| Abstract
| - The objective of this study was to improve the vehicularemissions inventory for the light- and heavy-duty fleet in themetropolitan area of São Paulo (MASP), Brazil. To thatend, we measured vehicle emissions in road tunnels locatedin the MASP. On March 22−26, 2004 and May 04−07,2004, respectively, CO, CO2, NOx, SO2, and volatile organiccompounds (VOCs) emissions were measured in twotunnels: the Janio Quadros, which carries light-duty vehicles;and the Maria Maluf, which carries light-duty vehiclesand heavy-duty diesel trucks. Pollutant concentrations weremeasured inside the tunnels, and background pollutantconcentrations were measured outside of the tunnels. Themean 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-dutyvehicles. The total VOCs emission factor for the Maria Maluftunnel was 1.4 ± 1.3 g km-1. The main VOCs classesidentified were aromatic, alkane, and aldehyde compounds.For the heavy-duty fleet, NOx emission factors wereapproximately 14 times higher than those found for the light-duty fleet. This was attributed to the high levels of NOxemissions from diesel vehicles.
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