Weather conditions such as wind, rainfall, temperature and terrain affect outdoor air quality. The types and amount of pollutants released into the air also affect outdoor air quality.

Sources of pollution include heating appliances, burning items, and exhaust from gas- and diesel-powered machines. When more pollution is released into the air, our air quality worsens. Air pollutants can also become trapped during calm and stable weather conditions. This means even if the amount of pollution created stays the same, the air quality can become worse if the local air is staying in one place. Over time, air quality is usually worse in places close to sources of pollution, like places next to busy roads.

We can experience poor air quality during any season, during both cold and hot weather. During hot weather, air quality often worsens due to increased ozone created by heat and sunlight. Wildfires can also contribute to poor air quality during summer. During cold weather, there can be increased pollution from burning fuels for heat.

Be alerted to poor air quality by downloading the WeatherCAN app and change your plans if needed.

The Air Quality Health Index (AQHI) is measured on a scale of one (low) to 10+ (very high). The AQHI index values are grouped into four categories that help you to easily and quickly identify your level of health risk:

  • Low health risk: AQHI values from one to three
  • Moderate health risk: AQHI values from four to six
  • High health risk: AQHI values from seven to 10
  • Very high health risk: AQHI values above 10 (a very rare occurrence usually connected to wildfire smoke)

When AQHI levels reach moderate, it is best to monitor how you and others are feeling, drink lots of water and spend time in indoor spaces with air filtration systems.

Postpone or reduce outdoor physical activity while particulate matter or PM2.5 concentrations are high, especially if breathing feels uncomfortable. Exposure to PM2.5 is particularly a concern for people with underlying conditions such as lung disease, heart disease, chronic obstructive pulmonary disease (COPD), asthma and/or diabetes; individuals with respiratory infections; pregnant women and infants; children; older adults and outdoor workers (e.g. construction and agricultural workers). Individuals who are socially marginalized may also be at elevated risk (e.g. people who are experiencing homelessness or are underhoused).

General resources

Resources for monitoring air quality

Please see this page for translated content from the BCCDC.