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March 18, 2024

By Nikolai Cook, Assistant Professor, Economics
(research co-authors: Anthony Heyes and Nicholas Rivers)

Research has shown that exposure to polluted air has a negative effect on mental function. In our , we found that air pollution affects Canadian university student performance. We believe these effects to be generalizable to the greater workforce, particularly those who work indoors. The type of air pollution we examined, PM2.5 (particulate matter in the air that has a diameter of 2.5 micrometers or less) is capable of seeping into buildings. Going indoors isn’t likely to protect us from the effects of air pollution.

The first surprising result of the study is that we find an air pollution effect where there is relatively clean air. Previous research has found negative effects of air pollution on students in India, Brazil and Israel, but these have all been under conditions where the level of air pollution is much higher. In Ottawa, where our data is from, the only real source of air pollution is from automobiles and air pollution exposure is low. What this means is that we find an effect of air pollution on student performance even when the air is relatively clean. This has implications for policy since there seems to always be a personal benefit to reducing air pollution.

Specifically, we find that a one standard deviation increase in PM2.5 is associated with a decrease in performance of 2.4 per cent of a standard deviation, which might be enough to move a student from an A- to a B if they are unlucky enough to write a final exam on a day that is more polluted. We find that the effects are most noticeable in STEM (science, technology, engineering, mathematics) courses, with the largest effects on non-STEM students branching out and trying STEM courses.

There are two easy ways to protect ourselves from air pollution. We find that writing exams in newer buildings – which have better building materials and air quality systems – seems to offer protection of approximately one third. What we find surprising is that moving to an upper floor protects against half the effect of air pollution. Why? Because the major source of pollution is at street level (automobiles), so simply moving further away from the source should lower exposure. Air pollution gets dispersed by air currents before it reaches an upper floor.

We hope that policymakers continue to make efforts to reduce the air pollution we all breathe. On a concrete level, I hope that awareness of air pollution helps workers adapt to the urban landscape. And students should study away from busy roads – ideally on a second floor or above – to maximize their chances of success. 

This paper fits into my larger research interests of how climate change and air pollution affect us on a personal level, whether it be through our grades or other economic outcomes such as gun violence, which is the focus of my next project.