| The air pollution in China is characterized by coal-smoke, which derives from the situation that coal is the most important energy source. Coal accounts for approximately 70% of the total primary energy consumption in China, which is greatly higher than the global average level (27.1%). The coal-smoke pollutants not only do great harm to environment and human health, but also affect directly regional or even global climate change.Besides CO2 and SO2, contaminants from coal combustion also comprise carbonaceous particulate (black and organic carbon), and black carbon (BC) has received much attention due to its effects on regional and global climate change. China is the greatest contributor of black carbon in the world, and most BC comes from coal utilities, especially from residential coal combustion. Because of poor burning conditions and without particle-controller, residential coal combustion has much higher emission factor of pollutants than larger scale coal-burners. A few foreigner researchers have estimated the BC emissions from China, and expected that about 52% of total BC emissions were originated from coal combustion, in which 87% were derived from residential coal burning. To date, however, there is scarce research on the emission factor of BC from various fuels (such as fossil fuels and biomass) in different combustion conditions, e.g., BC emitted from coals with different maturity and burned in residential conditions (in style of raw coal, briquette, or honeycomb briquette, and burned in corresponding stoves). This limited the certainties of previous estimates on BC emissions from China.Furthermore, organic carbon (OC) in coal smoke may comprise many toxic compounds (such as polycyclic aromatic hydrocarbons, PAHs), and these toxic compounds from residential coal combustion do greatly adverse effects on human health when the ventilation is poor. For example, the high lung cancer mortality in Xuanwei, Yuannan Province, was connected with the residential burning of smoky coal. Although some studies have reported the PAHs from coal combustion, there is no systematic study on the choice of various coals and corresponding burning conditions.Therefore, residential coal combustion is the biggest source of BC and PAHs emissions. Among various domestic coal burning, honeycomb-briquette consumed about 40% of total coal weight, and is one of the clean-coal-combustion stylesadvocated by our government. Five coals with different maturity were selected in present study, including JP, XW, YM, XA bituminous coals and YX anthracite coal, and made into honeycomb coal briquettes and burned in the common stove, and their smokes were collected through a self-designed smoke sampling system. There are two samplers, one can collect the particles and gaseous organics simultaneously in coal combustion smokes, and the other can divide the particles into six ranges according to their diameter (>7.2, 3.0-7.2, 1.5-3.0, 0.95-1.5, 0.49-0.95 and O.49 urn), which provides information of particle size distribution. BC and OC in particulate samples (glass fiber filters) were detected by thermal/optical OC/EC analyzer, and particulate and gaseous PAHs were analyzed by GC-MS after pre-treatments. The emission factors of BC, OC, and PAHs form five honeycomb-coal-briquettes combustion were calculated according the actual burned coal weight, and further emissions of these pollutants were estimated for residential coal combustion in China.The results of this work indicated that there are great differences among the emission factors of various pollutants from coals with different maturity, in which the anthracite coal emits the lowest, while coke-bituminous coals emit the highest. Sub-micron dominates the particle size distribution of particles and PAHs, and their MMAD values are about 0. 3 um. Although the smoke was cooled to ambient temperature, a great part of mass of PAHs was found in the vapor phases, while the toxic parameters showed the most toxicity of PAHs from residential coal burning was in particulate phase. Except that...
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