If you are sneezing, coughing, wheezing or have a headache that just won't go away, your house may be making you sick.

Cleaning the place from top to bottom won't make the problem go away. In fact, some of the household products you use to get the bathtub to sparkle or the kitchen floor to shine may cause eye, nose and throat irritation plus headaches in the short term.

In some cases, prolonged exposure to these cleaning agents can permanently damage your central nervous system, your liver and kidneys.

Many sources of indoor pollution are less well known, but health problems have been traced to mold spores caused by excessive moisture in walls, carbon monoxide from fireplaces and faulty furnaces, and products that are used to kill insects and pests.

In fact, the health risks from pollution within homes and offices may be greater than from exposure to outdoor pollution in our largest cities. A Mayo Clinic report has suggested that indoor contaminants contributed to the doubling of asthma rates among children between 1964 and 1983.

Experimental houses are being built to test techniques and products to reduce health risks. Research is being conducted at universities and by government environmental agencies to identify causes and solutions.

Indoor pollution can be costly to deal with.

Toxic mold, which has received a lot of press lately, is very costly to remediate, sometimes costing homeowners as much as to cure as the house cost to purchase.

But there are other problems.

Say you buy wall-to-wall carpeting. Carpeting contains a variety of volatile organic compounds, or VOCs, from adhesives, resins and preservatives used in its manufacture. The level of VOCs in carpeting is not very high, but if they make you dizzy or nauseous, they are a problem.

The carpeting industry has recognized the problem, and has reduced the use of formaldehyde in adhesives because of public concerns. Some smaller manufacturers are actually making area rugs of natural seaweed, while others are using nontoxic dyes.

Still, just testing for VOCs costs money - $500 to $1,000. To install an air exchanger and ventilation system in an older house will cost $5,000 to $10,000, while air-filtration systems for a single room cost between $100 and $200 and $1,000 to $5,000 for whole-house filtration units.

Building a house with such a system costs less, and this is why most of the field testing for ways to reduce indoor pollution is being done in new construction.

The American Lung Association has built a number of “healthy houses” to showcase modern technologies to be used in dealing with indoor pollution.

What is a healthy house? It is a dwelling built to help reduce exposure to a range of indoor pollutants: from radon and VOCs to common allergens, such as dust mites and molds that thrive in buildings prone to dampness and high humidity.

Healthy-house construction consists of systems and components that are both interrelated and interdependent. These include high energy efficiency through insulation, specialized windows and landscaping that captures natural energy.

Construction materials are recycled, environmentally benign and non-allergic.

To understand the issue, realize that Americans spend 90 percent of their lives indoors -- 65 percent at home and 25 percent at work, although the at-home percentage is increasing with the growth of home offices.

According to the National Association of Home Builders, 71 percent of respondents cited indoor air quality as an important environmental issue, just behind energy efficiency (80 percent).

To understand what makes a house healthy, you need to know what makes a house sick.

Here are some sources of pollutants identified by the American Lung Association:

• Respirable particles - fireplaces, woodstoves and kerosene heaters.
• Organic pollutants - household products including paints and paint strippers, wood preservatives, aerosol sprays, cleansers and disinfectants.
• Formaldehyde - hardwood plywood wall paneling, particleboard and fiberboard, urea-formaldehyde foam insulation (now banned), durable press drapes, other textiles and glues.
• Pesticides - insecticides and termite treatments; lawn and garden products that are tracked into the house.
• Lead - automobile exhausts seeping in from garages, sanding or burning lead-based paint, lead solder (now banned in plumbing).
• Asbestos - deteriorating insulation and fireproofing.
• Biological pollutants - wet or moist walls, ceilings and carpets; poorly maintained humidifiers, dehumidifiers and air conditioners; household pets.
• Carbon monoxide and nitrous dioxide - unvented kerosene and gas heaters; leaking chimneys and furnaces; down-drafting from wood stoves and fireplaces; all gas stoves.
• Radon - from earth, uranium and rock beneath some homes; well water and building materials.

Published: June 20, 2002

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Al Heavens writes about real estate and home repair and improvement. He is the author of What No One Ever Tells You About Renovating Your Home: Real-Life Advice For Hassle-free, Cost-Effective Remodeling.