Associations of Indoor Carbon Dioxide Concentrations and Environmental Susceptibilities with Mucous Membrane and Lower Respiratory Building Related Symptoms in the BASE Study: Analyses of the 100 Building Dataset
Using the U.S. EPA 100 office-building BASE Study dataset, we conducted multivariate logistic regression analyses to quantify the relationship between indoor CO2 concentrations (dCO2) and mucous membrane (MM) and lower respiratory system (LResp) building related symptoms, adjusting for age, sex, smoking status, presence of carpet in workspace, thermal exposure, relative humidity, and a marker for entrained automobile exhaust. In addition, we tested the hypothesis that certain environmentally-mediated health conditions (e.g., allergies and asthma) confer increased susceptibility to building related symptoms within office buildings. Adjusted odds ratios (ORs) for statistically significant, dose-dependant associations (p < 0.05) for dry eyes, sore throat, nose/sinus congestion, and wheeze symptoms with 100 ppm increases in dCO2 ranged from 1.1 to 1.2. These results suggest that increases in the ventilation rates per person among typical office buildings will, on average, reduce the prevalence of several building related symptoms by up to 70%, even when these buildings meet the existing ASHRAE ventilation standards for office buildings. Building occupants with certain environmentally-mediated health conditions are more likely to experience building related symptoms than those without these conditions (statistically significant ORs ranged from 2 to 11).