Nanjing City Streets Respirable Particulate Matter Diffusion Model

In order to carry on the research of the dispersion model of the concentration ofinhalable particles (PM(10)) in the urban street in Nanjing, the study has carried on themonitor experiment of measuring PM₁₀ concentration by using the portable aerosolmonitor and meteorological monitor equipment. It has determined the urban PM₁₀background concentration of Nanjing, and has analysed general change law of PM₁₀concentration in the city. At the same time, it has adopted plural linear Return Law toderive out the formulae for estimating the concentration of urban PM₁₀ background ofNanjing. The study has carried on the research on the traffic discharges in the street, andhas estimated out the PM₁₀ emission factor by using the fuel measurement. The mostimportant, it has verified the adaptability of STREET BOX model on the urban street ofNanjing especially, through revising the dispersion coefficient in model, has set up thedispersion model of the urban street PM₁₀ concentration in Nanjing.The concentration of PM₁₀ was measured by the monitoring and meteorologicalexperiments from February 2006 to December 2006, and the change law of PM₁₀concentration on daytime and every year have been got: PM₁₀ concentration in thedaytime in Nanjing reaches the supreme value in one day at 11 o'clock in the morning, butthe low ebb of PM₁₀ concentration from side to side at 16 o'clock in the afternoon; Springand summer is to hit in one year the low-level period of PM₁₀ concentration, but thefestival PM₁₀ concentration in autumn and winter presents higher level. The article adoptsthe plural linear Return Law of Statistics, and gets the mathematics formulae of Nanjingurban PM₁₀ background concentration.On the basis of traffic study in the road of Nanjing, using the fuel estimating the law,the study has estimated the PM₁₀ emission factors of vehicle, they are 0.0935mg/(m·veh),0.1040mg/(m·veh), 0.1109mg/(m·veh), respectively.The study has utilized the experiment and research to obtain the input parameters, hasproved the adaptability of STREET BOX model on the urban street of Nanjing. The resultshows, this model can predict PM₁₀ concentration value on the street of Nanjing basically,at a little windy state, the first linear relevant equation of predicted value is y=1.0006x,replies the coefficient correlation and reaches 0.9636; In the quiet wind state, STREETBOX model predicted value is lower than the surveying value. Like the condition to thequiet atmosphere, the study has adopted the least square method, perform the bestdispersion coefficient D value of calculating the model instead, revise from 1.5m²/s to0.4m²/s in STREET BOX model, and use a large number of independent samples todiffusion model to verify in setting up the urban street PM₁₀ concentration of Nanjingnewly.