Study On Polycyclic Aromatic Hydrocarbons And Their Alkyl Derivatives In Dustfall And Smog Emitted From Biomass Burning

Polycyclic aromatic hydrocarbons (PAHs) and their alkyl derivatives (APAHs) are a group of persistent organic pollutants (POPs) which largely resulted from combustion of fuels including oil, coal and biomass. There is a large amount of biomass in China, where 600 millions tons of straw are harvested every year. 31.5% of them were used as the residential energy source for cooking, and 25% were burnt in the field for land-clearing. Many pollutants were emitted form biomass burning, and more attentions were paid in the worldwide. However, little work was done on this field in China. So, a set of apparatus was designed and installed to simulate biomass burning. Total suspended particulate and PAHs/APAHs were sampled and analyzed to get emission factors (EF) of PAHs and APAHs and the total flux of PAHs/APAHs emitted from biomass burning.Dustfall is one of the main atmospheric components in the urbanized area. With the fast development of population and motors during the last decades, the atmospheric particulate matter has become one of the main issues in Shanghai. And in the Reports of Environmental Quality of Shanghai in 2003, dustfall is identified as the most abundant pollutant in urban, suburban and rural areas. By now, the research on the organic pollutants in dustfall in this megacity remains scarce. The objective of the present work was to determine the profiles, levels and spatial-temporal distribution of APAHs in dust, distinguish the sources and estimate the effect on the coastal environment.This work consists of three main parts, as following:The first part introduces the parameters optimization of supercritical fluid extraction. Simulative samples were employed for the selection of parameters, and real-world samples were extracted by orthotropic experiments to optimize the extraction conditions.In the second part, dustfall samples were collected form 13 sites in urban area of Shanghai from Nov, 2004 to Nov, 2005, and analyze by the above method. Profiles and levels of APAHs were obtained and compared with PAHs. On this basis, spatial-temporal distribution, sources and effect on environment were investigated.In the last part, PAHs/APAHs emitted from biomass burning were researched in detail. A set of apparatus was designed and installed to simulate biomass burning. TSP and PAHs/APAHs were collected from the smog of three straws burning, and analyzed for species, levels and the gas-particle partitioning. Further more, factors controlled PAHs/APAHs emission from biomass burning were explained. According to experimental data, emission factors (EF) of PAHs and APAHs were calculated, and then the total flux of PAHs/APAHs emtted from biomass burning was estimated.