Risk factors in heating, ventilating, and air-conditioning systems for occupant symptoms in U.S. office buildings: the U.S. EPA BASE study

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Journal Article

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Building-related symptoms in office workers worldwide are common, but of uncertain etiology. One cause may be contaminants related to characteristics of heating, ventilating, and air-conditioning (HVAC) systems. We analyzed data from 97 representative air-conditioned U.S. office buildings in the Building Assessment and Survey Evaluation (BASE) study. Using logistic regression models with generalized estimating equations, we estimated odds ratios (OR) and 95% confidence intervals (CI) for associations between building-related symptom outcomes and HVAC characteristics. Outdoor air intakes less than 60 m above ground were associated with significant increases in most symptoms: e.g., for upper respiratory symptoms, OR for intake heights 30 to 60 m, 0 to <30 m, and below ground were 2.7, 2.0, and 2.1. Humidification systems in poor condition were associated with significantly increased upper respiratory symptoms, eye symptoms, fatigue/difficulty concentrating, and skin symptoms, with OR= 1.5, 1.5, 1.7, and 1.6. Less frequent cleaning of cooling coils and drain pans was associated with significantly increased eye symptoms and headache, with OR=1.7 and 1.6. Symptoms may be due to microbial exposures from poorly maintained ventilation systems and to the greater levels of vehicular pollutants at air intakes nearer the ground. Replication and explanation of these findings is needed.


Indoor Air



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