Vector Health is a Google Map that shows the sources of pollution in the Los Angeles area. There are in fact so many sources of pollution in LA that you might need to view this map in Chrome (this map is in need of a marker clustering system and will severely test most browsers).
Users of the map can view pollution sources by type (including airports, oil fields, refineries etc). It is also possible to view the locations of schools, hospitals and parks on the map if you want to find how close they are to a source of pollution. Source