Biomass Burning Impacts On The Haze Weather And Its Emission Factors And PM Chemical Composition

In order to better understand biomass burning emission impacts on formation of the Yangtze River Delta haze weather, we analyse the haze weather caused by biomass burning and study the characteristics of emission from burning in stove and burning on the farm. Based on the results we estimate of biomass burning contribution to the urban atmosphere, the results show that:1. During the biomass burning episode,the PM2.5, OC, EC, K+, Cl-and inorganic secondary aerosols(SO42-, NO3-, NH4+)mass concentration increased remarkably. K+well correlation with PM10, PM2.5(0.59、0.68), suggesting biomass burning contribution to the local emission dominated the aerosol, especially for fine particle. and SO42-, NO3-and NH4+mainly existed in the form of NH4NO3and (NH4)2SO4.2. The average emission factors of CO, NOx and PM2.5in open farm burning were28.7g·kg-1,1.2g·kg-1and2.65g-kg-1. Due to insufficient burning in the low oxygen level environment, the emission factors of stove burning was higher than those of open farm burning, which were81.9g-kg-1,2.1g·kg-1and8.5g·kg-1.Oil rape straw had the highest emission factors in all tested straws samples.Carbonaceous matter, including organic carbon(OC)and element carbon(EC), was the foremost component of PM2.5from biomass burning.The average mass fractions of OC and EC were (38.92±13.93)%and (5.66±1.54)%by open farm burning and (26.37±10.14)%and (18.97±10.76)%by stove burning.Water soluble ions such as Cl-and K+had a large contribution. The average mass fraction of Cl-and K+were (13.27±6.82)%and (12.41±3.02)%by open farm burning and (16.25±9.34)%and (13.62±7.91)%by stove burning. The K+/OC value of particles from wheat straw, rice straw, oil rape straw and soybean straw by open farm burning were0.30,0.52,0.49and0.15, respectively, which can be used to evaluate the influence on the regional air quality in YRD area from biomass burning and provide direct evidence for source apportionment.3. Based on the weather quality monitoring results and Factor analysis were used to source apportionment, the results showed that four groups of sources were recognized in Shanghai during the biomass burning episode. The contribution rates of the four sources were roμghly estimated that biomass burning was42%, secondary formation was22%, Vehicle exhaust was12%, the mixing of Soil dust and coal combustion was10%. four groups of sources were explained85.29%of the total variance of the pollution, indicate that the four groups of sources were sufficient to represent the local pollution source. Final we estimate of biomass burning contribution to the urban aerosol organic carbon concentrations, Contribution rate is range from30.9～56.3%.