Development and Evaluation of a Diffusion Model for Particulate Matter

Application to Kashima area

Abstract

A diffusion model for particulate matter was developed, and source contributions in Kashima area, Ibaragi prefecture were calculated.
The model includes not only industrial sources but also the sources such as, straw burning and sea salt particle which had not been taken into consideration in previous simulation study. As for soil and secondary particle which were not easily calculated by diffusion model, contributions were estimated by the chemical component analysis and added to the calculated concentration by diffusion model. Emissions were classified into 4 groups (particle size 0-2, 2-10, 10-20, 20 μm-) and concentration smaller than 10 μm were compared with observed values of airborne particulates (suspended particulates and suspended dust).
The coincidence between observed and calculated concentration was satisfactorily good. Moreover, the intercept of the regression line whose gradient was 1.0 (A₀) was evaluated as 3.6 μg/m³, and about 90% of observed concentration was simulated by the present model.
Source contributions by diffusion model were compared with that by receptor model (CMB method), and the problems in the application of these two models were discussed.