Variation in Estimated Ozone-Related Health Impacts of Climate Change due to Modeling Choices and Assumptions

Ellen S. Post,¹ Anne Grambsch,² Chris Weaver,² Philip Morefield,² Jin Huang,¹ Lai-Yung Leung,³ Christopher G. Nolte,⁴ Peter Adams,⁵ Xin-Zhong Liang,⁶ Jin-Hong Zhu,⁶ and Hardee Mahoney¹

¹Environment and Resources Division, Abt Associates Inc., Bethesda, Maryland, USA; ²Global Change Research Program, National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC, USA; ³Pacific Northwest National Labs, Richland, Washington, USA; ⁴National Exposure Research Laboratory, U.S. Environmental Protection Agency, Athens, Georgia, USA; ⁵Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA; ⁶Department of Atmospheric Sciences, University of Illinois, Urbana, Illinois, USA


Abstract

Background: Future climate change may cause air quality degradation via climate-induced changes in meteorology, atmospheric chemistry, and emissions into the air. Few studies have explicitly modeled the potential relationships between climate change, air quality, and human health, and fewer still have investigated the sensitivity of estimates to the underlying modeling choices.


Objectives: Our goal was to assess the sensitivity of estimated ozone-related human health impacts of climate change to Key modeling choices. 


Methods: Our analysis included seven modeling systems in which a climate change model is linked to an air quality model, five population projections, and multiple concentration–response functions. Using the U.S. Environmental Protection Agency’s (EPA’s) Environmental Benefits Mapping and Analysis Program (BenMAP), we estimated future ozone (O₃)-related health effects in the United States attributable to simulated climate change between the years 2000 and approximately 2050, given each combination of modeling choices. Health effects and concentration–response functions were chosen to match those used in the U.S. EPA’s 2008 Regulatory Impact Analysis of the National Ambient Air Quality Standards for O₃.


Results: Different combinations of methodological choices produced a range of estimates of national O₃-related mortality from roughly 600 deaths avoided as a result of climate change to 2,500 deaths attributable to climate change (although the large majority produced increases in mortality). The choice of the climate change and the air quality model reflected the greatest source of uncertainty, with the other modeling choices having lesser but still substantial effects.


Conclusions: Our results highlight the need to use an ensemble approach, instead of relying on any one set of modeling choices, to assess the potential risks associated with O₃-related human health effects resulting from climate change.


Key words: climate change, mortality, ozone, population projections, sensitivity analysis. 


Environ Health Perspect 120:1559–1564 (2012). http://dx.doi.org/10.1289/ehp.1104271 [Online 12 July 2012]


Address correspondence to J. Huang, Abt Associates Inc., 4550 Montgomery Ave., Suite 800, Bethesda, MD 20814 USA. Telephone: (301) 347-5571. Fax: (301) 828-9662. E-mail: jin_huang@abtassoc.com


Supplemental Material is available online (http://dx.doi.org/10.1289/ehp.1104271).


Support for this analysis was funded through the U.S. Environmental Protection Agency (EPA) award RD-83337301-0. Additional support, provided by Abt Associates Inc., was funded through U.S. EPA Contract EP-D-08-100. The views expressed in this document are solely those of the authors and do not represent official U.S. EPA policy.


The authors declare they have no actual or potential competing financial interests.


Received 26 July 2011; Accepted 12 July 2012; Online 12 July 2012.