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

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