Provincial Air Quality Objectives for Nitrogen Dioxide

Nitrogen Dioxide (NO2) is a gaseous pollutant. It is produced along with other nitrogen oxide (NOx) during high-temperature fossil fuel combustion.

Exposure to NO2 affects human health and the environment. For example, long term exposure causes:

  • Allergic responses
  • Asthma
  • Respiratory infections
  • Harm to the cardiovascular and reproduction system

Short term exposure can reduce lung function and worsen:

  • Respiratory symptoms
  • Airway inflammation

Even at lower concentrations, NO2 can be harmful.

NO2 air quality objectives

In November 2021, B.C. adopted the 2020 Canadian Ambient Air Quality Standards (CAAQS) for NO2 as the new Provincial Air Quality Objectives.

This replaced the standards that have been used since 2014. 

Provincial Air Quality Objectives for NO2
Metric or Criteria Level Calculation Method
1-hour 60 parts per billion 98th percentile of daily 1-hour maximum over three years
Annual 17 parts per billion Average of 1-hour concentrations over one year