title: Variation of mass scattering efficiencies in IMPROVE.
abstract: The Interagency Monitoring of Protected Visual Environments (IMPROVE) equation used to assess compliance under the U.S. Environmental Protection Agency (EPA) Haze Rule assumes that dry mass scattering efficiencies for aerosol chemical components are constant. However, examination of aerosol size distributions and chemical composition during the Big Bend Regional Aerosol and Visibility Observational Study and the Southeastern Aerosol and Visibility Study suggests that volume and mass scattering efficiencies vary directly with increasing particle light scattering and aerosol mass concentration. This is consistent with the observation that particle distributions were shifted to larger sizes under more polluted conditions and appears to be related to aging of the aerosol during transport to remote locations.
authors.affiliation: Desert Research Institute, Reno, Nevada 89512, USA. Doug.Lowenthal@dri.edu
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Lowenthal
authors.forename: Naresh
authors.initials: N
authors.lastname: Kumar
mesh_terms: D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D008962:Models, Theoretical; D055095:Optics and Photonics; D010316:Particle Size
chemical_list: D000336:Aerosols; D000393:Air Pollutants