| Currently, the study of atmospheric fine particulate matter pollution has become a hot topic in air aerosol studies. Atmospheric fine particulate matter (PM) easily absorbing toxics in air, such as heavy metals, acidic oxides, and organic pollutants, has complex sources. The research on PM2.5is still in early stage in China, systematic research on PM2.5pollution characteristics, health effects and sources need to be carried out. In order to understand the physical and chemical characteristics of fine particulate matter and related purification technique of removing the indoor PM2.5, PM2.5was monitored in locations in city area in this paper. The air samplers and PM2.5portable analyzer were used for the fine particulate matter pollution characteristics, temporal and spatial variation analysis in typical locations. This paper centered on the PM2.5chemical composition, weather changes and influence, sources and risk assessment as well as purification technologies, purifying effect on indoor fine particulate matter pollution, including:(1) Analysis of PM2.5pollution using PM2.5portable analyzer is convenient, the PM2.5concentration can be shown immediately on the screen after1min sampling. The obtained results indicated serious indoor air pollution. It was related to outdoor PM2.5pollution and sources in Dalian residential area, mainly catering fumes and transportation vehicle emissions. Meteorological factors played a dominant role in the large fluctuation in PM2.5concentration in a day. Under open window ventilation conditions, weather condition greatly influenced the indoor PM2.5concentrations. Using medium flow sampling (100L/min) and weighing the collected PM2.5under constant moisture and temperature condition, the results revealed that the average PM2.5concentration during sampling period ranged from93μg/m3to117μg/m3in spring and ranged from40μg/m3to114μg/m3during sampling in summer.(2) PAHs (poly aromatic hydrocarbons) in air mainly exist in gas forms and in adsorbed state on fine particles. Glass fiber filters and PUF (polyurethane forms) were used for sampling and analysis of PAHs in room with printers and outdoor industrial pollution zone in this study. The result from those16total PAHs on outdoor PM2.5samples was1797ng/m3, while content of16PAHs on PUF was799ng/m3. Total PAHs on fine particulate matter is above gaseous PAHs, the most abundant PAH pollutant (phenanthrene) content on PM2.5was371ng/m3,accounting for76%of total PAHs measured on PM2.5. However, benzo (a) anthracene was the most abundant PAHs measured on PUF with160ng/m3, accounting for43%of total gaseous PAHs. (3) The designed brand purifier can significantly reduce indoor air pollution. When the purifier was switched on for half an hour and one hour, formaldehyde was reduced from0.130ppm to0.096ppm and0.081ppm, respectively, with removal rate of26%and37.7%. PM2.5concentration was reduced from88μg/m3to8μg/m3and9μg/m3, respectively, with removal rate of89.8%and91%, which proved that air purifiers has a high removal rate on fine particles.(4) Polypyrrole was used for modification of non-woven fabric to form a new and conductive membrane. Using the new membrane as negative electrode while stainless steel mesh as positive electrode, both dry and moist membrane were used for PM2.5removal with1V,2V,5V,10V,20V five levels of voltage supplied by a power source, under different air flow. It was found that the removal rate using the moist modified membrane is slightly higher than that using the dry modified membranes, reaching about90%; PM2.5removal under low air flow is greater than that under high air flow; Removal of PM2.5under high voltage is greater than that under low voltage. This PM purification with new material offers an alternative product design and choice for protecting human health from the negative influence of air pollution. |
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