Characterizing peak exposure of secondhand smoke with a real-time PM2.5 monitor

摘要

Peak exposure to pollutants can trigger adverse acute effects given the relatively high levels of exposure in a short period of time. Secondhand cigarette smoke (SHS) leads to peak exposure if the smoking occurs in a confined space. Multiple adverse health effects are associated with SHS, the majority of which occurs in the residential environment. The aim of this study was to explore whether peaks in real-time PM2.5 data can estimate SHS exposure. A total of 41 children (21 with and 20 without SHS exposure based on self-reported questionnaire responses) from 28 families in New York City (NY, USA) were recruited for this study. Both real-time personal and residential PM2.5 monitoring were performed for five consecutive days using MicroPEM portable PM2.5 sensors (RTI International, USA). A threshold detection method based on a cumulative distribution function was developed to identify peaks. When children were home, the accumulated peak area (APA) for peak exposures was 297 hour*ug/m3 for children from smoking families, six times that of those from non-smoking families (50 hour*ug/m3). PM mass concentrations for SHS exposed and unexposed children were 24 ug/m3 and 15 ug/m3, respectively. The average SHS exposure duration was 1.2 hr per day. This represents ～5% of total exposure time, but ～13% of children's total PM2.5 exposure. SHS-derived PM2.5 was equivalent to an additional 2.6 ug/m3 per day. This study demonstrated the feasibility of peak analysis for estimating SHS exposure.