| With the improvement of air pollution control,PM2.5 has been effectively controlled.At the same time,ozone(O3)pollution has become a major pollutant in many areas.Biogenic volatile organic compounds(BVOCs),as important precursors of the formation of O3 and secondary organic aerosols,play an important role in atmospheric photochemistry and the formation of O3 pollution.Hebei Province is a severely affected area of air pollution,the concentration of O3 and particulate pollution remains high.While controlling the emission of anthropogenic pollution sources,the control of biogenic volatile organic compounds 1s also included in the prevention and control of atmospheric pollution.In this paper,the forest in Hebei province was taken as the research object.According to the G93 emission estimation model,leaf biomass of dominant tree species was converted based on the survey data of second-class forest resources in Hebei province.Based on the measured emission rate of BVOCs and the emission factor values in relevant literatures,the 2015 Hebei province BVOCs emission list was simulated by using the calculation formula in the G93 model,and the distribution characteristics and emission characteristics of BVOCs were analyzed.The results are as follows:Sorted by volume,The dominant species in Hebei Province are:poplar,birch,Chinese pine,eucalyptus,hedgehog,willow,eucalyptus,oriental arborvitae,the results of leaf biomass calculation in 2015 were 1140.3Gg C、842.5Gg C、1068.8Gg C、460.2Gg C、193.7Gg C、58.5Gg C、59.3 Gg C and 24.8Gg C.The species with higher isoprene emission rate are robinia,sophora japonica and poplar.The species with medium emission rate were deciduous trees such as oak,birch and willow,and evergreen trees such as pinus and platycladius orientalis had lower emission rate.For monoterpenes,the species with high emission rate are pinus,platycladus orientalis,pinus armandii and sabina.The species with medium emission rate are poplar and robinia,and the species with low emission rate are elm and birch.Chengde city has the largest annual emission of BVOCs in Hebei province,while langfang city has the smallest.In 2015,the annual emissions of BVOCs in Hebei province were 152.1Gg C a－1,among which the annual emissions of isoprene were 116.3Gg C·a-1,the monoterpene emissions were 20.7Gg C·a-1,and the emissions of other VOCs were 15.1Gg C·a-1.In total VOCs emissions accounted for 76.5%,13.6%and 9.9%,respectively.Isoprene is the main component of BVOCs emission in Hebei Province,with a contribution rate of 76.5%.Among all cities in Hebei Province,Chengde City has the largest emissions,accounting for 64.61%of the total discharge of the province;among all the dominant species,Pinus tabulaeformis is the main species that emit BVOCs,with a contribution rate of 20.91%.July is the month with the highest BVOCs emissions in the 12 months of the year,with a discharge of 35.3Gg C;summer is the season with the highest emissions of BVOCs in Hebei Province. |
