226
Air Pollution and Turbulence: Modeling and Applications
(Trini Castelli et al., 2009a) on a waste incinerator, which is planned to be built in the
city of Turin (Northern Italy). This study was aimed at estimating the ground-level
concentrations (g.l.c.) distribution during particularly adverse dispersion conditions,
possibly causing severe pollution episodes. The rationale of this approach was based
on the principle that, if the infl uence on g.l.c. of the incinerator in the worst dispersion conditions does not bring to exceedances of the law limits imposed on shortterm concentrations for the considered pollutants, its construction could be proposed
without worsening or strictly causing pollution episodes. The typical wind and stability conditions of Turin very often do not favor the pollutant dispersion because of
its geographical position. Turin (220 m a.m.s.l and about one million of inhabitants)
is located at the western edge of the Po Valley. It is surrounded by a hill chain on the
eastern sector and by the Alps in the other three sectors. This peculiar orographic
position typically brings to low wind and/or calm conditions, thermal ground-based
inversions during night-time, föhn episodes and fog situations. In such highly complex situations, advanced 3-D modeling systems need to be used, and consequently
RMS system was applied. The importance of using advanced models, which can
take into account the meteorological variability and the topographical inhomogeneities, is clearly highlighted in Figure 8.3, where a snapshot of the evolution of the
plume during an episode of anticyclonic conditions associated to fair weather and
local-scale thermal circulation (February 10, 2000) is shown.
We notice that in the beginning of the day, 09 UTC, the plume elongates southeasterly, while after a few hours, at 13 UTC, due to the impact of the plume with the
hill chain on the east part of the area, it is split into two main puffs that separated
and moved toward north. Simulations were repeated in other severe meteo-dispersive conditions, which are common of the area, allowing to identify the subregions
where the pollution was bounded to give the highest impact. It was thus proved that a
research-based modeling system can be profi tably used for supporting the decisionmaking process for the control and protection of the environment and health.
Analogous applications were performed to study the atmospheric pollution due to
the traffi c in mountain valleys, characterized by peculiar meteorological and dispersive characteristics due to the complex topography. Even in these particular conditions, which largely affect the effectiveness of the dispersion of road traffi c pollutant,
simplifi ed models or parameterizations are not suffi cient to properly describe such
complexity. Hereafter we report two examples related to studies performed in the
Alps, in the Frejus and Brenner alpine transects.
In the frame of ALPNAP Project (Heimann et al., 2008), the pollutant dispersion,
related to the emissions from the major traffi c routes in Susa (Italy, national roads
SS24 and SS25, and highway A32) and Maurienne (France, national road RN6, and
highway A43) valleys, was simulated. For a detailed reproduction of the atmospheric
circulation in Frejus transect area, a downscaling from the regional to the local scale
was performed with RAMS up to 1000 m resolution and with a diagnostic massconsistent model up to a resolution of 100 m. Three periods, characterized by critical conditions of the dispersive scenarios, were chosen in the reference year 2004.
The output data, that is the main meteorological fi elds, the ground-level pollutant
concentration of NO x and PM10 and the plume dynamics, were transferred to other
ALPNAP partners to support the part of the project related to noise study and impact
© 2010 by Taylor and Francis Group, LLC
Air Pollution and Turbulence: Modeling and Applications
(Trini Castelli et al., 2009a) on a waste incinerator, which is planned to be built in the
city of Turin (Northern Italy). This study was aimed at estimating the ground-level
concentrations (g.l.c.) distribution during particularly adverse dispersion conditions,
possibly causing severe pollution episodes. The rationale of this approach was based
on the principle that, if the infl uence on g.l.c. of the incinerator in the worst dispersion conditions does not bring to exceedances of the law limits imposed on shortterm concentrations for the considered pollutants, its construction could be proposed
without worsening or strictly causing pollution episodes. The typical wind and stability conditions of Turin very often do not favor the pollutant dispersion because of
its geographical position. Turin (220 m a.m.s.l and about one million of inhabitants)
is located at the western edge of the Po Valley. It is surrounded by a hill chain on the
eastern sector and by the Alps in the other three sectors. This peculiar orographic
position typically brings to low wind and/or calm conditions, thermal ground-based
inversions during night-time, föhn episodes and fog situations. In such highly complex situations, advanced 3-D modeling systems need to be used, and consequently
RMS system was applied. The importance of using advanced models, which can
take into account the meteorological variability and the topographical inhomogeneities, is clearly highlighted in Figure 8.3, where a snapshot of the evolution of the
plume during an episode of anticyclonic conditions associated to fair weather and
local-scale thermal circulation (February 10, 2000) is shown.
We notice that in the beginning of the day, 09 UTC, the plume elongates southeasterly, while after a few hours, at 13 UTC, due to the impact of the plume with the
hill chain on the east part of the area, it is split into two main puffs that separated
and moved toward north. Simulations were repeated in other severe meteo-dispersive conditions, which are common of the area, allowing to identify the subregions
where the pollution was bounded to give the highest impact. It was thus proved that a
research-based modeling system can be profi tably used for supporting the decisionmaking process for the control and protection of the environment and health.
Analogous applications were performed to study the atmospheric pollution due to
the traffi c in mountain valleys, characterized by peculiar meteorological and dispersive characteristics due to the complex topography. Even in these particular conditions, which largely affect the effectiveness of the dispersion of road traffi c pollutant,
simplifi ed models or parameterizations are not suffi cient to properly describe such
complexity. Hereafter we report two examples related to studies performed in the
Alps, in the Frejus and Brenner alpine transects.
In the frame of ALPNAP Project (Heimann et al., 2008), the pollutant dispersion,
related to the emissions from the major traffi c routes in Susa (Italy, national roads
SS24 and SS25, and highway A32) and Maurienne (France, national road RN6, and
highway A43) valleys, was simulated. For a detailed reproduction of the atmospheric
circulation in Frejus transect area, a downscaling from the regional to the local scale
was performed with RAMS up to 1000 m resolution and with a diagnostic massconsistent model up to a resolution of 100 m. Three periods, characterized by critical conditions of the dispersive scenarios, were chosen in the reference year 2004.
The output data, that is the main meteorological fi elds, the ground-level pollutant
concentration of NO x and PM10 and the plume dynamics, were transferred to other
ALPNAP partners to support the part of the project related to noise study and impact
© 2010 by Taylor and Francis Group, LLC