[Pollution Characteristics and Source Analysis of Atmospheric PM2.5-bound Polycyclic Aromatic Hydrocarbons in a Port Area].

In order to explore the pollution characteristics and potential sources of polycyclic aromatic hydrocarbons (PAHs) in the polluted air of a port area, PM2.5 samples (n=59) were collected from Qingdao Port for four seasons from August 2018 to May 2019. The seasonal variation and composition characteristics of PM2.5-bound PAHs were analyzed, the influence of meteorological factors on PAH concentrations was explored using correlation analysis, and the potential sources were analyzed using positive definite matrix factorization and potential source contribution function models. The results showed that the total mean concentration of PAHs was (8.11±12.31) ng·m-3, which was higher in autumn and winter than that in spring and summer. The seasonal molecular compositions of PAHs were similar, dominated by 4-5 ring PAHs (75.43%). Fluoranthene, benzo[e]pyrene, benzo[a]anthracene, phenanthrene, pyrene, and chrysene were the dominant species of PAHs in the study area, which are similar to the major compounds in ship exhaust. Correlation analysis showed that PAH concentrations were significantly negatively correlated with temperature and relative humidity and significantly positively correlated with atmospheric pressure and wind direction and had a poor correlation with wind speed. PMF analysis extracted six contribution factors, and the results indicated that Qingdao Port was mainly influenced by shipping emissions (28.83%), followed by vehicle emissions (20.49%), as well as crude oil volatilization (13.47%). Summer had the greatest impact on shipping emissions. The PSCF results suggested that Beijing-Tianjin-Hebei, Bohai Rim, and northern Shandong were the main source regions for long-range transport.

Spatial and temporal variation, source identification, and toxicity evaluation of brominated/chlorinated/nitrated/oxygenated-PAHs at a heavily industrialized area in eastern China.

Some derivatives of polycyclic aromatic hydrocarbons (PAHs) such as chlorinated and brominated PAHs (Cl/BrPAHs), nitrated and oxygenated PAHs (N/OPAHs) have attracted significant concern due to their high toxicity. Knowledge of the profiles, formation mechanisms, and potential sources of these toxic chemicals near the industrial complexes is essential for their pollution control and management. In this study, we monitored Cl/BrPAHs, N/OPAHs, and PAHs at 24 sampling sites near a heavily industrialized area (steel, chemical, and rubber plants) using passive air samplers during the heating period (7 December 2019 to 15 April 2020) and the non-heating period (2 June 2020 to 4 October 2020). The total average concentrations of 16 BrPAHs, 8 ClPAHs, 17 NPAHs, 6 OPAHs, and 18 PAHs during both sampling periods were 471 pg/m3, 229 pg/m3, 312 pg/m3, 2120 pg/m3, and 63.1 ng/m3, respectively. Except for NPAHs, BrPAHs, ClPAHs, OPAHs, and PAHs all showed higher levels during the heating period. The spatial distributions of Cl/BrPAHs, N/OPAHs, and PAHs exhibited a similar pattern, with the highest concentrations detected in the vicinity of the steel industry. Congener profiles of PAH derivatives indicated that mono-substituted low molecular weight compounds (2-3 rings) were dominant. The major formation mechanisms of halogenated PAHs were discussed by correlation analysis and relative Gibbs free energies, and direct bromination of parent PAHs could be the major formation mechanism of BrPAHs in this study. Diagnostic ratios showed that NPAHs were mainly derived from primary emissions, but the contribution of secondary formation was increased at heavily contaminated sites. The positive matrix factorization model extracted four Cl/BrPAHs, three N/OPAHs, and four PAHs factors, and the result showed that PAHs and their derivatives mainly derived from industrial and combustion sources, photochemical reactions, vehicle emissions, and crude oil volatilization, etc.

Temporal profiles, source analysis, and health risk assessments of parent polycyclic aromatic hydrocarbons (PPAHs) and their derivatives (NPAHs, OPAHs, ClPAHs, and BrPAHs) in PM2.5 and PM1.0 from the eastern coastal region of China: Urban coastal area versus coastal background area.

The eastern coastal region of China is the area with the highest emission of PAHs in China. Therefore, understanding the sources and health risk of parent polycyclic aromatic hydrocarbons (PPAHs) and their derivatives in eastern coastal cities of China is the main basis for air pollution control. In this study, we measured the concentrations of 18 parent PAHs, 17 nitrated PAHs, 7 oxygenated PAHs, 8 chlorinated PAHs, and 13 brominated PAHs in PM1.0 and PM2.5 samples collected at an urban coastal city site and a coastal background site in 2019. We analyzed the temporal distribution, molecular composition, and sources and performed health risk assessments for both winter and summer samples. The average concentration of the PPAHs and their derivatives (all 63 compounds combined) in the PM1.0 samples accounted for 75.57% of the PAHs concentration in PM2.5 samples. The average concentration of PM2.5- and PM1.0- bound PPAHs in winter was 114.70 times higher than in summer, and their derivatives was 27.51 times. Both the combined concentrations of the 18 PPAHs and the combined concentrations of the 45 derivatives were higher in the coastal city compared to the background site during the winter (1.90 and 1.48 times, respectively), but they were comparable during the summer. The positive matrix factorization analysis indicated that the compounds mainly originated from coal/biomass combustion, industrial sources, vehicle emissions, and secondary formation. In addition, the concentration-weighted trajectories model revealed that the PAHs were mainly emitted locally in Shandong Province and surrounding areas, such as Hebei Province, Henan Province, and Bohai Sea. The compounds 1-NPYR, 2+9-BrPHE, 9,10-Cl2PHE, and 1-ClPYR dominantly contributed to the derivatives of TEQ during the winter due to their high concentrations or the high TEFs of these compounds.