title: The impact of traffic-flow patterns on air quality in urban street canyons.
abstract: We investigated the effect of different urban traffic-flow patterns on pollutant dispersion in different winds in a real asymmetric street canyon. Free-flow traffic causes more turbulence in the canyon facilitating more dispersion and a reduction in pedestrian level concentration. The comparison of with and without a vehicle-induced-turbulence revealed that when winds were perpendicular, the free-flow traffic reduced the concentration by 73% on the windward side with a minor increase of 17% on the leeward side, whereas for parallel winds, it reduced the concentration by 51% and 29%. The congested-flow traffic increased the concentrations on the leeward side by 47% when winds were perpendicular posing a higher risk to health, whereas reduced it by 17-42% for parallel winds. The urban air quality and public health can, therefore, be improved by improving the traffic-flow patterns in street canyons as vehicle-induced turbulence has been shown to contribute significantly to dispersion.
authors.affiliation: Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
authors.forename: Prashant
authors.initials: P
authors.lastname: Thaker
authors.affiliation: Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India. Electronic address: sharadbg@iitg.ernet.in.
authors.forename: Sharad
authors.initials: S
authors.lastname: Gokhale
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D000397:Air Pollution / Q000032:analysis*; D002947:Cities; D004782:Environmental Health; D004784:Environmental Monitoring; D006801:Humans; D008962:Models, Theoretical; D014186:Transportation; D001335:Vehicle Emissions / Q000032:analysis; D014919:Wind
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions
keywords: CFD; Public health; Street canyon; Traffic flow; Urban air quality; Urban system; Vehicle turbulence; Wellbeing