A simple, inexpensive method for gas-phase singlet oxygen generation from sensitizer-impregnated filters: Potential application to bacteria/virus inactivation and pollutant degradation

Airborne infectious diseases such as the new Coronavirus 2019 (COVID-19) pose serious threat to human health. Indoor air pollution is a problem of global environmental concern as well. Singlet oxygen ((1)O(2)) is a reactive oxygen species that plays important role in bacteria/virus inactivation and pollutant degradation. In this study, we found that commercially available filters typically deployed in air purifier and air conditioning units, when impregnated with Rose Bengal (RB) as a (1)O(2) sensitizer, can be used for heterogeneous gas-phase generation of (1)O(2). It was confirmed that irradiation of the RB filter under oxygen gas stream produced (1)O(2), which was measured using furfuryl alcohol trapping method followed by HPLC analysis. It was also observed that the amount of (1)O(2) generated increases as the light intensity increased. Similarly, the sensitizer loading also positively influenced the (1)O(2) generation. The heterogeneous gas-phase generation of (1)O(2) can find potential applications in air purifier and air conditioning units for the purpose of bacteria/virus inactivation and/or pollutant degradation thereby improving indoor air quality.