SPATIAL an‎d SEASONAL VARIATION OF PM2.5 / PM10 RATIO IN TEHRAN, IRAN, DURING 2016 - 2017

Introduction: PM2.5 is one of the most important air pollutants, affecting human health by penetrating in to the alveolar area. Thus prediction of PM2.5 concentration and its behavior and also its seasonal and spatial variation are necessary for public health protection. Materials and methods: For this purpose, PM2.5/ PM10 was calculated in different seasons and different stations in Tehran city during 2016. Also the PM2.5/PM10 ratio was compared in different area of the city. Then achieved results were analyzed by R. Results: Seasonal variation of this ratio was significant. It shows that the maximum and minimum value of PM2.5/ PM10 was in winter and summer, respectively. It seems it is due to the incomplete combustion of fuel in winter. Also we found that the PM2.5/ PM10 ratio in the western area of city is significantly higher than the east. It can be due to the pollutants transmission from the town located in close proximity to the west of Tehran. Conclusions: PM2.5 / PM10 ratio can be different in various situations. It can be affected by the several factors such as pollutant sources, meteorological and seasonal factors and also traffic pattern. The PM2.5/PM10 ratio can alert corresponding agencies for prediction the air quality that happens every year periodically.