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Emission factors of air pollutants from vehicles measured inside road tunnels in São Paulo: case study comparison
Pérez-Martínez, P.J.; Miranda, R.M.; Nogueira, T.; Guardani, M.L.; Fornaro, A.; Ynoue, R. & Andrade, M.F.
Abstract
Burning of fuels from the transport sector is
one of the main sources of air pollutants emission in urban
areas. In order to implement public policies concerning air
quality and public health, there is a need to develop
emission inventories. Measurements inside traffic tunnels
can provide an evaluation of emission factors of vehicles
in-use in real conditions. In this paper, we show measurements
of air pollutants for a mixed vehicle fleet, heavyand
light-duty vehicles (HDVs and LDVs), in two tunnels
in the metropolitan region of Sao Paulo in 2011 in order to
calculate the pollutant emission factors (EFs). Measurements
of carbon dioxide, carbon monoxide (CO), nitrogen
oxides (NOx) and particle matter (PM2.5) were taken. High
concentrations related to high-density traffic, especially
during weekdays. EFs were heavily influenced by the
pollutant species loads, so the total vehicle traffic and the
fraction of HDV. The EF values for HDV were 3.6 and
9.2 g km-1, for CO and NOx, respectively (5.8 and
0.3 g km-1 for LDV). To determine EF estimates,
parameters such as velocity of the air, cross-sectional area
and length of the tunnel and vehicles passing at 1-h time
interval were considered.
Keywords
Emission factors; Road traffic; Urban tunnels; São Paulo
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