Emission factors of particulate matter （PM）, element carbon （EC）, organic carbon （OC）, SO2, NOx, CO, CO2, and ten ions （Na^＋, NH4^＋, K^＋, Mg^2＋, Ca^2＋, Fˉ, Clˉ, NO2ˉ, NO3ˉ, SO42ˉ） were estimated from...Emission factors of particulate matter （PM）, element carbon （EC）, organic carbon （OC）, SO2, NOx, CO, CO2, and ten ions （Na^＋, NH4^＋, K^＋, Mg^2＋, Ca^2＋, Fˉ, Clˉ, NO2ˉ, NO3ˉ, SO42ˉ） were estimated from the domestic burning of four types of commonly produced crop residues in rural China： rice straw, wheat straw, corn stover, and cotton stalk, which were collected from the representative regions across China. A combustion tower was designed to simulate the cooking conditions under which the peasants burned their crop residues in rural China, to measure the emission factors. Results showed that wheat straw had the highest emission factor for the total PM （8.75 g/kg） among the four crop residues, whereas, corn stover and wheat straw have the highest emission factor for EC （0.95 g/kg） and OC （3.46 g/kg）, respectively. Corn stover also presents as having the highest emission factors of NO, NOx, and CO2, whereas, wheat straw, rice straw, and cotton stalk had the highest emission factors of NO2, SO2, and CO, respectively. The water-soluble ions, K^＋ and Clˉ, had the highest emission factors from all the crops. Wheat straw had a relatively higher emission factor of cation species and Fˉ, Clˉ, NO2ˉ than other residues.展开更多
Detailed high-resolution emission inventories of primary particles(PM2.5,BC and OC) and pollutant gases(SO2,NOx,NH3,CO and VOCs) for China in 2007 were constructed on the basis of the latest fuel consumption data,most...Detailed high-resolution emission inventories of primary particles(PM2.5,BC and OC) and pollutant gases(SO2,NOx,NH3,CO and VOCs) for China in 2007 were constructed on the basis of the latest fuel consumption data,mostly at the county level,and from socio-economic statistics and data on fossil and biomass fuels obtained from government agencies.New emission factors reflecting local features were also used.The calculated emissions were 13.212 Mt PM2.5,1.4 Mt BC,2.946 Mt OC,31.584 Mt SO2,23.248 Mt NOx,16.017 Mt NH3,164.856 Mt CO and 35.464 Mt VOCs.The national and regional emissions were gridded with 0.5°× 0.5° resolution for use in air quality models.Larger emissions were found in eastern and central China than in western China.The emissions estimated here are roughly equal to those obtained in previous studies,but with different contributions from because of seasonal changes in residential heating and biomass combustion.Finally,uncertainties in inventories were analyzed.展开更多
Focusing on three dust storms occurring in spring 2001,we developed a detailed aerosol parameterization scheme and integrated it in a radiative transfer model to characterize possible impacts of solar altitude angle o...Focusing on three dust storms occurring in spring 2001,we developed a detailed aerosol parameterization scheme and integrated it in a radiative transfer model to characterize possible impacts of solar altitude angle on dust direct radiative effects over China desert regions and the North Pacific,using actual daily solar altitude angles.Increasing solar altitude angle from early spring (or winter) to late spring (or summer) leads to increase of positive clear sky radiative forcing,and decrease of negative radiative forcing due to dust aerosols at the top of the atmosphere.Because solar altitude angle increases from early to late spring,dust-clear sky radiative forcing may change from negative to positive at the top of atmosphere,showing a change from cooling to heating of the earth-atmosphere system over high-albedo deserts and nearby regions.Over low-albedo ocean negative clear sky radiative forcing by dust may decrease,suggesting a change from strong to weak cooling on the earth-atmosphere system.The impacts of solar altitude angle on cloudy sky radiative forcing due to dust are similar to those of clear sky.Impacts of low cloud on dust radiative forcing are the same as increasing surface albedo.This causes the transition of dust cooling effects into heating effects over deserts to occur earlier,and causes decrease of negative radiative forcing over the ocean and even cause a change from weak negative radiative forcing to weak positive forcing over local areas.Even in the same East Asian desert regions and nearby areas,the strength and sign of the radiative forcings depend on storm dates and thus solar altitude angle.The nearer to early spring (or winter) a dust storm occurs,the easier it leads to negative radiative forcing at the top of atmosphere,which indicates cooling effects on the earth-atmosphere system.In contrast,the nearer to late spring (or summer) a dust storm occurs,the easier it leads to positive radiative forcing at the top of atmosphere,showing heating effects.Over East Asian deserts and nearby regions,dust layers may be regarded as cooling sources in early spring (winter) and warming sources in late spring (summer).展开更多
