| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 106 === PM2.5, known as respirable aerosol contains heavy metals and organic pollutants. PM2.5 may such as PAHs and Dioxins reach human alveoli when inhaled. The soluble contaminants in the particles are easily absorbed by the blood and endanger human health. Polycyclic aromatic hydrocarbons (PAHs) are common pollutants in the environment. Because many of them are definite or potential carcinogens, they have received great attention by the international community such as the World Health Organization (WHO). PAHs and PM2.5 have a common source such as combustion and vehicle exhaust. Therefore, they are easily combined and cause synergistic effect on human health. In the past, investigations on the airborne fine aerosol matrix mostly concentrated on the mass concentration of PM2.5. Studies on the pollutants such as PAHs existing on PM2.5 are limited due to low the detection limit of the analytical method (MDL) and the requirement of a large amount of sample acquisition, leading to prolonged sampling time and complicate pretreatment processes. Due to the difficulty compared to other environmental matrices, investigations on the PAHs in PM2.5 are limited. It is imperative to develop analytical techniques with lower MDL to overcome the sampling bottlenecks such that comprehensive air quality survey can be conducted for the assessment of human health hazards. In this study, thermal desorption technology is applied to directly introduce the PAHs in the PM2.5 into GC/HRMS for the analysis to significantly reduce the pretreatment processes steps and lower MDL, thereby reducing analysis loss and sampling time. The MDLs of the 27 PAHs in this study are in the range of 0.34 to 23.2 pg/m3, which can effectively detect highly toxic PAHs in the atmosphere, providing more accurate data for risk assessment. Pneliminary results indicate that the concentrations of solid-phase PAHs in ambient air of northern, central and eastern Taiwan are in the range of 0.13-6.63 ng/m3 and the average concentration is 2.23 ng/m3. The PAH concentration measured in winter is higher than that in summer, and the concentration per unit mass of PM2.5 range from 0.071 to 0.280 ng/μg and the average concentration is 0.133 ng/μg. In the future, this technology can be applied for the investigation of persistent organic pollutants (POPs) on fine particles.
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