Trend of ambient air particulate matter with aerodynamic diameter of 2.5 μm and smaller in Zahedan city in 2018-2019

Background and Objective: Air pollution is one of the most important environmental risk factors that exposure to it can cause many acute and chronic effects on human health. Some regions of Iran, especially the western, southern and southeastern provinces of the country, have been affected with dust storm for years. Studies on the frequencies of dusty days in the country show that central pits of Iran and the cities of Zabol and Zahedan have the highest incidence of dusty days. The purpose of this study was to determine the concentration of suspended particles with aerodynamic diameter of 2.5 μm or less (PM2.5) in various seasons and months during 2019 in Zahedan. Materials and Methods: In this descriptive-analytical and cross-sectional study samples were typically collected once every 6 days during a 24-hour period as well as on dusty days using an air sampler (PQ200 / BGI) from July 2018 to July 2019. Results: The results show that the mean concentration of PM2.5 in Zahedan during this study was 36.86 µg/m3. The maximum and minimum PM2.5 daily concentrations in the sampling days were also measured as 130.8 and 4.75 µg/m3, respectively. Conclusion: In conclusion, 88% of samples contained PM2.5 concentration above the WHO 24-hr air quality guideline level (25 µg/m3), which could be due to the high incidence of summer dust storms. This indicates that particulate matters are a serious health threat to people living in those areas and calls for the implementing measures to tackle the problem.