Polycyclic aromatic hydrocarbons and nitro-polycyclic aromatic hydrocarbons in five East Asian cities: Seasonal characteristics, health risks, and yearly variations

Total suspended particulate matter and fine particulate matter were collected in five East Asian cities (Sapporo, Sagamihara, Kirishima, Shenyang, and Vladivostok) during warm and cold periods from 2017 to 2018. Nine polycyclic aromatic hydrocarbons (PAHs) and three nitro-polycyclic aromatic hydrocarbons (NPAHs) were detected by high-performance liquid chromatography with a fluorescence detector. The average concentrations of SPAHs and Sigma PAHs differed significantly both temporally and spatially and were the lowest in Kirishima during the warm period (Sigma PAHs: 0.11 +/- 0.06 ng m(-3); Sigma NPAHs: 1.23 +/- 0.96 pg m(-3)) and the highest in Shenyang during the cold period (Sigma PAHs: 49.7 +/- 21.8 ng m (-3); Sigma NPAHs: 357 +/- 180 pg m(-3)). The average total benzo[a]pyrene-equivalent concentrations were also higher in Shenyang and Vladivostok than in Japanese cities. According to the results of source apportionment, traffic emissions impacted these cities in both the warm and cold periods, whereas coal combustion-generated effects were obvious in Shenyang and Vladivostok during the cold period. Furthermore, PAHs and NPAHs originating from the Asian continent, including Shenyang and Vladivostok, exerted some influence on Japanese cities, especially in the cold period. Compared to Japanese cities and Vladivostok, yearly variations in Sigma PAHs and 1-nitropyrene in Shenyang showed that their concentrations were considerably lower than those reported in past studies, indicating the positive effects of air pollutant control policies in China. These results not only describe the current characteristics and yearly variations of PAHs and NPAHs in typical urban cities in East Asia but also, more importantly, reveal that the effects of the East Asian monsoon play an important role in the analysis of atmospheric behaviours of PAHs and NPAHs. Furthermore, this study supports the role of multinational cooperation to promote air pollution control in East Asia.

Automated summary

The study found significant differences in the concentrations of PAHs and NPAHs between warm and cold seasons in East Asian cities. Traffic emissions have a major impact on air quality, with coal combustion being more pronounced in the cold season. PAHs and NPAHs from the Asian continent can influence Japanese cities, demonstrating the positive effects of air pollution control policies in China.