title: Cardiopulmonary benefits of reducing indoor particles of outdoor origin: a randomized, double-blind crossover trial of air purifiers.
abstract: BACKGROUND
  Indoor exposure to fine particulate matter (PM2.5) from outdoor sources is a major health concern, especially in highly polluted developing countries such as China. Few studies have evaluated the effectiveness of indoor air purification on the improvement of cardiopulmonary health in these areas.
  
  
  OBJECTIVE
  This study sought to evaluate whether a short-term indoor air purifier intervention improves cardiopulmonary health.
  
  
  METHODS
  We conducted a randomized, double-blind crossover trial among 35 healthy college students in Shanghai, China, in 2014. These students lived in dormitories that were randomized into 2 groups and alternated the use of true or sham air purifiers for 48 h with a 2-week washout interval. We measured 14 circulating biomarkers of inflammation, coagulation, and vasoconstriction; lung function; blood pressure (BP); and fractional exhaled nitric. We applied linear mixed-effect models to evaluate the effect of the intervention on health outcome variables.
  
  
  RESULTS
  On average, air purification resulted in a 57% reduction in PM2.5 concentration, from 96.2 to 41.3 μg/m3, within hours of operation. Air purification was significantly associated with decreases in geometric means of several circulating inflammatory and thrombogenic biomarkers, including 17.5% in monocyte chemoattractant protein-1, 68.1% in interleukin-1β, 32.8% in myeloperoxidase, and 64.9% in soluble CD40 ligand. Furthermore, systolic BP, diastolic BP, and fractional exhaled nitrous oxide were significantly decreased by 2.7%, 4.8%, and 17.0% in geometric mean, respectively. The impacts on lung function and vasoconstriction biomarkers were beneficial but not statistically significant.
  
  
  CONCLUSIONS
  This intervention study demonstrated clear cardiopulmonary benefits of indoor air purification among young, healthy adults in a Chinese city with severe ambient particulate air pollution. (Intervention Study on the Health Impact of Air Filters in Chinese Adults; NCT02239744).
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai, China; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Fudan University, Shanghai, China; Key Lab of Health Technology Assessment of the Ministry of Health, Fudan University, Shanghai, China.
authors.forename: Renjie
authors.initials: R
authors.lastname: Chen
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Ang
authors.initials: A
authors.lastname: Zhao
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina.
authors.forename: Honglei
authors.initials: H
authors.lastname: Chen
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Zhuohui
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Cai
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Cuicui
authors.initials: C
authors.lastname: Wang
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Changyuan
authors.initials: C
authors.lastname: Yang
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai, China.
authors.forename: Huichu
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Epidemiology, College of Public Health and Health Professional and College of Medicine, University of Florida, Gainesville, Florida.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Epidemiology, College of Public Health and Health Professional and College of Medicine, University of Florida, Gainesville, Florida.
authors.forename: Sandie
authors.initials: S
authors.lastname: Ha
authors.affiliation: Institute of Environmental Health and Related Product Safety, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Tiantian
authors.initials: T
authors.lastname: Li
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, Fudan University, Shanghai, China; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Fudan University, Shanghai, China; Key Lab of Health Technology Assessment of the Ministry of Health, Fudan University, Shanghai, China. Electronic address: haidongkan@gmail.com.
authors.forename: Haidong
authors.initials: H
authors.lastname: Kan
mesh_terms: D000328:Adult; D061808:Air Filters / Q000706:statistics & numerical data*; D016902:Air Pollution, Indoor / Q000009:adverse effects / Q000517:prevention & control*; D015415:Biomarkers / Q000097:blood*; D002318:Cardiovascular Diseases / Q000097:blood*; D002681:China; D002947:Cities; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D052638:Particulate Matter / Q000009:adverse effects*; D012129:Respiratory Function Tests; D055815:Young Adult
chemical_list: D015415:Biomarkers; D052638:Particulate Matter
keywords: air pollution; air purification; cardiovascular health; intervention; pulmonary health; randomized controlled trial