Compilation Of Emission Inventory Of Banning Boilers In Harbin And Evaluation Of Emission Reduction Effect Based On Numerical Model

In order to deal with the haze pollution in winter in Harbin in recent years and improve the air quality in the urban area,the Harbin government has issued a series of policies and measures to control coal pollution,such as the regulations on Prevention and Control of Coal pollution in Harbin and the Special Action Plan for the Prevention and Control of Air pollutio.Among them,one of the important control measures in the management of coal-burning facilities is to phase out small coal-fired boilers（less than30 tons of boilers）.The quantitative relationship between air pollutant emission and air quality is established by using air quality model,and the contribution of relevant policies to air quality improvement is quantitatively analyzed.The inventory of phased-out boilers in Harbin was compiled.Through the investigation of the activity level information of small coal-fired boilers phased out in Harbin in 2017 and 2018,the emission factors were obtained by literature investigation,and the emission of each small coal-fired boiler was calculated.The atmospheric pollutant emission inventory of Harbin phased-out small-sized coal-fired boilers was compiled,and the qualitative and quantitative uncertainty analysis of the inventory was carried out.The results of the inventory show that SO₂ emissions from small coal-fired boilers accounted for 29.6%and 47.2%of the city’s total SO₂ emissions in 2017 and 2018,respectively,followed by NO_X（5.1%and 24.8%）,PM₁₀（19.3%and 36.3%）and PM_2.5（1.6%and2.7%）.The WRF-SMOKE-CMAQ model simulation system is constructed,and the meteorological field and air quality in Harbin are simulated hourly by using the spatial resolution of 36km×36km.Through the multi-dimensional comparison of the monitoring data with the data of meteorological monitoring stations and national air quality monitoring stations,the model configuration scheme with the best simulation effect is selected.The WRF model simulates the changes of wind speed,wind direction,relative humidity and air pressure in Harbin in December 2016,which provides a meteorological field for the follow-up air quality model.The index of agreement（IOA）between the simulation results of CMAQ model and monitoring data from high to low are PM₁₀（0.74）,PM_2.5（0.73）,NO₂（0.67）,CO（0.60）and SO₂（0.56）.The simulation can meet the requirements of follow-up evaluation and provide effective and credible data support for follow-up scenario simulation.In order to evaluate the effect of the emission reduction policy of eliminating small coal-fired boilers in Harbin,four simulation scenarios are set up according to the scale of the boiler.Overall,in the policy,the contribution of small coal-fired boilers with less than10 steam tons to the improvement of air quality is more than 10 to 30 tons.The policy of phasing out small coal-fired boilers can effectively reduce the daily average concentrations of SO₂（45.6%）,PM₁₀（2.7%）,NO₂（2.4%）,PM_2.5（1.8%）and CO（0.7%）,and effectively reduce the peak concentrations of SO₂（99.5%）,NO₂（27.6%）,PM₁₀（11.4%）,PM_2.5（11%）and CO（2.5%）.The policy of phasing out small coal-fired boilers has achieved remarkable results in improving air quality.The elimination of small coal-fired boilers contributes significantly to the reduction of PM_2.5 concentration in the suburbs and rural areas.It is suggested that the small coal-fired boilers in the suburbs and rural areas outside the urban areas should be phased out in the next step.