The Hazards of Mold Toxicity

Damp conditions with inadequate ventilation create the perfect environment for mold, fungi, and bacteria to thrive, contributing to asthma and other adverse health effects. The fungal fragments that thrive can stay airborne and penetrate into the lungs, thus damaging airways and leading to respiratory disease.

In 2009 the World Health Organization (WHO) estimated that between 10% and 50% of indoor spaces in Europe, North America, Australia, India, and Japan had significant mold problems. According to WHO, an excess level of mold, fungi, and bacteria indoors is a potential health hazard.

Mold can thrive on organic matter such as clothing, paper, and the ceilings, walls, and floors of damp homes. It can grow on the dirt, dust, and organic residue that accumulates on inorganic materials such as concrete, glass, and metal. Telltale indicators of a household moisture problem are surface condensation, an odor of mold, and visible mold. Wet basements, leaking plumbing, and poorly maintained air conditioning systems are primary culprits.

The umbrella of conditions known as dampness and mold hypersensitivity syndrome (DMHS) include allergic respiratory diseases, asthma, allergic rhinitis, and bronchitis. The syndrome can entail increased susceptibility to infection. Research suggests a strong link between asthma and dampness and mold, with one 2007 study estimating that more than 20% of the asthma cases in the US were attributable to this factor. A 2018 meta-analysis of longitudinal studies involving children pointed to a causal relationship between indoor mold exposure and the development and worsening of asthma.

China, where childhood asthma is on the rise, has conducted significant research on mold toxicity. One large epidemiological study associated visible wall mold with childhood asthma. Research out of the US links fungal exposure to wheezing in infants and the development of childhood asthma. Mold toxicity is also linked to neurological and immunological diseases, including peripheral neuropathy and chronic fatigue syndrome.

Steps can be taken to reduce exposure to mold toxicity, beginning with measuring the level of humidity or contaminants in the air, on surfaces, or in dust. The Centers for Disease Control and Prevention has extensive resources on reducing exposure to household mold, including mold cleanup and remediation, as well as information for clinicians on diagnosing and treating patients with allergies and respiratory conditions following a hurricane or tropical storm.