Gaskin Janet, Zhou Liang Grace, Li Yunyi Ethan, Tardif Patrique
Construction Research Centre, National Research Council Canada, Ottawa, ON, Canada.
Front Public Health. 2025 Apr 10;13:1569494. doi: 10.3389/fpubh.2025.1569494. eCollection 2025.
Balanced mechanical ventilation with heat (sensible heat only) or energy (sensible and latent heat) recovery has the potential to dilute indoor radon and may be an appropriate first step at reducing moderate indoor radon concentration in a house with mechanical exhaust only. A field study of the effectiveness of heat/energy recovery ventilation systems at reducing moderate indoor radon concentration was conducted in 13 occupied houses and three test houses in Canada. Controlled experiments were also conducted at the test houses to evaluate indoor radon concentration under different depressurization and ventilation scenarios.
In the field study of heat recovery ventilation systems (HRVs) in occupied homes, the indoor radon concentration was measured for different HRV settings within a season to estimate the effectiveness of radon reduction. In the controlled depressurization experiments in the test houses, the change in pressure of the basement relative to the subslab and of the basement, main floor and second floor relative to outdoors was evaluated for a range of mechanical exhaust ventilation scenarios.
The initial radon concentrations measured on the lower floor in the study houses with the HRV off were moderate, ranging from 91 to 312 Bq/m, with a median of 175 Bq/m. The median (25th-75th percentiles) effectiveness of radon reduction was 39% (29-50) for continuous HRV operation at high fan speed in the 12 field study houses where it was connected directly to the forced air furnace heating systems. In the test houses, the sustained operation of mechanical exhaust ventilation devices, however, increased the depressurization and the indoor radon concentration, and the indoor radon concentrations observed at the depressurization of -5 Pa were higher than those observed at -10 and -20 Pa.
Balanced mechanical ventilation with heat recovery was shown to be an effective radon control strategy in a field study of occupied houses with a moderate initial indoor radon concentration. Improving the energy efficiency of the existing housing stock is a priority in many countries, and including balanced mechanical ventilation systems may be an effective radon control option when conducting energy retrofits in existing houses.
带有热量（仅显热）或能量（显热和潜热）回收的平衡机械通风有稀释室内氡气的潜力，对于仅有机械排风的房屋而言，这可能是降低室内中等氡浓度的合适第一步。在加拿大的13所居住房屋和3所测试房屋中，开展了一项关于热/能量回收通风系统在降低室内中等氡浓度方面有效性的实地研究。还在测试房屋中进行了对照实验，以评估不同降压和通风场景下的室内氡浓度。
在居住房屋中对热回收通风系统（HRV）进行实地研究时，在一个季节内针对不同的HRV设置测量室内氡浓度，以估算氡减排的有效性。在测试房屋的对照降压实验中，针对一系列机械排风通风场景，评估地下室相对于楼板下以及地下室、主楼层和二楼相对于室外的压力变化。
在HRV关闭的研究房屋中，底层测量的初始氡浓度为中等水平，范围为91至312贝克勒尔/立方米，中位数为175贝克勒尔/立方米。在12所直接连接到强制热风炉供暖系统的实地研究房屋中，以高风扇速度持续运行HRV时，氡减排的中位数（第25 - 75百分位数）为39%（29 - 50）。然而，在测试房屋中，机械排风通风装置的持续运行增加了降压程度和室内氡浓度，在降压 - 5帕时观察到的室内氡浓度高于在 - 10和 - 20帕时观察到的浓度。
在一项针对初始室内氡浓度中等的居住房屋的实地研究中，带有热回收功能的平衡机械通风被证明是一种有效的氡控制策略。提高现有住房存量的能源效率是许多国家的优先事项，在对现有房屋进行能源改造时，纳入平衡机械通风系统可能是一种有效的氡控制选择。
