Investigation and zoning of Mashhad metropolitan air quality in 2014 based on air quality index

This study was conducted with the aim of determining and zoning the air quality of Mashhad in 2014 based on air quality index (AQI). In this study, instantaneous concentrations of air pollutants in Mashhad were prepared and AQI was calculated. Data analysis was performed using Kruskal-Wallis and Mann-Whitney tests at a significant level of 5% in SPSSV.23 software. Moreover, Arc GIS was used to zone the air quality of the studied stations. The results showed that the months of September and October have the highest average of AQI with 168 and 156 (unhealthy status) and March with a value of 88 (moderate status) has the lowest amount among the studied months. Based on zoning maps, most stations in Mashhad were assessed as moderate and unhealthy status for sensitive groups. Also, Taghiabad and Khayyam South stations with an average AQI index of 107 (unhealthy condition for sensitive groups) as the most polluted and Machine Abzar station with a value of 37 (good condition) as the cleanest points among the studied stations. PM2.5 was the most important pollutant during the study.