Examining the impact of changing climate on regional airquality over the U.S.

摘要

The Climate Impact on Regional Air Quality (CIRAQ) project is acollaborative research effort involving multiple federal agencies andacademic institutions to assess the impact of present and futureclimate on regional air quality across the United States. Preliminaryresults are presented which highlight model biases, variability andchange of present (~2000) and future (~2050) regional climate,emissions and air quality model results for the summer season (June—August). The regional climate scenario derived for CIRAQ appearsto reasonably represent large-scale summer-season climate meansand variability in the western United States, but it fails to replicatesome key summertime features in the eastern United States. A com-parison of future and current climate simulation reveals that eventhough the general weather patterns change little in the future, thesummer temperatures are on average 2-3 K warmer over the south-west quadrant of the United States. Other regions of United Statesare also warmer, but generally by less than 1 K. Preliminary analysesof the interannual and seasonal variability of biogenic and mobileemissions driven by current climate scenarios indicate isoprene andbiogenic NO emissions are more temporally and spatially variablethan are model generated on-road mobile source emissions. Com-parison of these results with modeled emissions under future climatereveals similar spatial and temporal patterns, but elevated levels ofbiogenic emissions are present in the future simulation due to thewarmer future summer temperatures throughout the study domain.