SOURCE CONTRIBUTIONS TO AIRBORNE PARTICLE DEPOSITION AT THE YUNGANG GROTTOES, CHINA

The Buddhist cave temple complex at Yungang in northern China is affec ted by a rapid accumulation of airborne particles that settle onto the thousands of statues contained within those caves. Experiments have b een conducted to identify the most important air pollution sources tha t contribute to the dust deposition problem. The spatial distribution of the deposition rate of airborne particles within a 2 km x 2 km area surrounding the grottoes was measured during a 2-day period in April, 1991. Peak particle deposition rates of > 60 mu g m(-2) s(-1) were fo und at locations within the village of Yungang itself and along the ad jacent coal-haul highway. Moving away from the village and coal-haul h ighway, deposition rates decline to much lower values, indicating that the village and highway are significant sources of airborne particles . A comparison of the mineralogical composition of the dust deposits i n the caves with the composition of local soil dust, paved road dust f rom the coal-haul highway and deteriorated cave ceiling rock material indicates that the dust deposits in the caves are a combination of the above sources, with the paved road dust from the coal-haul highway pr oviding the closest match to the largest quantity of the material depo sited in the caves.