The United States Environmental Protection Agency (EPA) defines point source pollution as any contaminant that enters the environment from an easily identified and confined place.
The classic image of a factory smokestack belching smoke and fumes into the air or an industrial discharge pipe pouring contaminated liquid into a river are some great examples of point source releases to the environment.
Nonpoint source (NPS) pollution is pollution resulting from many diffuse sources, in direct contrast to point source pollution which results from a single source.
Relative humidity<span> (</span>RH<span>) is the ratio of the </span>partial pressure<span> of water vapor to the </span>equilibrium vapor pressure<span> of water at a given temperature. Relative humidity depends on temperature and the pressure of the system of interest. It requires less water vapor to attain high relative humidity at low temperatures; more water vapor is required to attain high relative humidity in warm or hot air.</span>
