Ozone (O3)

Ozone is both a natural component of the atmosphere and a major constituent of photochemical smog. At normal atmospheric concentrations it is an odourless, colorless gas. However, at concentrations higher than one ppm, such as found near photocopier machines and near electrical discharges, it has a sharp odour.

Ozone is considered a secondary pollutant as it is created through reactions with other airborne substances, and can react with other pollutants to form photochemical smog. The largest source is vehicle exhaust; other man-made sources are from industry and chemical solvents. Natural sources include lightning and some vegetation species.

Ozone is a strong oxidizer and can irritate eyes, nose and throat and decrease athletic performance. High concentrations can increase susceptibility to respiratory disease and reduce crop yields.

What Can We Do?

  • Reduce the amount of vehicle use.
  • Use alternative transportation (car pool, walk, bike, use public transportation)
  • Use Alternative fuels (wind & solar).
  • Conserve energy. Use ‘muscle power’ rather than fuel powered machines (eg: use rake rather than lawn blower).

Alberta Guidelines

Alberta Environment guidelines for ozone are:

  • a 1-hour average of 82 ppb; and
  • a 24-hour average of 25 ppb
Provincial and federal guidelines are currently under review.

Table of Human Symptoms and Other Effects

Concentration (ppb) Exposure Time Human Symptoms and Other Effects
10,000 Severe pulmonary edema; possible acute bronchiolitis; decreased blood pressure; rapid weak pulse
1,000 Coughing; extreme fatigue; lack of coordination; increased airway resistance; decreased forced expiratory volume
500 Chest constriction; impaired carbon monoxide diffusions capacity; decrease in lung function without exercise
300 Headache; chest discomfort sufficient to prevent completion of exercise; decrease in lung function in exercising subjects
250 Increase in incidence and severity of asthma attacks; moderate eye irritation
150 For sensitive individuals, reduction in pulmonary lung function; chest discomfort; irritation of the respiratory tract, coughing and wheezing
150 Threshold for injury to vegetation
120 US national primary and secondary ambient air quality standard
100 Maximum allowed by OSHA in industrial work areas
82 1 hour Alberta ambient air quality guideline
50 Maximum recommended by ASHRAE in an air conditioned and ventilated space
20–40 Range in which ozone occurs in healthy outdoor environments. Also ozone level produced by some indoor air ionizers when operated according to instructions.
3–10 Low range at which average person can smell ozone
1 Most indoor environments — windows open

Get Involved

As an airshed, educating about air quality is an essential part of what we do. It is important to us as an organization to inform through not only sharing air quality data but also providing tips on how we can all do our part to reduce air pollution and serve as environmental stewards at an individual level.

Learn more