Randomized trial of a portable HEPA air cleaner intervention to reduce asthma morbidity among Latino children in an agricultural community

Background Data on pediatric asthma morbidity and effective environmental interventions in U.S. agricultural settings are few. We evaluated the effectiveness of HEPA air cleaners on asthma morbidity among a cohort of rural Latino children. Methods Seventy-five children with poorly controlled asthma and living in non-smoking homes were randomly assigned to asthma education alone or along with HEPA air cleaners placed in their sleeping area and home living room. The Asthma Control Test (ACT) score, asthma symptoms in prior 2 weeks, unplanned clinical utilization, creatinine-adjusted urinary leukotriene E4 (uLTE4 [ng/mg]), and additional secondary outcomes were evaluated at baseline, six, and 12 months. Group differences were assessed using multivariable-adjusted generalized estimating equations. Incident rate ratios of ever experiencing the metrics of poorer asthma health during follow-up (suboptimal asthma management) were estimated using Poisson regression models in secondary analysis. Results Mean child age was 9.2 and 8.6 years in intervention and control groups, respectively, and two-thirds of participants were male. Primary analysis of repeated measures of ACT score did not differ between groups (HEPA group mean change compared to controls 10% [95% CI: − 12-39%]). A suggestion of greater decrease in uLTE4 (ng/mg creatinine) was observed (− 10% [95% CI: − 20 -1%]). Secondary analysis showed children with HEPAs were less likely to have an ACT score meeting a clinically defined cutoff for poorly controlled asthma using repeated measures (IRR: 0.45 [95% CI: 0.21–0.97]). In Poisson models, intervention participants had reduced risk of ever meeting this cutoff (IRR: 0.43 [95% CI: 0.21–0.89]), ever having symptoms in the past 2 weeks (IRR: 0.71 [95% CI: 0.52–0.98]), and lower risk of any unplanned clinical utilization (IRR: 0.35 [95% CI: 0.13–0.94]) compared to control participants. Discussion The HAPI study showed generally improved outcomes among children in the HEPA air cleaner group. However, primary analyses did not meet statistical significance and many outcomes were subjective (self-report) in this unblinded study, so findings must be interpreted cautiously. HEPA air cleaners may provide additional benefit for child asthma health where traditional asthmagens (traffic, tobacco smoke) are not prominent factors, but larger studies with more statistical power and blinded designs are needed. Trial registration ClinicalTrials.gov Identifier: NCT04919915. Date of retrospective registration: May 19, 2021.

Remote Work May Be Keeping Some Cities’ Air Cleaner

Widespread remote work may have kept air pollution lower than pre-COVID-19 lockdown levels even though restrictions were lifted in 2020, a new study finds.

Flow characteristics and noise reduction effects of air cleaners of automobile intake systems with built-in resonators with space efficiency

In an automobile intake system, Helmholtz resonator is often used to reduce intake noise. But there is a disadvantage in the engine room. Resonator brings low engine room space efficiency, because resonator needs some. In this paper, we propose air cleaner with built-in resonator for a limited space of air cleaner and analyze the pressure drop effect and the transmission loss performance of the resonator through flow analysis. The air cleaner with a built-in resonator had almost no difference in pressure drop with the conventional air cleaner. Some vortex in conventional air cleaner is removed, and also, the built-in resonator has noise reduction effect at 160Hz at 61dB such as same resonator.