DISPERSION21 is a local scale atmospheric pollution dispersion model developed by the air quality research unit at SMHI

SMHI

SMHI is an abbreviation for Sveriges Meteorologiska och Hydrologiska Institut, . SMHI is a government agency in Sweden and operates under the Ministry of Sustainable Development...

, the Swedish Meteorological and Hydrological Institute, located in Norrköping

Norrköping

Norrköping is a city in the province of Östergötland in eastern Sweden and the seat of Norrköping Municipality, Östergötland County. The city has a population of 87,247 inhabitants in 2010, out of a municipal total of 130,050, making it Sweden's tenth largest city and eighth largest...

.

The model is widely used in Sweden by local and regional environmental agencies, various industrial users, consultant services offered by SMHI and for educational purposes.

Features and Capabilities

Some of the basic features and capabilities of DISPLAY21 are:

• Source types: Multiple point, area , and volume
  Air pollution dispersion terminology
  Air pollution dispersion terminology includes the words and technical terms that have a special meaning to those who work in the field of air pollution dispersion modeling...
  
   sources as well as street canyons.
• Source releases: Surface, near surface and elevated sources
  Air pollution dispersion terminology
  Air pollution dispersion terminology includes the words and technical terms that have a special meaning to those who work in the field of air pollution dispersion modeling...
  
  .
• Source locations: Urban or rural locations
  Air pollution dispersion terminology
  Air pollution dispersion terminology includes the words and technical terms that have a special meaning to those who work in the field of air pollution dispersion modeling...
  
  .
• Plume types: Continuous or intermittent
  Air pollution dispersion terminology
  Air pollution dispersion terminology includes the words and technical terms that have a special meaning to those who work in the field of air pollution dispersion modeling...
  
   buoyant plumes
  Air pollution dispersion terminology
  Air pollution dispersion terminology includes the words and technical terms that have a special meaning to those who work in the field of air pollution dispersion modeling...
  
  
• Plume dispersion
  Atmospheric dispersion modeling
  Atmospheric dispersion modeling is the mathematical simulation of how air pollutants disperse in the ambient atmosphere. It is performed with computer programs that solve the mathematical equations and algorithms which simulate the pollutant dispersion...
  
   treatment: Gaussian model
  Air pollution dispersion terminology
  Air pollution dispersion terminology includes the words and technical terms that have a special meaning to those who work in the field of air pollution dispersion modeling...
  
   treatment using Green's function
  Green's function
  In mathematics, a Green's function is a type of function used to solve inhomogeneous differential equations subject to specific initial conditions or boundary conditions...
  
  s and includes multiple reflections.
• Terrain types: Simple terrain with no more than 10 degree slopes.
• Building effects: Building downwash
  Air pollution dispersion terminology
  Air pollution dispersion terminology includes the words and technical terms that have a special meaning to those who work in the field of air pollution dispersion modeling...
  
   algorithms are included.
• Meteorological
  Meteorology
  Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
  
   data: The model includes a preprocessor to produce the meteorological parameters needed to characterize the atmospheric turbulence as well as to produce wind speed and direction profiles.
• The street canyon module includes some atmospheric chemistry
  Atmospheric chemistry
  Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earth's atmosphere and that of other planets is studied. It is a multidisciplinary field of research and draws on environmental chemistry, physics, meteorology, computer modeling, oceanography, geology and...
  
   for photochemical reactions.

See also

• Bibliography of atmospheric dispersion modeling
• Atmospheric dispersion modeling
  Atmospheric dispersion modeling
  Atmospheric dispersion modeling is the mathematical simulation of how air pollutants disperse in the ambient atmosphere. It is performed with computer programs that solve the mathematical equations and algorithms which simulate the pollutant dispersion...
  
  
• List of atmospheric dispersion models
• SMHI
  SMHI
  SMHI is an abbreviation for Sveriges Meteorologiska och Hydrologiska Institut, . SMHI is a government agency in Sweden and operates under the Ministry of Sustainable Development...
  
  (Swedish Meteorological and Hydrological Institute)

Further reading

For those who are unfamiliar with air pollution dispersion modelling and would like to learn more about the subject, it is suggested that either one of the following books be read:
www.crcpress.com
www.air-dispersion.com

External links

• SMHI web site click on 'Products & Services', then on 'Environment', and then on 'Dispersion'