Time-Resolved Size Distributions of sub-4 micrometers Particle Sulfur and Nitrate

摘要

Size-segregated atmospheric aerosol was collected at Claremont, California during the 1987 Southern California Air Quality Study (SCAQS) using low pressure impactors. The single orifice impactors separated the aerosol into eight size fractions, ranging in aerodynamic diameter from 0.05 micrometer to greater than 4 micrometers. The size fractions were analyzed for sulfur using a flash volatilization-flame photometric method, for nitrate using ion chromatography, and for nitrate, carbonyl and aliphatic carbon using infrared spectroscopy. These measurements of aerosol composition were coordinated with experiments conducted by other CRC-APRAC contractors. The other contractors measured ambient visibility and the changes in particle size associated with changes in humidity. The data collected in these experiments will be a rigorous test of current visibility models and will help to guide future work in atmospheric visibility modeling.