Editor’s note: This article was originally published September 5, 2017. It has been updated, most recently September 8, with the most current information.
Because of widespread wildfires around the northwest—“from too many fires to count at this point,” noted the Northwest Weather Service (NWS) on Twitter—the weather report in the Seattle area once again includes smoke. Another feature that didn’t come with the last couple of smoke incidents: raining ash.
Here in Seattle, we’re lucky enough to stay put. But what does all the smoke and ash mean?
How bad is the smoke?
Friday morning, PNW Smoke Cooperators, a collaboration between various government agencies and Indian tribes, noted that a “last bit of smoke [is] holding on” in Western Washington—but conditions have improved compared to earlier this week.
While the air is slowly improving in Western Washington, the outlook isn’t as good east of the Cascades: “Limited relief [is] en route.”
According to the United States Environmental Protection Agency (EPA)’s map, Seattle’s air quality varies from good to moderate.
The U.S. Forest Service’s map, as of Tuesday morning, shows all weather-monitoring stations in Seattle as moderate—and not too far to the east in Bremerton, air quality is good again.
The Washington State Department of Ecology’s air quality map also shows mostly moderate conditions, with one outlying monitoring station in SoDo showing air as unhealthy for sensitive groups.
Those air readings don’t include the ash falling from the sky because the meters are designed to read smaller particles. Still, the ash is too large to affect air quality, says Smoke Cooperators—but it may cause eye and skin irritation.
What does that mean for me?
Here’s what that moderate air quality means, according to the Department of Ecology: “People with asthma, respiratory infection, diabetes, lung or heart disease, or have had a stroke may begin to have breathing problems,” says their guide to the ratings.
People affected may want to limit outdoor time or strenuous outdoor activities, says the guide.
The Washington State Department of Health has even more detailed recommendations, including how to tell if the smoke is adversely affecting you.
Is there a burn ban?
While there’s no air quality burn ban in effect for most of the Seattle area, fire danger is so high that the whole state is under a burn ban. Conditions are so bad that Governor Jay Inslee has declared a state of emergency.
How long will the smoke last?
While earlier this week, the EPA forecasted that Seattle’s air quality should be normal again on Thursday, that clearly didn’t happen. “What is that smoke still doing in western [Washington]?” asked Smoke Collaborators. “Overstaying it's welcome for sure!”
They said in a blog post that the reason air quality hasn’t “gone all green”—i.e., reached “good” status—is that “on-shore winds are very light... so ventilation is limited.”
They said air quality should be good again later on Friday or sometime over the weekend.