Emission factors of air pollutants from vehicles measured inside road tunnels in São Paulo: case study comparison

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 (NO x ) and particle matter (PM 2.5 ) 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 NO x , 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.

Characterization of Fine Particulate Matter Emitted from the Resuspension of Road and Pavement Dust in the Metropolitan Area of São Paulo, Brazil

“…Tunnel measurements were taken in order to characterize the true nature of the vehicle fleet in the MASP. In one tunnel study, Pérez-Martínez et al [12] showed that the emission factors of regulated pollutants were higher than those presented in official reports (CETESB, 2014). The authors compared their data with those of analyses performed under the same conditions in 2004 [11,13].…”

“…The authors compared their data with those of analyses performed under the same conditions in 2004 [11,13]. The CO and nitrogen oxide (NO x ) emission factors reported by Pérez-Martínez et al [12] for light-duty vehicles in 2011 were both significantly (2.2 times) lower than those reported by Martins et al [13] for light-duty vehicles in 2004, whereas they were five times and 2.5 times lower for CO and NO x , respectively, from heavy-duty vehicles. Analyzing the number and mass size distribution of particles, Pérez-Martínez et al [12] calculated the PM 2.5 emission factor to be 20 mg/km for light-duty vehicles and 277 mg/km for heavy-duty vehicles, showing the great contribution of diesel to the emission of fine particles.…”

Air quality forecasting system for Southeastern Brazil

“…The modeling approach taken in different cities in the southeastern region of Brazil has been evolving, and most of the efforts have been focused on the construction of a comprehensive emissions inventory. In the MASP, the emissions inventory is based on vehicle emission factors (dynamometer measurements) and tunnel measurements performed in the city of São Paulo in 2001and 2004Sánchez-Ccoyllo et al, 2009), as well as on experiments conducted in 2011 Pérez-martínez et al, 2014).…”

“…The modeling capability has been increased by experimental studies aimed at improving the emissions inventory and describing the atmospheric processes. Such experiments consist of measurements of ozone precursors ; fine and ultrafine particles (Almeida et al, 2014); and emission factors Pérez-martínez et al, 2014). Combining all the efforts that have been applied to the representation of pollutants with air quality models in the MASP, an operation was implemented in order to forecast the concentrations of ozone, carbon monoxide, and particles.…”

“…During the summer of 2013/2014 as a whole, there were 27 days on which the relative humidity was below 40%. The quality of the simulation, in comparison with direct measurement, was evaluated with the statistical parameters correlation, bias, root mean square decomposed into two components: Albuquerque et al, 2012) Emission factors for regulated pollutants and hydrocarbons 1 h Measurements inside road traffic tunnels Sánchez-Ccoyllo et al, 2009;Brito et al, 2013;Nogueira et al, 2014;Pérez-martínez et al, 2014) USP, University of São Paulo. systematic RMSDs and unsystematic RMSDu, and agreement index, according to Willmott et al (1985) and Lu et al (1997).…”