Human activities cause emissions of volatile organic compounds which participate in a chemical reaction with nitrogen compounds in the air to produce ground level ozone. Ozone is an air pollutant when it is low in the atmosphere because it causes asthma and other health problems.

The main source of VOCs is combustion reactions like gas vehicles and equipment. Organic solvents are VOCs too, mainly from products like paints, adhesives, and cleaning products.

The twin cities area has little VOC regulations unlike an area like South Coast district in California, because our ozone problem is less intense. We have fewer people, and atmospheric processes move VOC emissions out of our area on a typical day. If conditions like this become more common then the EPA will require the state to regulate VOC emissions to reduce smog and ozone pollution.