ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-12-5367-2012 Projections of mid-century summer air-quality for North America: effects of changes in climate and precursor emissions Kelly J. 1 3 Makar P. A. 1 Plummer D. A. 2 Air Quality Research Division, Environmental Science and Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario, Canada Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria, British Columbia, Canada now at: Golder Associates, 2390 Argentia Road, Mississauga, Ontario, L5N 5Z7, Canada 22 06 2012 12 12 5367 5390 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/12/5367/2012/acp-12-5367-2012.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/12/5367/2012/acp-12-5367-2012.pdf

Ten year simulations of North American current and future air-quality were carried out using a regional air-quality model driven by a regional climate model, in turn driven by a general circulation model. Three separate summer scenarios were performed: a scenario representing the years 1997 to 2006, and two SRES A2 climate scenarios for the years 2041 to 2050. The first future climate scenario makes use of 2002 anthropogenic precursor emissions, and the second applied emissions scaling factors derived from the IPCC Representative Concentration Pathway 6 (RCP 6) scenario to estimate emissions for 2050 from existing 2020 projections. Ten-year averages of ozone and PM<sub>2.5</sub> at North American monitoring network stations were used to evaluate the model's current chemical climatology. The model was found to have a similar performance for ozone as when driven by an operational weather forecast model. The PM<sub>2.5</sub> predictions had larger negative biases, likely resulting from the absence of rainwater evaporation, and from sub-regional negative biases in the surface temperature fields, in the version of the climate model used here. <br><br> The differences between the two future climate simulations and the current climate simulation were used to predict the changes to air-quality that might be expected in a future warmer climate, if anthropogenic precursor emissions remain constant at their current levels, versus if the RCP 6 emissions controls were adopted. Metrics of concentration, human health, and ecosystem damage were compared for the simulations. The scenario with future climate and current anthropogenic emissions resulted in worse air-quality than for current conditions – that is, the effect of climate-change alone, all other factors being similar, would be a worsening of air-quality. These effects are spatially inhomogeneous, with the magnitude and sign of the changes varying with region. The scenario with future climate and RCP 6 emissions for 2050 resulted in an improved air-quality, with decreases in key pollutant concentrations, in acute human mortality associated with air-pollution, and in sulphur and ozone deposition to the ecosystem. The positive outcomes of the RCP 6 emissions reductions were found to be of greater magnitude than the negative outcomes of climate change alone. The RCP 6 scenario however resulted in an increase in the deposition of nitrogen, as a result of increased ammonia emissions expected in that scenario, compared to current ammonia emissions levels. <br><br> The results of the study raise the possibility that simultaneous reductions of greenhouse gases and air pollution precursors may further reduce air pollution levels, with the added benefits of an immediate reduction in the impacts of air pollution on human and ecosystem health. Further scenarios to investigate this possibility are therefore recommended.

