Estimation of Dust Downfall Time in Dusty Days using the Correlation between PM10 and Sunphotometer Data

Urban air pollution has become a serious challenge in all societies. Nowadays, pollutants are measured by various tools and devices, including local particulate measurement instruments and ground-based remote sensing devices. This paper aims to estimate dust downfall time in dusty days of Zanjan city using the data obtained from ground-based aerosol sampling device and sunphotometer. The particulates with the size of less than 10 micrometers (PM10) were measured by ground-based measurement device in the height of 3 meters above the ground, while aerosol optical depth (AOD), which represents the amount of aerosols in vertical column of atmosphere, was measured by sunphotometer. According to correlation coefficient diagram, PM10 and AOD reached a maximum of 2, 6, 3 and 3 hours in dusty days of 9, 10, 24 and 25 June 2010. In other words, dust downfall took 2, 6, 3 and 3 hours respectively in the aforementioned days. Keywords: Downfall, dust, sunphotometer, correlation