Study of dispersion patterns for Oxides of Nitrogen (NOx) from major industrial and automobile sources in two modeling domains in Nova Scotia, Canada *Soumita Kundu, Satish Mysore

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Study of dispersion patterns for Oxides
of Nitrogen (NOx) from major industrial and
automobile sources in two modeling domains in
Nova Scotia, CanadaSoumita Kundu, Satish
Mysore Mark Gibson Corresponding Author
Soumita KunduDepartment of Civil and Resource
Engineering Dalhousie University(sm256830_at_dal.ca
)
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Background

• Air quality research in Nova Scotia
• NOx is a criteria air contaminant
• Nova Scotia emission inventory
• Motivation for conducting the dispersion study

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Oxides of nitrogen (NOx) dispersion study in Nova
Scotia

• Geographic location
• Modeling domains
• HFX location
• SYD location

SYD
HFX
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Sources of NOx-chimney stacks and highways

• HFX domain
• Chimney stacks-Dartmouth oil refinery, Tufts
  Cove generation station, Capital Health and
  Dalhousie University
• Highways-101,102,103,107,111and 118
• SYD domain
• Chimney stack-Lingan generation station
• Highways-105 and 125

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Dispersion Modeling

• US-EPA regulatory model AERMOD VIEW v6.2
• Components-AERMET, AERMAP
• Data requirements
• Meteorological data
• Land use
• Terrain Data
• Building downwash

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• Source characteristics
• Chimney stacks
• Geographical co-ordinatesLatitude Longitude in
  UTM coordinates (m)
• Base Elevation
• Release height (m)
• Diameter (m)
• Exit temperature(K)
• Exit velocity(m/sec)

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• Source Characteristics continued
• Highways
• Section length (m/km)
• Geographical co-ordinates of the starting and end
  point of a sectionLatitude Longitude in UTM co
  ordinates(m)
• Number of vehicles per section length (no per
  m/no per km)
• Total emission data
• Emission rate

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Meteorological data

• Surface air data
• Halifax International Airport
• Sydney station
• Upper air data-station
• Yarmouth station
• Onsite data

Halifax International Airport
Yarmouth
Sydney Station
Yarmouth
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Wind Rose Plot for the Sydney Model Domain(2004
2007)
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Wind Rose Plot for the Halifax Model Domain(2004
2007)
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Land use

• Sectors-urban area, cultivated land, water bodies
• Surface characteristics by month
• Albedo
• Bowen ratio
• Surface Roughness length
• Values suggested in AERMET

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Terrain Data

• Use of Geo-Tiff files
• Process using AERMAP

SYDNEY
HALIFAX
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Receptor Grid and output option

• 2.450 km spacing on Uniform Cartesian receptor
  grid
• HFX domain area 44 km x 48 km
• SYD domain area 23 km x 23 km
• Annual averaging - predict average NOx
  concentrations at receptor points

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AERMOD View Results( HFX-2004)
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AERMOD View Results( HFX-2005)
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AERMOD View Results( HFX-2006)
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AERMOD View Results( HFX-2007)
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AERMOD View Results( SYD-2004)
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AERMOD View Results( SYD-2005)
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AERMOD View Results( SYD-2006)
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AERMOD View Results( SYD-2007)
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Conclusion - Halifax Domain

• The chimney stacks and flare of Dartmouth
  Refinery had the most influence on the NOx
  dispersion pattern in the HFX domain
• Highway 102 was the major linear emission source
• During 2006 and 2007 the highest predicted NOx
  concentrations were at the intersection of
  highways 102 and 118
• During all four years (2004 2007) the maximum
  predicted NOx was observed within 2 km radius
  from the refinery

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Conclusion - Sydney Domain

• The NOx contribution to surface concentrations
  from Lingan station was predicted to be
  negligible when compared to the Canada Wide
  Standard
• Highway 125 had a minor contribution to ground
  level NOx concentrations in the Sydney domain
• In both model domains, the maximum annual NOx
  concentration predicted from line sources was
  within 100 m of the highways