COVID-19 Updates: Taking steps to return to normal.
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COVID-19 Updates: Taking steps to return to normal.
Air monitoring results for the concentration of nitrogen dioxide.
Nitrogen dioxide, or NO2, is an air pollutant that can negatively affect human health and the environment. Exposure to NO2 can lead to increased risk of respiratory problems. NO2 also adversely affects ecosystems when it is deposited onto the surface, for example through rain.
The major sources of NO2 are the burning of fuels for vehicles, home heating and industrial processes. NO2 also occurs naturally in the environment due to forest fires, lightning or emissions from the soil.
NO2 contributes to the development of other air pollutants, such as ozone, nitric acid and particulate matter. Near large cities, it is partly responsible for the brownish colour of the air in the lower atmosphere.
NO2 is part of the Air Quality Health Index (AQHI) that reports on health risks associated with local air quality across Alberta in real-time.
This indicator reports on the concentration of NO2 from 2000 to 2020 and compares it to Alberta’s Ambient Air Quality Objectives (AAQO). The Alberta objectives set thresholds for air pollutants to protect human and ecosystem health. This indicator also discusses future management of NO2 levels in Alberta under the Canadian Ambient Air Quality Standards (CAAQS).
This condition of environment indicator reports on the current state and trends in Alberta’s air across the province. The air indicators were selected, prepared and reported on to meet this purpose.
Other types of reporting, such as CAAQS reporting (through Alberta’s Air Zone Reports) or compliance reporting near an industrial facility have different purposes and requirements. Therefore, other reporting may use different data sets, data analysis methods, or time-periods and are not directly comparable to the condition of environment reporting. For further details, visit:
Levels of NO2 are higher in urban areas, with Alberta’s highest levels in Edmonton and Calgary.
Levels of NO2 have been decreasing throughout much of the province over the past 2 decades due to improved technology at emissions sources, including personal vehicles and industry.
Despite the decreasing trend, NO2 levels in urban areas will approach or even exceed the new Canadian Ambient Air Quality Standards, which are national standards to protect human health and the environment.
Figure 1. Annual average NO2 concentrations across Alberta for 2020
View large image: Figure 1 (PNG, 660 KB)
Figure 2. Trends in annual average NO2 concentrations over time. Trends are indicated in the legend (○ = no significant trend detected; ∆ = increasing trend; ∇ = decreasing trend)
View large image: Figure 2 (PNG, 22 KB)
On March 16 2020, Alberta declared a public health emergency and enacted measures to reduce the spread of COVID-19. Measures included the closure of schools and daycares, the restriction of gatherings, and mandated physical distancing. These actions were expected to temporarily decrease the concentration of air pollutants due to reduced road traffic in Alberta’s urban centres.
The change in NO2 concentrations during the spring 2020 COVID-19 public health emergency at selected urban centres is shown in Figure 3. Mean concentrations of NO2 during the spring 2020 public health emergency and the same time-period in previous years (2015-2019) are shown, with percent differences indicated in Figure 3 (PNG, 636 KB).
For further details, visit:
Figure 3. Mean NO2 concentrations in a number of urban centres. Data include sample period between March 16 to April 24 (excluding weekends and holidays). Significance was tested using Mann Whitney u test (p value ≤ 0.05). This test compares the distribution of the 2 data sets.
View large image: Figure 3 (PNG, 636 KB)
Alberta Air Data Warehouse
Access long-term air quality monitoring data for Alberta.
Air Monitoring
Information on air monitoring in Alberta.
Alberta Air Zone Reports
Annual reporting of Alberta’s air quality against Canadian Ambient Air Quality Standards.
Ambient Air Quality Objectives (AAAQOs)
Review the provincial standards used to evaluate air quality in Alberta.
Canadian Ambient Air Quality Standards
Alberta’s ambient air monitoring data and management levels are assessed annually against national standards.
Condition of the Environment Report – Air Component (PDF, 397 KB)
Information on data analysis methods and tools.
Environment and land use planning
Learn more about how air quality in Alberta is managed through regional land use planning.
Contact Alberta's Environmental Science Program or the Office of the Chief Scientist:
Email: [email protected]
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