IVAIRE - A Randomized Controlled Study on the impact of Ventilation on IAQ and the Symptoms of Asthmatic Children in Single Family Homes - Environmental Aspects

摘要

Background and Aims Our study evaluated the impact of improved ventilation on indoor air quality (IAQ) and the frequency of asthma symptoms in children in residential buildings. This paper discusses the impact of residential ventilation rates on IAQ. Methods A randomized controlled study was conducted with 83 asthmatic children (ages 3 to 12 years) living in homes with ventilation rates ＜ 0.3 h-1. During year 1 (pre-intervention) and 2 (post-intervention), the ventilation rates and a number of IAQ relevant chemical, biological and physical parameters were measured during two home visits in the heating-season and one visit in the summer. Following year 1, participants were randomized (43 I; 40 C).The ventilation rates were increased in the homes of participants of the intervention group by optimizing the existing mechanical ventilation systems or by the addition of a heat recovery ventilator (HRV) or an energy recovery ventilator (ERV). A generalized linear model was used to assess the difference in outcomes between intervention and control group. Results Following the intervention the mean air exchange rate (h-1) increased from 0.17 (1.06) to 0.34 (1.06) in the intervention group compared to 0.18 (1.06) and 0.21 (1.06) in the control group (p＜0.0001). The mean heating-season concentration of formaldehyde (μg m-3) decreased from 37.2 (1.07) to 24.1 (1.07) in the intervention group compared from 36.5 (1.08) to 35.4 (1.08) in control group (p＜0.0001). Following the intervention all homes in the intervention group were able to meet formaldehyde guideline of 50 μg m-3 for an 8-hour exposure compared with only two thirds prior to the intervention. Significant reductions in the concentrations of IAQ relevant parameters were also observed in the intervention group. Conclusions This study demonstrates that under-ventilated homes can be corrected through a careful retrofit with H(E)RV systems and that the concentration of potentially health relevant chemical and microbial IAQ parameters can be significantly reduced with increased ventilation.