Chemical Characterization of Airborne Particles Collected in an Underground Metro Station Platform in Delhi City

Transport systems in urban land spaces are shifting to underground due to the unavailability of space on the surface. Nowadays, the underground metro system has become an imperative mode of transport. Since people spend considerable time in underground metro stations (UMS), indoor air quality (IAQ) has become an important parameter of investigation. However, maintaining IAQ at UMS has become a major issue for developing countries. Hence, the assessment and management of IAQ in UMS is important for a healthier indoor environment. The present study includes an elemental composition of indoor/outdoor (I/O) particulate matter in a UMS in Delhi city, India during winter season. The study mainly focused on metals and carcinogenic elements. Out of 41 metals analyzed, the main contributors to the indoor pollution at the UMS platform and outdoor were Iron at a concentration of 24.54 ?g/cm2 and 2.58 ?g/cm2, followed by Manganese 0.36 ?g/cm2 and 0.08 ?g/cm2, Copper 0.73 ?g/cm2 and 0.15 ?g/cm2, Calcium 12.77 ?g/cm2 and 4.55 ?g/cm2 and Silicon 34.70 ?g/cm2 and 10.92 ?g/cm2, respectively. Further, it has been found that indoor elemental concentrations are higher than that of outdoor environment concentrations. The results of this study will help identify the different sources from various activities within the UMS, in order to select suitable environmental management techniques to manage the IAQ in UMS better.