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ADMSAtmospheric Dispersion
Modelling System
ADMSAtmospheric Dispersion
Modelling System
Dr David Carruthers, Professor Julian HuntCambridge Environmental Research Consultants
Cambridge, UK
US-EPA/EA Meeting, London, 7 October 2008
ADMSADMS
Development commissioned in 1988 following a CERC report to regulatory authorities in the UK
The CERC report highlighted the The CERC report highlighted the advantages of the use of surface/boundary layer scaling over Pasquill Gifford stability categories. Recommendations consistent with AMS / EPA meeting, Florida 1984
ADMSADMS Sponsors include UK’s Environment
Agency, UK Health and Safety Executive, nuclear industry, major power and chemical companies
Development by: CERC (including Prof. Julian Hunt, Dr. David
Carruthers, Dr. Christine McHugh, Dr. Rex Britter)
Power Companies, then University of Surrey (Prof. Alan Robins)
UK Meteorological Office (Dr. David Thomson)
ADMSADMS ADMS is the leading European Short Range Air
Dispersion Model and is used extensively in the
UK and across Europe, Far East (including China)
etc
ADMS has featured in all 12 European Workshops
on Harmonisation of Dispersion Models (1991-
present). The 12th is taking place in Croatia this
week.
It was proposed to US-EPA. Proprietory issues?
Now listed as alternative model by US-EPA.
Key Features of ADMSKey Features of ADMS
ADMS 4 can model:
plumes or puffs
NOx chemistry
odours
plume
fluctuations
plume rise
changes in surface roughness
flow over complex terrain
wet deposition
dry deposition
dispersion around buildings
radioactive decay and gamma dose
plume visibility
time varying emissions
Key Features of ADMSKey Features of ADMS
PC-based, with user friendly interface and graphical output
Continuous or discrete releases
Point, line, area, volume & jet sources Point, line, area, volume & jet sources
Skewed-Gaussian model using local boundary layer variables
Meteorological preprocessor
Integral plume rise model
Key Features of ADMSKey Features of ADMS
Building effects
Complex terrain
Wet and dry deposition
Chemical transformationChemical transformation
Radioactive decay and -dose
Jets and directional releases
Concentration fluctuations module
Coastline
Condensed plume visibility module
Regulatory ApplicationsRegulatory Applications
Multiple buoyant or passive industrial emissions
Surface, near surface or elevated releases
Urban or rural areas
Short (seconds) to long (annual) term averaging times
ADMS EvaluationADMS Evaluation
•Model comparison with field and wind tunnel experiments, numerical models; mainly datasetsfrom USA.
• Environment Agency test casesTable 2• Environment Agency test cases
• Comparisons with other Gaussian type models eg AERMOD
• All upgrades compared with previous versions
Modelling BuildingEffects
Modelling BuildingEffects
Two plume model Two plume model
Based on
modelled flow
field
3000
ADMS Complex Terrain EffectsBased on modelled mean flow and turbulence
Above: View of idealised hillAbove: View of idealised hill
-3000 0 3000-3000
0
Right: 80m flow field and ground level
concentration from an 80m stack. Slightly
stable flow.
ADMS and AERMOD Comparison:Terrain amplification factorsADMS and AERMOD Comparison:Terrain amplification factors
-1500
-1000
-500
0
500
1000
1500
2000
0.20.30.40.50.60.70.80.91.01.11.21.31.41.51.61.71.81.92.02.12.2
50m stack with Aermod
-1500
-1000
-500
0
500
1000
1500
2000
0.20.40.60.81.01.21.41.61.82.02.22.42.62.83.03.23.43.63.84.04.24.4
Lfet: ADMS CmaxRight: AERMOD Cmax
Ratio of complex terrain to flat terrain as function of stack
-2000 -1500 -1000 -500 0 500 1000 1500 2000-2000
-2000 -1500 -1000 -500 0 500 1000 1500 2000-2000
-2000 -1500 -1000 -500 0 500 1000 1500 2000
50m stack with ADMS
-2000
-1500
-1000
-500
0
500
1000
1500
2000
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
-2000 -1500 -1000 -500 0 500 1000 1500 2000
50m stack with Aermod
-2000
-1500
-1000
-500
0
500
1000
1500
2000
200
250
300
350
400
450
500
550
as function of stack location
• Neutral conditions• 50m stack• Idealised hill• Wind from left to right
Left: ADMS XmaxRight: AERMOD Xmax
US EPA Wind Tunnel Data
Lawson, Snyder and Thompson (1989) ADMS
ADMS and AERMOD Comparison:Complex terrain, Neutral flow, Terrain amplification Factors
AERMOD
ADMS and AERMOD Comparison:Complex terrain results
443000
449000
225
250 443000
449000
4.5
5.0
MaximumConcentration (ug/m3)
Long Term AverageConcentration (ug/m3)
ADMS (Max=178) ADMS (Max=4.0)
369000 375000 381000437000
25
50
75
100
125
150
175
200
369000 375000 381000437000
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
AERMOD (Max=1162) AERMOD (Max=10.3)369000 375000 381000
437000
443000
449000
369000 375000 381000437000
443000
449000
Stack and surrounding
terrain, Ribblesdale Valley,
North-West England.
Stack height = 100m
Terrain = up to 300m
Stack and surrounding
terrain, Ribblesdale Valley,
North-West England.
Stack height = 100m
Terrain = up to 300m
ADMS-UrbanADMS-Urban• Advanced, discrete source air quality model for major cities and airports.
• Includes algorithms for
LondonAnnual average NO2 concentration, 2005
algorithms for dispersion from roads and street canyons.
• Used in over 50 cities worldwide, including London, Rome, Budapest and in China
µg/m³< 2020 - 2424 - 2828 - 3232 - 3636 - 4040 - 4444 - 4848 - 52> 52
0 5 10 Kilometers
NO2
Other ADMS Models Other ADMS Models
ADMS-Roads cf CALINE
ADMS-Airport cf EDMS
ADMS-Star -- Emergency Response ADMS-Star -- Emergency Response
SummarySummary
ADMS 4 includes all the features of AERMOD – but
not all treated in same way
Additional algorithms include concentration
fluctuation, condensed plume visibility, fluctuation, condensed plume visibility,
radioactive decay and gamma dose algorithms
etc.
ADMS is listed on US-EPA’s list of alternative
models. Accepted for use in China and many other
countries.
Summary (cont.)Summary (cont.)
ADMS was first released in 1993 and has been
used in many critical applications. There are over
500 licenses worldwide
http://www.cerc.co.uk
