Determination of air quality index based on suspended particles and its zoning at the metro terminals of Tehran

The concentration of suspended particles is surveyed in metro terminals of Tehran and the relationship of some meteorological parameters on particle concentration. 18 stations were selected at different terminals. Sampling was carried out during four seasons. laser device was used to measure PM2.5and PM10 and then AQI values based on suspended particles were calculated and the results were zoned using GIS and spatial analysis method. Minimum and maximum concentrations of PM2.5suspended particles were obtained between 10.5 and 101.8 and 41.5 to 192.5 μg/m3 for PM10. The quality index of clients was from healthy to unhealthy (40 to 105). And air quality index was in an unhealthy range in most areas in the fall and winter. The concentration of suspended particles was 2.5 in winter and autumn more than in summer and spring. PM2.5suspended particle concentration showed a relationship with minimum and maximum daily temperature and humidity. At these terminals, the air quality index based on PM2.5suspended particles was set in the unhealthy winter for everyone and unhealthy in the summer and autumn for sensitive people. These results indicate that in winter, due to the large number of days with a temperature inversion, pollutants are concentrated on the Earth's surface.