Use of Time- and Chemically Resolved Particulate Data To Characterize the Infiltration of Outdoor PM2.5 into a Residence in the San Joaquin Valley

详细信息    查看全文

• 作者：Melissa M. Lunden ; Tracy L. Thatcher ; Susanne V. Hering ; and Nancy J. Brown
• 刊名：Environmental Science & Technology
• 出版年：2003
• 出版时间：October 15, 2003
• 年：2003
• 卷：37
• 期：20
• 页码：4724 - 4732
• 全文大小：202K
• 年卷期：v.37,no.20(October 15, 2003)
• ISSN：1520-5851

文摘

Recent studies associate particulate air pollution withadverse health effects. The indoor exposure to particlesof outdoor origin is not well-characterized, particularly forindividual chemical species. In response to this, a fieldstudy in an unoccupied, single-story residence in Clovis,CA, was conducted. Real-time particle monitors were usedboth outdoors and indoors to quantity PM_2.5 nitrate,sulfate, and carbon. The aggregate of the highly time-resolved sulfate data, as well as averages of these data,was fit using a time-averaged form of the infiltration equation,resulting in reasonable values for the penetrationcoefficient and deposition loss rate. In contrast, individualvalues of the indoor/outdoor ratio can vary significantlyfrom that predicted by the model for time scales rangingfrom a few minutes to several hours. Measured indoorammonium nitrate levels were typically significantly lowerthan expected solely on the basis of penetration anddeposition losses. The additional reduction is due to thetransformation of ammonium nitrate into ammonia and nitricacid gases indoors, which are subsequently lost bydeposition and sorption to indoor surfaces. This resultillustrates that exposure assessments based on total outdoorparticle mass can obscure the actual causal relationshipsfor indoor exposures to particles of outdoor origin.