Air Quality

Do you know what’s in the air you breathe? Air quality has a great impact on our health. Air pollutants − indoor and out − can damage lung tissue and increase your risk for allergies, asthma, chronic bronchitis, and other respiratory diseases. Using energy-efficient vehicles, carpooling, and combining errands are just a few ways you can collectively make a difference in air quality.

EPA's National Ambient Air Quality Standards

The EPA's National Ambient Air Quality Standards limits several air pollutants that have documented effects on public health:

  • Carbon Monoxide
  • Lead
  • Nitrogen Dioxide
  • Oxone
  • Sulfur Dioxide
  • Inhalable Particulates
  • Fine Inhalable Particulates


Asbestos is a naturally occurring mineral fiber that — because of its unique properties like fire resistance, high tensile strength, poor heat and electric conductivity and imperiousness to chemical attack — was used in a number of different materials. It is estimated that there have been more than 3,000 different commercial applications of asbestos containing materials. The most common utilization was in building construction and the manufacture of automobile brake pads, a process that continued until the 1970s.


Radon is an odorless, colorless and tasteless radioactive gas that occurs naturally when uranium deposits within the Earth decay. Outdoors, radon does not pose a health hazard because it is quickly diluted in the air, but it can become problematic indoors by seeping through cracks and gaps in foundations, drains or other openings. Becoming more concentrated in an indoor setting, this gas build-up may lead to health risks.


Mold may be found both indoor and outdoor in varying concentrations, depending upon where you live and the environmental conditions. Moisture control is the key to minimizing the growth of mold. While the Division of Environmental Health and Protection does not perform indoor air testing or assist with mold cleanup, you may report a concern for mold growth within St. Charles County buildings by contacting the municipality in which you live or the County's Community Development department.
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Open Burning

The St. Louis Metropolitan Area remains under restrictive open burning regulations because of unhealthful levels of ground-level ozone pollution (smog). In the St. Louis Ozone Non-attainment Area (which includes St. Charles County), open burning is banned during the hot summer months. The by-products of open burning are hydrocarbons, which can form smog in certain climatic conditions. Some hydrocarbons are also known carcinogens. A permit may not be necessary for the type and volume of open burning you plan, depending on your location. For information, permits, or complaints, please call the Department of Community Development at 636-949-7345, your local fire protection district or the Department of Natural Resources’ St. Louis Regional Office at 314-416-2960.

Vehicle Emissions 

Ground-level ozone, or smog, is harmful to human health and regulated by the Federal Clean Air Act. Missouri has ozone levels above the national health-based standards, and as a result, we are required to implement vehicle emissions inspection programs.

A clean air program was first implemented in the St. Louis Metropolitan Area in 2000 as part of the state’s overall strategy to reduce ground-level ozone in the area. Visit the Gateway Vehicle Inspection Program website to learn more, or contact the Missouri Department of Natural Resources at 1-800-361-4827.

Ride Finders

By sharing a ride to work or school, you can improve the quality of our air. Learn more about carpooling and discover how to save 7,500 miles of wear and tear on your car and about $900 a year on gas and operating costs.

MO Rides

If you live in St. Charles County and need a ride to meetings or appointments in Franklin, Lincoln, Montgomery, Warren or St. Charles counties, the MO Rides referral service may be able to help. To make an appointment, please call (636) 359-4656 during business hours.