@misc{27141,
  keywords = {Indoor Air Quality (IAQ), Ventilation rate, Illness absence, Respiratory illness},
  author = {Mark J Mendell and Ekaterina Eliseeva and Michael Spears and Wanyu R Chan and Sebastian Cohn and Douglas P Sullivan and William J Fisk},
  title = {A longitudinal study of ventilation rates in California office buildings and self-reported occupant outcomes including respiratory illness absence},
  abstract = {<h4 id="absSec_1">Background</h4><p id="abspara0010">Limited evidence has associated lower ventilation rates (VRs) in offices with higher illness-related absence rates.</p><h4 id="absSec_2">Methods</h4><p id="abspara0015">We studied spaces in office buildings, selected without knowledge of their VRs, in three California climate zones. In each study space, real-time logging sensors measured carbon dioxide and thermal parameters for one year. Web-based surveys every three months collected data on occupants’ health outcomes. Using multivariate models, relationships were assessed between CO<sub>2</sub>&nbsp;concentrations, or VRs estimated from CO<sub>2</sub>, and adverse occupant outcomes including respiratory infections and illness absences. For all outcomes, positive associations were hypothesized with higher CO<sub>2</sub>&nbsp;levels (and negative associations with higher VRs).</p><h4 id="absSec_3">Results</h4><p id="abspara0020">Low survey response limited sample size and study power. In the 16 study spaces, CO<sub>2</sub>&nbsp;concentrations were uniformly low over the year, and most estimated VRs ranged from twice to nine times the California office minimum VR standard (7&nbsp;L/s or 15 cfm per person). Primary CO<sub>2</sub>&nbsp;and VR metrics had no statistically significant relationships with occupant outcomes.</p><h4 id="absSec_4">Conclusions</h4><p id="abspara0025">Within the observed range of uniformly low CO<sub>2</sub>&nbsp;and high VRs (mostly 16–42&nbsp;L/s per person), little variation in contaminant concentrations would be expected, which would explain lack of relationships with occupant outcomes. These high VRs resulted partly from frequently used energy-saving “economizer” cycles in moderate California climates, but VRs at other times also substantially exceeded required VRs. These findings suggest, consistent with theory, that within a higher VR range, increased VRs do not reduce respiratory illness. Further studies are needed to better characterize such relationships.</p>},
  year = {2015},
  volume = {92},
  month = {10/2015},
  doi = {10.1016/j.buildenv.2015.05.002},
}