To avoid health problems, dry flooded homes as quickly as possible, says air quality expert

"There is a strong link between dampness in buildings and asthma, and part of this association is thought to be due to mold growth," says Christine Rogers, an environmental health scientist in the UMass Amherst School of Public Health and Health Sciences. "Mold will grow virtually anywhere if there is enough moisture, whether it’s just dampness or feet of flood waters. If you can dry out the building within 48 hours you can avoid most of the mold growth."

She and her colleague Mike Muilenberg know first-hand what a flood can do to living spaces, as they assessed the mold situation in New Orleans where homes were flooded for weeks after hurricane Katrina. They found that houses with open windows had less mold growth than those that had been closed up tightly.

They recommend opening all windows fully to get a lot of air circulation even if water still needs to be pumped or bailed out by hand. Also, removing all wet household items and putting them outside to dry will help. If safe electrical outlets are available, use a fan to circulate air and evaporate more water.

Above all, if mold is present, Rogers says, "Don’t panic. You can deal with mold yourself if it is a small enough area, such as 10 square feet." Use protective gloves, safety glasses, and an N95 mask during clean-up. Wash non-porous items with detergent and water. Wipe painted surfaces with a dilute bleach solution (one cup of bleach in a gallon of water) and dry them. Resist the temptation to use full strength bleach, because it will be no more effective and could cause its own health problems.

Once mold has formed, removing moldy items should be done carefully to avoid putting mold spores into the air where they can be inhaled. One trick to reduce exposure is to cover or wrap items in a plastic sheet or bag before removal. For drywall, cover the area with something like sticky shelf paper so spores stick to the adhesive and don’t become airborne. Then use a knife or saw to cut the affected piece out. Moldy carpets must be thrown out.

Rogers adds, "Don’t forget to think about who is doing this cleaning. Vulnerable individuals such as children and anyone with asthma or allergies should not do this work!"

Provided by University of Massachusetts Amherst