敦煌莫高窟大气颗粒物中水溶性离子变化及来源解析  

Variation and Source Analysis of Water-Soluble Ions in the Atmospheric Particles of Mogao Grottoes at Dunhuang

作　　者：杨小菊 武发思[1,4] 徐瑞红[1] 贺东鹏[1] 张国彬[1] 康世昌 李潮流[3] 汪万福[1,2,4] YANG Xiaoju;WU Fasi;XU Ruihong;HE Dongpeng;ZHANG Guobin;KANG Shichang;LI Chaoliu;WANG Wanfu(National Research Center for Conservation of Ancient Wall Paintings and Earthen Sites Dunhuang Academy,Dunhuang 736200,Gansu,China;Northwest Institute of Eco-Environment and Resources,University of Chinese Academy of Sciences,Lanzhou 730000,Gansu,China;Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100029,China;MOE Key Laboratory of Cell Activities and Stress Adaptations,Lanzhou University,Lanzhou 730000,Gansu,China)

机构地区：[1]敦煌研究院国家古代壁画与土遗址保护工程技术研究中心,甘肃敦煌736200 [2]中国科学院西北生态环境资源研究院,甘肃兰州730000 [3]中国科学院青藏高原研究所,北京100029 [4]兰州大学细胞活动与逆境适应教育部重点实验室,甘肃兰州730000

出　　处：《高原气象》2021年第2期436-447,共12页Plateau Meteorology

基　　金：国家科技支撑计划项目(2013BAC07B02);国家自然科学基金项目(31560160);甘肃省科技计划项目(18JR3RA004);中国科学院STS项目(29Y829731);甘肃省文物局课题(GWJ201609)。

摘　　要：为探明莫高窟大气颗粒物污染特征,采集了2014年4-12月第16窟及72窟外环境中大气颗粒物PM2.5和PM10~2.5样品,对比分析了样品中水溶性离子变化及影响因素,通过主成分分析法解析了其主要来源。结果表明:(1)窟区主风向为南风,起沙风频率仅为0.01%,不利于污染物的扩散;(2)窟外PM2.5和PM10~2.5、窟内PM2.5和PM10~2.5中水溶性离子总浓度分别为6.1±4.0μg·m^(-3)、12.2±9.1μg·m^(-3)、3.7±0.8μg·m^(-3)和7.5±1.6μg·m^(-3),SO_(4)^(2-)、Ca^(2+)、NO3^(-)、Na^(+)及Cl^(-)是主要组成,SO42-、NO3-和Ca2+之和在窟外和窟内PM2.5和PM10~2.5中占总离子比例分别为79.24%,76.81%,80.61%及77.74%,二次离子主要来自固定污染源;(3)PM2.5与PM10~2.5中各离子浓度的比值在窟外、内分别为0.33~0.88、0.25~0.94,9种水溶性离子在不同粒径粒子中富集程度有所差异,3-5月的沙尘、7-9月的降雨、11月农村农作物秸秆燃烧及冬季取暖燃煤等对水溶性离子都有一定影响,窟内PM2.5中游客数量与NH4+和NO^(3-)有一定的相关性(R2=0.27、0.35)、PM10~2.5中游客数量与NH4+有一定的相关性(R2=0.31);(4)沙尘天气下窟外和窟内的PM2.5与PM10-2.5中Cl-、SO_(4)^(2-)、Na^(+)、K+和Ca^(2+)的浓度增加,窟区微环境主要受区域环境气象因素影响,建议极端沙尘天气关闭洞窟;(5)莫高窟大气环境呈碱性;(6)PM2.5和PM10~2.5主要来源于当地秸秆燃烧、二次污染源、土壤沙尘及干涸的大泉河。With the purpose of exploring the characteristics of atmospheric particulate pollution at the Mogao Grottoes,the samples of PM2. 5 and PM10~2. 5 were collected in Cave 16 and exterior environment of Cave 72 from April to December,2014. The researcher conducted contrastive analysis on the variation and influence factors of the water-soluble ions in the samples,and studied their main sources by the approach of Principal Component Analysis(PCA). The results are as follows:(1)The main wind direction at Mogao Grottoes area is south wind and the frequency of wind with sand is only 0. 01%,which is unfavorable to the diffusion of pollutants.(2)The total concentration of water-soluble ions of PM2. 5 and PM10~2. 5 in the exterior environment of Cave 72 are 6. 1±4. 0μg·m^(-3) and 12. 2±9. 1 μg·m-3,while in the interior environment of Cave 16 are 3. 7±0. 8 μg·m^(-3) and 7. 5±1. 6μg·m-3. SO_(4)^(2-),Ca^(2+),NO^(3-),Na+,and Cl- are the main components of water-soluble ions. As for the proportion of water-soluble ions of PM2. 5 and PM10~2. 5 in the exterior environment,SO4^(2-),NO^(3-),and Ca^(2+)together account for79. 24% and 76. 81%. In the interior environment,the number is 80. 61% and 77. 74%. The Secondary ions originate mainly from stationary pollution sources.(3)The ratio of each ion concentration in PM2. 5 and PM10~2. 5 are 0. 33~0. 88(outside the cave)and 0. 25~0. 94(inside the cave). 9 water-soluble ions are different in terms of their concentration degrees in different particle sizes. Sand storms from March to May,rainfalls from July to September,straw burning in rural areas in November,and coal burning for heating in winter have some effects on water-soluble ions. The number of tourists inside the caves has certain correlation with NH4+and NO^(3-)from the perspective of PM2. 5(R2=0. 27,0. 35),and with NH4+(R2=0. 31)from PM10~2. 5.(4)Owing to the sand and dust weathers,the concentration of Cl-,SO4^(2-),Na^(+),K^(+) and Ca^(2+)increase in the PM2. 5 and PM10-2. 5 inside and outside the cave. The results i

关 键 词：敦煌莫高窟 文物保护 水溶性离子 大气颗粒物 壁画盐害 

分 类 号：P402[天文地球—大气物理学与大气环境]