Source and source region of carbonaceous species and trace elements in PM₁₀ over Delhi, India

This study investigated the carbonaceous species [elemental carbon (EC), organic carbon (OC),water soluble organic carbon (WSOC)] along with the trace elements (Al, S, Ti, Mn, Fe, Cu, Zn, As, Br, Pb, Cr, F, Cl, Na, K, Mg, Ca, P) in PM₁₀ over megacity Delhi, India (collected from 2015-2019) to address the significant scientific issues (i.e., what are the directionality or pathway of these emissions; what are the possible emission sources, which are distressing the observation site; periodical variations in these emissions; whether the emissions are local, regional or trans-boundary). Integration of these problem are addressed using the statistical approaches potential source areas (PSA) [using hybrid modelling i.e. potential source contribution factor (PSCF)], conditional bivariate probability function (CBPF) and principal component analysis (PCA). A profile of higher concentration of PM₁₀ was observed during post-monsoon (322 ± 73 µg m^-3) followed by winter (271±87 µg m^-3) and low concentration during summer (221 ± 89 µg m^-3) followed by monsoon (167±93 µg m^-3). Further, seasonal PSCF and CBPF indicates local sources (highly polluted residential, traffic congestions and industrial emissions) and regional sources (Haryana, Punjab) dominancy during winter and post-monsoon seasons at the receptor site whereas during summer and monsoon along with local source and the regional, trans-boundaries (Indo-Gangatic plane,Pakistan, Afganistan and Bay of Bengal) air parcel pattern also contribute to the aerosol loading at the site. Moreover, PCA approach framed four common sources [crustal/road dust (RD), industrial emission (IE), fossil fuel combustion +Biomass burning (FCC+ BB),vehicular emission (VE)] with one mixed source over the sampling site of Delhi.