10 Clean Air

Download the Report

Improving and protecting human health is a key part of a clean growth transition. Health and climate outcomes are linked by the emissions we release into the atmosphere: some are greenhouse gas emissions and contribute to climate change, while others are air pollutants that are harmful to human health. In many cases, these air pollutants and GHG emissions are emitted at the same time from the same sources. As a result, Canada has significant opportunities to improve health as it accelerates action to reduce GHG emissions.

Headline Indicator #10: Ambient Air Quality across Canadian Cities 

To measure air quality in Canada, we consider ambient air quality data in several Canadian cities across four major air pollutants (Figure 10.1). For comparison, we also include the Canadian Ambient Air Quality Standards (CAAQS) for 2020 and 2025, which are the baseline standards for air quality in Canada (see Box 10.1). Although we only have data for 2017–18 (see Data Gap section), the goal is to see ambient air quality improve over time.

The data in Figure 10.1 highlight a few notable trends. Overall, most Canadian cities in the figure achieved the 2020 and 2025 CAAQS in 2017–18, with a few exceptions. Vancouver was the only city in the figure that failed to meet the 2020 CAAQS for nitrogen dioxide; however, NO2 levels in Edmonton and Toronto exceeded the 2025 CAAQS. Two cities failed to meet the 2020 CAAQS for fine particulate matter (Edmonton, Saskatoon). None of the listed cities exceeded the CAAQS for ground-level ozone (smog), but many came close to the standard. As CAAQS continue to tighten over time, many towns and cities across the country (including many not in Figure 10.1) will need to improve ambient air quality to meet the national standards.

Box 10.1: Ambient Air Quality Standards in Canada

Ambient air quality refers to the concentration of pollution within a given airshed and changes based on the types and quantities of pollutants released into the local atmosphere. While pollution from human activities is the primary driver of poor air quality, weather conditions (wind, temperature, precipitation, etc.) and natural events (wildfires, volcanic eruptions) can also affect air quality.

To improve ambient air quality in Canada, the Canadian Ambient Air Quality Standards were developed collaboratively between federal, provincial, and territorial governments. Although there is no safe level of air pollution, the CAAQS establish baseline air quality standards for Canada that tighten every five years. 

Source: CCME (2017).

The figure also highlights major differences in air quality across cities. Hamilton, for example, had among the highest concentration of sulphur dioxide (SO2) emissions in the country (concentrations were higher only in Trail, B.C., and Saguenay, Quebec). Industrial activity—and smelters in particular—are the largest source of SO2 emissions in Ontario and likely contributed to these high levels in Hamilton (Government of Ontario, 2017). Levels of fine particulate matter were nearly twice as high in Saskatoon and Edmonton compared to St. John’s and Halifax, which were likely driven by differences in wildfire activity and heavy industry.

Air quality can also be dramatically different within a city, as illustrated by the concentration of nitrogen dioxide (NO2) in Vancouver, which was twice as high as many other cities. One of Vancouver’s two monitoring stations is located on a busy stop-and-go trucking corridor (Clark/Knight Street) that serves Canada’s busiest port. Concentrations of NO2 at this station were nearly twice as high as levels in downtown Vancouver (located only a few kilometres away), pulling up the city’s average. In these urban driving conditions, heavy-duty trucks can emit NO2 emissions equivalent to 100 cars (Badshah et al., 2019).

Air pollution is not just a big-city problem. Ozone levels in Whitehorse were the fourth highest out of the 15 cities surveyed. Small and rural communities in southeastern and northeastern British Columbia had the highest levels of fine particulate matter in the country in 2017–18.

Lastly, the data in Figure 10.1 show that air pollution is not just a big-city problem. Ozone levels in Whitehorse, for example, were the fourth highest out of the 15 cities surveyed. Similarly, small and rural communities in southeastern and northeastern British Columbia have the highest levels of fine particulate matter (PM) in the country for 2017–18 (not included in the figure). Heavy wildfires during these two years were likely the primary cause of these high PM emissions, although emissions from forestry and resource extraction industries may have also contributed to poor air quality. Many Indigenous communities also grapple with poor air quality due to their proximity to industrial facilities and a heavy reliance on diesel generators in remote communities (MacDonald, 2019; CIRNAC, 2012).

  1. Estimate is in 2015 dollars and based on 2015 population counts. It includes annual mortalities associated with three pollutants: PM2.5, NO2, and O3 (Health Canada, 2019). Dollar estimates are likely conservative.
  2. A similar policy at the national level—implemented after the Ontario coal phase-out—is expected to prevent approximately 1,008 premature deaths and 871 hospital admissions or emergency room visits between 2015 and 2035, a benefit valued at $5 billion (Pembina Institute, 2016). It is also expected to generate $3.4 billion in avoided climate change damage (ECCC, 2018b).
  3. Black carbon is a component of fine particulate matter and is generated through the incomplete combustion of fossil fuels and biomass (ECCC, 2019c). It is considered a short-lived climate pollutant because it stays in the atmosphere for only a few days or weeks (C2ES, 2020). Black carbon is the third-biggest contributor to global climate change, after methane and carbon dioxide emissions.
  4. Note that about 13 per cent of total PM2.5 emissions from on-road transportation are generated from brake and tire wear. These emissions would likely be unaffected by fuel efficiency improvements or a shift to EVs (ECCC, 2019a)
  5. Particulate matter and black carbon emitted from controlled burns are included in ECCC data at the national level, but they do not include emissions from uncontrolled wildfires and do not provide this information at a local level.