Any air contamination source the emissions of which alone or in combination with others can be expected to have an adverse effect on ambient air quality during an air pollution episode. This category includes, but is not limited to: fossil fuel burning equipment with a maximum operating heat input exceeding 200 million Btu per hour; processes and exhaust or ventilating systems with particulate emissions in excess of 100 lb/hr; incinerators with a refuse charging capacity of 2,000 lb/hr or more.