Physical And Chemical Characteristics Of Particulate Matters Emitted By Different Combustion Sources In Clean Room

The recent years have witnessed a dramatic rise in the air pollution episodes taken place in China and the situation of particulate pollution is getting worse.The PM2.5 is gradually raised to the level of major pollution in the ambient air of first and second tier cities,which pose a severe threat to the climate,environment and human health.In 2012,the State Council published a new ambient air quality standard which absorb the provision of fine particulate matter for the first time.Meanwhile,many monitoring platform of atmospheric particulates have been established to monitor and analyze particulate pollution.The data shows that the outdoor particulate pollution is difficult to meet the standard in the short term in China,while controlling the indoor particulate pollution is more likely to ensure healthiness for human beings.Indoor sources are an important source of particulate pollution,however,primary data about particulate matter concentration,particle size distribution and emission rate of indoor sources is relatively rare.Based on that,this research is focus on the physical and chemical characteristics of PMs emitted by different combustion sources in buildings.Firstly,literature review is conducted to analysis the micro-factors which affect the physical and chemical characteristics of PMs,including the mechanism about formation,movement,coagulation and sedimentation for PMs during the burning process of combustion sources.Also,the results provided a theoretical foundation for the varying patterns of PMs.Secondly,the experiment scheme was designed according to the relevant national standard and the basis of current experimental platform,in order to create a testing environment of particle for physical and chemical characteristics.Four kinds of combustion sources in residential buildings which are three Pingan incenses,three Golden incenses,a mosquito coil and a cigarette were selected as the research objects.PM emission,real-time monitoring and sampling were conducted in a sealed clean room of 46m3.The measured results show that the combustion process of the four different combustion sources all emit large amounts of particulates,which are mainly composed with PM2.5.The measured results present that the mass concentration of PM2.5 and PM10 emitted by Golden incenses is the largest,the number concentration of PM2.5 and PM10 emitted by Pingan incenses is the largest and cigarettes are the smallest.By analysis,the rate of PM2.5 emission by Pingan incenses during the combustion process is much higher than the other three combustion sources.2h after the four combustion source burnt out,the fine particle matter remain longer indoor,especially the particles with a diameter of 0~0.5?m.Finally,high resolution scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)were used to detect and analyze PMs emitted by four different kinds of combustion sources.The results show that PMs emitted by four different kinds of combustion sources are dominated by soot aggregates,which single particles are mainly spherical and polyhedral particles;the chemical composition of the particulates are O,C,Si,and contains micro Al and Mg elements.In conclusion,this research studied the physical and chemical characteristics of PMs emitted by indoor combustion sources through actual measurement combined with electron microscope and spectra detection.The results can provide foundation data for the concentration prediction model of indoor particulate matter,and promote the research of particulate matter image analysis as well as toxicologic study.