Bioaerosols and sick building syndrome: particles, inflammation, and allergy

Sick building syndrome is a poorly understood condition that can be vexing to clinicians and public health investigators alike. Concerns about possible causes have recently shifted to bioaerosols, especially indoor mold contamination. Recently, controversy over the health effects of indoor bioaerosols has intensified in the media and in medical forums. Allergists and other clinicians are increasingly being asked to evaluate cases of sick building syndrome attributed to bioaerosol exposure. Although allergy may play a role, it is unlikely to fully explain the nonspecific symptoms of the condition. This review of recent literature will attempt to put into context the roles of allergy and nonallergic mechanisms in sick building syndrome.

Epidemiological and toxicological studies have provided further evidence of a possible link between bioaerosol exposure and sick building syndrome, but continue to have methodological limitations. Cross-sectional studies of building occupants have found associations between bioaerosols and symptoms of the condition, but case definitions and exposure assessment remain problematic. Attempts to develop better exposure assessment and biomonitoring methods have made limited progress. Toxicological studies of inhalation of bioaerosols continue to indicate potential toxicity, but at doses that are not comparable to human exposures indoors.

Epidemiological studies suggest an association between bioaerosols and sick building syndrome, and toxicological studies have provided some evidence supporting biological plausibility. However, the extent to which bioaerosol exposure may explain the nonspecific symptoms of the condition is unclear. Nonspecific inflammatory responses to bioaerosols, modified by psychosocial factors such as stress, may be a promising area for continued research.