Home particulate concentration reduction during high efficiency particulate air (HEPA) filter use

Abstract

Background: Periods of high particulate air pollution have been associated with increased respiratory symptoms. Whether a stand-alone in home high efficiency particulate air (HEPA) filter reduces the air pollution burden in the home is unknown. Methods: A randomized, blinded, cross-over, controlled trial enrolling former smokers age 40 and older with respiratory symptoms during periods of high air pollution in the Salt Lake Valley, Utah is still enrolling. Patients had a HEPA filter in their sleeping zone for 6 weeks and a low-efficiency air filter for 6 weeks. Symptom scores, spirometry, labs, activity and sleep data, and filter weights were collected during the study period. Each participant had two low-cost air quality monitors (purpleair.com) installed in their home during the study period - one outside the home and one inside the home. Differences between the indoor and outdoor air monitor during the 12-week study period were collected and compared. Results: Here we report the first season data for the paired indoor-outdoor monitors of this study. 24 patients were enrolled and completed the study with adequate air monitor data during the study period. Figure 1 shows the median particulate concentration for the difference between the indoor and outdoor air monitors during the HEPA filter and low efficiency filter periods for the study participants. Median particulate concentration was reduced for all particulate sizes, PM1.0, PM2.5, and PM10, during the period of HEPA filter vs. low-efficiency filter (P = 0.027, 0.022, and 0.006, respectively). Conclusion: HEPA filters significantly reduce the particulate concentration in the sleeping zone during periods of air pollution.