For example, in the city of Philadelphia, O'Brien Cogeneration operates two separate plants that emit a total of approximately 17,000 pounds per year of air pollutants, making O'Brien a medium size industrial emitter in that city; in Philadelphia a total of six discrete chemical air pollutants are recognised, and a total of twelve distinct stack sources are present.
To provide an example, in the city of Philadelphia, O'Brien Cogeneration operates two separate facilities that release around 17,000 pounds of air pollutants annually, making O'Brien a medium-sized industrial polluter in that city; in Philadelphia, six distinct chemical air pollutants are acknowledged, and twelve separate sources of emissions are identified.