Size Distribution Of Carbonaceous Aerosols Emitted From Domestic Coal Burning And The Establishment Of Emission Inventory With High Spatial Resolution In China

Carbonaceous particles arethe key aerosol components produced by the incomplete combustion of carbon-containing fuels,which play an important role in global climate change,air quality and human health,which are currently the research hot-spots.In all kinds of emission sources of carbonaceous aerosols,residential coal combustion is a major one.China is one of the most important contributor to the global burden of carbonaceous aerosols.The emission inventory of carbonaceous aerosols from residental coal combustion still now has large uncertainties,which restricts the simulation of related effects.In the present study,based on domestic simulating burning testswith a dilution sampling system,nine size-segregated particles emitted from the burning of three kinds of honeycomb coals?considering flaming and smoldering burning conditions?and four kinds of chunk coals included bituminous and lignite were collected by a cascade impactor?FA-3?.Organic carbon?OC?and elemental carbon?EC?were analyzed by the thermal-optical method.Emission factors of particulate matter?PM?,OC and EC in nine size ranges??0.43,0.43⁰.65,0.65¹.1,1.1².1,2.1³.3,3.3⁴.7,4.7⁵.5,5.5⁹.0and 9.0¹0.0?m?were obtained.The emission amounts of OC and EC in the fine particles emitted from domestic coal combustion in 2015 based on the energy statistics of various regions of Chine and the measured emission factors were calculated,and then a 1km×1km griding inventory with the population data as the main weight factor was established,combined with the land use level data.The results indicate that:?1?For honeycomb coals burning,EFs of OC and EC in PM_2.1 are 0.07 g/kg and0.002 g/kgunder flaming burning and 0.10 g/kg and 0.001 g/kg under smoldering burning conditions,respectively.Carbonaceous particles exhibited higher EFs under flaming burning condition.For chunk coal burning,the EFs of OC and EC in PM_2.1 are1.4 g/kg and 0.02 g/kg,about one magnitude higher than those for honeycomb coal burning.?2?Particulate matter and associated carbonaceous components preferred to concentrate in fine particles.The EFs of carbonaceous components peaked at the size of?0.43?m and 0.43⁰.65?m for honeycomb coal burning and chunk coal burning,respectively.?3?Thetotal national emissions of OC and EC in the fine particles of domestic coal combustion are 237115 t and 3312 t for 2015,and the uncertainties are-8.55⁹.43%and-7.85⁸.76%,respectively.OC is the main emission of carbonaceous components,and its emission amount is 71.6 times of EC.?4?The contribution of chunk coal combustion to OC and EC is significantly higher than those of honeycomb coal burning,with a contribution rate about 99%.This shows evidently that the main source of OC and EC for domestic coal is the chunk coal combustion.Rural emissions have a significantly higher amounts of OC and EC than those of coal burning in urban regions,with a contribution rate of 71%.From the view of air pollution prevention and control,it is important for the emission reduction of domestic coal burning amounts in rural areas,especially for chunk coal burning?5?The OC emission in fine particles are much higher than that of EC.Considering that domestic coal is mainly used for indoor fuels of China and is the largest contributor to OC which contains a large number of toxic and harmful pollutants such as polycyclic aromatic hydrocarbons?PAHs?etc.,the impact of OC emissions from domestic coal combustion in limited enclosed indoor environments on human health is enormous.From the perspective of the prevention of indoor human health,domestic coal emission of OC needs to be focused.?6?The emissions of OC and EC from domestic coal burning in Hebei are much higher than those in other areas,and they account for about 34.1%and 31.8%of the national emission amount.Thus,the human health risk raised by OC and EC should be paid more attention in Hebei.The primary emission amounts of OC and EC at northern China are much higher than those in the south,which should be the one of the main reasons for the frequent serious air pollution at winter period in northern China.The spatial distribution shows that the emissions of OC and EC are mainly concentrated in Beijing,Baoding,Shijiazhuang,Tangshan and Xi'an.The above regions all held high coal consumption amounts.Their emissions are much higher than the surrounding,and the emission intensity in the north China is higher than that in the south.The control measures should be urgently strengthened in the future.For establishing the emission inventory with high accurancy and spatial resolution,the present study considered the coal quality distribution and climatic conditions to improve the validity of emission factors adopted for different regions.At the same time,the activity data were accurately compiled in provincial level and the pollutants were allocated by population and landuse data.Through these improvement,the the uncertainty of emission inventory was greatly reduced.However,the emission factors and activity data can still not reflect the real-world situations of domestic coal burning emission and consumption.In the future,it is still necessary to supplement more actual measured emission factors,refine regional activity data,and improve inventory allocation methods.