Skip to main content

Air Pollutants

  • Most Hazardous Air Pollutants (HAPs) are also Toxic Air Contaminants or TACs, however there are only 188 HAPs while Michigan has over 1,200 TACs regulated under our TAC rules. Our staff consider what level of TACs may be emitted from industrial processes when those process are getting an air permit. There are health-based screening levels that are looked at and compared with what pollutants a company is asking to emit into the outdoor or ambient air. These screening levels are designed to be protective of sensitive groups, such as the very young, the elderly and those with existing conditions.

    For more questions and answers about TACs, check out our Michigan Air Toxics Rules Overview

  • The Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) for six common air pollutants (also known as "criteria air pollutants"); Particulate Matter (PM), Volatile Organic Compounds (VOCs), Carbon Monoxide (CO) Oxides of Nitrogen (NOx), Sulfur dioxide (SO2) and Lead. These pollutants are found all over the U.S. They can harm your health and the environment, and cause property damage. More specific information on these pollutants can be found on our State Implementation Plan webpage.

  • Hazardous Air Pollutants or HAPs are those pollutants identified by the U.S. Environmental Protection Agency (USEPA) known or suspected to cause cancer or other serious health effects. USEPA has and continues to promulgate standards to reduce the release of these 188 HAPS into the environment. The standards are referred to as the National Emission Standards for Hazardous Air Pollutants or NESHAPs. They require the use of Maximum Achievable Control Technology (MACT) to reduce the particular HAP emission. 

    For additional information about HAPs and the NESHAPs visit the National Air Toxics Assessment website.