Nonpoint Source Pollution (NPS)
NPS is problematic from the perspective of control and due to their transport once released into the environment, and the general opinion is that these characteristics make it difficult to regulate NPS pollution.
NPS pollution can take several forms. These include: nutrient runoff; toxic chemicals; fertilizers; pesticides; and sediment.
Air pollution can be characterized both as point source (see, Point Source Pollution) and nonpoint source pollution. The emission of air pollution from, for example, an industrial smoke stack is point source pollution. However, once that pollution enters the atmosphere, it can be transported long distances, and the origins of the emission are no longer discernible. In this case, transported air pollution is referred to as NSP pollution.
In the US, the control of NPS pollution is addressed by the Clean Water Act (CWA) and the Coastal Zone Management Act.