Effect of cloud seeding on aerosol properties and particulate matter variability in the United Arab Emirates

In this study, satellite data and those obtained from air quality monitoring stations were used to evaluate the effect of cloud seeding missions conducted from January 2017 to March 2017 in the United Arab Emirates (UAE). To determine PM variability during and after the cloud seeding missions, information on daily mean particulate matter (PM10 and PM2.5) concentrations obtained from 20 air quality ground-based stations was analyzed from January 2017 to April 2017. The stations were divided according to four distinct geographic zones, which include petrochemical and non-petrochemical industrial, residential, and low populated areas. Moreover, data from the MAIAC 1-km product (MCD19A2) obtained using the Moderate Resolution Imaging Spectroradiometer onboard the Terra satellite were used to identify the correlation between aerosol optical depth and ground PM concentrations. The results showed that among the areas, the petrochemical and non-petrochemical industrial areas had the highest PM2.5 levels. Urban areas located adjacent to deserts had significantly higher PM10 concentrations than other urban areas. The PM concentration was high during the period of cloud seeding missions. This finding indicated that silver iodine crystals fired during the missions might have increased the concentration of PM in the air. Moreover, cloud seeding missions might have a more significant effect in increasing PM10 concentrations compared with PM2.5 concentrations. Hence, local weather conditions might have affected the decay of silver iodine particles during the missions. Long-range air mass transport may have an influence on the natural and anthropogenic particle concentrations in land and water bodies surrounding the UAE.