Assessment of Indoor/outdoor Particulate Matter in Residential Building: Tehran Metropolis, Iran

Indoor Air Quality and the prediction of indoor pollution levels have become more important subjects for health risks. This research will be investigated the ratio of the concentration of particles inside and outside residential houses in Tehran. The particulate matter (PM) sampling was performed in four seasons from August 2020 to July 2021. Four stations were selected as fixed sampling stations and sampling time varied from 6 hours to 12 hours. Due to the risk of fine particles and the possibility of their impact on human health, in this study, PM and PM were examined. A multi-stage virtual shock absorber that traps particles on steel plates with a constant airflow was used for sampling. The Scanning Electron Microscope (SEM) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) methods were used to study the size, morphology, and chemical composition and analyze the total concentration of particulate matter (PM). The results showed that in most stations, the penetration of outdoor particles into the building in the cold season was more than in the hot season. Due to the use of natural ventilation in most residential buildings in the study area, the I/O ratio of PM and PM was on average more than 0.752. At some stations in March, April, and May the I/O ratio was over 0.965. According to these results, in the eastern area, the exposure to particulate matter (PM) with a diameter of less than 0.4 µm was higher than in other areas.