Atmospheric polycyclic aromatic hydrocarbons (PAHs) at urban settings in Pakistan: Spatial variations, sources and health risks

For the first time, this study presents gaseous and particulate-bound (PM2.5) polycyclic aromatic hydrocarbons (PAHs) in ambient air samples collected from eight major cities of Pakistan. Diurnal air samples (gaseous and PM2.5) were collected in summer 2014 on polyurethane foam and quartz fiber filters using high volume-active air sampler. The US-EPA enlisted 16 priority PAHs in particulate and gaseous phase were measured on gas chromatograph equipped with mass spectrometer detector. The total PAHs concentrations ranged between 188 pg m−3 (in Gilgit), and 2340 pg m−3 (in Lahore). The decreasing order of PAHs concentrations in various cities was in the following order: Lahore > Rawalpindi > Multan > Faisalabad > Karachgi > Peshawar > Quetta > Gilgit. Phenanthrene showed the highest concentration, accounted 18% of total PAHs followed by fluoranthene (12% of total PAHs). This study showed that the gaseous fractions were predominant in the ambient air. Source apportionment analysis revealed that biomass combustion, vehicular emissions and diesel combustion in power generators were the potential PAHs emissions sources. The lifetime lungs cancer risk (LLCR) was in the range of 8.28 × 10−7 to 2.09 × 10−5 depicting mild cancer risk to the residents on exposure to atmospheric PAHs. Therefore, it is recommended to monitor atmospheric PAHs throughout the year and also adopt environmentally friendly fuels to reduce PAHs pollution and health risks in the country. [Display omitted] •First exposure assessment of gaseous and particle bound (PM2.5)-PAHs in eight major cities of Pakistan.•2–4 rings PAHs are predominant in all cities with 80% contribution of the total PAHs.•PAHs levels were higher in Lahore followed by Rawalpindi and Multan.•Biomass combustion, vehicular emissions and diesel combustion were identified as the major PAHs sources.•Lifetime lungs cancer risk (LLCR) model showed mild level cancer risk after PAHs exposure.