Cooperative Institute for Research in the Atmosphere

Air quality and haze across the U.S over the past 30 years: past and current issues

Over the past 30 years, dramatic changes in particulate matter composition across the U.S. have been evidenced by trends in speciated aerosol data collected by large-scale U.S. monitoring networks, such as the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. In this presentation, I will discuss how these trends point to the success of combined regulatory activities aimed at reducing anthropogenic emissions over the last three decades. However, as regulated sources of precursor emissions decline, the contributions to haze from unregulated sources, such as biomass burning, dust, agricultural activities, and oil and gas extraction, have increased. In addition to trends, I will discuss the current status of aerosol composition and haze across the U.S. in the context of these sources. Reducing haze from unregulated sources will require additional mitigation strategies and resource management plans in order to improve air quality and visibility in the U.S. for future generations.