Investigation of Air Quality Index and PM۱۰ and PM۲.۵ in Arak

Background and purpose: In this study, the air quality index and concentration of particles such as PM۱۰ and PM۲.۵ were investigated in Arak. Materials and Methods: To determine the concentration of PM۱۰ and PM۲.۵, ۶۰ samples were collected by laser TSI model ۸۵۲۰ in summer and winter ۲۰۱۲. The collection site was around Arak city center. Results: during the sampling period, as a matter of PM۱۰, the cleanest and the most polluted month were December and June with the average of ۳۴.۳۳ µg m-۳ and ۱۰۰.۱ µg m-۳, respectively. The concentration of PM۲.۵ was ۱۲.۹۳ and ۵۳.۱۷ µg m-۳ for December and June, respectively. Meanwhile, in terms of air quality index (AQI), in ۹۸.۳% and ۷۰% of cases, the concentrations of PM۱۰ and PM۲.۵, respectively were less than normal (AQI۱۰۰). Conclusion: The concentration of PM۱۰ in the study period was less than Environmental Protection Agency (EPA) ۲۰۰۶ guideline. Meanwhile, the concentrations of PM۲.۵ in ۳۰% of air samples were greater than EPA guideline. The average PM۲.۵/PM۱۰ ratio during the sampling period was ۰.۴۱ compared to range ۰.۱۵ to ۰.۲۵ reported by EPA.