| Biomass combustion emissions a large number of polluting gases and particulate matter,which will not only affect the light scattering and absorption,reduce the visibility of the atmosphere to promote the formation of haze,but also has a significant impact on the atmospheric environment,ecosystem and human health.China is rich in agricultural and forestry resources,every year a large number of biomass combustion and large amounts of smoke particles were released by burning straw,forest fires and burning afforestation.However,there are few reports about the characteristics and chemical composition of particulate matter released from biomass combustion in China.In view of this,the main crops(rice,wheat,corn,beans,cotton and rape)and tree species(Cinnamomum camphora,Cunninghamia lanceolata,Pinus massoniana and Michelia alba)in Fujian were studied in this study,an independent designde closed controlled biomass combustion flue gas analysis system was used,in order to simulate different biomass smoldering,burning process,and determination of the particulate emission factor and main chemical components,to provide scientific basis for the study of air pollution and environmental change.The main results are as follows:(1)F-,Cl-,SO42-are the main anion in the combustion smoke,the Cl-,SO42-content of most crops when burning was significantly higher than that in the smoldering,The F-content of smoldering is higher.The content of F-,Cl-,SO42-,which were measured in two kinds of combustion conditions,are more obvious differences.The content of F-in smoldering and burning are the highest,are 2.27 g/kg,3.20 g/kg respectively.The content of Cl-,and SO42-in rice was the highest at the time of burning,are 4.45 g/kg,1.63 g/kg respectively.The content of Cl-,SO42-in corn was the highest in smoldering,are 5.92 g/kg,1.17 g/kg respectively.(2)The contents of K,P,Mg,Pb,Ba were higher and there were differences among different crops in crop burning smoke.The range of contents of K,P,Mg,Pb,Ba are 61.24-70217.41 mg/kg,82.75-14577.01 mg/kg,28.08-3445.14 mg/kg,60.08-4425.78 mg/kg,4.34-211.24 mg/kg in burning,the highest content is cotton.The range of contents are 24.29-8903.92 mg/kg,19.69-2540.40 mg/kg,67.64-176.79 mg/kg,102.45-735.32 mg/kg,5.64-73.48 mg/kg in smoldering,the highest content are cotton and corn.(3)The content of Cl-,F-are higher of four species in the burning smoke.The contents of Cl-,SO42-,Br-in the different tree were significantly different in burning.The content of Cl-,SO42-,Br-in Camphor was significantly higher than other tree species.The highest content of NO2-is camphor in smoldering.The contents of Cl-,NO2-,SO42-,NO3-,Br-in burning were significantly higher than that in smoldering of same species.The biggest difference of the content was Cl-under different combustion conditions in Pinus massoniana.Burning is 7.7 times of smoldering.For the content of SO42-,burning is 3 times of smoldering in camphor,pine,and Prynne.The biggest difference of the content of NO3-and Br-in different situation are Prynne,Burning is 5 times,3.1 times of smoldering respectively.(4)The content of K,P,Na,Pb,Zn is higher than the whole in burning smoke of four tree species.The contents of Al,Ba,Cr,P and Pb in camphor tree were highest in two combustion states,and the contents of Li,Na,Zn in camphor tree were highest in smoldering.For Prynne,the contents of B and Li were higher than those of other species.(5)The mean values of Cl-,and SO42-for crops were significantly higher than that in trees in two combustion states,and the content of NO3-was lower than that of trees.The content of Br-in trees is higher than that of crops when it is burning.The content of F-,NO2-are higher than that of crop trees in smoldering,and the content of PO43-is lower.When the crop burning,the content of Cl-,SO42-,PO43-were significantly higher than the average content of smoldering,burning is 1.3-3.4 times of smoldering,while the content of F-is higher than that of smoldering crop burning.The content of Cl-,SO42-,PO43-,NO2-,NO3-,Br-in burning of tree were significantly higher smoldering,burning is 1.2-5.0 times of smoldering.(6)The elements with high content of soot in agricultural and forestry crops were K,Mg,Na,P,Pb,Zn,Ba,the content of burning is higher than that of the smoldering.There were significant differences between agricultural and forestry crops,the content of K,Mg,P,Ba in crops was higher than that of trees in burning,are 19280.93mg/kg,642.20 mg/kg,3461.58 mg/kg,74.96 mg/kg respectively.The Na,Zn of the tree are higher,are 6217.72 mg/kg,490.83 mg/kg.The contents of K,Mg,Pb in the crops were higher than that in the trees in burning,are 2141.02 mg/kg,82.09 mg/kg,381.54 mg/kg.The Na,Ba of the tree are higher,are273.75 mg/kg,36.36 mg/kg. |
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