 References Averny, S., Mauszerall, D. L., Liu, J., and Horowitz, L. W.: Global crop yield reductions due to surface ozone exposure: 2. Year 2030 potential crop production losses and economic damage under two scenarios of O<sub>3</sub> pollution, Atmos. Environ., 45, 2297–2309, 2011. Avise, J., Chen, J., Lamb, B., Wiedinmyer, C., Guenther, A., Salathé, E., and Mass, C.: Attribution of projected changes in summertime US ozone and PM$_2.5$ concentrations to global changes, Atmos. Chem. Phys., 9, 1111–1124, http://dx.doi.org/10.5194/acp-9-1111-2009doi:10.5194/acp-9-1111-2009, 2009. Bechtold, P., Bazile, E., Guichard, F., Mascart, P., and Richard, E.: A mass flux convection scheme for regional and global models, Q. J. Roy. Meteorol. Soc., 127, 869–886, 2001. Bell, M. L., Goldberg, R., Hogrefe, C., Kinney, P. L., Knowlton, K., Lynn, B., Rosenthal, J., Rosenzweig, C., and Patz, J. A.: Climate change, ambient ozone, and health in 50 US cities, Climatic Change, 82, 61–76, 2007. Brasseur, G. P., Schultz, M., Granier, C., Saunois, M., Diehl, T., Botzet, M., Roeckner, E., and Walters, S.: Impact of climate change on the future chemical composition of the global troposphere, J. Climate, 19, 3932–3951, 2006. Briggs, G. A.: Plume rise and buoyancy effects, in: Atmospheric Science and Power Productions, edited by: Randerson, D. J., DOE/PIC-27601, Technical Information Center, US DOE, Oak Ridge, TN, 327–366, 1984. Briggs, G. A.: Analytical parameterizations of diffusion: the convective boundary layer, J. Clim. Appl. Meteorol., 24, 1167–1186, 1985. Caya, D. and Laprise, R.: A semi-implicit semi-Lagrangian regional climate model: The Canadian RCM, Mon. Weather Rev., 127, 341–362, 1999. CEP: Carolina Environmental Program, Sparse Matrix Operator Kernel Emission (SMOKE) modelling system, University of North Carolina, Carolina Environmental Programs, Chapel Hill, NC, see http://www.smoke-model.org/index.cfm, 2003. Chang, H. H., Zhou, J., and Fuentes, M.: Impact of climate change on ambient ozone level and mortality in Southeastern United States, Int. J. Env. Res. Public Health, 7, 2866–2880, 2010. Chen, J., Avise, J., Guenther, A., Wiedinmyer, C., Salathe, E., Jackson, R. B., and Lamb, B.: Future land use and land cover influences on regional biogenic emissions and air quality in the United States, Atmos. Environ., 43, 5771–5780, 2009a. Chen, J., Avise, J., Lamb, B., Salathé, E., Mass, C., Guenther, A., Wiedinmyer, C., Lamarque, J.-F., O'Neill, S., McKenzie, D., and Larkin, N.: The effects of global changes upon regional ozone pollution in the United States, Atmos. Chem. Phys., 9, 1125–1141, http://dx.doi.org/10.5194/acp-9-1125-2009doi:10.5194/acp-9-1125-2009, 2009b. Cheng, C. S., Campbell, M., Li, Q., Li, G., Auld, H., Day, N., Pengelly, D., Gingrich, S., and Yap, D.: A synoptic climatological approach to assess climatic impact on air quality in south-central Canada. Part II: Future estimates, Water Air Soil Pollut., 182, 117–130, 2007. Cheng, C. S., Campbell, M., Li, Q., Auld, H., Day, N., Pengelly, D., Gingrich, S., Klaassen, J., MacIver, D., Comer, N., Mao, Y., Thompson, W., and Lin, H.: Differential and combined impacts of extreme temperatures and air pollution on human mortality in south-central Canada. Part II: Future estimates, Air Quality, Atmosphere and Health, 2, 223–235, 2009. Civerolo, K., Hogrefe, C., Lynn, B., Rosenthal, J., Ku, J., Solecki, W., Cox, J., Small, C., Rosenzweig, C., Goldberg, R., Knowlton, K., and