室内空气PM2.5污染水平及其分布特征研究

Pollution levels and distribution characteristics of PM2.5 in indoor air

目的研究北京市室内空气PM2.5浓度水平及其分布特征。方法选择北京市7个不同功能区的3个室内监测点(住宅、学校、办公场所)及1个室外监测点,采用重量法测定PM2.5质量浓度。监测时间为2013年5月—2014年4月,每月连续采集7 d,每天采集24 h。结果监测时间段内,3类不同场所(住宅、学校、办公室)室内空气PM2.5浓度均低于室外,差异均有统计学意义(P<0.05);住宅、学校、办公室、室外PM2.5高于GB 3095—2012《环境空气质量标准》二级标准的比例分别为42.7%,41.2%,39.5%,61.8%。室内PM2.5浓度在夏季(7—8月)最低,在冬季(1—3月)最高;室内PM2.5浓度由低至高为远郊区<汽车交通要道、化工工业区<机场、燃煤发电厂<建筑工地、水泥厂,差异有统计学意义(P<0.05)。室内PM2.5占室内PM10的浓度比值为0.83,PM2.5的室内/室外浓度比值(0.68)高于PM10(0.59),差异均有统计学意义(P<0.01)。结论本次调查地区的PM2.5质量浓度为冬季较高,建筑工地、水泥厂PM2.5质量浓度高于其他地区,且室内PM2.5浓度随室外浓度的增加而升高。

Objective To know the mass concentration and distribution characteristics of indoor PM2.5 in Beijing. Methods Seven typical regions were selected in Beijing for sampling. Within each region, an outdoor site and three indoor sites including residence, school and workplace were set for PM2.5 sampling with gravimetric method for one successive week in each month during one year. Results The overall levels of indoor PM2.5 were lower than those of outdoor in all seven regions.Indoor PM2.5 concentrations in residential,school, workplace and outdoor PM2.25 exceeded the level of secondary standard provided by GB 3095-2012, the related proportions were 42.7%, 41.2%, 39.5%, 61.8%, respectively. Significant seasonal and spatial variations of PM2.5 concentration were observed.The lowest PM2.5 concentration was observed in summer （July-August）, while the highest in winter （January, February and March）. Spatial variations followed this order： ecological residential area 〈 traffic area and chemical industrial area〈 airport area and coal-fired power plant 〈cement plant and construction area. The ratio of PM2.5 to indoor inhalable particles （PM10） was 0.83. The mean I/O （indoor concentration/outdoor concentration） value of PM2.5 （0.68） was higher than that of PMIO （0.59）. Conclusion The concentration of PM2.5 in Beijing is higher in winter and lower in summer, and higher in regions which have construction dust or industrial cement pollutant. Mass concentration of indoor PM2.5 increases significantly with increase of outdoor concentration.