Narrator: This is Science Today. Building dampness and mold raises the risk of a variety of respiratory and asthma-related health problems by up to 30 to 50 percent. Those were the findings of a Lawrence Berkeley National Laboratory analysis. William Fisk, acting director of the Berkeley Lab's Environmental Energy Technologies Division, co-wrote the paper.

Fisk: There's been a growing concern and interest in moisture problems and mold in buildings in the United States and throughout the world. There's long been some evidence of dampness in buildings being associated with various health effects, but it hadn't really been reviewed systematically.

Narrator: The latest analysis is based on a 2004 study that Fisk conducted, which found that excessive indoor dampness was a public health problem, but that study did not offer an overall quantitative assessment.

Fisk: The key point is that dampness and mold are an important public health problem. It's one that we can reduce. The key is to do a better job and to design construction, operation and maintenance of buildings. So, very practical ways of reducing this public health problem.

Narrator: For Science Today, I'm Larissa Branin.