Dear Vanessa,

My house is in a low-lying area near a lake, and I’m worried about mold prevention. My children have asthma, and in the summer their allergies seem to get worse inside. I don’t want to just blindly pay a mold removal company if that’s not the problem, but I also have heard that mold testing kits aren’t always reliable. What do you think I should do?


— RC in Michigan

Mold prevention is important. Spores will not grow without moisture so prevention depends on eliminating moisture.Dear RC,

You’re right to not blindly throw money at a removal service. Although there are tons of mold inspection services available, the major health organizations say first thing to do is simply to look. And smell. Generally, if mold is present, you will know. The best testing kits are your eyes and nose. Even if mold is not visible (behind a wall, for instance) its signature musty smell will likely give it away.

Mold spores will not grow without moisture, so control and prevention depend on eliminating moisture. Some areas (Atlanta, New Orleans, Seattle) may have such a high humidity level that you will always have some degree of mold issues, but if you have a real mold problem, you likely have more than high humidity levels. Figure out where moisture might be coming from: leaky plumbing, poorly ventilated kitchens or bathrooms, or gutter and terrain issues are the main culprits. The Alliance for Healthy Homes is a good resource for mold information that includes sections on assessment, and prevention and control.

Why is mold a problem anyway? The spores that mold releases are relatively small particulates, and particulate matter has a strong link to health risks: when the amount of fine particulates increases, so do levels of respiratory illness and heart disease. Common sources of fine particles are gasoline and diesel engines, fireplaces and wood-burning stoves, cigarette smoke, spray paint and toxic chemical compounds. The smallest particles are considered the most dangerous as they can be inhaled deep into the lungs. Larger particles like mold spores, pollen, or dander do not infiltrate as deeply but may cause strong reactions, as they produce allergens and irritants and can trigger asthma attacks. The EPA and CDC are good places to start your inquiry into allergens and particulates (aside from Ask V, of course).

Here are a few things you can do for mold prevention:

• Clean and dry surfaces. Quickly.

• Run a dehumidifier. Don’t forget to empty and wipe it dry every day. Also clean the water bucket with vinegar, and vacuum or wipe down the exterior regularly.

• Running a dry, clean AC system can lower humidity levels (but with larger environmental dangers looming, I can't in good conscious recommend running a HVAC system or dehumidifier.)

• Use a HEPA filter vacuum, and service your HVAC monthly with new, pleated filters.  Of course, don't allow the filters to get moist.

• Vent when cooking, running a dishwasher or clothes dryer, and showering (all produce water vapor that will increase humidity).

• Clean gutters, slope terrain or landscaping away from house, and fix pipes, faucets, or anything that is leaky.

• Dry out any wet materials — quickly — and get rid of musty carpet or upholstery ('getting rid of' is the common advice; as any waste gives me nightmares, I'd try a white vinegar spray or dust with baking powder first. No rush to vacuum up the baking powder). If it is dry and sunny, and you can carry it, take moldy items outside. Sunshine kills mold — and it's free!

• Don't use chlorine bleach — for anything, ever! Use vinegar instead. It's effective against mold, safe and less expensive. Spray it on mold and don't rinse. Tea tree oil is a fungicide, but it's expensive and has a very strong smell. Still, a little goes a long way. Mix it with water, spray on mold and don't rinse. For walls and such, try borax mixed with water; scrub the area with the mixture and vacuum or dust once the borax has dried (2- 3 days).

Not to diminish the impacts of mold but … you may want to look into other generally more hazardous indoor particulates. Children living in homes heated by wood-burning stoves have a greater occurrence of moderate and severe chronic respiratory symptoms than children in homes without those stoves. And it's not just that these particulates might be hard on your lungs. Wood smoke has high concentrations of toxic chemicals like benzene, formaldehyde and polycyclic aromatic hydrocarbons, all of which are considered possible carcinogens by the Centers for Disease Control and Prevention.

Don’t burn incense. Really. EPA tests show burning incense to be biggest source of indoor fine particulates. Air fresheners and synthetic or lead-wicked candles … yuck. Houseplants are a great natural air sanitizer.

Keep it dry … and green,


* Houseplants: All plants convert CO2 into oxygen, but some are effectual in removing chemicals and particulate irritants. Boston fern, spider plant, golden pothos and nephthytis are known to reduce levels of formaldehyde; areca palm, moth orchid and dwarfed date palm can remove xylene and toluene; and gerbera daisy, chrysanthemum, spider plant, and peace lily can remove benzene. Other beneficial houseplants include bamboo palm, Chinese evergreen, English ivy, indoor dracaena species and the snake plant (aka mother-in-law's tongue). Shoot for one plant per 100 square feet.