Variability of PM2.5 and health impacts in the Northeastern United States

Exposure to fine suspended particulate matter (PM2.5), has been associated with increased mortality around the world and in the United States. We analyzed the variability of ground level PM2.5 concentrations using station measurements from the Air Quality System of the Environmental Protection Agency in the Northeastern United States spanning from West Virginia to Maine for the period 1999-2013. The long-term variations as well as the occurrence of short-term high concentration episodes were investigated. The relative role of industrial versus biomass burning emissions was explored using data from the Modern-Era Retrospective Analysis for Research and Applications Aerosol Reanalysis (MERRAero) of the Goddard Space Flight Center of the National Aeronautics and Space Administration. There has been a substantial decrease in PM2.5 concentrations in the Northeastern United States region between 1999 and 2013, both in terms of regional mean values and the occurrence of high pollution episodes. High PM2.5 episodes in the North Eastern United States are, generally, the result of either long range transport of large Canadian wildfires or Midwestern and local emissions. Organic carbon is the dominant contributor for wildfires whereas sulfate dominates anthropogenic sources. The anthropogenic episodes are usually characterized by high-pressure systems that cause aerosols to concentrate in the region. There are roughly equal numbers of events due to wildfires and anthropogenic sources. We estimated differences in the exposure to ambient PM2.5 concentrations and hospitalizations for cardiovascular, pulmonary and injury outcomes, before and during the high concentration episodes. The results indicate that rapid increases in PM2.5 concentrations significantly impact the health of the population.