Quantification of the impact of climate uncertainty on regional air quality K.-J. Liao1, E. Tagaris1, K. Manomaiphiboon1,4, C. Wang2, J.-H. Woo3,5, P. Amar3, S. He3, and A. G. Russell1 1School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, USA 2Joint Program on the Science and Policy of Global Change, Massachusetts Institute of Technology, Boston, MA, USA 3Northeast States for Coordinated Air Use Management (NESCAUM), Boston, MA, USA 4Joint Graduate School of Energy and Environment, King Mongkut's University of Technology Thonburi, Bangkok, Thailand 5Department of Advanced Technology Fusion, Konkuk University, Seoul, Korea
Abstract. Uncertainties in calculated impacts of climate forecasts on future regional
air quality are investigated using downscaled MM5 meteorological fields from
the NASA GISS and MIT IGSM global models and the CMAQ model in 2050 in the
continental US. Differences between three future scenarios: high-extreme,
low-extreme and base case, are used for quantifying effects of climate
uncertainty on regional air quality. GISS, with the IPCC A1B scenario, is
used for the base case simulations. IGSM results, in the form of
probabilistic distributions, are used to perturb the base case climate to
provide the high- and low-extreme scenarios. Impacts of the extreme climate
scenarios on concentrations of summertime fourth-highest daily maximum
8-h average ozone are predicted to be up to 10 ppbV (about one-seventh of
the current US ozone standard of 75 ppbV) in urban areas of the Northeast,
Midwest and Texas due to impacts of meteorological changes, especially
temperature and humidity, on the photochemistry of tropospheric ozone
formation and increases in biogenic VOC emissions, though the differences in
average peak ozone concentrations are about 1–2 ppbV on a regional basis.
Differences between the extreme and base scenarios in annualized PM2.5
levels are very location dependent and predicted to range between −1.0 and
+1.5 μg m−3. Future annualized PM2.5 is less sensitive to the
extreme climate scenarios than summertime peak ozone since precipitation
scavenging is only slightly affected by the extreme climate scenarios
examined. Relative abundances of biogenic VOC and anthropogenic NOx
lead to the areas that are most responsive to climate change. Overall,
planned controls for decreasing regional ozone and PM2.5 levels will
continue to be effective in the future under the extreme climate scenarios.
However, the impact of climate uncertainties may be substantial in some
urban areas and should be included in assessing future regional air quality
and emission control requirements.
Citation: Liao, K.-J., Tagaris, E., Manomaiphiboon, K., Wang, C., Woo, J.-H., Amar, P., He, S., and Russell, A. G.: Quantification of the impact of climate uncertainty on regional air quality, Atmos. Chem. Phys., 9, 865-878, doi:10.5194/acp-9-865-2009, 2009.