How Mold Effects Human Health
Molds and other fungi grow easily in damp indoor environments. People who spend time in such environments sometimes complain of respiratory effects, headaches, and other physical symptoms. In addition to visible or hidden mold, damp spaces likely harbor mold break-down products, dust mites, bacteria, and chemicals, gasses, and particulate matter released from the materials on which molds are growing. Given the difficulties in testing for all of these elements, hard evidence of precise cause-and-effect can be elusive.
In an extensive 2004 report, the Institute of Medicine (IOM) did not find enough evidence to identify health effects which were definitely caused by spending time in damp indoor spaces. However, the experts found that being in damp indoor spaces seemed related to respiratory illnesses: nose and throat [upper respiratory] symptoms, cough, wheeze, and asthma symptoms. They also found limited evidence that these environments can be associated with shortness of breath, the development of asthma in people who did not previously suffer from it, and lower respiratory symptoms (coughing, wheezing, chest tightness, and shortness of breath) in healthy children. Based on available research, IOM was not able to substantiate claims of numerous other symptoms such as skin irritations, fatigue, cancer, lung disease, or respiratory infections. There was enough evidence of health effects overall, though, that IOM identified damp indoor spaces as a public health problem that needs to be addressed.
It can be difficult or impossible to assess all types of molds, spores, fungal fragments, chemicals from destruction of mold-colonized materials and second-hand smoke, and other airborne matter indoors at any given time. Though numerous studies associate the presence of dampness and mold with respiratory allergies and asthma, it can be equally difficult or impossible to establish the presence of these substances as the definitive cause of illness in particular patients.