Whether your house is new or old, the air quality inside it could be affecting your health. About 1 in 5 people have respiratory diseases, from asthma and emphysema to lung cancer. Even more suffer from allergies. With the average person spending up to 70% of the time at home, it’s no wonder so many respiratory problems begin there.

Older homes can often be subject to mold infestations because of leaky basements or pipes, and their heating and cooling systems may not do a good job of filtering out dust, mold spores, and other airborne irritants. On the other hand, newer homes built for energy efficiency may be too airtight, holding in harmful chemicals emitted by construction materials or improperly vented heaters and appliances.

What’s ailing you?

The most common indoor air polluters are combustion gases, tobacco smoke, and mold. Carbon monoxide is the major danger from gas or oil furnaces, water heaters, and stoves. This colorless, odorless gas can cause headaches, fatigue, and even death, in extreme cases. Nitrogen dioxide, which can be produced by faulty or improperly vented gas heaters, fireplaces, and other sources, contributes to respiratory diseases and eye problems.

Tobacco smoke is a known carcinogen and irritant, and can aggravate existing respiratory conditions as well as start new ones. It contains toxic gases such as carbon monoxide and formaldehyde, plus many other hazardous chemicals in gas or particle form.

Mold spores adversely affect the lungs, throat, sinuses, and eyes, and can cause fatigue and other troublesome symptoms; toxic black molds may infest houses and require major repairs. Many people with allergies and asthma are at risk from mold spores in their homes.

Other major indoor airborne contaminants come from construction materials. These may include asbestos fibers from old fireproofing or insulation materials; formaldehyde from wood composite materials, fabrics, and old foam insulation; radon gas entering foundation cracks from the decay of radioactive materials in the soil; and volatile organic compounds (VOCs) from paint, glues, carpet fabrics, and petroleum-based cleaning products. All these materials can cause serious health problems in high concentrations or over long exposures.

What can you do?

Homeowners can take many steps to improve indoor air quality and reduce risks. Source control, i.e making your home a no-smoking area, is the best protection against environmental tobacco smoke. Ozone-producing electronic air cleaners have recently been labeled ineffective by consumer research agencies, but HEPA (High Efficiency Particulate Air) filters can help remove smoke particles. They are available for central air conditioning and furnace systems or in stand-alone units for single-room air treatment.

Keeping humidity under control (no more than 50% in summer and 30% in winter) is the most effective way to discourage mold growth. Roof and wall maintenance and proper landscaping also keep excess moisture out of the home, and dehumidifiers can help dry out problem areas such as basements or laundry rooms. Proper venting of furnaces and appliances protects against carbon monoxide and other combustion gases; smoke and carbon monoxide detectors should also be installed (and checked frequently). Supply sufficient ventilation to the home, especially when and where paint or cleaning materials are used. Try to choose building materials and household products that emit the least harmful vapors.