Skip Global navigation and goto content


Environmental Health

House dust is the most common indoor pollutant and is a major contributor to indoor environment problems, although the public rarely implicates it as the cause of illness. A speck of dust may contain fabric fibers, insulation, skin, animal dander, dust mites, bacteria, cockroach parts, mold spores, food particles and other debris.

Another dust problem that is occasionally encountered is a phenomenon known as “sooting” that appears as an unexplained dark mark or film on an interior wall, carpet or furniture surface. Unlike house dust, sooting is caused by a carbon-generating source and is usually created during a combustion process like the indoor use of tobacco, candles and gas appliances. Sooting can look like and is frequently mistaken to be mold.

House dust is a common cause of year-round runny or stuffy nose, itchy, watery eyes and sneezing symptoms. Dust can also make people with asthma experience wheezing, coughing and shortness of breath. Animal dander, house dust mites and cockroaches are the most common substances in dust that cause these symptoms. Health effects can occur even though there are no visible signs of dust. While sooting can cause significant aesthetic problems, it is not normally considered to be a health threat.

Solving House Dust and Sooting Problems
Many materials in house dust can’t be removed by typical housekeeping methods. For example, no matter how vigorously one dusts or vacuums, the number of dust mites present deep within carpeting, pillows, and mattresses will not be reduced. Vigorous dusting, sweeping and vacuuming can put more dust into the air making symptoms worse. Use of a vacuum with HEPA filtration and dusting with a damp or oiled cloth is recommended for reducing house dust. If the dust-sensitive person must clean, they should wear a mask. The best approach to resolving house dust-related health problems is to consult with an allergist to identify what the affected person is allergic to and then eliminate those allergen contributors from the indoor environment.

It is extremely difficult for a homeowner to resolve a sooting problem without professional help. Resolution of these problems typically involves diagnostic tests of the house, HVAC system measurements, infrared measurements of wall insulation and air current studies

Does cleaning the ductwork in the home reduce indoor air contamination?
If air ducts are “dirty” and you want to remove the debris, duct cleaning may be appropriate. If your goal is to use duct cleaning to solve an indoor air-related health problem, duct cleaning is unlikely to be effective. An excellent discussion of this issue can be found in the EPA document, Should You Have the Air Ducts In Your Home Cleaned?.

Do I need an air cleaner, what kind should I buy?
The United States Environmental Protection Agency (EPA) has researched the issue of air filters and duct cleaning and recommends consumers refer to the following publications before purchasing a device:

Some allergens are small and can float in the air for a long time while others are large and rapidly fall to the floor or other surfaces. Air filters can only remove the allergens if they are suspended in air. If the allergen you are reacting to is a in the air, a filter may be able to remove allergen and alleviate your symptoms. If the allergen falls rapidly, the air filter will be unable remove the particle. Providing adequate ventilation to dilute the allergen concentration is usually the most effective method.

*Note: This page contains materials in the Portable Document Format (PDF). The free Adobe Acrobat Reader may be required to view these files.