Distribution of ring PAHs in particulate/gaseous phase in the urban city of Delhi, India: Seasonal variation and cancer risk assessment

Abstract

The present study was carried out to investigate the distribution of ring PAHs in the particulate/gaseous PAHs phase associated with the PM 2.5 bound particulate matter besides toxicity in the residential site. The higher molecular weight of PAHs was primarily associated with the particulate phase, whereas lower molecular weight PAHs were observed in the gaseous phase. After the analysis of the seasonal data, the average value for particulate TPAHs concentration at all sites was found to be 122.46 ng/m3, whereas gaseous was 48.47 ng/m3, respectively. The trend of ring TPAHs concentration in different rings was observed 5- ring >6- ring >4- ring >3- ring >2- ring for particulate phase, whereas in gaseous phase 3- ring >4- ring >2- ring in all seasons. The concentrations of ∑5- ring and ∑6- ring PAHs were more dominant in the particulate phase, whereas the concentrations 2- ring and 3- ring were more dominant in the gaseous phase in all seasons. The LLE for both gaseous and particulate PAHs was calculated in the range 8.89 to 12.0 min for the gaseous phase, whereas for the particulate phase, 17.2 to 37.2 min for South Delhi and North Delhi, respectively.