Kinney, P.: Estimating the effects of increased urbanization on surface meteorology and ozone concentrations in the New York City metropolitan region, Atmos. Env., 41, 1803–1818, 2007. CMOS: Canadian Meteorological and Oceanographic Society, 2007, Statement on Climate Change, Canadian Meteorological and Oceanographic Society Bulletin, 35, 99–106, 2007. Côté, J., Gravel, S., Méthot, A., Patoine, A., Roch, M., and Staniforth, A.: The operational CMC-MRB Global Environmental Multiscale (GEM) model. Part 1: Design considerations and formulation, Mon. Weather Rev., 126, 1373–1395, 1998. Dave, J. V.: Development of programs for computing characteristics of ultraviolet radiation, Final Report under Contract NAS 5-21680, NASA Report CR-139134, National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, Maryland, NTIS # N75-10746/6SL, 27 pp., 1972. Davies, H. C.: A lateral boundary formulation for multilevel prediction models, Q. J. Roy. Meteor. Soc., 102, 405–418, 1976. Dawson, J. P., Adams, P. J., and Pandis, S. N.: Sensitivity of ozone to summertime climate in the eastern USA: A modelling case study, Atmos. Environ., 41, 1494–1511, 2007. DeMore, W. B., Sander, S. P., Molina, M. J., Golden, D. M., Hampson, R. F., Kurylo, M. J., Howard, C. J., and Ravishankara, A. R.: Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling, Evaluation Number 8, National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 266 pp., 1988. Demuzere, M. and van Lipzig, N. P. M.: A new method to estimate air-quality levels using a synoptic-regression approach. Part I: Present-day O<sub>3</sub> and PM$_10$ analysis, Atmos. Environ., 44, 1341–1355, 2010a. Demuzere, M. and van Lipzig, N. P. M.: A new method to estimate air-quality levels using a synoptic-regression approach. Part II: Future O<sub>3</sub> concentrations, Atmos. Environ., 44, 1356–1366, 2010b. Engardt, M.: Modelling of near-surface ozone over South Asia, J. Atmos. Chem., 59, 61–80, 2008. Fiore, A. M., Levy II, H., and Jaffe, D. A.: North American isoprene influence on intercontinental ozone pollution, Atmos. Chem. Phys., 11, 1697–1710, http://dx.doi.org/10.5194/acp-11-1697-2011doi:10.5194/acp-11-1697-2011, 2011. Flato, G. M., Boer, G. J., Lee, W. G., McFarlane, N. A., Ramsden, D., Reader, M. C., and Weaver, A. J.: The Canadian Centre for Climate Modeling and Analysis Global Coupled Model and its climate, Clim. Dynam., 16, 451–467, 2000. Forkel, R. and Knoche, R.: Regional climate change and its impact on photooxidant concentrations in southern Germany: Simulations with a coupled regional climate-chemistry model, J. Geophys. Res.-Atmos., 111, D12302, doi:10.1029/2005JD006748, 2006. Forkel, R. and Knoche, R.: Nested regional climate-chemistry simulations for central Europe, Compt. Rendus Geosci., 339, 734–746, 2007. Fujino, J., Nair, R., Kainuma, M., Masui, T., and Matsuoka, Y.: Multigas mitigation analysis on stabilization scenarios using AIM global model, Multigas Mitigation and Climate Policy. The Energy Journal Special Issue, 343–354, 2006. Fung, C. S., Misra, P. K., Bloxam, R., and Wong, S.: A numerical experiment on the relative importance of H<sub>2</sub>O<sub>2</sub> and O<sub>3</sub> in aqueous conversion of SO<sub>2</sub> to SO$_4^2-$, Atmos. Environ., 25A, 411–423, 1991. Gal-Chen, T. and Sommerville, R. C.: On the use of a coordinate transformation for the solution of Navier-Stokes, J. Comput. Phys., 17, 209–228, 1975. Gent, P. R., Bryan, F. O., Danabasoglu, G., Doney, S. C., Holland, W. R., Large, W. G., and McWilliams, J. C.: The NCAR climate system model global ocean component, J. Climate, 11, 1287–1306, 1998. Gong, S. L., Barrie, L. A., and Lazare, M.: Canadian Aerosol Module (CAM): A size-segregated simulation of atmospheric aerosol processes for climate and air quality models 2. Global sea-salt aerosol and its budgets, J. Geophys. Res., 107, 4779, http://dx.doi.org/10.1029/2001JD002004doi:10.1029/2001JD002004, 2003a. Gong, S. L., Barrie, L. A., Blanchet, J.