Meteorological Influences on Anthropogenic PM2.5 in Future Climates: Species Level Analysis in the Community Earth System Model v2
Our study investigates the impacts of increasing anthropogenic greenhouse gas emissions on precipitation, wet deposition of aerosol particles, and resulting changes in air quality using the Community Earth System Model v2. Overall, we find that decreases in the frequency of moderate precipitation events lead to increases in the column aerosol burden and surface concentrations for many aerosol species through reductions wet removal.
The emissions of fine aerosol particles (PM2.5) can worsen air quality and are hazardous to human health. However, processes that influence the secondary production, transport, and removal of aerosol particles can also influence air quality. Our analysis contributes to understanding how changes in rainfall, temperature, and moisture contribute to the risks of this environmental hazard under anthropogenically driven climate change conditions.
Biomass and fossil fuel burning impact air quality by injecting fine particulate matter (PM2.5) and its precursors into the atmosphere, which poses threats to human health. However, the surface concentration of PM2.5 depends not only on the magnitude of emissions, but also secondary production, transport, and removal. In this experiment, we conduct new simulations by fixing aerosol emissions at present-day levels in the Community Earth System Model v2, but increasing greenhouse gases through the 21st century. We find changes in the patterns and intensity of PM2.5 associated with precipitation (via aerosol removal), temperature (via secondary organic aerosol (SOA) formation), and moisture and clouds (via sulfate production). Decreases in wet day frequency (∼1.2% global mean) contribute to increases in the surface concentrations of black carbon, primary organic matter, and sulfate in many regions. This is offset in some regions by an upward vertical shift in the level where SOA forms, which contributes to higher column burden but lower surface concentration. These results highlight a need to continually reassess aerosol regulations in response to anticipated climate changes.