Atmospheric Polycyclic Aromatic Hydrocarbon Inhalation Exposure and Human Health Risk Assessment at Traffic Site in Delhi, India

Polycyclic aromatic hydrocarbons (PAHs) generally form an integral component of air pollutants in the ambient atmosphere. This study focuses on how proximity to roadways affects the ambient concentration of PAHs. Spatial and seasonal distribution of sixteen PAHs, and collectively represented as Σ₁₆ PAHs were determined in the ambient atmosphere of Delhi, the National Capital Region (NCR) of India. The results showed that the average mass concentration of Σ₁₆ PAHs near the roadway (67.8 ± 40.2 ng m^-3) is significantly higher as compared to the urban background site (56 ± 30 ng m^-3). Moreover, a source apportionment study indicated that major PAH-emission sources in Delhi NCR are traffic and coal combustion. Health risks associated with inhalation of particulate PAHs were assessed using benzo(a)pyrene equivalent concentration (BaPeq) and incremental lifetime cancer risk (ILCR) approach. ILCR values at both sites fall in the range of 10^-2 to 10^-4 which corresponds to the priority risk level (10^-3) and not the acceptable risk level (10^-6). Thus, the present study concludes that the concentration of ambient PAHs is significantly higher at a site with busy traffic than at an urban background site, thereby indicating a significantly higher health risk to the population of Delhi.