About the indicator

Fine particulate matter, or PM2.5, is an air pollutant that can be harmful to human health. PM2.5 consists of very small particles 2.5 micrometres or less in diameter. Exposure to these small particles can cause serious health problems including lung and heart disease.

PM2.5 gets into the atmosphere due to human activities and natural emission sources, such as wildfire smoke. Some PM2.5 is emitted directly into the atmosphere, for example through dust or smoke. PM2.5 also forms through chemical reactions in the atmosphere involving other gases, such as nitrogen dioxide, sulphur dioxide, and volatile organic compounds.

Human caused sources of PM2.5 and other related gases include burning of fuels for vehicles, home heating, fire pits, power plants, industrial processes, brush burning, and road dust and construction operations.

In Alberta, the highest levels of PM2.5 are typically caused by wildfire smoke and wintertime smog. Smog is a mixture of gases and particles emitted into the air by human activities. Smog forms haze, reduces visibility, and negatively affects human health.

PM2.5 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 PM2.5 from 2000 to 2020 and compares it to Alberta’s Ambient Air Quality Objectives (AAQO), which set thresholds for air pollutants to protect human and ecosystem health. This indicator also discusses ongoing management of PM2.5 levels in Alberta under the Canadian Ambient Air Quality Standards (CAAQS).

How condition of environment indicators for air are used

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:

Results

The highest levels of PM2.5 in Alberta are caused by wildfire smoke and can reach levels that exceed Alberta’s Ambient Air Quality Objective, which is based on the protection of human health. The location and severity of smoke varies year-to-year depending on wildfire activity.

Human activities also significantly contribute to PM2.5 concentrations, primarily during wintertime smog air pollution episodes. Alberta is taking action to manage PM2.5 levels associated with human activities under the Canadian Ambient Air Quality Standards.

In 2020, provincial average concentrations of PM2.5 were lower than those observed over the past decade. This is related to reduced wildfire smoke impact, and may also be connected to changes in emissions of air pollutants due to the COVID-19 response.

  • Variation across Alberta

    • Figure 1 (PNG, 658 KB) shows that annual average concentrations of PM2.5 vary across Alberta and are driven by wintertime smog and wildfire smoke.
    • In 2020, PM2.5 concentrations were highest in population centres and near industrial emission sources due to wintertime smog. Wintertime smog occurs during temperature inversions, when cold air along with pollutants are trapped at ground level preventing dispersion of pollutants into the atmosphere.
    • Wildfire smoke affects different parts of the province each year. The location of wildfires and the wind patterns that transport smoke determine which regions are affected. In 2020, wildfire smoke from fires burning in western United States primarily affected southern Alberta, but was transported throughout Alberta on September 18 and 19.
    • The variation of PM2.5 across Alberta in 2020 was unusual because the impact from wildfire smoke was small. In other recent years, the location and timing of wildfire smoke affected the variation of annual PM2.5 concentrations across Alberta.
  • Changes over time

    • Figure 2 (PNG, 64 KB) shows that the difference in PM2.5 levels between years is largely driven by the extent of wildfire smoke and the frequency and severity of wintertime smog episodes.
    • In 2020, provincial average concentrations of PM2.5 were lower than other years over the past decade.
    • There was less influence from wildfire smoke in 2020 due to reduced fire activity in Alberta and limited impact from fires in surrounding jurisdictions.
    • Actions taken in response to COVID-19 may have also affected PM2.5, due to changes in emissions of air pollutants from sources such as vehicle traffic.
    • Figure 2.5 (PNG, 39 KB) shows that, in Alberta’s population centres, annual average concentrations of PM2.5 vary from year to year depending on the location and transport of wildfire smoke and conditions affecting wintertime smog.
    • Trends over time for PM2.5 cannot be tested statistically because of changes in monitoring equipment (see limitations section below).
  • Seasonal variation

    • Figure 3 (PNG, 103 KB) shows that higher concentrations of PM2.5 occur during periods affected by wildfire smoke. The seasonal variation in PM2.5 for 2017 to 2020 is shown using boxplots of monthly average PM2.5 concentrations at all long-term air monitoring stations, with major wildfire episodes indicated each year. Figure 3.5 (PNG, 6 KB) provides an explanation of the information shown in the boxplot.
    • Elevated concentrations also occur during wintertime smog episodes caused by human emissions from November to March. Wintertime smog has a smaller effect on PM2.5 levels compared to wildfire smoke effects, which is why smog contributions are not as apparent in Figure 3 as those from wildfire smoke.
  • Comparison to provincial objectives

