【摘要】 为有效预防突发沙尘暴天气下大气颗粒物对世界文化遗产地敦煌莫高窟壁画及彩塑的污染,文章选取了第138窟内、72窟前及九层楼顶3处监测点,探讨了大气颗粒物污染特征及影响因素。结果表明:72窟前平均风速为1.57 m/s,小于起沙风速,九层楼顶平均风速为10.66 m/s,大于起沙风速,占比为98.50%,主风向为东北偏东,占比为39.85%。九层楼顶颗粒物质量浓度比其他监测点更快达到最大值。第138窟内、72窟前PM2.5日均质量浓度为(43.82±15.51)、(59.85±29.78)μg/m~3,超标倍数为0.25、0.71,九层楼顶PM2.5超出仪器上限。第138窟内、72窟前、九层楼顶PM10日均质量浓度为(58.60±21.36)、(74.43±36.52)、(3 725.41±203.41)μg/m~3,超标倍数为0.17、0.49、73.51;TSP日均质量浓度为(80.15±29.02)、(102.33±48.22)、(5 593.68±707.98)μg/m~3,超标倍数为0、0、45.61。各监测点输送颗粒物的主要风向为ENE、NE、E和N、NNE。颗粒物质量浓度与气温、气压呈负相关,与风速呈正相关,除72窟前PM2.5外,其他颗粒物质量浓度与空气相对湿度呈负相关。更多还原

【Abstract】 In order to effectively prevent the murals and colored sculptures in the Dunhuang Mogao Grottoes, a renowned world cultural heritage site, from atmospheric PM(particulate matter) pollution in outburst of sandstorms, an in-site investigation was conducted, in which three monitoring points(within Cave 138; in front of Cave 72; and at the 9 thlayer(top layer) of the Grottoes) were set for investigating the characteristics and influencing factors of atmospheric PM pollution. The investigation revealed that average wind speed in front of Cave 72 was 1.57 m/s, which was lower than the wind speed of sand blowing;and the average wind speed at the top layer of the Grottoes was 10.66 m/s, which meant proportion of the wind speed greater than the sand-blowing wind-speed accounted for 98.50%, and the main wind direction was ENE, accounting for 39.85%, and the time to attained the maximum concentration of particle mass at the top layer of the Grottoes was relatively shorter compared to those at other two monitoring points. At the monitoring points Cave 138 and in front of Cave 72, the average daily mass concentrations of PM2.5 were(43.82±15.51),(59.85±29.78)μg/m~3, respectively and the exceeding multiples being0.25, 0.71, respectively, while at the top layer of the Grottoes the average daily mass concentrations of PM2.5 was too high to record(due to exceeding the upper limit of the instrument). The average daily mass concentrations of PM10 were(58.60±21.36),(74.43±36.52),(3 725.41±203.41)μg/m~3, respectively, and the exceeding multiples being 0.17, 0.49,73.51, respectively; and the average daily mass concentrations of TSP were(80.15±29.02),(102.33±48.22),(5 559.68±707.98)μg/m~3, respectively, and the multiples of exceeding the standard being 0, 0, 45.61, respectively. The main wind directions for transporting PM at each monitoring point were ENE, NE, E and N, NNE. In addition, the mass concentration of PM was negatively correlated with temperature and air pressure, and positively correlated with wind speed; and the mass concentration of PM was negatively correlated with the relative humidity of the air at the monitoring points except for PM2.5 at the point in front of Cave 72.更多还原