For background information, start in Google but don't stay there.
The library database, Credo Reference Online will naturally narrow your search, improve your research, increase your comfort in academic research and support your critical thinking. Credo is our academic Google! Try the Mirror Effect.
air pollution (How many of these sites can pass the CRAAP test?)
As an interdisciplinary researcher, when trying to find scholarly articles you should consider how the questions you want to answer have been approached by existing disciplines such as philosophy, anthropology, sociology, literary studies, ethics and policy studies, film and media studies, etc. Thus an important starting point should be subject-specific databases.
Need an overview? Opposing Viewpoints in Context. (Air pollution control)