Emission Characteristics Of Air Pollutants From Thermal Power In Guangdong Province And Its Influence On PM_2.5 Concentration

With the rapid development of economy and increasing demand of energy consumption,regional air pollutants emission increased significantly,which leading to frequently occurrence of severe haze pollution,especially in the Pearl River Delta?PRD?.Characterized with the small particle size and complex chemical composition,PM_2.5 deteriorates the air quality and visibility,as well as affects human health.As one of the most important contribution source of SO₂,NO_x and PM emissions,thermal power plays an important role in the formation of regional-wide PM_2.5,owing to the elevated plume emissions that can easily transport to a far way area.Therefore,aiming at comprehensive understand of the thermal power in Guangdong Province,this study compiled a emission inventory of thermal power and analyses its history and future tendency.In additionally,we also quantified changes of air pollution due to reductions of emission from thermal power by using numeircal simulations.These results intended to provide a scientific basis for decision making and air pollution study associated with thermal power.Based on material-balance method and emission-factor method,emission inventory of thermal power in GD was estimated.Results showed that the SO₂,NO_x,PM₁₀ and PM_2.5 emissions of thermal power presented downward trend,from 434.9,546.6,147.3,68.7kt to 183.5,350.9,57.5,36.8kt,respectively.Emission per unit of electricity generation decreased substantially between 2007 and 2014.Emissions of SO₂,NO_x,PM₁₀ and PM_2.5 were 269408,539565,135920 and 65050 t in 2012,which accounted for 35.2%,13.6%,17.7%,34.7% of the total SO₂,NO_x,PM₁₀ and PM_2.5 emissions of GD.In term of SO₂ and NO_x emissions,Thermal power was the second largest contributor.Meanwhile,analysis of emission characteristics of thermal power in 2012 at different aspect were also conducted.Thermal power with class units above 300 MW made main contribution in total emission,while those below 125 MW emitted more air pollutants per unit of coal consumption.Powerplant that used limestone-gypsum flue gas desulfurization,SCR and SNCR combined denitrification technology and electrostatic precipitator emitted less SO₂,NO_x,PM per unit of standard coal.Due to the higher emission intensity of coal,coal combustion account more than 95% of the total emissions of thermal power.In term of the seasonal emission,spring accounted 27.1%,followed by summer?25.4%?,fall?24.0%?and winter?23.5%?.For spatial distributions,emissions were mainly distributed in Guangzhou,Foshan,Dongguan,Jiangmen,Shantou,Chaozhou and Meizhou.With regards to the sub-categories area in Guangdong,about half of the emissions were concentrated in the Pearl River Delta region,with the percentage of 46.2%⁵2.3%,followed by the eastern?26.9%³4.3%?,western?11.9%¹4.4%?and northern area?5.5%¹0.0%?.Furthermore,the impacts of thermal power emissions on the air quality were estimated using sensitivity analysis and tracer method.Results showed that impacts were commonly more noticeable in the downwind areas of power plant,and they were highest in October,followed by August,April,January.Impacts on ??SO₂?and ??NO₂?appeared local feature,but showed a regional feature on ?(PM₁₀)and ?(PM_2.5).The contribution of ?(PM_2.5)from thermal power were 6.12%¹0.24%,7.43%¹1.20%,3.54%⁹.24%,6.26%¹0.36% in GD,PRD,northern and eastern of GD and Western of GD,respectively,and were larger than 10% in Guangzhou,Dongguan,Shenzhen,Zhongshan,Zhuhai and Huizhou.Typically,contributions was higher in April but lower in January.Finally,the potential emission reduction and the benefit were investigated on the basis of up-to-date control policy.Compared with those in 2012,emission reduction ratios of SO₂,NO_x,PM₁₀ and PM_2.5 due to the implementation of “ultra clean emission” were 81.9%,84.3%,92.2%,89.3%,respectively.Annual average concentrations of SO₂,NO₂,PM₁₀ and PM_2.5 in PRD decreased by 2.39?g/m3,2.93?g/m3,3.56?g/m3 and 2.99?g/m3 respectively.The decreased proportion of ??SO₂?and ??NO₂?was higher,but lower of ??PM?.This study highlight the importance of control of thermal power reduction and other anthropogenic sources.