Metro Vancouver has issued an Air Quality Advisory for Metro Vancouver and the Fraser Valley because of high concentrations of fine particulate matter (PM2.5) due to wildfires outside of the region.
The air quality advisory was issued on Tuesday morning and is expected to remain in place until at least Wednesday.
Smoke, which has primarily come from wildfires burning in North California, Oregon and Washington state, is the cause of the deteriorating air quality in and around Vancouver.
Fine particulate matter, also known as PM2.5, refers to airborne solid or liquid droplets with a diameter of 2.5 micrometres (µm) or less. PM2.5 can easily penetrate indoors because of their small size.
Meanwhile, concentrations of ground-level ozone are also expected to reach advisory levels in the region due to hot weather conditions, said the agency.
Ground-level ozone is formed when nitrogen oxides (pollutants emitted when fuels are burned) and volatile organic compounds (emitted from solvents) react in the air in sunlight.
Exposure to ozone and fine particulate matter is of concern for infants, the elderly and those with underlying medical conditions like lung disease, heart disease, diabetes or asthma.
Vancouverites are advised to avoid strenuous outdoor activities, particularly during mid-afternoon and early evening when ozone levels are highest.
If you are experiencing symptoms such as chest discomfort, shortness of breath, coughing or wheezing, follow the advice of your healthcare provider, says Environment Canada.
The advisory is expected to continue until there is a change in the current weather.
Information about real-time air quality readings for Metro Vancouver and the Fraser Valley communities and potential health impacts can be found here.