Air Emissions
Manufacturing and industrial facilities, thermal treatment plants, asphalt plants, rendering plants, concrete plants and others emit pollutants into the air either as a point source through stacks or as fugitive emissions. Air emissions from these types of facilities are assessed during the environmental assessment and licensing process. These facilities require an Environment Act Licence prior to construction, alteration or operation. Licence conditions may include emission limits, source emission monitoring, emission dispersion modelling, ambient air monitoring and reporting.
Emission Limits: are legal requirements specifying quantitative limits on the permissible amount of specific air pollutants that may be released to the environment from a specific source over a given timeframe. They are specified to achieve a standard ambient air quality to protect the environment and human health. The limits may be used to set standard thresholds above which a proper emission control technology might be needed. The emission limits established by Manitoba Environment and Climate Change, the Canadian Council of Ministers of the Environment, Environment Canada, the United States Environmental Protection Agency, Ontario Environment and others are used as references.
Source Emission Monitoring: Monitoring is a general term for on-going collection and use of measurement data to assess emission performance of a facility against a standard requirement. Generally there are two basic types of monitoring with two different functions: Stationary and ambient.
- A stationary source emission monitoring that collects and uses measurement data at individual stationary sources of emissions. It is often required to determine compliance with provincial or federal air emission limits. Therefore, the purposes of stationary source emissions monitoring are to provide:
- Data and information from a regulated stationary source (facility) to demonstrate compliance with a regulatory requirements, and
- Technology performance information to the facility operator so that corrective action can be taken, if necessary.
The applicable requirements may necessitate periodic or continuous monitoring as it may be specified in a licence terms and conditions issued to a facility. Source emission monitoring is mostly referred as stack testing or stack sampling that is done by a trained and experienced staff. The testing is performed during typical operating conditions at appropriate intervals or through in-stack continuous emission monitoring using accredited methods. Source testing can provide accurate annual emission estimates of a facility or be used for certification of a continuous emission monitoring system (CEM). A CEM system continuously measures actual emissions levels of a pollutant of concern or a surrogate pollutant for the pollutant of concern from a stationary source.
For any source sampling a facility operator shall provide a proper stack sampling facility and conduct the sampling in accordance with the latest version of Environment Canada's (EC) or the United States Environmental Protection Agency (US EPA) test methods. Any other methods shall be approved by the Department before being used for source testing. The following links provide additional information regarding stack sampling facilities and stack sampling methods.
Interim Stack Sampling Performance Protocol
Guidelines for Stack Sampling Facility
Ambient Air Quality Monitoring that collects and measures samples of ambient air pollutants to evaluate the status of the atmosphere as compared to Ambient Air Quality Criteria. This section focuses on the source specific ambient air quality monitoring requirements which might be a requirement for a given facility. The emissions of pollutants from a stationary source may impacts the ambient air quality of a region. The ambient air quality monitoring is required to assess trends in the ambient air quality of the vicinity of the facility and to evaluate the impact of pollutants released by the specific facility's operations or activities. This monitoring can also be used to determine compliance with Provincial Air Quality Guidelines and Objectives. A requirement to monitor ambient air for specific pollutants is determined based on the pollutants potentially released by a facility. This requirement including the sites for ambient air monitoring stations are specified in an Environment Act Licence. Similar to the stack testing the ambient air monitoring shall follow a standard method for pollutant sampling and analysis.
Emission Dispersion Modeling: is a group of mathematical algorithms used to estimate how pollutants are dispersed in the ambient atmosphere. Dispersion modeling is performed using computer programs that solve the mathematical equations which simulate the dispersion of pollutants and estimate the downwind ambient concentration of air pollutants emitted from stationary sources. The estimate of the resulting environmental concentrations depends on source air emissions, meteorological data, and other information. A model can also be used to predict future pollutant concentrations under specific scenarios such as changes in emission sources.
Although air dispersion modeling may be requested as part of the assessment process under the Environment Act or Dangerous Goods Handling and Transportation Act, it is also required to:
- Stipulate licence requirements for a development;
- Design/install a proper stack for a stationary source of emission;
- Design/select appropriate air pollution control equipment;
- Predict ambient air quality;
- Select proper sites for ambient air monitoring stations; and
- Evaluate the potential impact of a new source of air pollution?
There are many models currently available, both from regulatory agencies and the private sector for the air dispersion modelling of various contaminants. The models can deal with varying degrees of complexity of sources, events, operating conditions and terrain. Special modelling may also be required on a case by case basis. Any questions or concerns regarding a specific modeling selection should be directed to the provincial regulatory body. There may be unique features or special circumstances associated with specific facilities. For further information about dispersion modeling please review Guidelines for Air Dispersion Modelling in Manitoba.
