Air
The air surrounding us on the land and in our communities is called “ambient” air. It contains mostly nitrogen and oxygen, with a small amount of carbon dioxide and water vapour. It also contains trace amounts of contaminants such as gaseous chemicals and particulate matter (dust).
Research has linked the presence of air contaminants at certain concentrations to human health issues such as respiratory and cardiovascular problems, as well as to negative effects on property, vegetation, land and water.
The naturally occurring levels of particles and chemicals in the air are called “background levels”. Human activities and unusual natural events such as forest fires can cause pollution, and raise the levels of particles and chemicals above these background levels. Tracking levels of the most common contaminants (also known as air pollutants) provides an indication of air quality and the impacts of emissions from both industrial and community development.
12.1 Criteria Air Contaminants Indicator
Monitoring Criteria Air Contaminants (CACs) is an indicator of air quality.
CACs are the common trace particles and gases found in ambient air that monitoring programs target most often. CACs include total suspended particulate (TSP), particulate matter 10 microns or less in diameter (PM10), particulate matter 2.5 microns or less in diameter (PM2.5), and gaseous pollutants, including sulphur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO) and ground level ozone (O3).
National and territorial standards establish limits for the maximum amount of particles and gases that can be in ambient air. Actual measured concentrations are compared to these standards to determine the quality of our ambient air.
A variety of methods exist to measure individual CACs. These methods range in complexity and sophistication from relatively simple filter-based grab sampling and subsequent laboratory analysis to electronic particulate and gas analyzers providing continuous up-to-the-minute analysis.
Information for this indicator is obtained from the NWT Air Quality Monitoring Network3, which is operated by ENR in collaboration with Environment Canada.
The Network consists of four monitoring stations:
- Yellowknife – Taiga Shield
- Inuvik – Northern edge of Taiga Plains
- Fort Liard – southern Taiga Plains
- Norman Wells – central Taiga Plains
Pollutants monitored vary by station but include most, if not all, of the CACs. Wind speed, wind direction and temperature are also monitored.
NWT Focus
The NWT has limited industrial development and a small population located mostly in small communities. The only relatively large community is Yellowknife.
However, industrial development, in particular resource extraction such as mining and upstream oil and gas, is likely to increase in the future. This will be associated with an increase in emissions of air pollutants. Increased development activity may also result in community growth, which can produce additional emissions from sources such as diesel power generation, construction, commercial and residential heating, and increased vehicle use. It is therefore important to establish baseline conditions by measuring selected CACs in communities before development activities take place, to provide a basis for comparison and management of air quality and emissions. Ongoing monitoring allows us to track trends and cumulative impacts as development proceeds.
Current view: status and trend
Information from all air monitoring activities, along with some historical perspective and trend analysis, is presented annually in the NWT Air Quality Report2. Concentrations of CACs in the NWT are expected to be low, with readings at or close to what would be considered typical background values.
Monitoring to date generally confirms the expected very low readings for most air contaminants measured in the four selected NWT communities, with concentrations well below established air quality standards. Notable exceptions include the influence of forest fire smoke on PM2.5 concentrations and spring and summer dust events from residual gravel on the roads following thaw, or unpaved roads, producing short term elevated PM10 concentrations.
Historically, the influence of emissions from industrial operations on community air quality has been observed. Up until the end of the 1990s, gold mine ore roasters resulted in high sulphur dioxide readings in Yellowknife. As can be seen from the chart, hourly readings exceeded established air quality standards on a number of occasions but dropped to zero after 1999 when the last Yellowknife mine was closed. Since then, only background levels have been recorded. This emphasizes the importance of appropriately managing emissions from significant sources, such as industrial operations.
Looking forward
Industrial development is lexpected to increase in the NWT with the continued exploitation of mineral and oil and gas resources. Therefore it is reasonable to assume that the air emissions associated with these activities will also increase. Currently the vast majority of industrial activity is occurring in remote areas and therefore the potential risk to community air quality and residents is low. However, the potential for localized environmental impacts is present and, if the activity becomes sufficiently intense and widespread, the cumulative emissions could begin to affect regional air quality,including the air in communities.
Increased industrial activity would also likely trigger increased community growth in the form of commercial and residential developments and emissions associated with these activities (increased space heating, power demands, vehicles, etc) would have a more direct impact on community air quality. The challenge will be to effectively manage industrial and community growth to ensure that economic benefits for the residents of the NWT are realized, while ensuring that the impacts of emissions from this development activity do not result in unacceptable impacts to air quality. Since combustion sources are a large source of CAC emissions, efforts to improve energy efficiency or use alternative energy sources to reduce greenhouse gas production can also have the co-benefit of reducing CAC emissions.
Looking around
The measurement and use of CACs to determine air quality is a well-established approach across North America, Europe and many other countries. Two of the NWT monitoring stations (Inuvik and Yellowknife) are designated as part of the National Air Pollution Surveillance (NAPS) program1 which monitors and compares air quality in communities across Canada, summarizing the information in annual reports. The data from the NWT monitoring network is also used by other jurisdictions for comparative purposes in their air quality reports, by air quality specialists in the NWT to manage and track air quality issues, by consultants providing assessments in support of development projects in the NWT and by the residents of the NWT and across Canada through the NWT Air Quality Monitoring Network web site3.
Air quality monitoring data from our Yellowknife station is used in the Canadian Environmental Sustainability Indicators (CESI) reports. NWT air quality data is supplied by ENR to the National Air Pollution Surveillance (NAPS) Program which in turn makes it available to the CESI authors: http://www.ec.gc.ca/indicateurs-indicators/default.asp?lang=En&n=2102636F-1.
Find More
The NWT Air Quality Monitoring Network web site is available at http://www.air.enr.gov.nt.ca/NWTAQ/NetworkSummary.aspx. It links to a data management, analysis and reporting system to provide public access to ‘almost real-time’ air quality data for each monitoring location. Access to archived data is available by querying the database using web-based tools. The web site also provides additional information on the NWT Air Quality Monitoring Network, air pollutants, monitoring equipment and air quality standards, as well as links to monitoring information collected in other jurisdictions.
Monitoring data from all NWT stations is analyzed and presented in the annual NWT Air Quality Report available at http://www.enr.gov.nt.ca/_live/pages/wpPages/Air_Quality.aspx under the 'NWT Air Quality Program Reports' heading.
Other focal points
Go to ENERGY USE for indicators on fossil fuel use and sources of greenhouse gas emissions, which produce CACs.
Technical Notes
More detailed information on monitoring methodology is available on the NWT Air Quality Monitoring Network website. Each station is a climate-controlled trailer with state-of-the-art monitoring equipment capable of continuously sampling and analyzing a variety of air pollutants and meteorological conditions. Using sophisticated data acquisition system and communications software, data from each station is automatically transmitted every hour to ENR headquarters in Yellowknife, allowing almost real time review of community air quality by ENR staff. The data also undergoes a series of validity checks before being archived by ENR’s data management, analysis and reporting system.
References
Ref 1 - Environment Canada. 2008. National Air Pollution Surveillance (NAPS) program. http://www.ec.gc.ca/mspa-naps/default.asp?lang=En&n=5C0D33CF-1
Ref 2 - GNWT ENR Environmental Protection. 2006. NWT Air Quality Report, GNWT. http://www.enr.gov.nt.ca/_live/pages/wpPages/Air_Quality.aspx
Ref 3 - GNWT ENR Environmental Protection. 2011. NWT Air Quality Monitoring Network, http://www.air.enr.gov.nt.ca/NWTAQ/NetworkSummary.aspx
Updated: 31 May 2011
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