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Real-time measurements of PM2.5 and ozone to assess the effectiveness of residential indoor air filtration in Shanghai homes |
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| Authors: | Karoline K Barkjohn Christina Norris Xiaoxing Cui Lin Fang Tongshu Zheng James J Schauer Zhen Li Yinping Zhang Marilyn Black Junfeng |
| Affiliation: | 1. Civil and Environmental Engineering, Duke University, Durham, NC, USA;2. Civil and Environmental Engineering, Duke University, Durham, NC, USA
Contribution: Conceptualization (supporting), Data curation (equal), ?Investigation (equal), Methodology (supporting), Writing - review & editing (supporting);3. Nicholas School of the Environment, Duke University, Durham, NC, USA;4. School of Architecture, Tsinghua University, Beijing, China Contribution: ?Investigation (equal), Writing - review & editing (supporting);5. Civil and Environmental Engineering, Duke University, Durham, NC, USA Contribution: Data curation (supporting), Formal analysis (supporting);6. Civil and Environmental Engineering, University of Wisconsin at Madison, Madison, WI, USA;7. Shanghai First People’s Hospital, Shanghai Shi, China Contribution: ?Investigation (supporting), Resources (supporting);8. School of Architecture, Tsinghua University, Beijing, China Contribution: Resources (supporting), Writing - review & editing (supporting);9. Underwriters Laboratories Inc., Marietta, GA, USA Contribution: Conceptualization (supporting), Funding acquisition (equal);10. Nicholas School of the Environment, Duke University, Durham, NC, USA Contribution: Conceptualization (supporting), Funding acquisition (equal), Writing - review & editing (supporting);11. Civil and Environmental Engineering, Duke University, Durham, NC, USA Contribution: Conceptualization (supporting), Funding acquisition (lead), Supervision (lead), Writing - review & editing (lead) |
| Abstract: | Portable air cleaners are increasingly used in polluted areas in an attempt to reduce human exposure; however, there has been limited work characterizing their effectiveness at reducing exposure. With this in mind, we recruited forty-three children with asthma from suburban Shanghai and deployed air cleaners (with HEPA and activated carbon filters) in their bedrooms. During both 2-week filtration and non-filtration periods, low-cost PM2.5 and O3 air monitors were used to measure pollutants indoors, outdoors, and for personal exposure. Indoor PM2.5 concentrations were reduced substantially with the use of air cleaners, from 34 ± 17 to 10 ± 8 µg/m3, with roughly 80% of indoor PM2.5 estimated to come from outdoor sources. Personal exposure to PM2.5 was reduced from 40 ± 17 to 25 ± 14 µg/m3. The more modest reductions in personal exposure and high contribution of outdoor PM2.5 to indoor concentrations highlight the need to reduce outdoor PM2.5 and/or to clean indoor air in multiple locations. Indoor O3 concentrations were generally low (mean = 8±4 ppb), and no significant difference was seen by filtration status. The concentrations of pollutants and the air cleaner effectiveness were highly variable over time and across homes, highlighting the usefulness of real-time air monitors for understanding individual exposure reduction strategies. |
| Keywords: | air filtration air sensors ozone personal exposure PM2 5 portable air cleaner |