Source identification and health risk assessment associated with particulate- and gaseous-phase PAHs at residential sites in Delhi, India

Polycyclic aromatic hydrocarbons (PAHs) have a ubiquitous presence in nature and are among the first atmospheric pollutants to be suspected of having carcinogenic and mutagenic nature. For the present study, five representative sites for 16 PAHs were selected for ambient air sampling in Delhi. The concentration of a total of 16 particulate-phase PAHs at all sites was found to be in the range from 30.04 to 222.94 ng/m3 during the sampling period. The concentration of particulate TPAHs was found to be in order as Mukherjee Nagar > Anand Vihar > Rohini > CP > JNU during the sampling period. The mean concentration of gaseous-phase TPAHs at all sites was found to be in the range from 30.16 to 80.16 ng/m3. The mean concentration of gaseous TPAHs was found to be in order as CP > Rohini > Anand Vihar > Mukherjee Nagar > JNU. The health risk values both gaseous- and particulate-PAHs varied from 3.42 × 10−6 (JNU) to 4.96 × 10−6 (Rohini) and 3.43 × 10−5 (JNU) to 7.43 × 10−5 (Mukherjee Nagar) for child and adult respectively. The results of the diagnostic ratio, principal component analysis (PCA), and correlation at different residential sites in Delhi indicated that fossil fuel (diesel and gasoline) and wood burnings were major contributors of total PAHs in all seasons.