title: Quantifying the impact of traffic-related air pollution on the indoor air quality of a naturally ventilated building.
abstract: Improper natural ventilation practices may deteriorate indoor air quality when in close proximity to roadways, although the intention is often to reduce energy consumption. In this study, we employed a CFD-based air quality model to quantify the impact of traffic-related air pollution on the indoor air quality of a naturally ventilated building. Our study found that the building envelope restricts dispersion and dilution of particulate matter. The indoor concentration in the baseline condition located 10m away from the roadway is roughly 16-21% greater than that at the edge of the roadway. The indoor flow recirculation creates a well-mixed zone with little variation in fine particle concentration (i.e., 253nm). For ultrafine particles (<100nm), a noticeable decrease in particle concentrations indoors with increasing distance from the road is observed due to Brownian and turbulent diffusion. In addition, the indoor concentration strongly depends on the distance between the roadway and building, particle size, wind condition, and window size and location. A break-even point is observed at D'~2.1 (normalized distance from the roadway by the width of the road). The indoor particle concentration is greater than that at the highway where D'<2.1, and vice versa. For new building planning, the distance from the roadway and the ambient wind condition need to be considered at the early design stage whereas the size and location of the window openings, the interior layout, and the placement of fresh air intakes are important to the indoor air quality of existing buildings adjacent to roadways.
authors.affiliation: Center for Green Buildings and Cities, Graduate School of Design, Harvard University, Cambridge, MA 02138, USA. Electronic address: ztong@gsd.harvard.edu.
authors.forename: Zheming
authors.initials: Z
authors.lastname: Tong
authors.affiliation: Center for Green Buildings and Cities, Graduate School of Design, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Yujiao
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Center for Green Buildings and Cities, Graduate School of Design, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Malkawi
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Adamkiewicz
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Spengler
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis* / Q000517:prevention & control; D004784:Environmental Monitoring / Q000379:methods*; D008962:Models, Theoretical; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D001335:Vehicle Emissions / Q000032:analysis*; D014691:Ventilation; D014919:Wind
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions
keywords: Computational fluid dynamics (CFD); I/O ratio; Indoor air quality; Natural ventilation; Particulate matter; Ultrafine particles (UFPs)