Urban Air Quality:
Meteorological Processes
David Carruthers
1 , Silvana Di Sabatino
2 and
Julian Hunt
3
1 Cambridge Environmental Research
Consultants, Cambridge, UK
2 Dipartimento di Scienza dei Materiali, Università
del Salento, Lecce, Italy
3 University College London, London, UK
Article Outline
Glossary
Definition of the Subject
Introduction
Characteristic Regions of the Flow and Drivers
Urban Data
Computational Models for Meteorology and Air
Flow in Urban Areas
Examples of Output of Modelling Calculations
Future Directions
Notation and Abbreviations
Subscripts
Abbreviations
Bibliography
Glossary
Building and street scales Scales of buildings or
streets; tens to hundreds of meters.
Fast approximate model (FAM) A model
which uses approximations and parameterizations of the fine scale flow to speed up model
run times and reduce complexity.
Fully computational model (FCM) A model
which explicitly represents flow and turbulence around buildings.
Mesoscale Scale of weather systems smaller
than synoptic scale but larger than microscale or urban scale; tens to hundreds of
kilometers.
Neighborhood scale Scale typical of groups of
buildings or streets; hundreds of meters to a
few kilometers.
Porosity The volume fraction of air between
buildings and therefore a measure of building
density.
Urban air quality A general term representing
concentrations of pollutants in an urban area.
Good air quality corresponds to low concentrations of pollutants.
Urban meteorology Meteorology within an
urban area; the urban environment significantly
affects mean flow turbulence and temperature.
Definition of the Subject
Meteorological processes in urban areas that are
relevant to urban air quality. Of most significance
are the impacts of the urban morphology on the
mean flow and turbulence, which determines the
transport and dispersion of pollutants and therefore their concentration.
Introduction
Concentrations of pollutants within an urban area
depend on a number of different factors. These
include the emissions of pollutants within the
urban area, pollutant concentrations transported
into the area, and the meteorology within the urban
area, in particular, the mean airflow and turbulence
(which determines the movement and mixing of the
emitted pollutants) and the temperature and solar
insolation (which impacts on chemical transformation taking place). This entry discusses meteorology
within the urban area with the focus being on the
mean flow and turbulence, as these may be substantially different from the upstream flow. Discussed
here are the current understanding, experimental and
numerical simulation data, and the relative merits of
different modelling approaches. For discussions of
dispersion within urban areas, see, for example, [1].
© Springer Science+Business Media, LLC 2012
M. E. Goodsite et al. (eds.), Air Pollution Sources, Statistics and Health Effects,
https://doi.org/10.1007/978-1-0716-0596-7_427
Originally published in
R. A. Meyers (ed.), Encyclopedia of Sustainability Science and Technology, © Springer Science+Business Media LLC, 2012
https://doi.org/10.1007/978-1-4419-0851-3_427
163
Meteorological Processes
David Carruthers
1 , Silvana Di Sabatino
2 and
Julian Hunt
3
1 Cambridge Environmental Research
Consultants, Cambridge, UK
2 Dipartimento di Scienza dei Materiali, Università
del Salento, Lecce, Italy
3 University College London, London, UK
Article Outline
Glossary
Definition of the Subject
Introduction
Characteristic Regions of the Flow and Drivers
Urban Data
Computational Models for Meteorology and Air
Flow in Urban Areas
Examples of Output of Modelling Calculations
Future Directions
Notation and Abbreviations
Subscripts
Abbreviations
Bibliography
Glossary
Building and street scales Scales of buildings or
streets; tens to hundreds of meters.
Fast approximate model (FAM) A model
which uses approximations and parameterizations of the fine scale flow to speed up model
run times and reduce complexity.
Fully computational model (FCM) A model
which explicitly represents flow and turbulence around buildings.
Mesoscale Scale of weather systems smaller
than synoptic scale but larger than microscale or urban scale; tens to hundreds of
kilometers.
Neighborhood scale Scale typical of groups of
buildings or streets; hundreds of meters to a
few kilometers.
Porosity The volume fraction of air between
buildings and therefore a measure of building
density.
Urban air quality A general term representing
concentrations of pollutants in an urban area.
Good air quality corresponds to low concentrations of pollutants.
Urban meteorology Meteorology within an
urban area; the urban environment significantly
affects mean flow turbulence and temperature.
Definition of the Subject
Meteorological processes in urban areas that are
relevant to urban air quality. Of most significance
are the impacts of the urban morphology on the
mean flow and turbulence, which determines the
transport and dispersion of pollutants and therefore their concentration.
Introduction
Concentrations of pollutants within an urban area
depend on a number of different factors. These
include the emissions of pollutants within the
urban area, pollutant concentrations transported
into the area, and the meteorology within the urban
area, in particular, the mean airflow and turbulence
(which determines the movement and mixing of the
emitted pollutants) and the temperature and solar
insolation (which impacts on chemical transformation taking place). This entry discusses meteorology
within the urban area with the focus being on the
mean flow and turbulence, as these may be substantially different from the upstream flow. Discussed
here are the current understanding, experimental and
numerical simulation data, and the relative merits of
different modelling approaches. For discussions of
dispersion within urban areas, see, for example, [1].
© Springer Science+Business Media, LLC 2012
M. E. Goodsite et al. (eds.), Air Pollution Sources, Statistics and Health Effects,
https://doi.org/10.1007/978-1-0716-0596-7_427
Originally published in
R. A. Meyers (ed.), Encyclopedia of Sustainability Science and Technology, © Springer Science+Business Media LLC, 2012
https://doi.org/10.1007/978-1-4419-0851-3_427
163