Investigating the impact of filters on long-term particle concentration measurements in residences (RP-1649)

Filters in heating, ventilation, and air-conditioning (HVAC) systems are the most prevalent air cleaning method in residential environments in North America. This study evaluated the long-term impact of residential filtration systems on indoor particle concentrations by examining concentration measurements from low-cost monitors over one year in twenty homes in Toronto, Ontario, Canada. These concentration results suggested that in general, indoor concentration had a similar seasonal trend as the ambient concentration, and indoor activities (e.g., cooking) elevated indoor particle levels for 40-50% of the time. Further, the impacts of electret filters were examined using a non-electret filter with a minimum efficiency reporting value (MERV) of 8 as the reference point at each home. The mean effectiveness of the filters (MERV 8E = −4.19%, MERV 11E = −0.51%, and MERV 14E = 14.5%) were lower than values found in the literature, most likely due to lower HVAC system runtime in our sample of homes (median = 9.6%). Overall, this filter effectiveness analysis reveals that the real-life filter performance was strongly influenced by system and house characteristics (e.g., system runtime, in-situ efficiency, air change rate, and particle source strength), and thus can be different from modeling and laboratory test results.

采暖通风与空气调节（Heating, Ventilation, and Air-Conditioning，HVAC）系统中的过滤器是北美住宅环境中最主流的空气净化方案。本研究通过分析加拿大安大略省多伦多市20户住宅为期一年的低成本颗粒物监测数据，评估了家用过滤系统对室内颗粒物浓度的长期影响。监测结果显示，整体而言室内颗粒物浓度与环境浓度呈现相似的季节变化趋势，且烹饪等室内活动会使40%~50%的时段内室内颗粒物水平升高。进一步以每户安装的最低效率报告值（Minimum Efficiency Reporting Value，MERV）为8的非驻极体过滤器作为参照基准，本研究分析了驻极体过滤器的过滤效果。本次研究中三类过滤器的平均过滤效率分别为MERV 8E = −4.19%、MERV 11E = −0.51%、MERV 14E = 14.5%，均低于已有文献报道的数值，这一差异大概率源于本研究样本中暖通空调系统的运行时长中位数仅为9.6%，系统运行率偏低。总体而言，本次过滤效率分析表明，实际工况下的过滤器性能会受到系统与住宅特性（如系统运行时长、现场过滤效率、换气次数以及颗粒物源强）的显著影响，因此其实际性能可能与模型模拟及实验室测试结果存在差异。