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Air Quality and Climate Change. Weather has a large effect on U.S. air quality. Loretta Mickley Harvard University. What U.S. city is this?. Co-authors: Amos Tai, Eric Leibensperger , and Xu Yue, Daniel Jacob, Jennifer Logan. U.S. Air Quality Smog Blog, alg.umbc.edu / usaq. - PowerPoint PPT Presentation
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Air Quality and Climate Change
Co-authors:Amos Tai, Eric Leibensperger, and Xu Yue, Daniel Jacob, Jennifer Logan
What U.S. city is this?
Loretta MickleyHarvard University
U.S. Air Quality Smog Blog, alg.umbc.edu/usaq
Weather has a large effect on U.S. air quality.
2
Weather has a large effect on U.S. air quality.
Jan 23, 2013
Persistent temperature inversions this January over Northern Utah led to unhealthy air 11 out of 31 days.
Airnow; NASA Earth Observatory
cooler
warmer
Salt Lake City
3
Both emissions and weather have been changing over the United States.
Thanks to Bryan Duncan
OMI NO2 data
4
Temperatures have been increasing rapidly since the 1980s.
NASA GISS temperature analysis, GISTEMP
Contiguous US
-1
1
0Warming trend after 1980
Tem
pera
ture
ano
mal
y (o C
)
1880 2000
What do these trends mean for surface air quality?
5
Number of ozone exceedances in Chicago and St. Louis looked promisingly low in recent years.
Number of days MDA8 ozone > 75 ppb
Chicago
St. Louis
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w.e
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ozco
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tml
Airnow
6
Drought + heat wave in 2012 ramped up number of ozone exceedances.
Number of days MDA8 ozone > 75 ppb
Chicago
St. Louis
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7
We know that surface ozone is sensitive to stagnation.
Stagnant air covers East.Clear skies.High temperatures.
Cold front moves through. Cool, clean air.
Leibensperger et al., 2010
8
Cold fronts clear away pollution in central and eastern United States.
High ozone levels Clean air
Leibensperger et al., 2010
9
Cyclones passing through Great Lakes/ Southern Canada region are associated with cold fronts .
Stagnant air. Cold front moves through.
Cyclone
Leibensperger et al., 2010
10
Climate models predict decreasing trend in number of Great Lakes cyclones in warming atmosphere.
Num
ber o
f cyc
lone
s ove
r Gr
eat L
akes
regi
on
RCP 8.5
Turner et al., 2013
Climate model projection of JJA cyclone number over Great Lakes region.
30% decrease
11
Climate models predict more persistent weather in future atmosphere over mid-latitudes.What are the implications for air quality?
As high latitudes warm, slower eastward progression of Rossby waves in the upper-level flow.
Francis et al., 2012
12
Climate penalty for ozone air quality: Increased stagnation + high temperatures will likely increase surface ozone.
Climate generated by NASA GISS Model 3; Tai et al., 2013
-4 -2 0 2 4
2000-2050 change in JJA MDA8 ozone due to climate change.
ppb
D MDA8 JJA ozone
6 ppb
13
Response of PM2.5 to changing meteorology is more complicated.
Observed relationships with Temperature (% K-1)
Observed sulfate correlates with temperature, but . . . .nitrate anti-correlates with temperature.
Tai et al., 2010
14
Net effect of 2000-2050 climate change on PM2.5 is small, at least when considering circulation changes.
2000-2050 change in annual mean PM2.5 due to changing circulation.
D annual mean PM2.5
Tai et al., 2012
Increased maritime flow
Increased stagnation
Changes are small, on the order of 0.5 mg m-3.
15
Wildfires may become the dominant player in changing PM2.5 in future atmosphere.
Tai et al., 2012; Yue et al., 2013
Modeled 2050s response of surface PM2.5 to trends in circulation and in wildfires.
16
Doubling of wildfire activity in warmer and drier 2050s significantly increases PM2.5 in the western U.S.
2000-2050 change in JJA mean organic carbon particles due to changing wildfires.
NASA GISS Model 3; Yue et al., 2013
D organic PM2.5
17
NASA GISS Model 3; Yue et al., 2013
Increase in organic PM2.5 in 2050s is especially large during extreme wildfire events.
Cumulative probability of daily mean concentrations of organic particles
2050s
Present-day
doubling Projection shows doubling of organic particles during fire events over Rocky Mountains in May-October timeframe for the 2050s.
18
Take home message 1
The response of air quality to climate change depends on trends in extreme events: stagnation, inversions, or wildfires.
Persistent temperature inversions this January over Northern Utah led to unhealthy air 11 out of 31 days.
cooler
warmer
Salt Lake City
Airnow; NASA Earth Observatory
19
Take home message 2:
The climate penalty for ozone air quality could be large.
-4 -2 0 2 4
2000-2050 change in MDA8 JJA ozone due to climate change.
ppb
D MDA8 JJA ozone
NASA GISS Model 3; Tai et al., 2013
20
Take home message 3:
Air quality in the West is vulnerable to changing wildfire in a warmer, drier climate.
Cumulative probability of daily mean concentrations of organic particles
2050s
Present-day
doubling Projection shows doubling of organic particles during wildfires over Rocky Mountains in 2050s.
NASA GISS Model 3; Yue et al., 2013