Status of Sulphur Dioxide in B.C. (2019-2021)

British Columbia operates a network of air monitoring stations that measure sulphur dioxide and other air pollutants. This indicator reports on the concentration of fine particulate matter from 2019-2021 and compares it to the Canadian Ambient Air Quality Standards established by the Canadian Council of Ministers of the Environment.

Sulphur dioxide is a colourless gas with a pungent odour at higher concentrations. The largest sources of SO₂ in B.C. include the oil and gas sector, the pulp and paper sector, and metal smelters. Marine vessels and off-road diesel vehicles are additional sources of SO₂. ¹
Sulphur dioxide can be harmful to humans and the environment. Short-term exposure to elevated SO₂ can cause difficulties breathing for asthmatics. The long-term impacts of SO₂ exposure are not well understood. Increased SO₂ in the environment can affect vegetation and aquatic ecosystems through acid rain deposition¹.

The map below summarises the assigned management levels for sulphur dioxide in B.C.'s air zones, as well as the levels of the pollutant at individual monitoring stations. It features stations with sufficient data to report for the 2019-2021 reporting period.

Tip: Click or tap on an air zone or monitoring station to see details on the status of sulphur dioxide levels for the 2019-2021 reporting period.

Image of interactive map of air quality monitoring stations and air zones that meet or exceed Canadian Ambient Air Quality Standards for sulphur dioxide.

Your screen is too small to display the interactive map. Click to see the interactive visualization in full-screen.

Sulphur dioxide levels met both Canadian Ambient Air Quality Standards at 94% of assessed monitoring stations in B.C. There are two standards for SO₂: an annual standard and a 1-hour standard (see sidebar). The annual standard was met at 32 of the 34 stations (94%) for which valid data was obtained, while the 1‑hour standard was met at 32 of the 33 stations (97%) with sufficient data for analysis.
Sulphur dioxide levels met both Canadian Ambient Air Quality Standards in five of B.C.'s seven air zones. The Coastal, Central Interior, Georgia Strait, Northeast, and Lower Fraser Valley air zones met both the SO₂ annual and 1-hour standards. The Southern Interior air zone exceeded both standards. Currently, there are no air monitoring stations in the Northwest air zone.

Canada-wide Air Quality Management System

The Air Quality Management System is Canada's approach for protecting air quality. Under the Air Quality Management System, provinces and territories monitor, report and manage local air quality within air zones, with the goal of continuously improving air quality and keeping pollutants below the Canadian Ambient Air Quality Standards.

There are seven air zones in British Columbia: Coastal, Georgia Strait, Lower Fraser Valley, Southern Interior, Central Interior, Northeast and Northwest.

The Air Zone Management Framework defines air zone management levels for sulphur dioxide based on the higher of the annual and 1-hour sulphur dioxide levels reported from monitoring stations within the air zone.

The four management levels are (1) green (actions for keeping clean areas clean); (2) yellow (actions for preventing air quality deterioration); (3) orange (actions for preventing Canadian Ambient Air Quality Standard exceedance); and (4) red (actions for achieving air zone Canadian Ambient Air Quality Standard). Each management level is associated with a suite of actions that become more rigorous as sulphur dioxide levels approach the standard. Actions for each management level are detailed in the Guidance Document on Air Zone Management (2019) (PDF).

The Southern Interior air zone was assigned to a red management level; the Central Interior, Northeast and Lower Fraser Valley to a yellow management level; and the Coastal and Georgia Strait air zones were assigned to a green management level. There are currently no air quality monitoring stations in the Northwest air zone.

Methods

R package and code: We have developed an R package to facilitate the calculation of air quality metrics according to the Canadian Ambient Air Quality Standards. Download the 'rcaaqs' package from GitHub. The source code for repeating the analysis presented on this page is also available on GitHub.

Air

Status of Sulphur Dioxide in B.C. (2019-2021)

Sulphur Dioxide (SO2): Canadian Ambient Air Quality Standard

What is an Air Zone?

More about the Canadian Ambient Air Quality Standard Sulphur Dioxide:

Canada-wide Air Quality Management System

Methods

References and Other Useful Links

Data