Comparison of volume and mass distributions for denver aerosols

Abstract Using data of the Denver 1971 aerosol characterization study, volume concentration distributions calculated from size distribution measurements by the Minnesota Aerosol Analyzing System (MAAS) are compared to mass concentration distributions measured by 8-stage Andersen impactors. In this study, the upper mode was confirmed by the impactor measurements. The lower mode was not confirmed, probably due to poor resolution resulting from impaction onto the glass fiber filters used as impaction surfaces. However, the total mass in the lower impactor mode was in agreement with the mass inferred from the volume of the lower MAAS mode. In the submicron range, estimates of densities of 1.6–1.8 g cm −3 are inferred for background aerosols and 1.1–1.5 g cm −3 for pollution aerosols.