Deposition of atmospheric particles within the Buddhist cave temples at Yungang, China
The Buddhist cave temples at Yungang, China, are soiled at a rapid rate by the deposition of airborne particles. Average mass deposition rates to horizontal surfaces of 13.42 μg m^(−2) s^(−1) outdoors and 5.23 μg m^(−2) s^(−1) inside Cave 6 were measured over a 1 yr period in 1991–1992. These rates are comparable to the rates inferred by examination of historically accumulated deposits within the caves. The surface area coverage by coarse particles is dominated by particles larger than about 10–20 μm in diameter, while the mass flux is dominated by even larger particles greater than 20–30 pm in diameter. Comparison of the deposition rate in Cave 6, which retains its wooden temple front structure, to that in Cave 9 which is open to the outdoors shows that the temple front does provide some protection. During spring 1991, the deposition rate to horizontal surfaces in Cave 6 was 4.5 μg m^(−2)s^(−1) compared to 13.4 μg m^(−2)s^(−1) in Cave 9 and 21.5 μg m^(−)2s^(−1) outdoors.
© 1994 Elsevier Science Ltd. First received 7 June 1993 and in final form 22 December 1993. Available online 7 April 2004. This work is supported by a research agreement from the Getty Conservation Institute (GCI). The co-operation and assistance of the staff of the Yungang Grottoes and the State Bureau of Cultural Relics, Beijing is gratefully acknowledged including Huang Kezhong, Zhu Changling, Sheng Weiwei, Li Xiu Qing, Li Hua Yuan, Xie Ting Fan, Yuan Jin Hu, Huang Ji Zhong, Zhi Xia Bing, Bo Guo Liang of the Shanxi Institute of Geological Science, and Zhong Ying from Taiyuan University. Assistance critical to this work was provided by the Getty Conservation Institute and their consultants, and we especially thank Neville Agnew, Po-Ming Lin, Shin Maekawa, and Roland Tseng for their help.