A Comparative Assessment of the Some Commercially Available Portable Bipolar Air Ionizers Particulate Pollutants (PM2.5, PM10) Removal Efficacies and Potential Byproduct Ozone Emission

Abstract

Indoor air cleaning interventions such as bipolar air ionizers have increased lately due to rampant air pollution and the COVID-19 pandemic. Hitherto, the bipolar air ionizer efficacy against particulate pollutants and byproduct ozone emission has not been fully understood and remained a critical concern. Currently, available diverse and complex methods are insufficient to determine commercially available bipolar air ionizer reliability. The National and International market of bipolar air ionizers is proliferating, while safety standards and information are comparatively limited, in such cases, any misleading information by manufacturers could be detrimental to consumers. To focus on those gaps, the present study comprised five different types of commercially available bipolar air ionizers labeled as BAI 1, BAI2, BAI3, BAI4, and BAI5, which were examined against the most concerned indoor particulate pollutants and potential byproduct ozone. Seven days of consecutive experiments were performed in five acrylic boxes, each box assembled with a testing bipolar ionizer model, calibrated air quality monitor, and particulate pollutant source (incense sticks). Two runs/day for each individual bipolar ionizer were performed for up to seven consecutive days. Overall performance was procured from the daily cumulative arithmetic average. All tested bipolar air ionizers models showed notable, up to 80% particulate matter (PM_2.5 and PM₁₀) removal efficiencies. The highest particulate matter removal was associated with bipolar air ionizers model 4 (PM₁₀ 79.7%, PM_2.5 80.4%) and the minimum with BAI model 5 (PM₁₀ 72.2%, PM_2.5 72.3%). Abnormal ozone emission was not observed with any bipolar air ionizer conduction in this study. Almost negligible elevation in background temperature (0.4 °C) and relative humidity (0.6%) were also observed. In conclusion, bipolar air ionizers could be byproduct ozone-free, indoor particulate matter removal, and low maintenance indoor air cleaning option.