title: Emission factors for gas-powered vehicles traveling through road tunnels in São Paulo, Brazil.
abstract: The objective of this study was to improve the vehicular emissions inventory for the light- and heavy-duty fleet in the metropolitan area of São Paulo (MASP), Brazil. To that end, we measured vehicle emissions in road tunnels located in the MASP. On March 22-26, 2004 and May 04-07, 2004, respectively, CO, CO2, NOx, SO2, and volatile organic compounds (VOCs) emissions were measured in two tunnels: the Janio Quadros, which carries light-dutyvehicles; and the Maria Maluf, which carries light-duty vehicles and heavy-duty diesel trucks. Pollutant concentrations were measured inside the tunnels, and background pollutant concentrations were measured outside of the tunnels. The mean CO and NOx emission factors (in g km(-1)) were, respectively, 14.6 +/- 2.3 and 1.6 +/- 0.3 for light-duty vehicles, compared with 20.6 +/- 4.7 and 22.3 +/- 9.8 for heavy-duty vehicles. The total VOCs emission factor for the Maria Maluf tunnel was 1.4 +/- 1.3 g km(-1). The main VOCs classes identified were aromatic, alkane, and aldehyde compounds. For the heavy-duty fleet, NOx emission factors were approximately 14 times higher than those found for the light-duty fleet. This was attributed to the high levels of NOx emissions from diesel vehicles.
authors.affiliation: Department of Atmospheric Sciences, Institute of Astronomy, Geophysics and Atmospheric Sciences, University of São Paulo, São Paulo, 05508-900, Brazil. leiladro@model.iag.usp.br
authors.forename: Leila D
authors.initials: LD
authors.lastname: Martins
authors.forename: Maria F
authors.initials: MF
authors.lastname: Andrade
authors.forename: Edmilson D
authors.initials: ED
authors.lastname: Freitas
authors.forename: Angélica
authors.initials: A
authors.lastname: Pretto
authors.forename: Luciana V
authors.initials: LV
authors.lastname: Gatti
authors.forename: Edler L
authors.initials: EL
authors.lastname: Albuquerque
authors.forename: Edson
authors.initials: E
authors.lastname: Tomaz
authors.forename: Maria L
authors.initials: ML
authors.lastname: Guardani
authors.forename: Maria H R B
authors.initials: MH
authors.lastname: Martins
authors.forename: Olimpio M A
authors.initials: OM
authors.lastname: Junior
mesh_terms: D000392:Air Movements; D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D000397:Air Pollution / Q000032:analysis*; D001938:Brazil; D002248:Carbon Monoxide / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D005579:Fossil Fuels / Q000032:analysis*; D018986:Motor Vehicles; D009569:Nitric Oxide; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D014186:Transportation; D001335:Vehicle Emissions / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D005579:Fossil Fuels; D011084:Polycyclic Aromatic Hydrocarbons; D001335:Vehicle Emissions; D009569:Nitric Oxide; D002248:Carbon Monoxide