Li Na, Chang Junrui, Li Yunpu, Liu Zhe, Wang Qin, Xu Dongqun, Xu Chunyu
China CDC Key Laboratory of Environment and Population Health, National Institute of Environmental Health, Chinese Center for Disease Control and Prevention, Beijing 100021, China.
Wei Sheng Yan Jiu. 2024 Jul;53(4):631-638. doi: 10.19813/j.cnki.weishengyanjiu.2024.04.017.
To investigate the black carbon (BC) pollution in the indoor air of typical residential houses in urban areas of Beijing, and to explore the relationship between indoor and outdoor BC concentrations as well as the main influencing factors.
The indoor and outdoor PM_(2.5) samples were collected simultaneously from 33 apartments in the urban areas of Beijing during both the heating season (January to March) and the non-heating season (June to August) in 2016. Subsequently, optical method were employed to analyze BC concentrations in PM_(2.5)samples. The Spearman correlation coefficient (r_s) and the indoor/outdoor (I/O) ratio of BC concentrations were both calculated to characterize the relationship between indoor and outdoor BC concentrations. The factors may influence indoor BC pollution was collected through a questionnaire, including the basic characteristics of the residential buildings and households, smoking, cooking, window opening behavior, the use of air conditioner or air purifier and so on. Additionally, a linear mixed-effects model or multiple linear regression model was applied to identify the main factors influencing the I/O ratio.
The(M(P25, P75)) concentrations of indoor and outdoor BC for season-pooled analysis were2.84 (2.59, 3.26)μg/m3 and 3.08 (2.90, 3.63)μg/m3, respectively. There were significant seasonal differences in both indoor and outdoor concentrations (P<0.05), with higher levels observed during the heating season compared to the non-heating season. There was a strong correlation between indoor and outdoor BC (r_s=0.74). The correlation during the heating season (r_s=0.78) was stronger than that during the non-heating season (r_s=0.44). The ■ of I/O ratio was 0.90±0.11, with 93.5%(29/31)and 86.7%(26/30) of I/O ratios being less than 1 during the heating season and non-heating season, respectively. Statistical analysis also showed that outdoor BCconcentrations were significantly higher than indoors (P<0.05). In season-pooled analysis, the result of the linear mixed-effects model showed that window opening duration was the most important factor affecting the I/O ratio, explaining 21.3%of the total variation. The I/O ratio increased with longer window opening duration. In season-specific analysis, the characteristics of residential buildings (including building age and floor level) and window opening duration were the main factors affecting the I/O ratio during the heating season and non-heating season, respectively in 2016.
Residents in the urban areas of Beijing experienced relatively high indoor levels of BCpollution, but lower than the outdoor concentration during the same period in 2016. The window opening and the characteristics of residential buildings were the most important factors affecting the I/O ratio of BC.
调查北京市区典型住宅室内空气中的黑碳（BC）污染情况，探讨室内外BC浓度之间的关系以及主要影响因素。
于2016年供暖季（1月至3月）和非供暖季（6月至8月），同时从北京市区33套公寓中采集室内外PM₂.₅样本。随后，采用光学方法分析PM₂.₅样本中的BC浓度。计算Spearman相关系数（rₛ）和BC浓度的室内/室外（I/O）比值，以表征室内外BC浓度之间的关系。通过问卷调查收集可能影响室内BC污染的因素，包括住宅建筑和住户的基本特征、吸烟、烹饪、开窗行为、空调或空气净化器的使用等。此外，应用线性混合效应模型或多元线性回归模型来确定影响I/O比值的主要因素。
季节合并分析中，室内外BC的（M(P25, P75)）浓度分别为2.84（2.59，3.26）μg/m³和3.08（2.90，3.63）μg/m³。室内外浓度均存在显著的季节差异（P<0.05），供暖季的浓度高于非供暖季。室内外BC之间存在强相关性（rₛ=0.74）。供暖季的相关性（rₛ=0.78）强于非供暖季（rₛ=0.44）。I/O比值的■为0.90±0.11，供暖季和非供暖季分别有93.5%（29/31）和86.7%（26/30）的I/O比值小于1。统计分析还表明，室外BC浓度显著高于室内（P<0.05）。在季节合并分析中，线性混合效应模型的结果表明，开窗时长是影响I/O比值的最重要因素，解释了总变异的21.3%。I/O比值随开窗时长的增加而升高。在特定季节分析中，2016年供暖季和非供暖季影响I/O比值的主要因素分别是住宅建筑特征（包括建筑年代和楼层）和开窗时长。
2016年北京市区居民室内BC污染水平相对较高，但低于同期室外浓度。开窗和住宅建筑特征是影响BC的I/O比值的最重要因素。