-P., von Salzen, K., Lohmann, U., Lesins, G., Spacek, L., Zhang, L. M., Girard, E., Lin, H., Leaitch, R., Leighton, H., Chylek, P., and Huang, P.: Canadian Aerosol Module: A size-segregated simulation of atmospheric aerosol processes for climate and air quality models. 1. Module development, J. Geophys. Res., 108, 4007, http://dx.doi.org/10.1029/2001JD002002doi:10.1029/2001JD002002, 2003b. Gong, W., Dastoor, A. P., Bouchet, V. S., Gong, S. L., Makar, P. A., Moran, M. D., Pabla, B., Menard, S., Crevier, L.-P., Cousineau, S., and Venkatesh, S.: Cloud processing of gases and aerosols in a regional air quality model (AURAMS), Atmos. Res., 82, 248–275, 2006. Hijioka, Y., Matsuoka, Y., Nishimoto, H., Masui, M., and Kainuma, M.: Global GHG emissions scenarios under GHG concentration stabilization targets, Journal of Global Environmental Engineering, 13, 97–108, 2008. Hogrefe, C., Lynn, B., Civerolo, K., Ku, J.-Y., Rosenthal, J., Rosenzweig, C., Goldberg, R., Gaffin, S., Knowlton, K., and Kinney, P. L.: Simulating changes in regional air pollution over the eastern United States due to changes in global and regional climate and emissions, J. Geophys. Res., 109, D22301, doi:10.1029/2004JD004690, 2004. Houyoux, M. R., Vukovich, J. M., Coats Jr., C. J., and Wheeler, N. J. M.: Emission inventory development and processing for the Seasonal Model for Regional Air Quality (SMRAQ) project, J. Geophys. Res., 105, 9079–9090, 2000. Intergovernmental Panel on Climate Change (IPCC): Special Report on Emissions Scenarios, edited by: Nacenovic, N. and Swart, R., Cambridge Univ. Press, New York, 612 pp., 2000. Intergovernmental Panel on Climate Change (IPCC): Summary for Policymakers, in: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, 12–17, 2007. Jacob, D. J. and Winner, D. A.: Effect of climate change on air quality, Atmos. Environ., 43, 51–63, 2009. Jackson, J. E., Yost, M. G., Karr, C., Fitzpatrick, C., Lamb, B. K, Chung, S. H., Chen, J., Avise, J., Rosenblatt, R. A., and Fenske, R. A.: Public health impacts of climate change in Washington State: Projected mortality risks due to heat events and air pollution, Climate Change, 102, 159–186, 2010. Jacobson, M. Z. and Streets, D. B.: Influence of future anthropogenic emissions on climate, natural emissions, and air quality, J. Geophys. Res., 114, D08118, doi:10.1029/2008JD011476, 2009. Kain, J. S. and Fritsch, J. M.: A one-dimensional entraining/detraining plume model and its implication in convective parameterization, J. Atmos. Sci., 47, 2784–2802, 1990. Kawase, H., Nagashima, T., Sudo, K., and Nozawa, T.: Future changes in tropospheric ozone under Representative Concentration Pathways (RCPs), Geophy. Res. Lett., 38, L05801, doi:10.1029/2010GL046402, 2011. Kelly, J., Makar, P. A., and Plummer, D. A.: Projections of mid-century summer air-quality for North America: effects of changes in climate and precursor emissions, Atmos. Chem. Phys. Discuss., 12, 3875–3940, http://dx.doi.org/10.5194/acpd-12-3875-2012doi:10.5194/acpd-12-3875-2012, 