The federal Clean Air Act (CAA), which was significantly amended in the 1990s, requires the U.S. Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards (NAAQS) for six principal pollutants, called "criteria pollutants," that are common in outdoor air, considered harmful to public health and the environment, and that come from numerous and diverse sources. These pollutants include: Ozone (O3), Nitrogen dioxide (NO2), Carbon monoxide (CO), Lead (Pb), Sulfur dioxide (SO2), and Particulate matter (PM).

Generators of these air pollutants are classified into four main types: stationary sources, area sources, non-road mobile sources, and on-road mobile sources. Of the six monitored pollutants, emissions resulting from transportation-related, on-road mobile sources include O3, PM, NO2, and CO2, which mainly come from vehicles on the roadways such as cars, trucks, and buses.

​

Preventing and relieving these mobile sources are the primary goals of Tri-County's technical and outreach initiatives, including local road and transit projects planned in the Transportation Improvement Program (TIP) and partnerships with community organizations to achieve cleaner air through public education.

​

From 2017-2019, Tri-County staffed and coordinated the Greater Lansing Area Clean Cities, a coalition of stakeholders working locally to implement alternative and renewable fuels, idle reduction measures, fuel economy improvements, and emerging transportation technologies. The coalition has since expanded to become Michigan Clean Cities and continues to be an advocate and partner for local efforts.

Most recently, Tri-County has partnered with the Capital Area Transportation Authority (CATA) to build support for commute alternatives, including public transit and clean commute options, as a primary tool to reduce regional emissions and address congestion. Learn how you can participate below!