The Establishment Of Emission Inventory For Routine Air Pollutants And Particle Chemical Species From Residential Coal Burning In China

Residential coal burning（RCB）is one of the important emission sources of air pollutants in China.It’s important to establish emission inventories from RCB for studies on simulating air pollution and assessment of air pollution control policies.However,there are still many problems and insufficient studies on RCB emission inventory that need to be resolved.For example,the difference between emission factors in flaming and smoldering phases were not reflected in emission inventories.The emission factors lied in the shortage of sampling conditions,which cannot represent the emissions in local regions.The high time resolution activity dataset and hourly emission factors were rarely reported.These reasons limited high time resolution estimations of air pollutants from RCB.With a dilution sampling system,a high-precision electronic balance,and series of online analyzers,a real-time monitoring platform for RCB emission was established.Hourly emission factors（EFs）from eleven kinds of chunk coals and nine kinds of honeycomb coals burning in China were obtained.The monthly and hourly coal consumption amounts were calculated with literature reviews and our field survey.Then,this study established the RCB emission inventories in China,including multi-year,monthly and hourly pollutions emission inventories.GEOS-Chem and Risk Quotients Models were utilized to map the spatialized health risks of hazardous elements,including the gridded hazard index（HI）and carcinogenic risk（CR）.This study filled the research gap of RCB emission inventories in China,and provided scientific support for the RCB emission prevention and control policies.In this study,the EFs of gas pollution（SO₂,NO,NO₂,NO_x and CO）,EFs of PM_2.5,the EFs of black carbon（BC）,AEFs of brown carbon（Br C）and EFs of 18 types trace elements（TEs）,EFs of 6 types of water-soluble ions（WSIs）in flaming and smoldering conditions were established.The EFs of pollution(SO₂,NO,NO₂,NO_x,CO and PM_2.5as examples)from RCB were 0.01-2.3,0.003-9.5,0.009-22.9,0.01-26.5,0.001-0.5,0.2-191.8 g/kg.The EFs of SO₂ and NO in flaming phase were 1.1 and 1.3 times higher than EFs in smoldering phase.The EFs of NO₂,NO_x,CO and PM_2.5 in smoldering phase were2.7,1.6,2.8 and 14.4 times higher than EFs in flaming phase.In this study,the people’s habit of operating the stoves influence values of hourly EFs.The hourly EFs of black carbon（BC）,AEFs of brown carbon（Br C）,EFs of 18 types trace elements（TEs）,EFs of 6 types of water-soluble ions（WSIs）,EFs of gas pollution（SO₂,NO,NO₂,NO_x and CO）and EFs of PM_2.5were obtained.The peak values of EFs of SO₂,NO,NO₂,NO_x and 15 types trace elements were at the cooking period（7:00,12:00 and 17:00）.The peak values of EFs of BC,Na⁺,NH₄⁺,F^-,Cl^-,SO₄^2-and PM_2.5 were at the smoldering dominated period（19:00-23:00）.The result indicated that the EFs（take TEs and WSIs as examples）would underestimate if the tests only consider flaming conditions.The emission of TEs from chunk coal may overestimate 1.1-3.2 times and emission of TEs from honeycomb may underestimate 2.2-4.9 times.The emission of WSI from chunk and honeycomb coal was underestimated 3.2-5.0 and 2.6-4.8 times,respectively.The result shows the historical emission trends of BC and ACS_{Br C} from RCC in urban and rural areas in 2003-2017.The lowest amounts of BC and ACS_{Br C}（in 370 nm）were 90.7 Gg and 1314.8 Gm² in 2008 due to higher price of domestic coal in year 2008.Emissions of BC and ACS_{Br C} in winter seasons were 60.1 Gg and 1064.1 Gm²,which accounted for 54.3%and 55.1%of the total BC and ACS_{Br C} emissions correspondingly.The hourly coal consumption amounts were calculated with literature reviews and our field survey.The hourly emission of pollution from RCB emission were established.The result indicated that the peak values of hourly emission amounts of K,Ti,Fe,Sn,Sb,SO₂,NO,NO₂ and NO_x were under flaming dominated periods（7:00,12:00 and 17:00）.The emission amounts of K,Ti,Fe,Sn and Sb during these periods were 153.0,8.4,28.1,5.9 and 4.2 tons,which accounted for 48.2%,45.9%,31.8%,42.8%and 33.8%of their daily emission.The emission amounts of SO₂,NO,NO₂ and NO_x during these periods were767.1,1196.1,2679.9 and 4418.5 tons,which accounted for 50.5%,54.2%,25.6%and 35.9%of their daily emission.The hourly emission peak values of BC,V,Co,As,Hg and Pb were at smoldering dominated period（19:00-23:00）,which account for 43.0%,2.2%,32.9%,27.6%,34.7%and 28.4%of their daily emission.The NH₄⁺,Cl^-and SO₄^2-show the similar results,the emission was 31.9,10.5 and 218.6 ton during these periods which 7.7,8.5 and 8.8 times higher than daily average emission.Based on the hourly emission inventories of hazard heavy metals in PM_2.5 from RCB and the GEOS-Chem model,we simulated the hourly heavy metals concentration from RCB in winter time.The spatial distributions of HI and CR for hazardous elements in PM_2.5 during the winter season were also established.Most provinces have suffered non-carcinogenic effects,which were lower than the maximum acceptable level of 1 except Sichuan province.The HI in China for children and adults were lower than 7.6×10^-1and5.0×10^-1,respectively.For carcinogenic effects,carcinogenic risk level(≥1×10^-6)occurred in parts of region in Sichuan,Shanxi,Hunan and Hubei,which was up to 2.0×10^-5.Cr was the dominant component that contributed to the major city of the risks（20 times higher）,which should be raised enough attention.This study obtained and updated the hourly emission factors for air pollutants from RCB in China.The multi-year and hourly emission inventories of air pollutants from RCB can reflect the trends of interannual and diurnal variation emission characteristics,respectively.The result can provide the basic data for the reduction of RCB policy evaluation,health risk simulation of particles and air pollution prevention in both sub-region and periods of time,correspondingly.