Analyzing Temporal-Spatial Distribution of CO Pollutants during COVID-19 Epidemic (Case Study: Khuzestan Province, Isfahan, Tehran)

To prevent the spread of COVID-19 epidemics, restrictions such as "quarantine" have been imposed worldwide led to significant changes in the environment, especially the air. The purpose of this study is to investigate the temporal-spatial distribution of pollutants (CO) and the effect of corona constraints on it. For this purpose, CO data was extracted from MERRA-2 satellite with monthly and spatial time steps of 0.5 x 0.625 with time coverage of 2015-20. Then, the data distribution was analyzed by ArcGIS software. In this study, in order to measure the effect of applying corona restrictions on the level of CO pollutants, the data related to the period of applying corona restrictions (July 2020) were compared with the corresponding months in the base period (July 2015-2019), then the control effect of synoptic systems and atmospheric factors for the distribution and dispersion of this pollutant were studied in the provinces that had maximum of this pollutant in Iran. The results showed that the monthly average of this pollutant decreased not only in the provinces that had the maximum CO anomaly, but also over the whole atmosphere of Iran. The results of synoptic factors of geo-potential height and vertical air movement at the level of 500 hPa showed that in both periods, synoptic conditions were the same above the atmosphere of Tehran, Isfahan and Khuzestan provinces, so the studied synoptic factors have no role in this decrease. Examining the factory closure and the average condition of vehicle traffic in some of the busiest roads of these provinces, a decrease in transportation was also observed. The decrease in CO during periods of economic restrictions can be seen as a positive message of COVID-19 for air quality.