Pollution Maps Japan is a free Android app developed by seigo that displays real-time PM2.5 data on maps in Japan. The app provides an hourly update of the amount of particulates PM2.5 in the air in different regions of Japan. The app is specifically designed for users who are concerned about air pollution and want to avoid highly polluted areas.

The app is easy to use and provides a clear and simple interface. The app only provides information in Japanese text, which may be a drawback for non-Japanese users. However, the app's real-time update feature and the ability to zoom in on specific areas of the map make it a valuable tool for users who want to monitor the air quality in their area or plan their travels to avoid highly polluted regions.