Variability and potential sources of summer PM2.5 in the Northeastern United States

摘要: Abstract The variability of ground-level concentrations fine suspended particulate matter (PM2.5) in the Northeastern United States is examined using observed PM2.5 from multiple data networks together with output Modern-Era Retrospective Analysis for Research and Applications Aerosol Reanalysis (MERRAero). long-term variations as well occurrence short-term high-concentration episodes region are investigated period 1999–2013. This analysis shows that over this there has been a significant decrease summer-mean PM2.5. A magnitude high-PM2.5 events U.S. also observed. potential sources analyzed MERRAero aerosol optical depth two main components pollutant: organic carbon ammonium sulfate. indicates are, generally, result long range transport smoke large boreal wildfires, Midwestern industrial emissions, or combination both. There roughly equal numbers due to natural anthropogenic 2002–2012 region. have an source characterized by strong high pressure system Southern cause aerosols be advected Midwest into meteorology related wildfire more variable, consistent varied locations fires