The PIAJ mark is a certification mark that the Photocatalysis Industry Association of Japan gives to photocatalyst products of which performance, usage and other features are recognized as appropriate by the association. The association adopted JIS test methods as the yardstick to measure photocatalyst performance, and set specific performance standards through verification and examination from diverse angles. In addition, the association obtained feedback about performance standards from customers and governmental agencies, and established the standards based on the feedback. The PIAJ mark is given to photocatalyst products that meet the performance standards established in this way. Although the mark is currently given to products that are manufactured in Japan, the association plans to make the mark available in Asia and throughout the world in the future.