Everything You Need to Know About Atmospheric Modelling

19 December, 2018 | Blog

DAVID GIARD, P.Eng., M.Sc.

Project Leader - Environment

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Atmospheric dispersion modelling is a mathematical simulation of how air pollutants disperse in the atmosphere. These pollutants are most often dispersed in the form of gases (e.g., formaldehyde, nitrogen oxides, etc.), in the form of solids (e.g., dusts, metals and semi-metals) or in the form of odours.

These atmospheric pollutants can be released through many different sources: chimneys, exhaust vents, liquid or solid surfaces, access roads (paved or not), stockpiles, etc.

In general, modelling is used to verify compliance of an industrial facility with current applicable air quality regulations. These regulations often propose maximum pollutant concentrations that must be respected at ground level outside the emitting plant property. Exceeding maximum ground level concentrations can be considered a violation of air quality or environmental regulations. Atmospheric dispersion modelling is therefore the ideal tool to determine the impact a plant will have on air quality and its ability to comply with air quality laws and regulations in the event it exceeds standards.

When should atmospheric modelling be used?

  • When applying for a certificate of authorization from the government
  • When designing the point of emission into the air (e.g., vent or chimney) to ensure good atmospheric dispersion
  • When it is necessary to determine the origin of a pollutant detected in the air (e.g., discover the origin of dust accumulation in a natural environment or discover the origin of a harmful odour)
  • When it is necessary to validate or quash air quality complaints made by neighbouring communities about an industrial operation (e.g., legal expertise on olfactory pollution coming from landfill)

What are the benefits for industrial companies?

When modelling is included in a project at the design stage, it can help determine the optimal location and characteristics of any point where dusts, gases or odours can be released into the atmosphere. For example, modelling helps:

  • Precisely determine the minimum height a chimney must be to release emissions.
  • Verify whether or not mitigation measures are necessary to reduce dust emissions from an ore concentrate stockpile at a mining site.
  • Determine whether a traffic area should be paved or cleaned regularly to reduce dust emissions caused by vehicles.
  • Check whether process gases must be treated to prevent harmful ground level odours.
  • Check whether a material transfer point must be partitioned to prevent dust emission.
  • Check whether a tailings pond must be covered to prevent odour emissions.

What are the risks to industrial companies?

Atmospheric dispersion modelling included in a project at the design phase can help prevent surprises and the potential for air quality problems. All too often, modelling is used by industrial companies after an air quality problem is discovered (mainly citizen complaints) and not during the design phase to prevent this type of issue from occurring.

To learn more about the benefits of atmospheric dispersion modelling, read our article Air Dispersion Model: a Tool for Informed Decision-Making by Hugues Châteauneuf, BBA Industrial Ventilation Expert.

This content is for general information purposes only. All rights reserved ©BBA

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