EXAMINING THE RELATIONSHIP BETWEEN ATMOSPHERIC AEROSOLS AND LIGHT EXTINCTION AT MOUNT-RAINIER-NATIONAL-PARK AND NORTH-CASCADES-NATIONAL-PARK

During the summer of 1990, the National Park Service carried out a stu dy in the state of Washington called the Pacific Northwest Regional Vi sibility Experiment using Natural Tracers (PREVENT). The goal of the s tudy was to apportion atmospheric aerosols to scattering and extinctio n and to source types at Mount Rainier and North Cascades National Par ks. The study was designed to collect all necessary emissions, meteoro logy, ambient concentrations, and atmospheric optical data necessary t o support a variety of source attribution techniques. This paper will report on the apportionment of various aerosol species to measured fin e mass concentrations and ambient scattering coefficients. One highlig ht of this study was the near-ambient measurement of atmospheric scatt ering with a modified integrating nephelometer. It is therefore possib le to explore the relationship between hygroscopic aerosols and scatte ring in the ambient atmosphere.