An air stagnation advisory is in effect for the South Puget Sound until Monday afternoon. The National Weather Service says a ridge of high pressure over the Pacific Northwest will keep the weather dry through Monday and will allow a strong temperature inversion to form. Strong east winds are expected near the Cascade foothills but light winds are expected elsewhere, especially over areas around south Puget Sound. These conditions will cause the air to gradually become stagnant and allow pollutants to build up. Air quality will likely deteriorate over the weekend. Pollution could increase to dangerous levels. Persons with respiratory illness should follow their doctor’s advice for dealing with high levels of air pollution.