Modeling Airflows and VOC Source Strengths to an Occupied School

Volatile organic compounds (VOCs) are a group of air pollutants that can adversely impact human health, engage in chemistry indoors, and meaningfully degrade indoor and outdoor urban air quality. Utilizing data extracted from a three-month campaign conducted at Harriet Tubman Middle School in Portland, Oregon—an institution built near Interstate 5—this study modeled airflows through the school and quantified source strengths for VOCs over the course of two days. Emission rates for seven compounds that are traditionally associated with human metabolism and activity were calculated, as were source strengths for BTEX compounds (benzene, toluene, xylenes, and ethylbenzene), which are typically associated with traffic-related air pollution (TRAP). In terms of per-person VOC emission rates, it was found that the values determined for some of the chosen compounds were in close agreement with the limited literature that exists on the subject, and that some varied greatly, likely due to differences in the buildings themselves, the occupants and their activities, and dissimilar experimental designs across studies. In terms of BTEX compounds, source apportionment revealed that the majority of their presence was due to supply air, which was expected considering the elevated levels of outdoor TRAP constituents in the near-roadway building. Please provide feedback using the following form:Presentation Feedback For