Study of Winter Air Pollution in Toronto

Welcome to our winter scientific study of air pollution – we call it SWAPIT!

SWAPIT stands for Study of Winter Air Pollution in Toronto. It’s an examination of the mixture of air pollutants in Toronto and will help us learn about other Canadian cities as well. Even though a lot of attention has been focused on air pollution in recent decades, some air pollutants are still present at levels that are a concern for human or environmental health. We’re innovating with special measurements that will gather fresh data in Toronto over six weeks from January to March 2024! See Study of Winter Air Pollution: Science Plan for the full report.

Who is doing the study?

SWAPIT is led by Environment and Climate Change Canada (ECCC), the federal government department that’s responsible for preventing and managing pollution. There are many study partnerships at work that include public organizations and researchers from several Canadian universities. Over ninety scientific and technical experts are involved directly in collecting data and interpreting results under the study.

Where in Toronto is air pollution being measured during SWAPIT?

There are several long-term air monitoring sites operating in Toronto, and temporary measurements have been added at locations for SWAPIT. These temporary locations help us to understand how the pollutant mixture varies among different areas of the city.

in High Park in the west end of Toronto
at Evergreen Brick Works near the Don Valley Parkway
at campuses of the University of Toronto (Scarborough and St George) and York University
on the CN Tower
on roadside poles across the city
on vehicles driving routes around Toronto
at Toronto Pearson International Airport

Text description

Map of Toronto showing the locations of:

9 fixed ground-based measurements locations:
- 6 National Air Pollution Surveillance (NAPS) stations:
  - NAPS Etobicoke South
  - NAPS Toronto West – Ontario Ministry of the Environment, Conservation and Parks (ON MECP) Resources Road
  - NAPS Highway 401 – Ontario Ministry of the Environment, Conservation and Parks (ON MECP) Resources Road
  - NAPS Toronto North – ECCC Downsview
  - NAPS Toronto East
  - NAPS Toronto Downtown
- 1 ECCC Meteorological Research Division (MRD) station:
  - Pearson Airport
- 2 university stations:
  - York University
  - University of Toronto – St. George
4 temporary measurement locations (SWAPIT):
- High Park
- Evergreen Brick Works
- University of Toronto – Scarborough
- CN Tower

Why is gathering air samples in the winter useful?

Much air pollution research has focused on photochemical smog, which tends to occur in summer. We now know that levels of some pollutants are highest in winter. Winter is different from the rest of the year because colder weather and emissions from indoor heating or de-icing of roads and aircraft become factors. Understanding the way that pollutants are emitted and transformed in all seasons helps in the design of effective management strategies.

What will SWAPIT tell us?

The core questions to be addressed by this scientific study are:

What sources and processes are responsible for the urban air pollutant mixture?
What makes up the urban air pollutant mixture and in what quantities?
How does the urban air pollutant mixture vary in space and time?
How is the urban air pollutant mixture related to human and environmental health risks?

Why is this air quality information we’re gathering important?

SWAPIT is important because air pollution levels have not decreased as expected, and in some cases, they are increasing. We are also becoming aware that some communities are disproportionately affected by air pollution. Reversing such trends relies on understanding the whole air pollution mixture and how it changes from neighbourhood to neighbourhood within urban areas.

The air pollution measurements taken this winter in Toronto will provide sound scientific evidence in support of actions to protect human and environmental health.

Language selection

Search