    • Alberta’s Ambient Air Quality Objectives (AAQOs) provide maximum acceptable thresholds for over 30 airborne compounds to protect human and ecosystem health. All industrial facilities must be designed and operated to remain below these thresholds. When air quality exceeds an AAQO, Alberta Environment and Parks assesses the cause and determines whether corrective action is required.
    • Exceedances of the 24-hour Alberta objective for PM2.5 are mainly caused by wildfire smoke and wintertime smog episodes. In 2020, there were 62 exceedances of the 24-hour Alberta objective for PM2.5 in various locations across Alberta. Some air monitoring stations experienced up to 5 days of exceedances. The objective for PM2.5 is 29 µg/m3 for 24-hour periods based on the protection of human health.
    • Of the 62 exceedances, 60 occurred in central/southern Alberta, of which 52% were attributed to wildfire smoke from wildfires in western United States and 48% occurred outside of wildfire season, primarily in January, likely due to smog or prescribed burning activity. The remaining 2 exceedances occurred in northern Alberta.
  • Comparison to national standards

    • To drive improvement of air quality across Canada, the Canadian Ambient Air Quality Standards (CAAQS) have been developed for the following air pollutants:
      Analysis against the Canadian standards specifically assess human-caused air quality issues that can be controlled through local management actions while events outside the control of jurisdictions, such as wildfire smoke, are not included.
    • PM2.5 levels approach the Canadian standards in several regions of the province, primarily due to wintertime smog caused by human emissions.
    • For example, for the 2017 to 2019 reporting period, 5 areas of the province were at the Orange Level – Actions for Preventing CAAQS Exceedances. Therefore, work is ongoing to prevent exceedances of Canadian standards through air quality management plans. The remaining area of the province (the Peace Region) was at the Yellow Level – Actions for Preventing Air Quality Deterioration. For details, see the Canadian Ambient Air Quality Standards under 'Management plans'.
    • Annual reporting of Alberta’s air quality against Canadian Ambient Air Quality Standards is available in Alberta’s Air Zone Reports.
  • Limitations of the dataset

    • Between 2010 and 2017, new monitoring equipment for PM2.5 was installed to replace older equipment at Alberta’s monitoring stations. These new instruments measure an additional portion (semi-volatile) of the PM2.5 mass not captured by older instruments.
    • As older monitoring equipment used between 2000 and 2010 likely underreported levels of PM2.5 under some conditions, after 2010, the increase in PM2.5 levels may be a result of changes in monitoring equipment. Concentrations measured with the new monitors may not be directly comparable with measurements from years in which older instruments were used.
Annual average PM2.5 concentrations across Alberta for 2020

Figure 1. Annual average PM2.5 concentrations across Alberta for 2020

View large image: Figure 1 (PNG, 658 KB)

Trend in annual average PM2.5 concentrations over time

Figure 2. Trends in annual average PM2.5 concentrations over time

View large image: Figure 2 (PNG, 15 KB)

Seasonal variation in PM2.5 for 2017 to 2020

Figure 3. Seasonal variation in PM2.5 for 2017 to 2020

View large image: Figure 3  (PNG, 104 KB)

Focused study

Annually, Alberta Environment and Parks deploys air quality monitoring to support emergency response during wildfires. During the 2016 Horse River wildfire in Fort McMurray, air monitoring was deployed to support decisions to protect the health of emergency response personnel and the public. The report, Characterization of air quality during the 2016 Horse River wildfire, summarizes air quality data collected during the fire. Very high levels of PM2.5 that exceeded health-based objectives were observed from both permanent and portable air quality monitoring equipment due to wildfire smoke.

In the first monitoring phase, when the wildfire plume affected Fort McMurray and surrounding areas, the Mobile Air Monitoring Laboratory (MAML) collected 45 hours of data, of which 18 hours saw exceedances of the hourly Alberta guideline of 80 µg/m3 for PM2.5. The hourly MAML PM2.5 data are shown, with the Alberta guideline indicated by the red dashed line.

Average hourly PM2.5 concentrations at various locations prior to and during the public re-entry to support the emergency response during the 2016 Horse River wildfire in Fort McMurray.

Figure 4. Average hourly PM2.5 concentrations at various locations prior to and during the public re-entry to support the emergency response during the 2016 Horse River wildfire in Fort McMurray. The Alberta guideline for PM2.5 is indicated by the red dashed line.

View large image: Figure 4 (PNG, 99 KB)

Related

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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