Effects of the Use of Air Purifier on Indoor Environment and Respiratory System among Healthy Adults

Abstract

Air purifiers have become popular among ordinary families. However, it remains controversial whether indoor air purification improves the respiratory health of healthy adults. A randomized crossover intervention study was conducted with 32 healthy individuals. The subjects were categorized into two groups. One group continuously used true air purifiers, and the other followed with sham air purifiers for 4 weeks. Following this first intervention, all the subjects underwent a 4-week washout period and continued with the second 4-week intervention with the alternate air purifiers. We collected fine particulate matter (PM) ≤ 2.5 µm in aerodynamic diameter (PM2.5), coarse particulate matter between 2.5 and 10 µm in aerodynamic diameter (PM10–2.5) and ozone (O3). The subjects’ pulmonary function and fractional exhaled nitric oxide (FeNO) were measured during the study period. The indoor PM2.5 concentrations decreased by 11% with the true air purifiers compared to those with sham air purifiers. However, this decrease was not significant (p = 0.08). The air purification did not significantly improve the pulmonary function of the study subjects. In contrast, an increase in the indoor PM10–2.5 and O3 concentration led to a significant decrease in the forced expiratory volume in one second (FEV1.0)/forced vital capacity (FVC) and maximal mid-expiratory flow (MMEF), respectively. In conclusion, air purification slightly improved the indoor PM2.5 concentrations in ordinary homes but had no demonstrable impact on improving health.

A review on reducing indoor particulate matter concentrations from personal‐level air filtration intervention under real‐world exposure situations

“…The measurement durations of indoor air pollutants were mostly over a short period of time, such as several hours or days. In addition, serval studies reported lower indoor‐to‐outdoor (I/O) PM ratios and PM infiltration efficiency during filtration periods than non‐filtration periods 14,21,44–46 …”

“…In addition, serval studies reported lower indoor-to-outdoor (I/O) PM ratios and PM infiltration efficiency during filtration periods than non-filtration periods. 14,21,[44][45][46]…”

Effectiveness of portable HEPA air cleaners on reducing indoor endotoxin, PM 10, and coarse particulate matter in an agricultural cohort of children with asthma: A randomized intervention trial

“…Three recent studies from East Asia, although not focused explicitly on homes of children with asthma, provide additional evidence on the effectiveness of portable HEPA cleaners on indoor concentrations of these particle size fractions in non‐smoking homes. In a crossover trial conducted at several urban locations in Japan, two groups of 16 healthy adults were randomly assigned to either HEPA or sham filtration (in the living room) for 4 weeks followed by the alternate treatment with a 4 weeks washout period in between 98 . Mean PM 10‐2.5 and PM 2.5 (PM 10 was not reported) decreased slightly during true compared with sham filtration but the differences were not statistically significant in a two‐sample t test 98 .…”

“…In a crossover trial conducted at several urban locations in Japan, two groups of 16 healthy adults were randomly assigned to either HEPA or sham filtration (in the living room) for 4 weeks followed by the alternate treatment with a 4 weeks washout period in between 98 . Mean PM 10‐2.5 and PM 2.5 (PM 10 was not reported) decreased slightly during true compared with sham filtration but the differences were not statistically significant in a two‐sample t test 98 . Mean PM 10‐2.5 levels in this study were generally low (~3 μg/m 3 ) compared with what we and others have measured.…”

Indoor air quality improvement in COVID-19 pandemic: Review

“…Air purifiers can capture a substantial amount of airborne dust particles and airborne allergens ( Sublett, 2011 ). For instance, experimental studies conducted by ( Park, Park, & Seo, 2020 ; Yoda et al, 2020 ) under everyday life conditions stated that the air purifiers were effective in reducing indoor PM concentration depending on the user location and the subject characteristics. The study done by ( Chen et al, 2010 ; Zhang et al, 2019 ) signified that the usage of air purifiers limited the exposure of aerosols and droplets on healthcare workers in dental clinics significantly.…”