Chemical characterization of sub-micron particles in indoor and outdoor air at two different microenvironments in the western part of India

In this study, the concentration of sub-micron particulate matter (PM) and its associated metals concentration have been discussed. Monitoring of sub-micron particulate matter has been made by using Leland legacy sample pump with five-stage Sioutas Cascade Impactor. Total, 150 samples from urban and sub urban areas of western part of India were analysed using ICP-OES. For PM1.0–2.5, PM0.50–1.0 and PM0.25–0.50 the average mass concentration ranged from 28.33 to 38.86 µg m−3, 30.46 to 39.44 µg m−3, 25.43 to 46.30 µg m−3 for indoor environment, while outdoor environment concentrations ranged from 23.15 to 54.01 µg m−3, 22.38 to 36.20 µg m−3, 22.32 to 44.30 µg m−3, respectively. On the other hand, in sub urban area, the average mass concentrations ranged from 23.15 to 69.44 µg m−3, 27.72 to 51.73 µg m−3, 17.72 to 54.01 µg m−3 for indoor environment, while for outdoor environment, the average mass concentrations ranged from 30.86 to 77.16 µg m−3, 23.15 to 54.01 µg m−3, 24.25 to 46.30 µg m−3 for PM1.0–2.5, PM0.50–1.0 and PM0.25–0.50, respectively. Among all eight toxic metals, Al and Fe were found to be abundant. Human health risk factor also being calculated which showed that these metals were threat to human life. The sources of the sub-micron particulate matter associated metals in outdoor air were found to be the emissions from industries, vehicular activities, and dust from construction sites and in indoor it was mostly from cooking, cleaning and other human activities.