If your facility emits Hazardous Air Pollutants (HAP), you are a major or an area source of HAP.
Major sources are medium to large industrial facilities that emit 10 tons per year of any of a single HAP, or 25 tons per year of a combination of HAPs. These sources may release HAPs from equipment leaks, when materials are transferred from one location to another, or during discharge through emission stacks or vents.
Area sources consist of smaller-size facilities that release lesser quantities of HAPs into the air. Area sources emit less than 10 tons per year of a single HAP, and less than 25 tons per year of a combination of HAPs. Though emissions from individual area sources are often relatively small, collectively their emissions can be of concern - particularly where large numbers of sources are located in heavily populated areas. Area sources include, but are not limited to, dry cleaners, gas stations and paint and body shops.