秦俑博物馆室内气溶胶化学组成初步研究

The concentrations of indoor aerosols in Emperor Qin's Terra-cotta Museum

目的 为了科学有效保护地保护秦俑，研究遗址区室内空气工作势在必行。方法 通过夏季在秦俑馆采集气溶胶进行分析。结果 0．3～0．7μm范围内的气溶胶PM2．5、TSP浓度随游客的增加而增加；室内PM2．5和TSP平均浓度分别为108．4μg／m^3和172．4μg／m^3，PM2.5占TSP总质量的62．9％。进一步分析证实硫酸盐、有机物及地壳矿物是室内PM2.5。的主要组成部分，分别占（32．4±6．2）％、（27．7±8．0）％，（12．5±3．4）％。元素碳、铵盐、硝酸盐分别占室内PM2．5的（3．9±1．5）％．（8．9±2．8）％，（7．0±2．9）％；高含量的硫酸盐、有机物、元素碳、硝酸盐及铵盐的粒径在0．43～3．3μm之间，根据离子平衡计算显示出室内气溶胶酸性特征。结论 为科学、有效地控制室内环境，保护秦俑提供了重要依据。

Aim To effectively protect the Emperor Qin＇s Terra-cotta. Method Aerosol samples were collected during an intensive campaign in August 2004 both inside and outside the Emperor Qin＇s Terra-cotta Museum, Xi＇an, China, and analysized. Results The size-separated number concentrations of indoor aerosols ranging from 0.3 to 7.0 μm were increased largely with tourist in the museum. The concentrations of PM2.5, TSP and size-differentiated samples, as well as the chemical compositions, were determined. Average indoor PM2.5 and TSP levels were 108.4 and 172.4 μg/m^3, respectively, with PM2.5 constituting 62.9% of the TSP mass. Sulfate, organics, and geological material were found to be the most dominants in indoor PM2.5, accounting for （32.4 ± 6.2）% ,（27.7±8.0）% and （12.5 ± 3. 4）%, respectively. Elemental carbon, ammonium and nitrate constituted （3.9 ± 1. 5） %, （8.9±2.8）%, and （7.0±2.9）%, respectively, of indoor PM2.5. High portions of sulfate, organics, elemental carbon, nitrate, and ammonium were found in the small sizes between 0. 43-3.3 μm. Ion balance calculations of sulfate, nitrate and ammonium implied that ammonium ions are present in non-sufficient levels to account for the neutralization of sulfuric and nitric acids, resulting in the acidic nature of indoor aerosols. High concentrations of acidic aerosols will erode the Terra-cotta warriors and horses especially under high temperature （30 ℃） and relative humidity （70%） with undesired solar radiation inside the museum during summer season. Conclusion It should be attracted more attentions to protect the work of arts with more than 2000 years old.