Study On Gaseous Pollutants Emission Characteristics And Influence On The Air Quality Over Surrounding Regions From Straw Burning

As a large grain-producing country,china has abundant straw production.In recent years,crop straw gradually lost as energy feedstock and livestock feed with the change in energy structure,and straw burning has become a common way for farmers to deal with straw.It not only a waste of resources but also has direct or indirect impact on ecological environment and human health.Therefore,the emission factors and emission characteristics of gaseous pollutants in burning of wheat,corn and rice straw were obtained by simulation experiments,and the emission inventory of gaseous pollutants was constructed and the effects on air pollution in surrounding areas were evaluated.First,the box-type sampling device for pollutants from straw burning was used for simulation experiment,and the characteristics of gaseous pollutant emissions under different burning conditions were explored by controlling the moisture content of the straw,the stacking method,and the burning status.The CO2 emission factors of wheat,corn and rice straw in laboratory simulation were 593 ± 67,702±107,675±46 g/kg,CO emission factors of 53±3,53±11,77±23 g/kg,SO2 emission factors of 0.10±0.04、0.04±0.01、0.06±0.04 g/kg and NOx emission factors of 0.8±0.3、1.8±0.4、1.3±0.4 g/kg,respectively.Loose stacking and low moisture content are beneficial to the complete combustion,and CO and SO2 emissions will be less.Then,the straw burning emission inventory in the 9 provinces or municipalities of China in 2015 was constructed by using measured emission factors and the actual investigation.In 2015,the total output of typical crop straw in the 9 provinces was 460 million tons,and the total amount of open burning about 93.6 million tons,accounting for 20.2%of the total output of straw.Among them,the pollutant emissions of wheat and corn straw were higher than that of rice,and the emissions of Henan province were the highest in summer harvest season,and the highest in autumn harvest season in Heilongjiang province.Finally,conventional meteorological data,HYSPLIT trajectory simulation and radiosonde data were used to analyzed a heavily polluted weather in Harbin during the time period between Nov.1 to Nov.7,2017.The local pollutants and transmission due to straw burning is the main reasons for the heavy pollution weather,and the the outside weather conditions of the static and high humidity in the late stage of the pollution make the haze weather maintained and intensified.