of ozone
as well as PM2.5.
- Account for global transport, and long-term
influences via methane.
Major uncertainties
• Only adults >30 years accounted for. (low bias)
• Co-benefits of GHG mitigation would be greater had
the reference scenario not assumed decreased air
pollution.
• RCP emissions do not include primary inorganics
(fly ash). (low bias for PM2.5)
• Coarse grid resolution for air pollution exposure.
(low bias for PM2.5)
• Applying concentration-response functions from the
present-day US, globally and into the future.
Alternative approach: value as avoided air
pollution control costs.
Co-benefits: conclusions
• Global abatement of GHG emissions brings substantial
air quality and human health co-benefits.
• Global GHG mitigation (RCP4.5 relative to REF)
causes 0.5±0.2 million avoided deaths in 2030, 1.3±0.5
in 2050, and 2.2±0.8 in 2100
• Global average monetized co-benefits are $50-380 /
ton CO2
– Greater than previous estimates
– Greater than abatement costs in 2030 and 2050.
• The direct co-benefits from air pollutant emission
reductions exceed those via slowing climate change.