Metro Vancouver is now issuing an Air Quality Advisory for eastern Metro Vancouver and the Fraser Valley Regional District because of high concentrations of ground-level ozone that are expected to persist for the next couple of days during the hot and sunny weather. The current forecast indicates hot temperatures through Saturday, with some cooling on Sunday.Metro Vancouver is also monitoring conditions associated with wildfire smoke from fires burning in the interior of B.C. and Washington. Wildfire smoke models are forecasting that smoke from these fires may reach parts of Metro Vancouver and the Fraser Valley Regional District on Saturday and continuing in to Sunday. A change in the weather on Monday is forecast to bring onshore winds to help clear the smoke. Smoke concentrations may vary widely across the region as winds and temperatures change, and as wildfire behaviour changes.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 HEPA air cleaner filtration and air conditioning may offer relief from both heat and air pollution, but please 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). 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  For more information, contact: Metro Vancouver Information Centre at 604-432-6200 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 andearly 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.What is fine particulate matter?Fine particulate matter, also known as PM2.5, refers to airborne solid or liquid droplets with a diameter of 2.5 micrometres or less. PM2.5 can easily penetrate indoors because of its small size. PM2.5 concentrations tend to be highest around busy roads, industrial operations, major ports and areas with residential wood burning.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.Most masks worn to reduce transmission of COVID-19 provide limited protection from fine particulate matter and ground-level ozone, though a tightly-fitted, multi-layer mask can help to reduce exposure to fine particulate matter.And especially for persons with chronic underlying medical conditions:Stay in cool, air-conditioned environments, especially during the afternoon and early evening when ozone levels are highest.Reduce indoor sources of pollution such as smoking and vacuuming, and run an air cleaner. Some room air cleaners, such as those with HEPA filters, can help reduce indoor particulate levels provided they are the right size for your home and filters are changed regularly.Consider taking shelter in air-conditioned buildings which have large indoor volumes and limited entry of outdoor air, but be aware that space may be limited due to physical distancing guidelines for COVID-19 and any COVID-19 protocols must be observed.Voluntary emission reduction actionsReducing sources of fine particulates throughout Metro Vancouver and the Fraser Valley will be beneficial to air quality. Actions people can take:Minimize the use of diesel powered equipment.Follow local regulations for recreational fires. Avoid lighting a fire where possible.Additional InformationFine particulate matter is emitted from transportation sources, non-road engines, heating and burning.Fine particulate matter levels are compared to medium-term (24-hour) objectives.Nitrogen oxides are emitted from fuel combustion processes including transportation, boilers and building heating.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.