2012. Kuhn, M., Builtjes, P. J. H., Poppe, D. Simpson, D., Stockwell, W. R., Andersson-Skoeld, Y., Baart, A., Das, M., Fiedler, F., Hov, O., Kirchner, F., Makar, P. A., Milford, J. B., Roemer, M. G. M., Ruhnke, R., Strand, A., Vogel, B., and Vogel, H.: Intercomparison of the Gas-Phase Chemistry in Several Chemistry and Transport Models, Atmos. Environ., 32, 693–709, 1998. Lam, Y. F., Fu, J. S., Wu, S., and Mickley, L. J.: Impacts of future climate change and effects of biogenic emissions on surface ozone and particulate matter concentrations in the United States, Atmos. Chem. Phys., 11, 4789–4806, http://dx.doi.org/10.5194/acp-11-4789-2011doi:10.5194/acp-11-4789-2011, 2011. Laprise, R., Caya, D., Frigon, A., and Paquin, D.: Current and perturbed climate as simulated by the second-generation Canadian Regional Climate Model (CRCM-II) over northwestern North America, Clim. Dynam., 21, 405–421, 2003. Lelieveld, J., Butler, T. M., Crowley, J. N., Dillon, T. J., Fischer, H., Ganzeveld, L., Harder, H., Lawrence, M. G., Martinez, M., Taraborrelli, D., and Williams, J.: Atmospheric oxidation capacity sustained by a tropical forest, Nature, 452, 737–740, doi:10.1038/nature06870, 2008. Leung, L. R. and Gustafson Jr., W. I.: Potential regional climate change and implications to U.S. air quality, Geophys. Res. Lett, 32, L16711, doi:10.1029/2010GL046402, 2005. Liao, H., Seinfeld, J. H., Adams, P. J., and Mickley, L. J.: Global radiative forcing of coupled tropospheric ozone and aerosols in a unified general circulation model, J. Geophys. Res.-Atmos., 109, D16207, doi:10.1029/2003JD004456, 2004. Liao, H., Chen, W.-T., and Seinfeld, J. H.: Role of climate change in global predictions of future tropospheric ozone and aerosols, J. Geophys. Res.-Atmos., 111, D12304, doi:10.1029/2005JD006852, 2006. Liao, H., Henze, D. K., Seinfeld, J. H., Wu, S., and Mickley, L. J.: Biogenic secondary organic aerosol over the United States: Comparison of climatological simulations with observations, J. Geophys. Res.-Atmos., 112, D06201, doi:10.1029/2006JD007813, 2007. Lin, J.-T, Wuebbles, D. J., Huang, H.-C., Tao, Z., Caughhey, M., Liang, X.-Z., Zhu, J.-H., and Holloway, T.: Potential effects of climate and emissions changes on surface ozone in the Chicago area, J. Great Lakes Res., 36 (supplement 2), 59–64, 2010. Makar, P. A., Bouchet, V. S., and Nenes, A.: Inorganic Chemistry Calculations using HETV – A Vectorized Solver for the SO$_4^2-$-NO$_3^-$-NH$_4^+$ system based on the ISORROPIA Algorithms, Atmos. Environ., 37, 2279–2294, 2003. Makar, P. A., Moran, M. D., Zheng, Q., Cousineau, S., Sassi, M., Duhamel, A., Besner, M., Davignon, D., Crevier, L.-P., and Bouchet, V. S.: Modelling the impacts of ammonia emissions reductions on North American air quality, Atmos. Chem. Phys., 9, 7183–7212, http://dx.doi.org/10.5194/acp-9-7183-2009doi:10.5194/acp-9-7183-2009, 2009. Makar, P. A., Zhang, J., Gong, W., Stroud, C., Sills, D., Hayden, K. L., Brook, J., Levy, I., Mihele, C., Moran, M. D., Tarasick, D. W., He, H., and Plummer, D.: Mass tracking for chemical analysis: the causes of ozone formation in southern Ontario during BAQS-Met 2007, Atmos. Chem. Phys., 10, 11151–11173, http://dx.doi.org/10.5194/acp-10-11151-2010doi:10.5194/acp-10-11151-2010, 2010a. Makar, P. A., Gong, W., Mooney, C., Zhang, J., Davignon, D., Samaali, M., Moran, M. D., He, H., Tarasick, D. W., Sills, D., and Chen, J.: Dynamic adjustment of climatological ozone boundary conditions for air-quality forecasts, Atmos. Chem. Phys., 10, 8997–9015, http://dx.doi.org/10.5194/acp-10-8997-2010doi:10.5194/acp-10-8997-2010, 2010b. Meehl, G. A., Covey, C., Delworth, T., Latif, M., McAvaney, B., Mitchell, J. F. B., Stouffer, R. J., and Taylor, K. E.: The WCRP CMIP3 Mulitmodel dataset: A new era in climate change research, B. Am. Meteorol. Soc., 88, 1383–1394, 2007. Mickley, L. J., Jacob, D. J., Field, B. D., and Rind, D.: Climate response to the increase in tropospheric ozone since preindustrial times: A comparison between ozone and equivalent CO<sub>2</sub> forcings, J. Geophys. Res.