Review on scientific studies and commercial indoor air purification devices: Focus on plasma-catalytic technology

Abstract

According to World Health Organization, urban populations spend 90 % of their time in indoor environments. Accentuated by the recent COVID-19 pandemic, this raises important concerns about the quality of the indoor air, which often contains various types of contaminants within three main categories: biological, volatile organic compounds, and particulate matter. Several technologies already exist for removing contaminants from indoor air, such as electrostatic based methods or filtration. Although these technologies are well established, they often target only one or two groups of contaminants. This review focuses on a promising technology: nonthermal plasma combined with catalysts. After an overview of indoor air contaminants, their sources, and the typical methods used for their removal, a highlight is put on the available commercial indoor air purification devices. The latter are rarely described in literature, and the comparison with lab-scale experiments are difficult due to the lack of information and available data from the manufacturers. The limitations of those systems are also discussed. As most of these commercial devices use combinations of various conventional technologies, the last part focuses on the ongoing research on plasma-catalytic systems. The main mechanisms are presented along with recent literature. Finally, some perspectives for its future development are proposed.