Elemental variation of PM_2.5 and health risk assessment at Delhi during north east monsoon and south west monsoon

This study elucidates the variation of PM_2.5 at Delhi, during the northeast monsoon (NEM) and the southwest monsoon (SWM) of 2014-2019. The seasonal concentrations were observed as during NEM (2014: 178 ± 56 µg/m³, 2015: 125 ± 56 µg/m³, 2016: 71 ± 32 µg/m³, 2017: 144 ± 50 µg/m³, 2018: 77 ± 49 µg/m³, 2019: 83 ± 43 µg/m³) and SWM (2014: 61 ± 18 µg/m³, 2015: 54 ± 23 µg/m³, 2017: 37 ± 20 µg/m³, 2019: 48. ± 13 µg/m³). Further, the elemental composition was achieved by using wavelength dispersive X-ray Fluorescence (WD-XRF). During NEM it was observed that Na, K, and Br contributed dominatingly, whereas, Si, K, and Cr dominated during the SWM season. Moreover, the trajectory profile was adopted to study the long-range transport over the site. Major air parcels were observed from the Sahara Desert (SD), Arabian Sea (AS), and Bay of Bengal (BOB) for both seasons (NEM and SWM), thus significantly affecting the loading of mass concentration at the site Delhi. We have also calculated the hazard quotient (HQ) and hazard index (HI) of elements over Delhi during this period