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Association Between Bedroom Particulate Matter Filtration and Changes in Airway Pathophysiology in Children With
Xiaoxing Cui1, Zhen Li2, Yanbo Teng3
1Nicholas School of the Environment, Duke University, Durham, North Carolina.
Importance:
Fine particles (particulate matter 2.5 μm [PM2.5]), a ubiquitous air pollutant, can deposit in the small airways that play a vital role in asthma. It appears to be unknown whether the use of a PM2.5 filtration device can improve small airway physiology and respiratory inflammation in children with asthma.
Objective:
To discover what pathophysiological changes in the small airways are associated with using a PM2.5-removing device in the bedrooms of children with asthma.
Design, Setting, And Participants:
Children with mild or moderate asthma were enrolled in this double-blind, crossover study. The participants used a true filtration device and a sham filtration device in their bedrooms in a random order for 2 weeks each with a 2-week washout interval. The study was conducted in a suburb of Shanghai, China, during a low-ozone season.
Exposures:
Ozone and PM2.5 were measured inside bedrooms and outside a window.
Main Outcomes And Measures:
Impulse oscillometry, spirometry, and fractional exhaled nitric oxide were measured at the beginning and the end of each intervention. Peak expiratory flow was measured twice daily at home.
Results:
Forty-three children (5-13 years old; 26 boys [60%]) participated. Outdoor 24-hour mean PM2.5 concentrations were moderately high, ranging from 28.6 to 69.8 μg/m3 (median, 53 μg/m3). During true filtration, bedroom PM2.5 concentrations were a mean (SD) of 63.4% (35.9%) lower than during sham filtration. Compared with sham filtration, true filtration was significantly associated with improved airway mechanics, reflected in a 24.4% (95% CI, 11.8%-37.1%) reduction in total airway resistance, a 43.5% (95% CI, 13.7%-73.3%) reduction in small airway resistance, a 22.2% (95% CI, 2.2%-42.2%) reduction in resonant frequency, and a 73.1% (95% CI, 0.3%-145.8%) increase in airway reactance. True filtration was also associated with significant improvements in fractional exhaled nitric oxide (a 27.6% [95% CI, 8.9%-42.4%] reduction) and peak expiratory flow (a 1.6% [95% CI, 0.8%-2.5%] increase). These improvements were significantly associated with bedroom PM2.5 reduction. Improvements in small airway function were nonsignificant (8.4% [95% CI, -1.4% to 18.3%]) in all participants but significant (13.2% [95% CI, 1.2%-25.1%]) in participants without eosinophilic airway inflammation at baseline. No improvements were observed for forced vital capacity, forced expiratory volume during the first second, and the ratio of these in all participants or subgroups.
Conclusions And Relevance:
Per these results, indoor PM2.5 filtration can be a practical method to improve air flow in an asthmatic lung through improved airway mechanics and function as well as reduced inflammation. This warrants a clinical trial to confirm.
Trial Registration:
ClinicalTrials.gov Identifier: NCT03282864.
Insights
Using indoor air filtration significantly reduced particulate matter 2.5 (PM2.5) in bedrooms, improving airway mechanics and reducing inflammation in children with asthma. This suggests air filtration is a practical approach to managing childhood asthma.
Area of Science:
- Environmental Health
- Pediatric Respiratory Medicine
- Allergy and Immunology
Background:
- Fine particles (particulate matter 2.5 μm [PM2.5]) are ubiquitous air pollutants that can affect small airways, crucial for asthma control.
- The impact of PM2.5 filtration devices on small airway physiology and respiratory inflammation in pediatric asthma remains largely unknown.
Purpose of the Study:
- To investigate the pathophysiological changes in small airways associated with using a PM2.5-removing device in the bedrooms of children with asthma.
- To assess the efficacy of indoor air filtration in improving asthma-related respiratory parameters.
Main Methods:
- A double-blind, crossover study involving children with mild to moderate asthma.
- Participants used true and sham PM2.5 filtration devices in their bedrooms for 2-week periods with a 2-week washout interval.
- Measurements included impulse oscillometry, spirometry, fractional exhaled nitric oxide, and peak expiratory flow.
Main Results:
- True filtration significantly reduced bedroom PM2.5 concentrations by 63.4% compared to sham filtration.
- Significant improvements were observed in airway mechanics (total and small airway resistance, resonant frequency, airway reactance), fractional exhaled nitric oxide, and peak expiratory flow with true filtration.
- Improvements in small airway function were significant in participants without eosinophilic airway inflammation at baseline.
Conclusions:
- Indoor PM2.5 filtration is a practical method to enhance airflow in asthmatic lungs by improving airway mechanics and reducing inflammation.
- These findings support the need for clinical trials to confirm the benefits of indoor air filtration for managing childhood asthma.
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