Lajoie P, Aubin D, Gingras V, Daigneault P, Ducharme F, Gauvin D, Fugler D, Leclerc J-M, Won D, Courteau M, Gingras S, Héroux M-È, Yang W, Schleibinger H
Environmental Health and Toxicology Division, Institut national de santé publique du Québec (INSPQ), Quebec City, QC, Canada.
NRC Construction, National Research Council of Canada, Ottawa, ON, Canada.
Indoor Air. 2015 Dec;25(6):582-97. doi: 10.1111/ina.12181. Epub 2015 Jan 21.
A randomized controlled trial was carried out to measure the impact of an intervention on ventilation, indoor air contaminants, and asthma symptoms of children. Eighty-three asthmatic children living in low-ventilated homes were followed over 2 years. Several environmental parameters were measured during the summer, fall, and winter. The children were randomized after Year 1 (43 Intervention; 40 Control). The intervention included the installation of either a Heat Recovery Ventilator (HRV) or Energy Recovery Ventilator (ERV). During the fall and winter seasons, there was a significant increase in the mean ventilation rate in the homes of the intervention group. A statistically significant reduction in mean formaldehyde, airborne mold spores, toluene, styrene, limonene, and α-pinene concentrations was observed in the intervention group. There was no significant group difference in change in the number of days with symptoms per 14 days. However, there was a significant decrease in the proportion of children who experienced any wheezing (≥1 episode) and those with ≥4 episodes in the 12-month period in the intervention group. This study indicates that improved ventilation reduces air contaminants and may prevent wheezing. Due to lack of power, a bigger study is needed.
Positive findings from this study include the fact that, upon recruitment, most of the single family homes with asthmatic children were already equipped with a mechanical ventilation system and had relatively good indoor air quality. However, the 8-h indoor guideline for formaldehyde (50 μg/m3) was frequently exceeded and the ventilation rates were low in most of the homes, even those with a ventilation system. Both ERVs and HRVs were equally effective at increasing air exchange rates above 0.30 ACH and at preventing formaldehyde concentrations from exceeding the 50 μg/m3 guideline during the fall and winter seasons. Furthermore, the ERVs were effective at preventing excessively low relative humidities in the homes. Based on observed difference of risk, intervention to increase ventilation in five sample homes and children would prevent 1 home to exceed the indoor air long-term formaldehyde guideline and prevent 1 asthmatic child experiencing at least one episode of wheezing over a year.
开展了一项随机对照试验，以评估一项干预措施对儿童通风、室内空气污染物及哮喘症状的影响。对83名居住在通风不良家庭中的哮喘儿童进行了为期2年的跟踪研究。在夏季、秋季和冬季测量了多个环境参数。在第1年后将儿童随机分组（43名干预组；40名对照组）。干预措施包括安装热回收通风机（HRV）或能量回收通风机（ERV）。在秋冬季节，干预组家庭的平均通风率显著增加。干预组的甲醛、空气中霉菌孢子、甲苯、苯乙烯、柠檬烯和α-蒎烯的平均浓度有统计学意义的显著降低。每14天有症状天数的变化在两组间无显著差异。然而，干预组中在一年期间出现任何喘息（≥1次发作）的儿童比例以及出现≥4次发作的儿童比例有显著下降。本研究表明，改善通风可减少空气污染物并可能预防喘息。由于样本量不足，需要开展更大规模的研究。
本研究的积极发现包括，在招募时，大多数有哮喘儿童的独栋家庭已经配备了机械通风系统且室内空气质量相对较好。然而，甲醛的8小时室内指导值（50μg/m³）经常被超过，大多数家庭的通风率较低，即使是那些有通风系统的家庭。ERV和HRV在将空气交换率提高到0.30ACH以上以及在秋冬季节防止甲醛浓度超过50μg/m³指导值方面同样有效。此外，ERV在防止家庭中相对湿度过低方面有效。根据观察到的风险差异，对五个样本家庭和儿童进行增加通风的干预可防止1个家庭超过室内空气中甲醛长期指导值，并防止1名哮喘儿童在一年内至少经历一次喘息发作。
