Study On Emission Characteristics Of Typical Construction Machinery For Non-road Mobile Sources In Wuhan

With the full implementation of industrial pollution sources and road mobile source emission control,and the further improvement of ambient air quality,the discharge of non-road mobile sources has gradually attracted widespread attention.Therefore,based on the construction of the portable emission measurement system(PEMS)platform,this paper carried out the emission characteristics,particulate matter and VOCs composition spectrum of typical atmospheric pollutants under different working conditions of excavators,loaders and forklifts.The main conclusions are as follows:(1)Based on the analysis of engineering machinery power and fuel consumption,it is found that the average fuel consumption of construction machinery is the working condition>walking condition>idle speed condition,and the average volume flow rate is idling condition>walking condition>Work conditions.In addition,the laws of CO and HC emission factors of construction machinery are the highest in idle speed conditions.NO is the main component of NO_X emitted by construction machinery,which is in line with the general rule of general fuel combustion NO_X generation.(2)Based on the statistical analysis of the concentration of particulate matter discharged from the construction machinery,it was found that the proportion of carbonaceous components in the mass concentration of excavators,loaders and forklifts was71.00%,58.12%and 78.23%,respectively,indicating carbonaceous The component is the main component of the engineering machinery particulate matter.Among them,the OC emission concentrations of excavators,loaders and forklifts were 34.6469mg/m~3,53.3714mg/m~3 and 22.4899mg/m~3,respectively,and the EC emission concentrations were29.5203mg/m~3,39.6442mg/m~3 and 10.6616mg/m~3,respectively.Cl-is the main water-soluble ion emitted by construction machinery,and K,Na,Mg and Ca elements are the main crust elements emitted by construction machinery.On this basis,the particle source composition spectrum of the three engineering machinery excavators,loaders and forklifts were constructed.(3)Based on the statistical analysis of the concentration of VOCs,it was found that the components of VOCs emitted by construction machinery are mainly oxygenates,or VOCs composed of C3 and C4.In addition,acetone,acrolein,and n-hexane are generally high concentrations of VOCs emitted by construction machinery.The VOCs emitted by construction machinery are mainly composed of components with smaller molecular weight.Among them,the excavator exhaust gas is mainly composed of the first 24 kinds of VOCs with smaller molecular weight,and the sum of the concentrations accounts for 50.91%of the total concentration of VOCs;The top 27 VOCs with smaller molecular weight are mainly used in the tail gas of the loader,and the sum of the concentrations accounts for50.52%of the total concentration of VOCs;The first 14 VOCs with smaller molecular weight are mainly used in the exhaust of the forklift,and the sum of the concentrations accounts for 61.48%of the total concentration of VOCs.There are large differences in the types and concentrations of major pollutants discharged by construction machinery under different working conditions.(4)Based on the analysis of the concentration,chemical structure,molecular weight ordering and carbon number ordering of each VOCs component analyzed by GC-MS,the three engineering machinery excavators,loaders and forklifts were constructed.VOCs source composition spectrum.