Indoor Air Quality

Indoor air quality is generally worse than most people believe, but there are things you can do about it.

Some Quick Facts:

  • Indoor air quality can be worse than that of outdoor air.
  • Problems can arise from moisture, insects, pets, appliances, radon, materials used in household products and furnishings, smoke, and other sources.
  • Effects range from minor annoyances to major health risks.
  • Remedies include ventilation, cleaning, moisture control, inspections, and following manufacturers’ directions when using appliances and products.

Research has shown that the quality of indoor air can be worse than that of outdoor air. Many homes are built or remodeled more tightly, without regard to the factors that assure fresh and healthy indoor air. Our homes today contain many furnishings, appliances and products that can affect indoor air quality.

Signs of indoor air quality problems include:

  • unusual and noticeable odors;
  • stale or stuffy air;
  • a noticeable lack of air movement;
  • dirty or faulty central heating or air-conditioning equipment;
  • damaged flue pipes and chimneys;
  • unvented combustion air sources for fossil-fuel appliances;
  • excessive humidity;
  • the presence of molds and mildew;
  • adverse health reaction after remodeling, weatherizing, bringing in new furniture, using household and hobby products, and moving into a new home; and
  • feeling noticeably healthier outside.

Common Sources of Air Quality Problems

Poor indoor air quality can arise from many sources. At least some of the following contaminants can be found in almost any home:

  • moisture and biological pollutants, such as molds, mildew, dust mites, animal dander, and cockroaches;
  • high humidity levels, inadequate ventilation, and poorly maintained humidifiers and air conditioners;
  • combustion products, including carbon monoxide, from unvented fossil-fuel space heaters, unvented gas stoves and ovens, and back-drafting from furnaces and water heaters;
  • formaldehyde from durable-press draperies and other textiles, particleboard products, such as cabinets and furniture framing, and adhesives;
  • radon, which is a radioactive gas from the soil and rock beneath and around the home’s foundation, groundwater wells, and some building materials;
  • household products and furnishings, such as paints, solvents, air fresheners, hobby supplies, dry-cleaned clothing, aerosol sprays, adhesives, and fabric additives used in carpeting and furniture, which can release volatile organic compounds (VOCs);
  • asbestos, which is found in most homes more than 20 years old. Sources include deteriorating, damaged and disturbed pipe insulation, fire retardant, acoustical material (such as ceiling tiles) and floor tiles;
  • lead from lead-based paint dust, which is created when removing paint by sanding, scraping and burning;
  • particulates from dust and pollen, fireplaces, wood stoves, kerosene heaters and unvented gas space heaters; and
  • tobacco smoke, which produces particulates, combustion products and formaldehyde.

Remedies to Indoor Air Quality Problems

Living Areas

Utility Room

Garage

Kitchen

Bathroom

Bedroom

Basement

  • Ground moisture encourages biological allergens, including mold and mildew.

    Remedy: Inspect for condensation on walls, standing water on the floor, and sewage leaks. To keep the basement dry, prevent outside water from entering indoors by installing roof gutters and downspouts, by not watering close to the foundation, by grading soil away from the home, and by applying waterproofing sealants to the basement's interior walls. To prevent the accumulation of standing water, consider installing a sump pump. If sewage is the source of water intrusion, have drains professionally cleaned. If moisture has no obvious source, install an exhaust fan controlled by humidity levels. Remove mold and mildew. Regularly clean and disinfect the basement floor drain.

  • Radon is an invisible, radioactive gas which poses the risk of lung cancer.

    Remedy: Test your home for radon. Do-it-yourself kits are inexpensive and easy to use. Have an experienced radon contractor mitigate your home if your radon level is 4 picocuries per liter (pCi/L) or higher.

  • Chemicals in hobby products, such as solvents, paint, glue and epoxy, release organic gases.

