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Indoor Exposures

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When most people talk about pollution, they are generally referring to the outdoor environment. In Missoula County, aside from the seasonal forest fires we tend to experience, we are lucky to have few problems with outdoor air pollution. But what many don’t realize is that indoor air pollution, in our homes and workplaces, is very common, and it can be extremely dangerous.

The Environmental Protection Agency (EPA) defines indoor air pollution as chemical, physical or biological contaminants in the breathable air inside a habitable structure or conveyance, such as in homes, schools, offices and vehicles.  

The Agency says that most Americans spend about 90 percent of their time indoors, where pollutant levels may be 2-5 times higher, and occasionally 100 times higher, than outdoors. 

As home owners, the first step is to understand—and eliminate—the sources of indoor air pollution. Some of the top issues include:


Molds are fungi that can grow and prosper in warm, damp environments. They spread and multiply through their spores, and there are thousands of varieties. Those sensitive to mold may experience nasal stuffiness, eye irritation, wheezing, or skin irritation. More severe reactions include fever and shortness of breath, and those with chronic lung illnesses may develop mold infections in their lungs.


Radon is a naturally occurring radioactive gas that may seep into your home from the soil or groundwater. Some homes in Missoula County have been found to have elevated radon levels, and it is recommended that homes are tested for radon to determine if mitigation is needed.  Test kits can be purchased at the Environmental Health Department located on the 2nd floor of the City-County Health Department building, 301 W Alder. For more information visit Missoula Radon.

Secondhand smoke

Secondhand smoke  is a mixture of the smoke given off by the burning end of a cigarette, pipe, or cigar, and the smoke exhaled by smokers. Secondhand smoke is also called environmental tobacco smoke (ETS) and exposure to secondhand smoke is sometimes called involuntary or passive smoking. Secondhand smoke contains more than 4,000 substances, several of which are known to cause cancer in humans or animals.


Lead is a toxic metal that was used for many years in products found in and around our homes. Lead also can be emitted into the air from motor vehicles and industrial sources and lead can enter drinking water from plumbing materials. Lead may cause a range of health effects, from behavioral problems and learning disabilities, to seizures and death. Children six years old and under are most at risk.


Asbestos is the name given to a number of naturally occurring fibrous minerals with high tensile strength, the ability to be woven, and resistance to heat and most chemicals. Because of these properties, asbestos fibers have been used in a wide range of manufactured goods, including roofing shingles, ceiling and floor tiles, paper and cement products, textiles, coatings, and friction products such as automobile clutch, brake and transmission parts.