What does advisory mean?

What does an "air stagnation advisory" mean?

• There's an advisory in effect where I live, and I'm not sure what it means. Like, what should I look out for, what should I do, etc. Any help would be great!

• Answer:

  "Air stagnation is a phenomenon which occurs when an air mass remains over an area for an extended period of time. Due to light winds and lack of precipitation, pollutants cannot be cleared from the air, either gaseous (like ozone) or particulate (like soot or dust). In the United States, the National Weather Service issues an Air Stagnation Advisory when these conditions are likely to occur." "Air Stagnation - A meteorological situation in which there is a major buildup of air pollution in the atmosphere. This usually occurs when the same air mass is parked over the same area for several days. During this time, the light winds cannot "cleanse" the buildup of smoke, dust, gases, and other industrial air pollution." Under these conditions, fine particles trapped in smoke at ground level can be inhaled deeply into lungs and damage delicate lung tissues. Young children, pregnant women, people with asthma and other lung or heart conditions, and people over 50 are at greatest risk and should consider restricting their outdoor activities. The Oregon Department of Environmental Quality (DEQ) is asking residents in the affected advisory areas to avoid using fireplaces and woodstoves unless absolutely necessary, refrain from outdoor burning, and limit driving and vehicle idling.