Abstract
For this study, the interior surface of a lobby wall on the 9th floor of a municipal complex was coated with a visible light responsive photocatalyst (VLRP) using a spray gun. The study seeks to verify the indoor environmental improvement effect of a VLRP certified by the Photocatalyst Industry Association of JAPAN (PIAJ). Indoor illuminance, adenosine tri-phosphate (ATP) wiping inspection, and chemical pollutant density were measured in the lobby every few months over a period of approximately two years. The results confirmed that as a result of sunlight incident entering through the south glass window, the illuminance in the lobby met the minimum illuminance of 200 lx, which is the guideline set by the PIAJ for indoor photocatalytic effect for one year. The ATP wiping inspection confirmed that the ATP in the photocatalyst-applied sample group was 64% lower than the average value of that of the photocatalyst-unapplied sample group at a 1% significance level. This indicates that the photocatalytic effect occurred continuously in the environment over a long period of time. Measurements of the chemical pollutant density confirmed that the density of acetaldehyde in the photocatalyst-applied sample group was 40% lower than the average value of that in the photocatalyst-unapplied sample group at a 1% significance level. In conclusion, our findings suggest that the photocatalytic effect on indoor environments can be quantified using statistical analysis of long-term data; however, it is difficult to quantify the photocatalytic effect caused by environmental disturbance factors, such as the introduction of outside air, in the short term.
