The Biggest Threats to a Healthy Home

Be on the lookout for signs of a water leak or condensation: water stains that get bigger over time, musty odors, continually damp carpet, or beads of water or puddles on hard surfaces. When you do have water damage, thoroughly clean and dry carpets and building materials within 24 hours if possible, and consider replacing waterlogged items to eliminate the risk of mold.

If you suspect a problem (or better yet, as preventive maintenance), hire professionals to inspect for damaged shingles and siding, poorly connected plumbing and leaky pipes, and other moisture problems, such as inadequate vapor barriers. Mitigate the issues as soon as possible.

The EPA considers bacteria, molds, mildew, viruses, animal dander, cat saliva, house dust, mites, cockroaches and pollen all biological contaminants. Excessive moisture creates breeding grounds for these contaminants, so ventilate adequately and keep relative humidity between 30 percent and 50 percent to prevent condensation on building materials.

Regular household cleaning and maintenance go a long way toward limiting exposure. Change filters and have heating and cooling equipment cleaned and checked regularly by a professional; these systems can become not only breeding grounds for mold and other biological contaminants but also superhighways for dispersing them throughout the home.

If these methods don't suffice, an indoor air-cleaning device may help an affected area. However, avoid ozone generators that are sold as air cleaners. The EPA warns: "Whether in its pure form or mixed with other chemicals, ozone can be harmful to health."

Basements can be a particular trouble zone. The EPA recommends you clean and disinfect basement drains regularly and that you not finish a basement unless all moisture issues are abated.

No one knows exactly how many homes have mold behind the walls, but the best current estimate is about 70 percent, according to Ronald E. Gots, M.D., Ph.D., of the International Center for Toxicology and Medicine. The EPA and World Health Organization state that some molds have the potential to cause health problems, particularly allergic reactions and asthma, in people who are susceptible.

To get rid of mold, scrub surfaces with detergent, preferably a water-based, VOC-free product like Microbloc dsinfx as opposed to bleach. Replace porous materials such as ceiling tile and carpet with non-porous or mold-resistant ones. If the mold damage covers more than 10 square feet, the EPA recommends hiring a professional.

Most important: Fix the underlying issue. "Mold is not the problem. It's an indicator of a moisture problem," says Kurt Salomon, president of the American Society of Home Inspectors. "You can get rid of the mold but if you don't address the leaky pipes, high humidity and water intrusion, the mold will come back."

To cut down on household dust, declutter, reduce paper, eliminate smoking and regularly change or clean the furnace and air conditioner filters. Also, park your shoes at the door — two-thirds of all dust contaminants are tracked into the home from the outside.

To minimize the amount of dust kicked up during cleaning — especially if you are concerned about lead dust — wipe down floors with a damp mop, dust with a damp cloth and clean surfaces with a vacuum cleaner with a HEPA filter.

You probably don't need to have your air ducts cleaned unless there is mold growing inside, they are infested with vermin or they are excessively clogged with debris. Duct cleaning costs between $400 and $1,000. The National Air Duct Cleaners Association cautions consumers against air duct cleaning companies that make sweeping claims about health benefits of their services and/or are not upfront about fees.