Polycyclic aromatic hydrocarbons in PM₁, PM_2.5 and PM₁₀ atmospheric particles: identification, sources, temporal and...

This study reports temporal and spatial variations of 16 different species of particulate polycyclic aromatic hydrocarbons (particle-bonded PAHs) in the indoor and outdoor environments of three sampling sites in Bandar Mahshahr city, Iran. A low-volume air sampler was employed to collect size-segregated particulate matter during winter (October to December 2015), and summer (July to September 2016). The results showed that the annual concentrations of indoor and outdoor PM₁₀ and PM_2.5 were much higher than the related World Health Organization guidelines. The concentration of total particle-bonded PAHs (TPAHs) was higher in winter than in summer and a significant difference between the two sampling seasons was observed. The indoor and outdoor carcinogenic PAHs to TPAHs concentrations ratios in the sampling sites in summer and winter were as follow: for PM₁₀ 40.15-42.51%, PM_2.5 41.30-42.97%, and PM₁ 43.07-44.36%, respectively; furthermore, the smaller the particle size, the higher the percentage of carcinogenic PAHs. 2 ring PAHs had a very small contribution to the total PAHs (about 1%), whereas PAHs with 3-to-4 rings had much larger contributions, ranging from 71.65% to 75.17%. The results demonstrated that as PM size decreased, the proportion of 5-to-6-ring PAHs to the total PAHs increased. Since 5-to-6- ring PAHs are considered to be more toxic, hence more attention should be paid to fine particles. The diagnostic ratios of indoor and outdoor of three sampling sites in both seasons suggested that petrogenic sources, as well as combustion of petroleum and other fossil fuels were the main PAHs sources.