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Published on: February 14, 2019
Respiratory Benefits of Multisetting Air Purification in Children: A Cluster Randomized Crossover Trial
Jian Lei1,2, Qinghua Sun3, Renjie Chen1
1School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, National Health Commission Key Lab of Health Technology Assessment, Fudan University, Shanghai, China.
Insights
Indoor air purification significantly improved children's lung function and reduced airway inflammation. This study highlights the importance of air purifiers in areas with high air pollution levels for pediatric respiratory health.
Area of Science:
- Environmental Health
- Pediatric Pulmonology
- Clinical Trials
Background:
- Particulate matter exposure is linked to poor respiratory health in children.
- The benefits of air purification for children's respiratory health require further investigation.
Purpose of the Study:
- To assess respiratory health outcomes in children exposed to multi-setting air purification compared to sham purification.
- To evaluate the impact of air purification on pulmonary function, airway inflammation, and exhaled breath condensate metabolites.
Main Methods:
- A cluster randomized, double-blind, crossover trial involving healthy school-aged children (10-12 years) in China.
- Intervention involved multi-setting air purification (classrooms and bedrooms) versus sham purification over two 76-day periods with an 88-day washout.
- Primary outcomes included pulmonary function tests, airway inflammation markers, and exhaled breath condensate (EBC) analysis using linear mixed-effects models and metabolomics.
Main Results:
- Air purification reduced personal fine particulate matter (PM2.5) by 45.14%.
- Significant improvements were observed in forced expiratory volume in 1 second (8.04%), peak expiratory flow (16.52%), forced vital capacity (5.73%), and other lung function measures.
- Fractional exhaled nitric oxide decreased by 22.38%, and specific metabolites (L-tyrosine, β-alanine) in EBC were identified as potential mediators.
Conclusions:
- Indoor air purification demonstrates significant benefits for children's pulmonary health.
- The findings underscore the importance of air purification interventions in high air pollution environments for improving pediatric respiratory outcomes.
Importance:
Particulate matter exposure has been linked to impaired respiratory health in children, but the respiratory benefits of air purification have not been fully elucidated.
Objectives:
To assess the respiratory health outcomes among children exposed to multisetting air purification vs sham purification.
Design, Setting, And Participants:
This cluster randomized, double-blind, crossover trial was conducted among healthy school-aged children (10-12 years) in China from April to December 2021. Data were analyzed from December 2021 to July 2024.
Interventions:
A multisetting (both in classrooms and bedrooms) air purification intervention compared with sham purification in a 2-stage intervention with more than 2 months (76 days) for each period and a washout period (88 days) to estimate the respiratory benefits of air purification.
Main Outcomes And Measures:
The primary outcomes were pulmonary function, airway inflammation markers, and metabolites in exhaled breath condensate (EBC) before and after the air purification intervention. Linear mixed-effects models were used to estimate the respiratory benefits of children related to air purification. Differential metabolites in EBC were identified using metabolomics analysis to explore their possible mediation roles.
Results:
A total of 79 children (38 male [48%]; mean [SD] age, 10.3 [0.5] years) were included in the statistical analyses. During the study period, the mean (SD) concentration of outdoor fine particulate matter (PM2.5) at the school site was 32.53 (24.06) μg/m3. The time-weighted personal PM2.5 concentration decreased by 45.14% during the true air purification period (mean [SD], 21.49 [8.72] μg/m3) compared with the sham air purification period (mean [SD], 39.17 [14.25] μg/m3). Air purification improved forced expiratory volume in 1 second by 8.04% (95% CI, 2.15%-13.93%), peak expiratory flow by 16.52% (95% CI, 2.76%-30.28%), forced vital capacity (FVC) by 5.73% (95% CI, 0.48%-10.98%), forced expiratory flow at 25% to 75% of FVC by 17.22% (95% CI, 3.78%-30.67%), maximal expiratory flow at 75% of FVC by 14.60% (95% CI, 0.35%-28.85%), maximal expiratory flow at 50% of FVC by 17.86% (95% CI, 3.65%-32.06%), and maximal expiratory flow at 25% of FVC by 18.22% (95% CI, 1.73%-34.70%). Fractional exhaled nitric oxide in the true air purification group decreased by 22.38% (95% CI, 2.27%-42.48%). Several metabolites in EBC (eg, L-tyrosine and β-alanine) were identified to mediate the effect of air purification on respiratory health.
Conclusions And Relevance:
This randomized clinical trial provides robust and holistic evidence that indoor air purification notably improved pulmonary health in children, highlighting the importance of intensified indoor air purification in regions with high air pollution levels.
Trial Registration:
ClinicalTrials.gov Identifier: NCT04835337.
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