Combined Intervention Removes More Aerosols From the Environment—A Quantitative Assessment

Aerosols such as dust, pollen, smoke, soot, or viruses in our environment can significantly affect air quality, impacting climate and health. For example, virus transmission through aerosols is an important mode of spread for certain respiratory viruses, including the SARS-CoV-2 virus responsible for the COVID-19 pandemic. Numerous measures were proposed for mitigating the harmful effects of aerosol transmission on health. Though these measures are effective, they were found to have intrinsic disadvantages. Combined intervention is promising, with progress being made in combining different technologies to enhance aerosol removal and improve indoor air quality. While the combined or layered intervention was previously proposed as a rational measure to overcome some of the disadvantages associated with individual approaches, there is a lack of availability of quantitative experimental data for at least some of the many possible combinations from the viewpoint of the number of aerosol particles removed from the surrounding environment. This study assesses the efficacy of one possible layered approach on aerosol removal. Particle flow visualization was employed to quantitatively investigate the combined effect of two measures—filtration and air ionization—on aerosol removal. The results of particle counting showed that for the experimental configuration studied, the combined intervention had a synergistic effect and removed 15%–85% more aerosol particles from the environment compared to a single intervention (filtration) in the same duration. It is observed that combined approaches demonstrate the potential to address the disadvantages of the constituent approaches; for example, in this case, effective aerosol removal was shown to be a possibility even with a medium-quality filter (which is economical and accessible) and a weak ionizer (with low ozone generation).