Particulate matter emission is an important threat to sustainable development due to its various effects on the atmosphere. Particulate matter originates from natural sources or human activities. Since Birjand is located between Sistan plain and Karakum desert, numerous dust events have been reported in this area. In the present study, concentration of PM10 was divided into annual, seasonal, monthly, weekly, and hourly time scales from 2014 to 2018. HYSPLIT model and AOD products were used for examining the movement pattern and origins of the particles. Pearson correlation was calculated between the frequency of dusty days and climate variables. The results revealed that PM10 concentration and dusty days frequency trends were similar. Additionally, the mean temperature and wind speed had a similar trend as PM10 concentration. Furthermore, PM10 was significantly related to dust and most of the climate variables. The closest correlation of PM10 was with dusty days in seasonal (Pearson correlation = 0.494) and monthly (Pearson correlation = 0.619) time scales. Based on PM10 daily concentration, 34 unhealthy days were identified. To track the particles on unhealthy days, HYSPLIT model was employed. Except in spring, the wind roses showed that the main direction of the wind was to the west. Meanwhile, based on AOD images, the particles originated from dust sources. A big amount of PM10 concentration originated from the surrounding regions, and the majority of dust particles came from the north. Therefore, the local climate variables as well as dust events of the surrounding regions had crucial roles in the rise in PM10 concentration, which should be taken into consideration by managers so that PM10 concentration could be taken under control.

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