Status of Sulphur Dioxide in B.C. (2018-2020)

British Columbia operates a network of air monitoring stations that measure sulphur dioxide and other air pollutants. This indicator reports on the concentration of sulphur dioxide from 2018-2020 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 2018-2020 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 2018-2020 reporting period.

  • Sulphur dioxide levels met the Canadian Ambient Air Quality Standards at 49 percent 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 35 of the 71 stations (49%) for which valid data was obtained, while the 1‑hour standard was met at 37 of the 40 stations (92%) with sufficient data for analysis. The three 1-hr standard exceedances are located in the City of Trail and nearby Village of Warfield.
  • 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. Currently, there are no air monitoring stations in the Northwest air zone.