Landlords and realtors want to know if they're liable for mold problems. Most homeowners simply want to know if the mold they've spotted is dangerous, and if so, what can be done.

That depends.

Calculating a mold's toxicity is not easily done, because mold's effects on human health vary case by case. As with all indoor air quality hazards, the people most vulnerable are kids, the elderly, smokers, and anyone with a compromised immune system.

But, more important than identifying which type of mold has taken up residence is pinpointing its cause.

"To control mold, you must control moisture,". Find the source of moisture, and you're a long way toward ridding your abode of mold. Sometimes the moisture source is painfully obvious, such as in a flooded basement. Other times, high humidity-moisture from showering or cooking is the culprit. Most People think their homes would not be susceptible to mold. However, people compensate (and occasionally over-compensate) for the dry air by adding moisture through humidifiers and other sources, which can lead to mold.

Other factors contribute, including prolonged elevated temperatures (70-80 degrees F) which is why bathrooms, utility rooms and kitchens tend to be vulnerable; availability of organic material (mold grows faster on natural fibers like wool carpet) and time (in other words, tend to that dripping basement sink right now!)

Homeowners can tackle a small area of mold (say 10 square feet or less) with a soap solution. Larger infestations greater than 20 square feet may require professional cleaning.