Reductions in Personal PM_(2.5) Exposure via Indoor Air Filtration in the Reducing Air Pollution in Detroit Intervention Study (RAPIDS)

摘要

The Reducing Air Pollution in Detroit Intervention Study (RAPIDS) was designed to evaluate PM_(2.5) exposure reduction and cardiovascular health improvement with indoor air filtration among seniors. In this paper we evaluate the utility of indoor air filtration to reduce indoor PM_(2.5) exposure, discuss whether the reduction of indoor home PM_(2.5) concentrations is sufficient to measurably decrease personal PM_(2.5) exposure, and describe how effectively economical low-efficiency (LE) filters reduce indoor PM_(2.5) concentrations compared to high-efficiency (HE) filters. We enrolled 40 participants from a low-income senior-citizen residential facility in Midtown Detroit, Michigan for a blinded crossover trial randomized to order. Each participant was subjected to three intervention scenarios: HE, LE, or no filter (control) of three consecutive days each, separated by washout periods. Personal, indoor, and ambient PM_(2.5) concentrations and cardiovascular health outcomes were measured daily during each scenario. Indoor PM_(2.5) concentrations were significantly higher for control (17.5±17.0 μg m~(-3)) than for LE (8.4±5.4 μg m~(-3)) and HE (7.0±4.5 μg m~(-3)). The personal PM_(2.5) concentrations were 15.7±13.8 μg m~(-3) for control, 10.9±9.6 μg m~(-3) for LE, and 7.4±4.2 μg m~(-3) for HE, and the distribution of personal PM_(2.5) concentration based on generalized Friedman and post-hoc Wilcoxon signed ranks tests was significantly different for each scenario. These findings indicate that LE filters do significantly reduce indoor PM_(2.5) compared to control, and personal PM_(2.5) exposure are measurably reduced by using either HE or LE indoor air filtration in the home compared to no filtration. To our knowledge, this is the first study to show that both LE and HE indoor filtration systems significantly reduce not only indoor but also personal PM_(2.5) exposure.