Atmospheric Polycyclic Aromatic Hydrocarbons (PAHs) and Nitro- PAHs, their adsorption and absorption partitioning at a traffic dominated Indo-Gangetic site

16 priority PAHs and Nitro-PAHs was measured simultaneously both in gas and particulate phase between October 2015 to July 2016 in the ambient air of Agra, India. Gas and particulate phase samples were collected using High volume sampler on Poly-urethane foam plugs and Quartz micro fibre filter papers respectively. Samples were extracted in a mixture of n-hexane and DCM and further analysed using Gas Chromatograph Mass Spectrometer. During the sampling period the average total PAH concentration in particulate and gas phase were 3121 ± 308.9 and 1732.5 ± 175.1 ng m^-3 respectively whereas the concentration of Nitro-PAHs was 65.3 ± 16.3 and 24.6 ± 6.55 ng m^-3 in the particulate and gas phase respectively. Gas-particle partitioning of PAHs was investigated employing the K_OA absorption and Junge-Pankow adsorption model. Statistically significant correlation (p<0.001) for log Kp vs log P^º_l was obtained for individual PAHs. Clausius-Clapeyron plots of PAHs suggests that the concentration of high volatile PAHs is influenced by temperature. Positive slope of log Kp and 1/T suggest that the density of PAHs (m³ µg^-1) is directly proportional to ambient temperature. DbA was found as the most carcinogenic and mutagenic as compared to other PAHs followed by BaP.