    Remedy: Follow manufacturers' directions for use, ventilation, application, clean-up, and container storage and disposal. Use outdoors when possible. When using indoors, open a window or use an exhaust fan. Re-seal containers tightly. Clean tools outside or in a well-ventilated area.

Smoke and Carbon Monoxide Detectors

  • Install a smoke detector in each bedroom or in the adjacent hallway.
  • If you have gas or other fossil-fuel appliances in the house, install carbon monoxide detectors in these locations.
  • Combination smoke and carbon monoxide detectors are available.
  • Check the batteries frequently, at least annually.

Amount of Ventilation

If too little outdoor air enters a home, pollutants can accumulate to levels that can pose health and comfort problems. Unless they are built with a special mechanical means of ventilation, homes that are designed and constructed to minimize the amount of outdoor air that can “leak” into and out of the home may have higher pollutant levels than other homes. However, because some weather conditions can drastically reduce the amount of outdoor air that enters a home, pollutants can build up even in homes that are normally considered “leaky.”

How Does Outdoor Air Enter a House?

Outdoor air enters and leaves a house by infiltration, natural ventilation and mechanical ventilation. In a process known as infiltration, outdoor air flows into the house through openings, joints and cracks in walls, floors and ceilings, and around windows and doors. In natural ventilation, air moves through opened windows and doors. Air movement associated with infiltration and natural ventilation is caused by air-temperature differences between the indoors and outdoors, and by wind. Finally, there are a number of mechanical ventilation devices, from outdoor-vented fans that intermittently remove air from a single room, such as the bathroom and kitchen, to air-handling systems that use fans and ductwork to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house. The rate at which outdoor air replaces indoor air is described as the air-exchange rate. When there is little infiltration, natural ventilation or mechanical ventilation, the air-exchange rate is low and pollutant levels can increase.

Indoor Air Pollution and Health

Health effects from indoor air pollutants may be experienced soon after exposure or, possibly years later.

Immediate Effects

Immediate effects may show up after a single exposure, or it may take repeated exposures. These include irritation of the eyes, nose and throat, headaches, dizziness and fatigue. Such immediate effects are usually short-term and treatable. Sometimes, the treatment is simply eliminating the person’s exposure to the source of the pollution, if it can be identified. Symptoms of some diseases, including asthma, hypersensitivity pneumonitis, and humidifier fever, may also show up soon after exposure to some indoor air pollutants.

The likelihood of immediate reactions to indoor air pollutants depends on several factors. Age and pre-existing medical conditions are two important influences. In other cases, whether a person reacts to a pollutant depends on individual sensitivity, which varies tremendously from person to person. Some people can become sensitized to biological pollutants after repeated exposures, and it appears that some people can become sensitized to chemical pollutants, as well.

Certain immediate effects are similar to those from colds and other viral diseases, so it is often difficult to determine if the symptoms are a result of exposure to indoor air pollution. For this reason, it is important to pay attention to the time and place that symptoms occur. If the symptoms fade or go away when a person is away from home, for example, an effort should be made to identify indoor air sources that may be possible causes. Some effects may be made worse by an inadequate supply of outdoor air, or from the heating, cooling or humidity conditions prevalent in the home.

Long-Term Effects

Other health effects may show up years after exposure has occurred, or only after long or repeated periods of exposure. These effects, which include some respiratory diseases, heart disease and cancer, can be severely debilitating or fatal. It is prudent to try to improve the indoor air quality in your home even if symptoms are not noticeable.

While pollutants commonly found in indoor air are responsible for many harmful effects, there is considerable uncertainty about what concentrations or periods of exposure are necessary to produce specific health problems. People also react very differently to exposure to indoor air pollutants. Further research is needed to better understand which health effects occur after exposure to the average pollutant concentrations found in homes, and which occur from the higher concentrations over short periods of time.

In summary, indoor air contaminants can be a source of ill health. Hire our Detroit Home inspectors trained in air quality to perform your next home inspection.