Health Risks of Dampness or Mold in Workplaces

Substantial research has been completed to investigate the associations of adverse health effects with dampness and mold in workplaces. (For information on the health consequences of dampness and mold in schools, see the section of this web site on IAQ in Schools). Sixteen studies published in 18 peer-reviewed journal articles were identified and key study features and findings are provided in Table 6. Five studies [54-58] report statistically significant increases in asthma health outcomes (asthma diagnosis, asthma exacerbation, or asthma onset) in buildings with visible dampness or mold or mold odor. A sixth study reported in three papers [59-61] found statistically significant increases in asthma outcomes in buildings with damp concrete causing an increase in airborne concentration of the chemical 2-ethyl-1-hexanol from degradation of PVC flooring placed on that concrete. Importantly, three studies [55-57] found dampness and mold associated with statistically significant increases in asthma onset (development of new asthma). The study of Jaakkola et al. [55], which has the strongest design of these three studies, reports approximately a 50% increase in onset of asthma in work places with dampness and mold. Ten out of 11 studies with health symptoms as outcomes reported a statistically significant increase in at least one type of health symptom with increased indications of dampness and mold and in many instances the prevalence of symptoms more than doubled. In most studies, some symptoms were not associated with dampness and mold. The dampness-related risk factors associated with increased health symptoms varied among these 10 studies. For three studies, symptoms increased with increased visible dampness or mold or mold odor [54, 62, 63]. In one study, increased symptoms were associated with dampness in the heating, ventilating, and air conditioning systems [64]. In one study, ultraviolet irradiation of the wet cooling coils (which reduces fungal and bacterial growth) reduced symptoms [65]. One study found symptoms increasing with higher levels of mold in chair dust but not air [66] while another study reported symptoms increasing with increased molds in floor dust but not chair dust [67]. Finally, in one study [59-61] symptoms increased in buildings with damp concrete that caused degradation of PVC flooring and increases of airborne levels of 2-ethyl-1-hexanol. One study [68] failed to find statistically significant increases in health outcomes with dampness and mold, although most health symptoms increased non-significantly and there was a statistically significant increase in workdays lost to respiratory symptoms. Most of the studies had a cross sectional design that can identify associations but not provide proof of causal relationships, although most studies controlled for a substantial set of potential confounding factors. The study of Jaakkola et al. [55] had a stronger case-control design and the study of Menzies et al. [65] was a very strong blinded crossover intervention study. In summary, the published literature indicates an association of asthma and other respiratory health outcomes in damp or moldy workplaces.