Indoor Mold Pervasive in U.S. Homes, According to Study Presented at Allergy and Asthma Meeting

DENVER -- A new study has found that mold is pervasive in homes nationwide, thriving in household sites that are not routinely cleaned and disinfected. The study, which also measured the home resident's understanding of the problem, found that most people underestimated the presence of mold in their homes. Mold was found in 100 percent of homes tested.

Results of the University of Arizona study were presented today at the 60th annual meeting of the American Academy of Allergy, Asthma and Immunology (AAAAI).

"Mold is flourishing in places that people tend not to think about when cleaning, as well as in more obvious places," said Dr. Reynolds. "If the mold is not destroyed by cleaning and disinfecting, it will continue to grow and exposure levels will mount."

In the seven-state study, mold was most prevalent on windowsills, where it was found in 88 percent of the homes studied. Other common household sites with mold were refrigerator seals (83 percent of households), the area beneath the kitchen sink (83 percent) and air vents (82 percent).

Mold was also found at high levels at sites where people tend to concentrate cleaning efforts such as the bathroom. Mold was found growing in 49 percent of shower grouts and 50 percent of the walls above the showers -- even though most study participants (73 percent) realized that mold was most likely to be a problem in the moist environment of a bathroom.

Although 96 percent of study respondents realized that mold could cause or aggravate health problems, the study also showed that they tended to think household mold was somebody else's problem. Only 17 percent of participants felt they had a mold problem in their own home, even though mold was found in 100 percent of the homes tested.

The study did not seek to determine the incidence of Stachybotrys -- commonly referred to as "hidden," "toxic" or "black" mold in news reports -- which generally grows behind walls, under stairs, and beneath ceiling tiles. It is suspected that exposure to this toxic mold is linked to debilitating symptoms such as lung tissue damage and memory loss. If the presence of Stachybotrys is suspected, the home should be checked immediately by a trained professional.

"People need to realize that mold exists in their home no matter how well they think they clean," Dr. Reynolds said. "The greater problem today is not the scary, toxic molds you read about. Fortunately, black mold problems are rare. Most of us have more common, allergy-causing molds growing in our homes, which can be destroyed with regular cleaning with disinfectants."

Mold, a fungus that occurs naturally in the environment, becomes a problem when it colonizes in indoor environments and starts to grow. Moisture, such as water leaks or condensation, feeds mold growth, and mold spreads to new areas by releasing microscopic spores. These spores can aggravate symptoms of both allergies and asthma. In fact, mold spores are suspected in the tripling of the asthma rate in the past 20 years and have been cited by a 1999 Mayo Clinic study for nearly all of the chronic sinus infections afflicting 37 million Americans.

"If mold spores are deposited in the lining of the nose, they can cause hay fever-like symptoms, including sneezing, itching and congestion," said Bill McLin, executive director, AAFA. "If these spores reach the lungs, they have the potential to trigger asthma."

According to AAFA, there are steps people can take to help reduce mold growth throughout the home:

* Keep Humidity below 40 percent

* Use an air conditioner or dehumidifier during humid months

* Make sure your home has adequate ventilation

* Dry any water leak within 24 hours

* Do not carpet bathrooms and basements

* Get rid of mold materials immediately, once they're found

* Clean hard surfaces regularly with products certified to kill mold.

Allergy or asthma sufferers should ask nonsensitive people to apply

cleaning products.

It is important that mold be killed and removed from the surface. Soap and water or detergents remove only mold stains, but can leave mold spores behind. Those remaining spores, which are often invisible to the naked eye, are then able to re-colonize. Because of the potential sensitivities of allergy and asthma sufferers to cleaning products, cleaning should be done by nonsensitive individuals and the area should be allowed to ventilate before reentry. Always read and follow all precautions and usage directions before using cleaning products.

The study was conducted in a total of 160 homes across the U.S. Samples were collected from Chicago, Tampa, Atlanta, Tucson, San Francisco, New York and Dallas. Surface samples from the homes were examined microscopically for a range of different molds. Study samples were taken from accessible areas; therefore the study does not assess the prevalence of hidden mold. Homes in Dallas and New York had the highest rates of mold-infested sites, while Tampa households had the lowest rate. The study was funded by an educational grant from The Clorox Company.

Source: The Clorox Company