Sources of Pollution per Type

Air
Point source: Ammonia is a pollutant that is commonly released because of industrial processes.

Non-point source: Nitrogen oxides are pollutants that are released into the air due to the combustion of fossil fuels and other human activities such as cars and other vehicles, and agricultural sources.

Water
Point source:
Wastewater treatment plants are a source of pollutants ranging from organic nutrients to chemical agents. This is considered a point source pollutant because the plants have identifiable discharge pipes.

Non-point source:

1. Excess nutrients that can come from industrial or agricultural runoff or even animal wastes and soil gathered along a water's path.
2. Chemical contaminants that enter a body of water through urban runoff and contaminated stormwater.
   

Soil
Point source: Industrial wastes and agricultural pesticides are a source of contaminants that release chemicals into the soil, compromising its health.
Non-point source: Runoff can also affect soil because contaminated groundwater seeps into it. If the runoff carries excessive nutrients, these could also become soil pollutants.


Notes
It can be seen in this comparison that when talking about waste and pollution management, each case need to be considered on an individual basis because a pollutant can come from a non-point source or a point source.