Air Quality in Canada

How did emissions of major air pollutants change over the last 30 years?

Grades 9 - 12

According to Health Canada, every year air pollution contributes to the death of more than 15,000 people in Canada alone. In 2022, the Government of Canada launched an ambitious 2030 Emissions Reduction Plan, which aims to reduce pollutant emissions to zero by 2050.

In this plan, the government identified sulphur oxides, nitrogen oxides, volatile organic compounds, particular matter, carbon monoxide, ammonia, and ground-level ozone as the most common air contaminants in Canada. In this exercise, we investigate trends in air pollution by looking at emissions of these air pollutants over a period of 30 years, from 1990 to 2020.

Did the total emissions of these pollutants decrease or increase during this period? Which province in Canada emits the most air pollutants?

To answer our question we:

Visualizing the data

To investigate the provincial emissions of air pollutants per capita, we created a stacked bar graph that displays emissions across all provinces. This graph also allows us to observe yearly trends in pollutant emissions. To take a closer look at a specific year, drag the button on the sliding bar at the bottom of the graph.

In the plot above, we notice a significant drop in air pollutant emissions since 1990 in all provinces. In Alberta, the annual emissions per capita of carbon monoxide (CO) decreased from 0.7 tonnes in 1990 to 0.2 tonnes in 2020. Manitoba emitted the most sulphur dioxides (SOX) in 1990 (~ o.5 tonnes per capita), but by 2020, the province stopped emitting SOX altogether.

Second, we plotted a pie graph to see the provincial contributions to total air pollutant emissions per capita from 1990-2020.

In the plot above, we notice that Alberta has been a huge contributor to ammonia, nitrogen oxide, sulphur oxide, and volatile organic compounds emissions over the last 30 years. Alberta alone contributed 24.7% of the total nitrogen oxide emissions per capita since 1990, followed by the province of Newfoundland and Labrador, with total emissions of 18.7%. Newfoundland and Labrador has been a major contributor to total ammonia emissions (35.1%), whereas Ontario has led in total sulphur dioxide emissions in Canada (26.3%).

What do you notice in this data visualization? Are some provinces doing better than others in controlling emissions in recent years? What factors could be causing that (what additional data would you want to look at to find out why emissions are so high/low?)

Reflect on what you see

Look and interact with the data visualizations above. When you hover your mouse over the plots, you’ll notice more information appears. You can also use the legend to make plots appear and disappear.

Think about the following questions.

  • What do you notice about these graphs?
  • What do you wonder about the data?

Use the fill-in-the-blank prompts to summarize your thoughts.

  • “I used to think _______”
  • “Now I think _______”
  • “I wish I knew more about _______”
  • “These data visualizations remind me of _______”
  • "I really like _______”

Share your reflections

Below are some ways to share your thoughts about the data visualizations. If you want to publish your reflections online, make sure you check in with your teacher or guardian

Consider adding @callysto_canada to your reflections if you decide to share them on social media.

Learn how we visualized the data

Go to our walk-through (in Jupyter notebook format) to see how the data science process was applied to create these graphs, from formulating a question, to gathering the data, and analyzing the data with code.