One can come up with a pretty large list of air pollution sources,
especially for the anthropogenic ones. Note that the same processes and activities
can occur on both the natural and anthropogenic lists. On the anthropogenic
side, this means that humans are doing things that are enhancing the "natural"
emission of air pollutants. For example, commerical agriculture could increase
the emissions of gases associated with organic waste decay and the production
of dusts from plowed, dry fields.
Air pollution sinks are the opposite of sources.