-Atmos., 109, D05106, doi:10.1029/2003JD003653, 2004a. Mickley, L. J., Jacob, D. J., Field, B. D., and Rind, D.: Effects of future climate change on regional air pollution episodes in the United States, Geophys. Res. Lett., 31, L24103, doi:10.1029/2004GL021216, 2004b. Mladjic, B., Sushama, L., Khaliq, M. N., Laprise, R., Caya, D., and Roy, R.: Canadian RCM projected changes to extreme precipitation characteristics over Canada, J. Climate, 24, 2565–2584, 2011. Murazaki, K. and Hess, P.: How does climate change contribute to surface ozone change over the United States?, J. Geophys. Res.-Atmos., 111, D05301, doi:10.1029/2005JD005873, 2006. Murphy, J. M., Sexton, D. M. H., Barnett, D. N., Jones, G. S., Webb, M. J., Collins, M., and Stainforth, D. A.: Quantification of modelling uncertainties in a large ensemble of climate change simulations, Nature, 430, 768–772, 2004. Odum, J. R., Jungkamp, T. P. W., Griffin, R. J., Flagan, R. C., and Seinfeld, J. H.: The atmospheric aerosol-forming potential of whole gasoline vapour, Science, 276, 96–99, 1996. Peterson, J. T.: Calculated actinic fluxes (290–700 nm) for air pollution photochemistry applications, US Environmental Protection Agency Report Number EPA-600/4-76-025, 55 pp., 1976. Pierce, T., Geron, C., Bender, L., Dennis, R., Tonneson, G., and Guenther, A.: Influence of increased isoprene emissions on regional ozone modeling, J. Geophys. Res., 103, 25611–25629, 1998. Plummer, D. A., Caya, D., Frigon, A., Cote, H., Gigurere, M., Paquin, D., Biner, S., Harvey, R., and de Elia, R.: Climate and climate change over North America as simulated by the Canadian RCM, J. Climate, 19, 3112–3132, 2006. Racherla, P. N. and Adams, P. J.: Sensitivity of Global Tropospheric Ozone and Fine Particulate Matter Concentrations to Climate Change, J. Geophys. Res., 111, D24103, http://dx.doi.org/10.1029/2005JD006939doi:10.1029/2005JD006939, 2006. Racherla, P. N. and Adams, P. J.: The response of surface ozone to climate change over the Eastern United States, Atmos. Chem. Phys., 8, 871–885, http://dx.doi.org/10.5194/acp-8-871-2008doi:10.5194/acp-8-871-2008, 2008. Racherla, P. N. and Adams, P. J.: U.S. ozone air quality under changing climate and anthropogenic emissions, Environ. Sci. Technol., 43, 571–577, 2009. RCP Database: http://www.iiasa.ac.at/web-apps/tnt/RcpDb/dsd?Action=htmlpage&page=compare, last access: 18 May 2012. Richtmyer, R. D.: Difference methods for initial value problems, Krieger Pub. Co., Malabar, Fla., 405 pp., 1994. Riette, S. and Caya, D.: Sensitivity of short simulations to the various parameters in the new CRCM spectral nudging, in: Research Activities in Atmospheric and Oceanic Modelling, edited by: Ritchie, H., WMO/TD-No. 1105, Rep. 32, 7.39–7.40, 2002. Scinocca, J. F. and McFarlane, N. A.: The parameterization of drag induced by stratified flow over anisotropic orography, Q. J. Roy. Meteor. Soc., 126, 2353–2393, 2000. Scinocca, J. F., McFarlane, N. A., Lazare, M., Li, J., and Plummer, D.: Technical Note: The CCCma third generation AGCM and its