It’s almost Summer. That makes the humidity a greater risk factor for mold and a time to be even more vigilant about preventing it.
Remember, mold can be risky to health. In particular, Black mold is the fungus associated with what’s been called “toxic mold syndrome.” While there aren’t standard guidelines about how much or what kind of mold is toxic, mold, especially in high concentrations. According to the World Health Organization’s 2009 Guidelines for Indoor Air Quality: Dampness and Mold, “Exposure to microbial contaminants is clinically associated with respiratory symptoms, allergies, asthma and immunological [immune system] reactions.” http://www.euro.who.int/__data/assets/pdf_file/0018/43326/E92645sum.pdf
Water damage and dangerous mold growth can be caused by improperly applied “tar paper,” stucco, or other building surfaces; faulty roof construction, installation, or use of defective roofing materials; improper painting or other weather-proofing systems; and inadequate vapor barrier under slab, slab cracks, or improperly designed and constructed slabs. Water and mold damage can also be caused by leaky doors and windows due to the use of defective products; improper installation of waterproofing paper or flashing or tears in waterproofing paper; failure to install flashing at heads, jambs, and sills; and the use of non-galvanized lath.
A comprehensive report on this is available here: http://www.osha.gov/Publications/3430indoor-air-quality-sm.pdf