Effectiveness of TiO2-coated stainless steel mesh reactor with UV-LED on the reduction of cigarette smoke pollutants in a closed room

Indoor air pollution, particularly from cigarette smoke, contains harmful Total Volatile Organic Compounds (TVOC) that poses significant health risks. This study aims to evaluate the effectiveness of a Photocatalytic Oxidation (PCO)-based air purification system utilizing a Titanium Dioxide (TiO2)-coated stainless steel mesh reactor and Ultraviolet Light Emitting Diode (UV-LED) sources at 365 nm and 390 nm wavelengths. The methodology involved synthesizing TiO2 sol and immobilizing it onto a stainless steel 304 mesh substrate via a dip-coating technique. Performance testing was conducted in a closed room (volume approx. 136 m³) where smoke from two cigarettes was introduced as the pollutant source. TVOC concentrations were monitored every 5 minutes at five distinct measurement points (center and corners) over a 2-hour period to assess spatial distribution and degradation performance. The results demonstrated that the PCO system with a 365 nm UV-LED reduced the average TVOC concentration from 0.78 ppm to 0.33 ppm, achieving a reduction rate of 57.69%. Meanwhile, the 390 nm UV-LED system decreased the concentration from 0.86 ppm to 0.32 ppm, corresponding to a 62.8% reduction. While the difference in UV-LED wavelength did not significantly alter the photocatalytic performance, light intensity and initial pollutant concentration were found to influence the degradation rate. Overall, the TiO2-coated stainless steel mesh reactor proved to be an effective solution for reducing indoor cigarette smoke pollutants.