Friday, October 9, 2020

And with that we wrap up our coverage for 2020, but before you go there are a few things to know

As always, good news first

Wildfires in WA and most of OR are out and there is no risk of returning to the terrible conditions we endured last month. Fall meteorology is active enough to keep air moving along and prevent a buildup of pollutants.

What to watch for

  • Northern CA fires are still burning and an occasional whiff of smoke is still possible. Western WA got a small dose earlier this week, causing Moderate air in some areas. 
  • Wintertime wood smoke season is coming and while it almost never gets as bad as what we've just been through, temperature inversions and light winds can cause smoke to stagnate. Valley communities are more prone to this and often experience poor air.
  • Check if an air quality burn ban has been called for your area (not to be confused with fire safety burn bans). 
  • We recommend our readers keep an eye on the map at the top of this page. It is automatically updated with measured fine particle pollution data and a two-day forecast, year round. 
  • This blog also contains resources on how to safeguard your health during polluted periods. 

See you in summer 2021!

Thursday, October 1, 2020

You can see it, but you don't have to breathe most of it. How cool is that

Smoke continues to hover overhead and the previous forecast still holds. As explained there the temperature inversion is still keeping the smoke at bay. We've hardly seen air quality deteriorating beyond Moderate anywhere in the state, or further upwind in Oregon for that matter. 

There is fog in the Puget Sound lowlands and this will recur each morning through Sunday. Fog should not be confused with smoke. Here's an illustration of what's what as seen from above, but only an air quality monitor can distinguish between the two at ground level.

Things will stay that way and start to "improve" by Saturday night as a slight wind shift s-l-o-w-l-y disconnects us from the CA smoke late in the weekend. Models are persisting with the inversion in western WA so any residual smoke aloft wont mix down all that much. But inversions also lock in our own local emissions at the surface. Overall, we can expect:

  • Good to Moderate air in much of the state
  • Moderate or areas of Unhealthy for Sensitive Groups in the higher terrain of the Olympics and Cascades (hard to pin down what elevation the transition occurs).
  • Saturday's sunset may not be as colorful

BTW the air quality monitoring data map at the top of this blog has been upgraded to show both the new EPA Fire/ Smoke map that incorporates corrected low-cost sensor data, and our 2-day PM2.5 forecast. Might take a moment to load. If you're using a mobile device, scroll to the bottom of this page and click "View web version" to see this.