Mold isn't all bad. It's key in a compost pile, for example, where it helps breaks down organic matter into nutrients usable by plants. In our homes, however, mold is fungi non grata—and it’s far more worrisome than a few unsightly black patches would lead you to believe.
In fact, one study found that children living in homes with water damage and visible mold were more 49 percent more likely to have asthma and 39 percent more likely to have nasal allergies. (Here are 6 alarming reasons why your allergies are getting worse.) They also had more wheezing problems than children in less-moldy homes. Children, along with the elderly and those with compromised immune systems such as cancer patients, are at greater risk for experiencing mold-related health symptoms.