Characterization, sources and health risk analysis of PM2.5 bound metals during foggy and non-foggy days in sub-urban atmosphere of Agra

A study was conducted at a campus site of Agra to determine the metals in fine mode particles (PM2.5) and assess their associated health effects in adults and children during the period from 7th December 2015 to 17th February 2016. PM2.5 mass concentrations (190 mu g/m(3) and 132 mu g/m(3)) exceeded the air quality standards of India by a factor of 3.2 and 2.2 during the foggy and non-foggy days, respectively. Total concentration varied from 11.9 mu g/m(3) to 40.6 mu g/m(3) during the fog period and from 5.7 mu g/m(3) to 25.8 mu g/m(3) during the non-foggy period for seventeen metals (including metals with concentration > 1 mu g/m(3), 0.1-1 mu g/m(3), 0.01-0.1 mu g/m(3) and < 0.01 mu g/m(3)) with maximum contribution from K and minimum from Co. At this site in winter, coal and biomass combustion, vehicular emissions, crustal dust and iron producing industrial processes were identified as the major contributors to metals as determined by correlation analysis and Principal Component Analysis. Cr and Mn showed the highest carcinogenic and non-carcinogenic risks. Cumulated non-carcinogenic risk in children (HI: 3.90 for foggy days; HI: 2.74 for non-foggy days) was higher compared to the adults (HI: 1.81 for foggy days; HI: 1.29 for non-foggy days) during both periods while the cumulated effect of carcinogenic risk was higher for adults (ILCR: 2.25E-04) than for children (ILCR: 1.31E-04).