Trend of acid rain and neutralization by yellow sand in east Asia; A Numerical study

Terada, Hiroaki   ; Ueda, Hiromasa*; Wang, Z.*

Acid rain and its neutralization by yellow-sand in East Asia was investigated numerically by an Air Quality Prediction Modeling System (AQPMS). AQPMS consists of advection, diffusion, dry and wet deposition, gas- and liquid-phase chemistry. A new deflation module of the yellow-sand was designed to provide explicit information on the dust loading, and linked to the AQPMS. For model validation, the predicted pH values and sulfate- and nitrate-ion levels of precipitation, together with the surface concentrations of gaseous pollutants, were compared with measured values at atmospheric monitoring stations, and a reasonable agreement was obtained. Firstly, trend of the acid rain in East Asia due to the rapid increase of Chinese pollutants emission was investigated, and a remarkably rapid increase of acid rain area was predicted in the period from 1985 to 1995. Secondly, the simulation results of April 1995 exhibited a strong neutralization of the precipitation by the yellow-sand.