US EPA

33983 

Journal Article 

On the nature and origins of visibility-reducing aerosols in the Los Angeles air basin 

White, WH; Roberts, PT 

1977 

1 

Atmospheric Environment
ISSN: 1352-2310
EISSN: 1873-2844 

11 

9 

803-812 

WOS:A1977DZ38500003 

#Simultaneous measurements of the light-scattering coefficient and chemical composition of ambient aerosols were made during selected smog episodes in the Los Angeles air basin. These data are statistically analyzed to determine the effective scattering efficiencies of the major secondary aerosol species. The individual scattering efficiencies are then used to estimate the contributions of major sources of reactive gases to the reduction of visibility in Los Angeles. Sulfate and nitrate compounds appear to have scattered more light at a given mass concentration than did other chemical fractions of the aerosol. The observed relationship of SO2 and NOx concentrations to the concentrations of tracers for major source types was consistent with existing inventories of SO2 and NOx emissions in the basin. Because of the high scattering efficiency of sulfates, the estimated contribution of large stationary sources of SO2 to the reduction of visibility was comparable with that of the automobile.