Abstract:Relationship between atmospheric visibility and particulate matter was analyzed using the observed hourly visibility, relative humidity, wind speed and particulate sample data at Tianjin atmospheric boundary station in 2009. Visibility had significant negative correlation with the mass concentration of the particulate matters. The ratio of mass concentration between PM2.5 and PM2.5~10 increased considerably when the visibility reduced, implying that PM2.5 played major role in the poor visibility. Atmospheric visibility also had significant negative correlation with the mass concentration of the total carbon. The average contribution of SO42-,NO3-,OC and EC to atmospheric extinction coefficient was 28.7%, 6.1%, 27.6% and 19.2%, showing that sulfate and organic carbon were the main components influencing the visibility.