British Columbia operates a network of air monitoring stations that measure nitrogen dioxide and other air pollutants. This indicator reports on the concentration of nitrogen dioxide and compares it to the Canadian Ambient Air Quality Standards established by the Canadian Council of Ministers of the Environment.

• Nitrogen Dioxide (NO₂) is a gaseous pollutant. It is formed along with other nitrogen oxides (NO_x) during the combustion of fossil fuels in cars, trucks, ships, and industrial facilities.
• NO₂ exposure is known to affect human health and the environment. Long term exposures, for example, has been shown to induce the development of allergic responses, asthma, increases the susceptibility for respiratory infections (including COVID-19), and has been linked to cardiovascular system and reproductive effects. Short term exposures can reduce lung function and aggravate respiratory symptoms and airway inflammation. These effects have no observed lower threshold, i.e., negative effects are observed even at low concentrations.
• Environmental effects of NO₂ (and NO_x in general) include altered plant growth due to absorption through their leaves and from nitrogen deposition. Impact on plants can negatively affect animals like caribou that depend on arboreal lichens for sustenance. NO₂ also has indirect effects including its role in ozone formation and acid rain. Ozone is detrimental to plant life because exposure oxidizes (burns) plant tissues, and acid rain results in the acidification and eutrophication of ecosystems. Reddish-brown haze commonly found over urban centres is the result of higher concentrations of NO₂ pollution.

The map below summarises the assigned management levels for nitrogen 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 nitrogen dioxide levels for the 2018-2020 reporting period.

• Nitrogen dioxide levels met the Canadian Ambient Air Quality Standards at 73% of the assessed monitoring stations in B.C. There are two standards for NO₂—an annual standard and a 1-hour standard (see sidebar). The annual standard was met at 46 of the 63 stations (73%) for which valid data was obtained, while the 1‑hour standard was met at 45 of the 45 stations (100%) with sufficient data for analysis.
• Nitrogen dioxide levels met both of the Canadian Ambient Air Quality Standards in five of B.C.’s seven air zones. All air zones met the annual standard. Central Interior, Coastal, Georgia Strait, Northeast, and Southern Interior air zones met the 1‑hr standard, while the Lower Fraser Valley air zone exceeded it. Currently,there are no air monitoring stations in the Northwest air zone.