After my basement flooded, the carpet was removed, but I still smell a musty odor. Why?
If moisture remained on materials in the basement for a sufficient amount of time, the materials, such as sheetrock, insulation, cardboard boxes, walls studs, paneling, etc., molds will continue to grow and produce the volatile organics or the mold odor. If, in addition to the flood, moisture is entering slowly through the foundation, the condition will be chronic until the moisture sources are resolved.
Why does the mold odor in a basement usually go away in the winter?
This musty odor is produced by actively growing molds that are metabolizing (breaking down) a food source (wallboard, wood, cardboard, etc.) While the molds are feeding on the materials, they produce mold volatile organic compounds or mVOCs, which are simply chemicals that travel easily in the air and therefore disperse throughout a house or building. Because basements dry out in the winter, mold is relatively starved for moisture and grows more slowly or not at all and the odor may lessen in strength. However, this is not the end of the mold problem.