Metro Vancouver is continuing 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 through Sunday. Hot and sunny conditions are forecast to continue through the weekend. Wildfire smoke from the Nohomin Creek fire (near Lytton, BC) and other fires in the province may occasionally contribute to hazy conditions over the region but measured fine particulate matter concentrations remain below air quality objectives at ground level.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 and other sources) 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 to early evening, when ozone levels are highest, especially if breathing feels uncomfortable. Consider choosing easier outdoor activities, such as walking instead of running, where you don’t have to breathe as hard. Exposure is particularly a concern for people with underlying conditions such as lung disease, heart disease, chronic obstructive pulmonary disease (COPD) including bronchitis and emphysema, as well as 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).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. Consider using a portable air conditioner to keep your indoor space comfortable (if you do not have central air conditioning).If you are experiencing symptoms such as chest discomfort, shortness of breath, coughing or wheezing, seek prompt medical attention. Call 911 in the case of an emergency.Metro Vancouver works in cooperation with Environment and Climate Change Canada, Fraser Valley Regional District and BC Ministry of Environment and Climate Change Strategy to look after air quality.Information about real-time air quality readings for Metro Vancouver and Fraser Valley communities and potential health impacts can be found at www.airmap.ca and www.env.gov.bc.ca/epd/bcairquality/readings/find-stations-map.html.To sign up for air quality alerts in your area, go to www.metrovancouver.org/services/air-quality/engagement/mailing-list.BACKGROUNDERWhat is ground-level ozone?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 and other sources) 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. A brief video by Metro Vancouver explaining how ground-level ozone is formed can be found at player.vimeo.com/video/218925373.Tips to reduce your personal health risk:• Stay cool and drink plenty of water.• Use symptom management medications such as inhalers if needed.• Continue to manage acute infections such as COVID-19, or pre-existing chronic medical conditions such as lung disease, heart disease, COPD, asthma, and/or diabetes. If symptoms continue to be bothersome, seek medical attention.• Maintaining good overall health is a good way to prevent health effects resulting from short-term exposure to air pollution.• Masks worn to reduce transmission of COVID-19 provide little protection from gases such as ground-level ozone.And especially for persons with chronic underlying medical conditions:• Stay in cool, air-conditioned environments, especially during the afternoon when ground-level ozone levels are at their highest, and reduce indoor pollution sources such as smoking and vacuuming.• Consider creating a comfortable space at home with a portable air conditioner if you do not have central air conditioning.Voluntary emission reduction actionsReducing air emissions throughout Metro Vancouver and the Fraser Valley will be beneficial to air quality. Actions people can take:• Minimize the use of vehicles, and avoid idling your vehicle.• Avoid refuelling with gasoline during the hottest time of day.• Minimize the use of other gasoline and diesel engines, such as lawn mowers and trimmers.Additional Information• Nitrogen oxides are emitted from transportation sources, boilers, building heating, and other combustion processes.• Volatile organic compounds commonly arise from burning fossil fuels, solvent evaporation (including paint, varnishes and thinners), fuel refining and storage, fuel refilling and agricultural activities, as well as natural sources such as vegetation.• Ozone levels are compared to short-term (one-hour) and medium-term (eight-hour) objectives. The short-term objective measures the peak/highest concentration and the medium-term objective represents the average over the period of the day when levels are generally elevated.Under provincial legislation, Metro Vancouver is responsible for monitoring air quality, controlling industrial, commercial and some residential emissions, creating long-term plans, and conducting emission inventories for the Metro Vancouver region.To help reduce air emissions throughout the Lower Mainland, Metro Vancouver works cooperatively with Fraser Valley Regional District, BC Ministry of Environment and Climate Change Strategy, Environment and Climate Change Canada and other agencies to develop and implement emission reduction programs for businesses and local residents. Further information about air quality programs in the region can be found on Metro Vancouver's website at www.metrovancouver.org.