Aerosol Concentrations During the 1999 Fresno Exposure Studies as Functions of Size,Season,and Meterology

摘要

Two 1999 Fresno exposure studies took place in February (winter season) and April/May (spring season) for periods of four week each. During that time, nearly continuous measurements of out. door aerosol concentrations were made with a TSI Scanning Mo. bility Particle Sizer (SMPS) and a PMS optical particle countel (LASX). These instruments provide particle size distribution in. formation from about 0.01 to 3 #mu#m. Although the primary concen. tration measurements were performed with integrated samplers, the SMPS/LASX combination provided useful information on th( real-time variations of concentration and particle size distributions. This paper describes the agreement between the real-time instru- mentation and the integrated measurements and examines somE of the information available from the SMPS/LASX combination. In particular, two different types of aerosols contributing to PM25 were deduced from the instrumental data.