A High-tech Park’s PAHs Pollution In Air And Human Health Risk Assessment

Atmospheric fine particles—PM2.5 can reach and deposit deep in the lung, for its small particle size, the huge surface area adsorb toxic and hazardous substances, cause serious atmospheric environmental hazard for human health. Among many types of toxic and hazardous substances in PM2.5, the polycyclic aromatic hydrocarbons (PAHs) are one kind of the typical organic compounds. PAHs are mainly produced by incomplete combustion of fossil fuels and biomass with carcinogenic, mutagenic and immunotoxic properties and widely present in various environmental media. PAHs are of first class environment carcinogenic compounds. PAHs in the atmosphere is mostly present either in gas phase or adsorbed on particles which has high toxicity, persistence, accumulation and mobility characteristics. The high molecular weight PAHs proportion adsorbed in fine particulate matter is higher, which has higher carcinogenic activity. Prolonged exposure to PAHs may increase the risk of lung cancer, skin cancer and other malignancies. Inhalation exposure is one major way of exposure to PAHs. A significant correlation between PM2.5 and particulate phase PAHs. Industrial enterprises in the study region is the main source of PAHs.Through the study about the area PM2.5, the sampling and analysis of PAHs, the pollution level from particulate phase PAHs in the study area is the medium to high levels. PAHs concentration in the gas phase is about 2 times higher than in the particle phase. Similar concentration appeared for high and low molecular weight PAHs in particulate phase, and the fourth ring PAHs was about 50%(half of the total). According to the relationship between migration and ring number, our results indicated the presence of PAHs sources close to the sampling point. Using the ratio method, it is initially identified that particulate phase PAHs mainly from combustion of fossil fuels and biomass.The PM2.5 concentrations distribution calculated in study region with AERMOD simulation results show that the PM2.5 pollution phenomenon is heavier and has a high environmental background value. PM2.5 concentration change is directly affected by the weather conditions, because of the sea in the south of the study area and PM2.5 is mainly from the inland, north or northerly winds in the study area resulted in increase of PM2.5 concentrations. PM2.5 sources is complex, nearby emission from chemical manufacturers, contribution from Panjin and neighboring cities (such as Anshan). There is a significant correlation with the particulate phase PAHs and PM2.5.Using lifetime cancer risk assessment model (ILCR), health risks from PAHs and heavy metals in PM2.5 was evaluated. Monte Carlo simulation was used in analyzing the risk uncertainty. The results shows that the ILCR value for inhalation exposure to PAHs is between 10-6-10-4, which indicate a certain risk of cancer. Cancer risk is in the order of adult> Youth> children> infant. The risk value difference is mainly due to different exposure time and adjustment factor. Infant is most sensitive to contaminant exposure, need special attention. The risk of non-carcinogenic heavy metals detected in PM2.5 value is very small, but As the carcinogenic metal’s ILCR value is between 10-5 and 10-3, reflected by the higher value of ILCR.In this study, only a small sampling area was studied, and time span was short, therefore the analysis and prediction based on the limited data (time and areas) may not be so accurate. But it is certain that in this region there are both PM2.5 and PAHs pollutants, though with varying degrees, and potentially harmful to human health risks, that seriously affect the health of the population in the area. In the long run it is not conducive to future development of the region. With the rapid development of the new district, more residents settled and increased manufacturing activities may further make the atmospheric environment worse. Further it is necessary to investigate the sources of pollution in the region, strengthen the monitoring of key sources emissions, and finally separating the industrial area and living district to reduce exposure risk. Reduction of pollutant emissions from the source is the best solution.