Some Facts about Air Quality in the Home
- 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.
- 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
- 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 & Biological Pollutants: Mold, mildew, dust mites, pet dander, cockroaches.
- Ventilation Issues: High humidity, poor airflow, and neglected humidifiers or air conditioners.
- Combustion Products: Carbon monoxide from unvented heaters, gas stoves, ovens, and back-drafting from furnaces or water heaters.
- Formaldehyde: Found in draperies, particleboard furniture, and adhesives.
- Radon: A radioactive gas from soil, groundwater, or some building materials.
- Household Products & Furnishings: VOCs released by paints, solvents, air fresheners, dry-cleaned clothing, and aerosol sprays.
- Asbestos: Present in older homes in pipe insulation, ceiling tiles, and floor tiles.
- Lead: Dust from lead-based paint when disturbed by sanding or scraping.
- Particulates: Emitted by dust, pollen, wood stoves, kerosene heaters, and fireplaces.
- Tobacco Smoke: Releases particulates, formaldehyde, and combustion byproducts.
Remedies to Indoor Air Quality Problems
Living Areas
- Formaldehyde: Choose low-emission furniture, ventilate after setup.
- Carpets: Dry water-damaged carpets or replace them; vacuum regularly.
- Asbestos Tiles: Inspect often, call professionals for damage.
- Moisture: Use dehumidifiers, exhaust fans; clean mold with bleach.
- Fireplace: Open flue, install carbon monoxide detectors.
- Pets/Dust Mites: Clean regularly, wash bedding in hot water.
- Tobacco Smoke: No smoking indoors.
Kitchen
- Cleaners: Use non-toxic, non-aerosol products.
- Gas Stoves: Clean, maintain, and ventilate during use.
Bathroom
- Personal Products: Choose low-odor, non-aerosol types and ventilate.
- Air Fresheners: Use natural options, ventilate.
Bedroom
- Humidifiers: Clean daily to prevent mold.
- Moths: Store repellents in sealed containers.
- Dry Cleaning: Air out clothes; opt for green cleaning methods.
Utility Room
- Dryers: Clean lint traps, vent outdoors.
- Furnaces/Water Heaters: Get yearly inspections.
- Asbestos: Don’t disturb; call experts for removal.
Basement
- Moisture/Mold: Address leaks, use sump pumps, clean visible mold.
- Radon: Test for radon and mitigate if needed.
- Hobby Chemicals: Ventilate well or use outdoors.
Garage
- Emissions: Never idle vehicles or tools indoors.
- Chemicals: Store safely, use green alternatives.
Safety Tips
- Install smoke and carbon monoxide detectors in key areas.
- Open windows and use exhaust fans regularly for ventilation.
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.
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 an InterNACHI inspector trained in air quality to perform your next home inspection.