extension into the middle atmosphere, Atmos. Chem. Phys., 8, 7055–7074, http://dx.doi.org/10.5194/acp-8-7055-2008doi:10.5194/acp-8-7055-2008, 2008. Selin, N. E., Wu, S., Nam, K. M., Reilly, J. M., Paltsev, S., Prinn, R. G., and Webster, M. D.: Global health and economic impacts of future ozone pollution, Environ. Res. Lett., 4, 044014, doi:10.1088/1748-9326/4/4/044014, 2009. Sharf, G., Pleg, M., Livnat, M., and Luria, M.: Plume rise measurements from large point sources in Israel, Atmos. Environ., 27A, 1657–1663, 1993. Sheffield, P. E., Knowlton, K., Carr, J. L., and Kinney, P. L.: Modeling of regional climate change effects on ground-level ozone and childhood asthma, Am. J. Preventative Med., 41, 251–257, 2011. Smolarkiewicz, P. K. and Pudykiewicz, J. A.: A class of semi-Lagrangian approximations for fluids, J. Atmos. Sci., 49, 2082–2096, 1992. Stainforth, D. A., Aina, T., Christensen, C., Collins, M., Faull, N., Frame, D. J., Kettleborough, J. A., Knight, S., Martin, A., Murphy, J. M., Piani, C., Sexton, D., Smith, L. A., Spicer, R. A., Thorpe, A. J. and Allen, M. R.: Uncertainty in predictions of the climate response to rising levels of greenhouse gases, Nature, 433, 403–406, http://dx.doi.org/10.1038/nature03301doi:10.1038/nature03301, 2005. Steiner, A. L., Tonse, S., Cohen, R. C., Goldstein, A. H., and Harley, R. A.: Influence of future climate and emissions on regional air quality in California, J. Geophys. Res.-Atmos., 111, D18303, doi:10.1029/2005JD006935, 2006. Stella, P., Personne, E., Loubet, B., Lamaud, E., Ceschia, E., Béziat, P., Bonnefond, J. M., Irvine, M., Keravec, P., Mascher, N., and Cellier, P.: Predicting and partitioning ozone fluxes to maize crops from sowing to harvest: the Surfatm-O<sub>3</sub> model, Biogeosciences, 8, 2869–2886, http://dx.doi.org/10.5194/bg-8-2869-2011doi:10.5194/bg-8-2869-2011, 2011. Stieb, D. M., Burnett, R. T., Smith-Doiron, M., Brion, O., Hwashin, H. S., and Economou, V.: A new multipollutant, no-threshold air quality health index based on short-term associations observed in daily time-series analyses, J. Air Waste Manage., 58, 435–450, 2008. Stevenson, D. S., Dentener, F. J., Schultz, M. G., Ellingsen, K., van Noije, T. P. C., Wild, O., Zeng, G., Amann, M., Atherton, C. S., Bell, N., Bergmann, D. J., Bey, I., Butler, T., Cofala, J., Collins, W. J., Derwent, R. G., Doherty, R. M., Drevet, J., Eskes, H. J., Fiore, A. M., Gauss, M., Hauglustaine, D. A., Horowitz, L. W., Isaksen, I. S. A., Krol, M. C., Lamarque, J.-F., Lawrence, M. G., Montanaro, V., Müller, J.-F., Pitari, G., Prather, M. J., Pyle, J. A., Rast, S., Rodriguez, J. M., Sanderson, M. G., Savage, N. H., Shindell, D. T., Strahan, S. E., Sudo, K., and Szopa, S.: Multimodel ensemble simulations of present-day and near-future tropospheric ozone, J. Geophys. Res.-Atmos., 111, D08301, doi:10.1029/2005JD006338, 2006. Stockwell, W. R. and Lurmann, F. W.: Intercomparison of the ADOM and RADM gas-phase chemical mechanisms. Electrical Power Research Institute Topical Report, Electrical Power Research Institute, 3412 Hillview Avenue, Palo Alto, CA, 401 pp., 1989. Sushama, L., Khaliq, M. N., and Laprise, R.: Dry spell characteristics over Canada in a changing climate as simulated by the Canadian RCM, Global Planet. Change, 74, 1–14, 2010. Tagaris, E., Manomaiphiboon, K., Liao, K.-J., Leung, L. R., Woo, J.-H., He, S., Amar, P., and Russell, A. G.: Impacts of global climate change and emissions on regional ozone and fine particulate matter concentrations over the United States, J. Geophys. Res., 112, D14312, doi:10.1029/2006JD008262, 2007. Tagaris, E., Liao, K.