Sources and health risks of polycyclic aromatic hydrocarbons during haze days in eastern China: A 1-year case study in Nanjing City

The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) in ambient air were investigated for a 1-year period to assess their sources and health risks during haze days in Nanjing City, eastern China. The highest level of total PAHs (∑16 PAHs) in the gaseous phase during the haze days was 18.0±13.3µg/m3. Their sources may be attributable to pyrogenic products (55.2%), petrochemical refining industry (8.7%), and petrol volatilization (36.1%). The incremental lifetime cancer risk during the haze days exceeded or was close to the priority level of risk (10-4), indicating that PAH pollution during the haze days has caused public health problems associated with the respiratory system. The priority PAHs in the particle phase are mainly composed of low-ring components (