As we’ve tracked the smoky, ashy air in recent days – with murky skies, and reddened sun and full moon (photo at right is by Jim Spraker), plus Weather Service alerts – one question came up in comment discussion: Why didn’t the Puget Sound Clean Air Agency order a burn ban this time? We sent the question to the agency’s communications team two days ago. Today, they sent air-quality scientist Phil Swartzendruber our way to explain. And even though the smoke is clearing, so it’s a moot point for now, we thought you might be interested in how he explained it during our phone conversation:
First, the agency’s authority to call for burn bans is “pretty specific about the criteria” – a particular level of particulate matter, which is what’s in the smoke, NOT the ash, and forecasting that it’s going to be at an “unhealthy” level.
And they need to be able to predict it – and that it’s going to last at least two days – if it’s just going to be a day (or less), he says, it’s not worth the effort, because they figure it’ll take a day or so just for the news to get out. (We did suggest the agency might reconsider that, given that online and social media tend to spread that news fairly quickly – this has long since ceased being a world where you might not hear about something until the evening TV news or morning newspaper.)
What’s been happening, Swartzendruber explained, is “unprecedented,” and something their network isn’t set up to predict – trying to figure out how the smoke is coming in and how weather factors will affect it. In this case, the smoke was coming in from “upstream” – above us – not moving along the surface. Rain, wind, clouds all can be seen via radar and other equipment, but not something like this. “It takes a huge amount of guesswork,” he said. And their best guess has to be that the air will remain in the “unhealthy” category for more than 24 hours.
On Tuesday, the best guess they had was that things would be getting better faster. But “it didn’t clear out as much as we had hoped” after all, and ended up lingering into Wednesday.
Today, he says, they are fairly certain we’re “over the hump.”
So last month, when burn bans were called, things were actually worse? we asked. Swartzendruber said yes, though it might have LOOKED worse these past few days, especially once the ash showed up, the air quality overall was better than it was, minus ash, back in August. In addition, he said, various factors at that time left them fairly confident “the conditions (would) last three, four days.”
P.S. The Weather Service’s extended Air Quality Alert has indeed expired, indicating that things are getting back to normal … for now. The fires around the region, however, continue to burn.