GH009-08
Air pollution related health impacts under a changing climate—methodological choices and challenges with a case study of 968 U.S. counties

Monday, 14 December 2020: 10:35
Virtual
Chen Chen1, Yang Zhang2 and Michelle L Bell1, (1)Yale University, School of the Environment, New Haven, CT, United States, (2)Northeastern University, Department of Civil and Environmental Engineering, Boston, United States
Recorded Presentation
Abstract:
Estimating how health will be impacted by air pollution under climate change is essential to understand the overall health burden of climate change for informed decisions about mitigation and adaptation policies. In this study, we critically evaluated the current status of methodological choices and corresponding uncertainties in the estimation of health impacts from changes in air pollution under climate change in four key methodological aspects: health linkage function, concentration-response function (CRF), projection of ambient air pollutant concentrations, and projection of population characteristics.

We demonstrated these concepts through an example application for 968 continental U.S. counties with fine particulate matter (PM2.5) concentrations in past decade (2001—2010) and future decade (2046—2055) simulated with Representative Concentration Pathways (RCPs) 4.5 and 8.5. We produced county-level estimates of average PM2.5-related excess number of circulatory and respiratory hospitalizations considering several of the key methodological aspects, including change in CRF. After incorporating different assumptions for CRFs (temporal change in CRF, assuming CRFs of the most recent year (2016) persist to future decades, or assuming CRF of high urban areas in the past decade apply for all counties in the future decade due to trends in urbanization), the excess hospitalizations were estimated to be positive for both RCPs. Without considering the different assumptions for CRF, we observed positive national average PM2.5-related excess circulatory and respiratory hospitalizations for RCP4.5, but negative values for RCP8.5. Projected reduction in air pollution emissions and resulting decreases in PM2.5 in future decade were the major contributors for the decrease in the average number of annual PM2.5-related hospitalizations. This work provides insights into the methodological choices in estimates of climate change-related air pollution impacts. County-level estimates also provide policymakers with evidence supporting development of local mitigation policies.

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