METRO Vancouver is now issuing an Air Quality Advisory for eastern parts of Metro Vancouver and the Fraser Valley because of high concentrations of ground-level ozone that are expected to persist until tomorrow and potentially longer as hot sunny weather continues.

Ground-level ozone is not emitted directly into the air. It is formed when nitrogen oxides (pollutants emitted when fuels are burned) and volatile organic compounds (emitted from solvents) react in the air in the presence of sunlight. The highest levels of ground-level ozone are generally observed between mid-afternoon and early evening on summer days.

Avoid strenuous outdoor activities during mid-afternoon, when ozone levels are highest. Exposure is particularly a concern for infants, the elderly and those who have underlying medical conditions such as lung or heart disease and asthma. If you are experiencing symptoms such as chest discomfort, shortness of breath, coughing or wheezing, follow the advice of your healthcare provider. As we are in the summer season with warm temperatures, it is also important to stay cool and hydrated. Indoor spaces with air conditioning may offer relief from both heat and air pollution.

Smoke from a wildfire burning north of Harrison Hot Springs is also occasionally reaching parts of the Lower Fraser Valley, causing fine particulate matter concentrations to be slightly higher than normal but remaining below advisory levels. This has affected visual air quality conditions with a noticeable haze, and may be contributing to ozone levels as well.

This advisory is expected to continue until temperatures cool.

Metro Vancouver works in cooperation with Environment Canada, the Fraser Valley Regional District and B.C. Ministry of Environment to look after air quality.

Information about real-time air quality readings for Metro Vancouver and the Fraser Valley communities and potential health impacts can be found at http://www.airmap.ca and http://www2.gov.bc.ca/gov/content/environment/air-land-water/air.