Tesis doctoral de Fulvio Amato
Atmospheric particulate matter (pm) affects urban air quality and consequently our health and daily life. Among pm sources, resuspension of inhalable particles from paved roads is a major one in cities, and this process is responsible of a large number of urban exceedances of the pm10 air quality limit values, especially in countries with low rainfall. road sediments are made up mostly of mineral particles, but also of carbonaceous and heavy metals particles (such as fe, cu, ba, cr, sn, sb among others) originated from the wear of vehicle brakes, tires and road surface. This dust is continuously re-entrained into the atmosphere by the traffic-induced turbulence. Consequently, whilst in the past a number of these trace pollutants were typical tracers of industrial emissions, nowadays their highest concentrations in ambient air are registered inside large cities, where most people live and work. moreover, in the last years there is a growing concern of road dust emissions: whilst a decreasing trend has been observed for motor exhausts and industrial emissions, road dust emissions are currently uncontrolled. Despite this, the knowledge of this source is still scarce. the present study offers novel findings on sources and properties of road dust, emission estimates, impact on air quality and effectiveness of remediation measures. These objectives were reached by applying a number of innovative experimental and modelling techniques in different european cities, with particular emphasis on a typical mediterranean city such as barcelona (ne spain). firstly, a new sampling device was developed and deployed to collect and quantify the load of road sediments lower than 10 µm from one square meter in the surface of active traffic lanes. Subsequently, the spatial, chemical and time variability of road sediments was investigated. In the city centre of barcelona levels of deposited particles were strongly affected by contributions from mineral dust (50%) resulting in considerably higher levels (4-23 mg m-2) than in zí¼rich (0.2-1.3 mg m-2, mostly carbonaceous particles) or girona (1.4-7.1 mg m-2). Furthermore, in barcelona levels were increasing considerably next to ring roads (13-80 mg m-2), where a high number of uncovered trucks transport dusty materials. Very high concentrations were measured along the preferred route of trucks from/to construction sites. the chemical analyses of collected samples were also implemented as chemical emission profiles in receptor modelling using multilinear engine 2 (me-2) in order to estimate the impact of non-exhaust emissions in the air quality (pm10 pm2.5 and pm1) registered in the barcelona urban background. Results showed that non-exhaust emissions contributed with 6.9 µg m-3 (17%) in pm10, 2.2 µg m-3 (8%) in pm2.5 and 0.3 µg m-3 (<2%) in pm1 (on an annual mean basis). When contributions from exhaust emissions are also considered, total road traffic emissions accounted for 18 µg m-3 (46%), 14 µg m-3 (51%) and 8 µg m-3 (48%) to annual means of ambient air pm10, pm2.5 and pm1, respectively. real-world emission factors (ef) were quantified by linear regression between increments of road traffic emissions (nox/efnox) and ambient air particulate pollutants concentrations (pm10, fe, cu, sn and sb) between two street canyons with different traffic intensities. Emission were expressed per mass of pollutant emitted by a single vehicle of the average local fleet and estimated in 98 mgpm10 veh-1 km-1, 7400 µgfe veh-1 km-1, 486 µgcu veh-1 km-1, 106 µgsn veh-1 km-1 and 86 µgsb veh-1 km-1. The total non-exhaust emissions in the barcelona protection zone 1 (community decree 226/2006) are estimated in 1133, 86, 6, 1.2 and 1.0 tons of pm10, fe, cu, sn and sb per year, respectively. These findings allow an exhaustive assessment of this source for air quality management. two pm sampling campaigns undertaken in a street canyon of barcelona were oriented to evaluate the effectiveness of street cleaning as possible mitigation measure. Results showed that a combination of sweeping and consecutive water-jet washing could be a reliable practice to mitigate pm emission from road dust resuspension. After street cleaning, concentrations of pm10 at kerbside decreased, as a maximum, 4-5 µg m-3 (7-10% of the daily mean), with respect to reference monitoring sites. The mitigation of road dust emissions was confirmed by the decrease of hourly concentrations of specific tracers such as ca-al-si-ti-sr (-12-28%) and fe-cu-zr-cr (-10%) and the abatement of road sediment loadings (-90%). the novel findings from this work give new insights on the role of non-exhaust emissions on air quality. Results suggest that further acquisitions of experimental and modelling data are needed in order to better interpret the impact of local meteorology on road dust emissions and atmospheric dispersion and to investigate effectiveness of street cleaning on wider urban areas.
Datos académicos de la tesis doctoral «Particulate matter resuspension from urban paved roads: impact on air quality and abatement strategies«
- Título de la tesis: Particulate matter resuspension from urban paved roads: impact on air quality and abatement strategies
- Autor: Fulvio Amato
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 15/10/2010
Dirección y tribunal
- Director de la tesis
- Xavier Querol Carceller
- Tribunal
- Presidente del tribunal: begoña Artiñano
- martin Schaap (vocal)
- (vocal)
- (vocal)