-J., Manomaiphiboon, K., He, S., Woo, J.-H., Amar, P., and Russell, A. G.: The role of climate and emission changes in future air quality over southern Canada and northern Mexico, Atmos. Chem. Phys., 8, 3973–3983, http://dx.doi.org/10.5194/acp-8-3973-2008doi:10.5194/acp-8-3973-2008, 2008. Tagaris, E., Liao, K.-J., Delucia, A. J., Deck, L., Amar, P., and Russell, A. G.: Potential impact of climate change on air pollution-related human health effects, Environ. Sci. Technol., 43, 4979–4988, 2009. Tagaris, E., Liao, K.-J., DeLucia, A. J., Deck, L., Amar, P., and Russell, A. G.: Sensitivity of air pollution-induced premature mortality to precursor emissions under the influence of climate change, Int. J. Env. Res. Public Health, 7, 2222–2237, 2010. Timbal, B., Fernandez, E., and Li, Z.: Generalization of a statistical downscaling model to provide local climate change projections for Australia, Environ. Modell. Softw., 24, 341–358, 2009. Turner, D. B.: Proposed pragmatic methods for estimating plume rise and plume penetration through atmospheric layers, Atmos. Environ., 19, 1215–1218, 1985. US EPA: Assessment of the impacts of global change on regional US air quality: a synthesis of climate change impacts on ground-level ozone. An Interim Report of the US EPA Global Change Research Program, National Center for Environmental Assessment, Washington, DC; EPA/600/R-07/094F, available from the National Technical Information Service, Springfield, VA, and online at: http://www.epa.gov/ncea, 2009. \hack Van Dingenen, R., Dentener, F. J., Raes, F., Krol, M. C., Emberson, L., and Cofala, J.: The global impact of ozone on agricultural crop yields under current and future air quality legislation, Atmos. Environ., 43, 604–618, 2009. Venkatram, A., Karamchandani, P. K., and Misra, P. K.: Testing a comprehensive acid deposition model, Atmos. Environ., 22, 737–747, 1988. Verseghy, D. L.: The Canadian Land Surface Scheme (CLASS): Its history and future, Atmosphere-Ocean, 38, 1–13, 2000. Wise, E. K.: Climate-based sensitivity of air quality to climate change scenarios for the southwestern United States, Int. J. Climatol., 29, 87–97, 2009. Wu, S., Mickley, L. J., Jacob, D. J., Logan, J. A., Yantosca, R. M., and Rind., D.: Why are there large differences between models in global budgets of tropospheric ozone?, J. Geophys. Res.-Atmos., 112, D05302, doi:10.1029/2006JD007801, 2007. Wu, S., Mickley, L. J., Leibensperger, E. M., Jacob, D. J., Rind, D., and Streets, D. G.: Effects of 2000–2050 global change on ozone air quality in the United States, J. Geophys. Res., 113, D06302, doi:10.1029/2007JD008917, 2008a. Wu, S., Mickley, L. J., Jacob, D. J., Rind, D., and Streets, D. G.: Effects of 2000–2050 changes in climate and emissions on global tropospheric ozone and the policy-relevant background surface ozone in the United States, J. Geophys. Res.-Atmos., 113, D18312, doi:10.1029/2007JD009639, 2008b. Young, T. R. and Boris, J. P.: A numerical technique for solving stiff ordinary differential equations associated with the chemical kinetics of reactive-flow problems, J. Phys. Chem., 81, 2424–2427, 1977. Zhang, G. J. and McFarlane, N. A.: Sensitivity of climate simulations to the parameterization of cumulus convection in the CCCGCM, Atmos. Ocean, 3, 407–446, 1995. Zhang, L., Gong, S. L., Padro, J., and Barrie, L.: A Size-segregated Particle Dry Deposition Scheme for an Atmospheric Aerosol Module, Atmos. Environ., 35, 549–560, 2001.