| Climate change is forecast to affect ambient temperatures, precipitation frequency and stagnation conditions, all of which impact regional air quality. An issue of primary importance for policymakers is how well currently planned control strategies for improving air quality that are based on the current climate will work under future global climate change scenarios. The US EPA's Regional Air Quality Modeling System, CMAQ, with DDM-3D are used to investigate sensitivities of ozone and PM2.5 to emissions for current and future scenarios. Sensitivities are predicted to change slightly in response to climate change. In many cases, mass per ton sensitivities to NOx and SO2 controls are predicted to be greater in the future due to both the lower emissions as well as climate. Another objective of this study is to investigate the impacts of climate uncertainities on regional air quality predictions using multiple climate futures in order to evaluate the robustness of currently planned emission controls under impacts of climate change. The results show that planned controls for decreasing regional ozone and PM2.5 will continue to be effective in the future under the extreme climate scenarios. However, the impacts of climate uncertainties may be substantial in some urban areas and should be included in assessing future regional air quality and emission control requirements. Furthermore, cross-responses of ozone and PM2.5 to emissions are investigated for current and future scenarios. Cost analysis of offsetting impacts of climate change on air quality is also presented for five U.S. cities. |
