Abstract
Urban air contains various kinds of organic pollutants. Among them, several polycyclic aromatic hydrocarbons (PAHs) and nitropolycyclic aromatic hydrocarbons (NPAHs) are carcinogenic and/or endocrine disrupting. PAHs and NPAHs in the atmosphere mainly originate from imperfect combustion of organic matter, such as petroleum and coal. In this study, total suspended particles (TSP) were collected in three different particulate size fractions by using Andersen low-volume air samplers in Shenyang, Shanghai and Fuzhou, China, in the winter and summer seasons in 2010. Nine PAHs and twelve NPAHs in the extracts from the TSP were analyzed by HPLC with fluorescence detection and chemiluminescence detection, respectively. The mean concentrations of the sums of the nine PAHs and twelve NPAHs were highest in Shenyang and lowest in Fuzhou. In each city, more than 80% of the total PAHs and total NPAHs were found in the fine particulate fraction (<2.1 μm). All PAHs and NPAHs were clearly higher in the winter than in the summer. Furthermore, the ratio of the molar concentrations of 1-nitropyrene to pyrene ([1-NP]/[Pyr]), which is a suitable indicator to estimate the contribution of diesel-engine vehicles and coal combustion to urban TSP, were smaller in Shenyang in the winter. However, in Shanghai, Fuzhou and Shenyang (summer), the [1-NP]/[Pyr] ratios were close to those of particulates released from diesel-engine automobiles. Our study showed that the major contributors of atmospheric PAHs and NPAHs were diesel-engine vehicles both in the winter and the summer in Shanghai and Fuzhou, and in the summer in Shenyang. However, in the winter in Shenyang, atmospheric PAHs and NPAHs seemed to be affected by the mixture of coal combustion systems, such as coal heating and diesel-engine vehicles.
