If you're sensitive to outdoor weather conditions, this app could literally be a lifesaver. OzoneMap maps hazardous ozone levels so you can anticipate dangerous weather before you're stuck in it. If this app worked in all cities and states, it'd be a must-have app for anyone with weak lungs or allergies. Since it's limited to a really small area, you probably won't be able to use it.
This mapping app uses Google Maps and data from ozone monitors in Houston, so it only gives data for the Houston region. For that area, you can see two different color codes that tell you how bad the air quality is and if there are any "ozone events" nearby. You can even see both tracking systems overlaid on each other and see changes from the last four hours with animated playback. The buttons on OzoneMap are difficult to press on smaller screen phones, since they're really tiny. If you can manage to press them, you can learn about the adverse health effects of smog and other great information from the settings menu.
This app offers a great teaching tool and seems to be a really useful idea. If OzoneMap tracked more than just the Houston area, it would be awesome. As of now, it's fine for anyone who lives in Texas, but will be useless to anyone else. Hopefully the researchers behind it can incorporate more cities in the future.