Monitoring the water surface of wetlands in Iran and their relationship with air pollution in nearby cities.

Understanding the impact of wetland water area (WWA) fluctuations on air pollution in nearby cities is of great environmental importance. This study is the first effort for investigating the WWA changes in Iran and their impacts on air pollution in the surrounding cities during different seasons. Three-hourly data related to wind speed, wind direction, and horizontal visibility recorded in meteorological stations around Iranian wetlands were used to identify cities located in the direction of dusty winds blown from shrinking wetlands in Iran. Meteorological data were also used to calculate the pollution of dust storm index (PDSI) as a representative of dust pollution in the surrounding areas. Global water surface (GWS) product for a long-term period (1988 to 2018) was used to monitor the WWA in Iran. The correlation between PDSI in dusty cities and WWA in nearby wetlands were analyzed using the Pearson correlation coefficient (r). The results showed that the cities located around Hamoun, Jazmourian, Parishan, and Hourolazim wetlands were affected by dusty winds blown from the wetlands in most seasons. However, the cities around Gavkhouni International Wetland have been affected by the winds only in the warm season. In winter and spring, the strongest negative correlations between PDSI-WWA was respectively observed in Shiraz-Parishan (r =  - 0.33; p-value < 0.05) and Zabol-Hamoun (r =  - 0.32, p-value < 0.05). However, in the summer and autumn, no strong correlation was observed between the studied variables. On the annual scale, 25% and 15% of changes in dust pollution across the cities around the Hamoun and Parishan international Wetlands were due to the decrease in their water area from 1988 to 2018. On a seasonal scale, about 11% of the changes in PDSI were due to changes in the water area in these wetlands. These results can be useful for implementing air pollution reduction programs in cities affected by dusty winds blowing from the destroyed wetlands.