Buildings, Indoor Environment, and Human Health and Performance

Abstract

Indoor environmental quality in office buildings can impact the health and performance of office workers. Characterizing these impacts and evaluating solutions for reducing harmful exposures are important in order to protect office workers from negative health outcomes and from reduced productivity. The aim of this dissertation was to evaluate the impacts of building operations on indoor environmental quality and how indoor exposures impact health and work performance, with a focus on three specific indoor environmental quality parameters. First, we characterized indoor fine particulate matter (PM2.5) levels in 37 office buildings in China, India, the United Kingdom, and the United States and used statistical models to evaluate associations between building filter efficiency and indoor PM2.5 concentrations during work hours and non-work hours. We found that indoor PM2.5 sometimes exceeded health-based outdoor exposure guidelines during work hours in China and India and that buildings with filters with higher efficiencies tended to have lower indoor PM2.5 levels. Second, we evaluated associations between building features and indoor relative humidity (RH) levels in 43 office buildings in China, India, Mexico, Thailand, the United Kingdom, and the United States. We also evaluated associations between building RH levels and occupant-reported symptoms. RH was more commonly low (% RH) than high (>60% RH) and RH levels tended to be lower in less tropical regions, in winter months, when outdoor RH or temperature was low, and late in the workday. For RH levels between 14% and 70%, we also found gender-specific linear associations between RH and several occupant-reported symptoms, with higher adjusted odds of reporting three symptoms among females (dry or itchy skin and two mucous membrane symptoms) and two symptoms among males (dry or itchy skin and unusual tiredness, fatigue or drowsiness) occurring at lower RH levels. Third, we evaluated associations between temperature and outcomes of creativity and intuitive judgement in 78 young adults in a laboratory environment. We found that increasing temperatures across the range of 65.5-78.6 F were consistently associated with higher scores on tests of divergent and convergent creativity among males and females. We also found that females tended to be uncomfortable in slightly cool temperatures and that females who reported being thermally uncomfortable had lower scores on a test of divergent creativity compared to females who were thermally comfortable. In summary, we found that building design and operations can impact indoor environmental quality in ways that affect building occupants’ health and work performance. Our work also points to solutions that can be implemented in office buildings to reduce exposures that harm health and performance.