INVESTIGATION OF TSP, PM10, PM2.5 CONCENTRATIONS IN UNDERGROUND an‎d GROUND – LEVEL STATIONS OF TEHRANMETRO SYSTEMS

Introduction: Among air pollutants, particles are the primary and major pollutant. Particulate matters in closed environments like underground subway stations have many severe effects on human health. The aim of this study was to evaluate the concentration of PM in various parts of indoor and outdoor air line 1 of Tehran subway stations. Materials and methods: Surveys were conducted during peak- hours of working days in January 2016 using a portable photometric aerocet 531 sampler. Samples were taken from indoor and outdoor air at each station from platform. Results: The highest PM concentration was observed at Darvazeh Dowlat Station ( PM2.5, PM10 and TSP were 48, 108 and 140 μg/m3 ). The highest PM concentration is related to the evening, beginning of the platforms and the lowest PM concentration is related to the before noon. As can be seen, PM2.5 / PM10 ratio ranges from 0.45 to 0.50 and PM10 / TSP ratio from 0.55 to 0.65. Conclusions: The results of this study indicate that the average concentration of PM2.5 in Tehran metro stations was higher than EPA and there was a strong correlation between PM concentrations at platform station and outdoor air. Also air quality in metro stations was inappropriate.