文摘Emission factors of particulate matter （PM）, element carbon （EC）, organic carbon （OC）, SO2, NOx, CO, CO2, and ten ions （Na^＋, NH4^＋, K^＋, Mg^2＋, Ca^2＋, Fˉ, Clˉ, NO2ˉ, NO3ˉ, SO42ˉ） were estimated from the domestic burning of four types of commonly produced crop residues in rural China： rice straw, wheat straw, corn stover, and cotton stalk, which were collected from the representative regions across China. A combustion tower was designed to simulate the cooking conditions under which the peasants burned their crop residues in rural China, to measure the emission factors. Results showed that wheat straw had the highest emission factor for the total PM （8.75 g/kg） among the four crop residues, whereas, corn stover and wheat straw have the highest emission factor for EC （0.95 g/kg） and OC （3.46 g/kg）, respectively. Corn stover also presents as having the highest emission factors of NO, NOx, and CO2, whereas, wheat straw, rice straw, and cotton stalk had the highest emission factors of NO2, SO2, and CO, respectively. The water-soluble ions, K^＋ and Clˉ, had the highest emission factors from all the crops. Wheat straw had a relatively higher emission factor of cation species and Fˉ, Clˉ, NO2ˉ than other residues.
基金supported by the National Basic Research Program of China (2011CB403404)the National R&D Special Fund (Meteorology) for Public Welfare Industry (GYHY200706036)
文摘Detailed high-resolution emission inventories of primary particles(PM2.5,BC and OC) and pollutant gases(SO2,NOx,NH3,CO and VOCs) for China in 2007 were constructed on the basis of the latest fuel consumption data,mostly at the county level,and from socio-economic statistics and data on fossil and biomass fuels obtained from government agencies.New emission factors reflecting local features were also used.The calculated emissions were 13.212 Mt PM2.5,1.4 Mt BC,2.946 Mt OC,31.584 Mt SO2,23.248 Mt NOx,16.017 Mt NH3,164.856 Mt CO and 35.464 Mt VOCs.The national and regional emissions were gridded with 0.5°× 0.5° resolution for use in air quality models.Larger emissions were found in eastern and central China than in western China.The emissions estimated here are roughly equal to those obtained in previous studies,but with different contributions from because of seasonal changes in residential heating and biomass combustion.Finally,uncertainties in inventories were analyzed.
基金supported by the National High-Tech Research & Development Program of China(2008BAC40B02)the Key Project of the Basic Research and Work Funding of Chinese Academy of Meteorological Sciences(2009z001)+1 种基金the National Department Public Benefit Research Foundation(GYHY200706036)the National Natural Science Foundation of China(40775063)
文摘Focusing on three dust storms occurring in spring 2001,we developed a detailed aerosol parameterization scheme and integrated it in a radiative transfer model to characterize possible impacts of solar altitude angle on dust direct radiative effects over China desert regions and the North Pacific,using actual daily solar altitude angles.Increasing solar altitude angle from early spring (or winter) to late spring (or summer) leads to increase of positive clear sky radiative forcing,and decrease of negative radiative forcing due to dust aerosols at the top of the atmosphere.Because solar altitude angle increases from early to late spring,dust-clear sky radiative forcing may change from negative to positive at the top of atmosphere,showing a change from cooling to heating of the earth-atmosphere system over high-albedo deserts and nearby regions.Over low-albedo ocean negative clear sky radiative forcing by dust may decrease,suggesting a change from strong to weak cooling on the earth-atmosphere system.The impacts of solar altitude angle on cloudy sky radiative forcing due to dust are similar to those of clear sky.Impacts of low cloud on dust radiative forcing are the same as increasing surface albedo.This causes the transition of dust cooling effects into heating effects over deserts to occur earlier,and causes decrease of negative radiative forcing over the ocean and even cause a change from weak negative radiative forcing to weak positive forcing over local areas.Even in the same East Asian desert regions and nearby areas,the strength and sign of the radiative forcings depend on storm dates and thus solar altitude angle.The nearer to early spring (or winter) a dust storm occurs,the easier it leads to negative radiative forcing at the top of atmosphere,which indicates cooling effects on the earth-atmosphere system.In contrast,the nearer to late spring (or summer) a dust storm occurs,the easier it leads to positive radiative forcing at the top of atmosphere,showing heating effects.Over East Asian deserts and nearby regions,dust layers may be regarded as cooling sources in early spring (winter) and warming sources in late spring (summer).
