An air monitoring network using continuous particle size distribution monitors: Connecting pollutant properties to visibility via Mie scattering calculations

Abstract

Aerosol size distribution data collected by the Southern California Air Quality Study (SCAQS) air monitoring network have been combined with values of the aerosol refractive index estimated from filter-based determinations of aerosol chemical composition. The resulting data have been used to calculate the aerosol light scattering coefficient values in time series at four air monitoring sites via Mie theory. It was found that the time series of the measured light scattering coefficient values could be reproduced well by the visibility model in those cases where redundant nephelometer measurements were available to assure that the measured light scattering coefficient values were not in doubt. Based on this study, it appears practical to maintain a network of monitoring sites that can be used to acquire size-distributed aerosol data simultaneously over a large geographic region. Such data will be needed in the near future for evaluation and testing of grid-based air quality models for the formation and transport of size-distributed particulate matter. Such data can be used at present to connect pollutant properties to visual range via modeling calculations based on Mie theory.

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