Metro Vancouver is continuing an Air Quality Advisory for eastern Metro Vancouver and central Fraser Valley Regional District that was initiated on June 26 due to high concentrations of ground-level ozone. The high concentrations are expected to persist during this hot and sunny weather. While temperatures are forecasted to be slightly lower tomorrow, hot temperatures are still expected. The region is also experiencing increased haziness, which is likely being caused by secondary formation of particulate matter. At this time, levels of fine particulate matter remain better than ambient air quality objectives.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 such as COVID-19; pregnant women and infants; children; outdoor workers (e.g. construction and agricultural workers); and older adults. 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. Indoors and outdoors, please continue to observe any COVID-19 protocols. Consider creating a comfortable space at work and home. If you are experiencing symptoms such as chest discomfort, shortness of breath, coughing or wheezing, seek prompt medical attention. Call 9-1-1 in the case of an emergency.Metro Vancouver works in cooperation with Environment and Climate Change Canada, Fraser Valley Regional District and B.C. 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  Backgrounder What 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) 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.Continue to observe any COVID-19 protocols.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 InformationNitrogen 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, B.C. 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.