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Integrating nephelometers were installed at each station of the dust storm monitoring net by the China Meteorological Administration. This is the first time that the optical porperties of aerosol were monitored using integrating nephelometers on a large scale in China. The variation feature of scattering coefficient and the relation between scattering coefficient and PM10 mass concentration and visibility were analyzed based on the primary principles of integrating nephelometers,using the scattering coefficient data and PM10 mass concentration from Beijing Observatory and meteorological data from September to November 2003.The results indicate that the mean value (standard deviation) is 306 2 Mm -1(292 78 Mm -1).Wind speed has an important effect on scattering coefficient,while scattering coefficient has good correlation with PM10 mass concentration ( r = -0 761),and there exists a negative correlation between scattering and visibility ( r = -0 716).