Evolving Issues in Air Quality Related to a Changing Climate

摘要

The magnitude and pace of anthropogenic climate change have profound implications for related air quality problems. Aerosols (and some trace gas species) are well-known as climate drivers, directly via backscatter and absorption of radiation and indirectly via cloud impacts. Both direct and indirect aerosol impacts are spatially and temporally heterogeneous and uncertain. On the other hand, climate shifts underway pose uncertain feedbacks on air quality related values including visibility, deposition, and human health effects. Among the most impacted air quality parameters are ozone and aerosol concentrations. Whereas anthropogenic emissions of greenhouse gases are just beginning to be addressed, emission reductions in aerosols and their precursors have been remarkably successful in the US over the last 50 years. Thus perturbed natural sources of aerosols have become more important in urban and, in particular, rural areas. Trends related to this include the growing importance of primary and secondary carbonaceous aerosols as well as an upward trend in mineral dust species observed in the Western US over two decades. The panel consists of experts on ambient air quality, aerosols and their optical properties, biomass smoke, desert dust, and cloud-climate interactions. The panel will address the following related questions: 1. Warming and extreme weather: what are the expected changes and how will it impact air quality? 2. A warming climate: what does this mean for visibility and regional haze? 3. What trends are emerging with "perturbed natural sources" of PM including windblown dust and biomass burning smoke? 4. What are the feedback processes involving inter-connected changes in air quality and climate? 5. What are the current research needs to further reduce uncertainties in aerosol-climate interactions?