Smoky 'unhealthy' air is now worst in Seattle this century. How'd it get so bad?

Sigma Sreedharan Photography

SEATTLE -- The thick brownish/orange haze of wildfire smoke that is blanketed over Seattle for a second day has air quality managers seeing red.

As the smoke has become even thicker overnight, air quality readings across much of Western Washington had degraded into the red or "unhealthy for all" category.

Data from the Puget Sound Clean Air Agency shows the Tuesday-Wednesday 24 hour average for particulate matter is the highest since records began in 2000, beating out the terribly smoky day on Aug. 4, 2017. (But it's been worse in the 1980s!)

At this level, air quality managers stress that anyone who is sensitive to air quality not to do any strenuous physical activity outside. That would include those with heart or lung issues, diabetes, over the age of 65, children or pregnant women. Even those who aren't in the sensitive groups should try to limit physical activity out in the smoke. The Puget Sound Clean Air Agency is simply recommending people in the Puget Sound region just stay indoors Wednesday.

What can bad air quality do for your health? The Puget Sound Clean Air Agency says wildfire smoke can create a range of health problems, including Wildfire smoke can cause a range of health problems including: asthma attacks, trouble breathing, coughing, stinging eyes, irritated sinuses, headaches, chest pain and fast heartbeats.

While indoors, here are some steps from the Department of Health to limit exposure to wildfire smoke:

  • Keep windows and doors closed. Track the outside air quality and open your windows for fresh air when the air quality improves. Use fans to circulate the air.
  • If you have an air conditioner, set it to re-circulate and close the fresh-air intake. Make sure to change the filter regularly. (Also make sure to set this back to normal after the smoke clears)
  • Use an air cleaner with a high-efficiency particulate air (HEPA) filter to reduce indoor air pollution, this will reduce the number of irritating fine particles in indoor air. A HEPA filter with charcoal will help remove some of the gases from the smoke. Don’t use an air cleaner that produces ozone. See California’s air cleaning devices for the home fact sheet.
  • Don’t add to indoor pollution. Don’t smoke. Don’t use food broilers, candles, incense, fireplaces, or gas stoves. Don’t vacuum unless your vacuum has a HEPA filter, because vacuuming stirs up particles already inside your home.

Same advice goes for if you're in a car: Set the air conditioner to recirculate instead of draw in from outside.

The agency also recommends schools, camps, sports teams, and daycare providers should consider postponing outdoor activities or moving them indoors. Already school officials in Shelton have moved their football practices for the day indoors.

MORE | Current Smoke Info | Health tips for dealing with smoke

How did it get so bad?

The smoky air is rivaling the worst of last year's smoke events and is among the worst it gets around Seattle. How did we manage that?

This is among the meteorological worst case scenarios for bringing in dense smoke into Seattle and Western Washington. First of all, we're essentially surrounded by wildfire smoke on three sides -- B.C. Fires to the north, Central and Eastern Washington wildfires to the east and the still raging fires in Northern California to the south. Even the Maple Fire burning in the Olympics is giving localized smoke from the west.

For the past few weeks, we've been getting smoke blown in at upper levels from the California fires, but that switched around after Saturday's rainfall briefly brought in northerly flow and lower smoke from the closer fires burning in B.C. Then high pressure rebuilt overhead. High pressure systems bring sinking air -- that's why there's usually sunshine with high pressure because sinking air warms and dries out. But in this case, the sinking air is dragging the smoke to the surface and creating an inversion lid that makes it more difficult to air to mix up vertically.

Closer to the ground, the way the high is positioned -- nearly overhead -- it's creating very little in the way of pressure difference to bring in much wind, but what little wind we have been getting is coming from the east/northeast, not the typical west.

That's a double whammy: The east wind is importing even more smoke from the fires in Central Washington and lower B.C. *and* it holds back the typical ocean seabreezes. We were hopeful that the marine breeze would come in and at least scour out some of the smoke Tuesday night but it was too weak.

Even more: what should have been a day in the 90s with high pressure and a light east wind was instead held to the mid 80s due to the smoke-filtered sun. The lesser heating meant less rising air that can sometimes draw in at least localized seabrezes.

So in a nutshell: Our wind machine was broken. The result: Another day trapped in the gunk.

"For Seattle, this is as high as we can ever generally get," said meteorologist Erik Saganic with the Puget Sound Clean Air Agency.

When will it get better?

In the short term we should get some relief from the ground smoke Wednesday night. I know, famous last words as we promised that Tuesday but there is more solid evidence we'll get a better push of ocean breezes overnight to at least get improvement. Conditions look better on the ground through the weekend.

But this current "worst case" pattern looks to regenerate next week for a second potential round of lowland smoke. Meanwhile, smoke will likely remain aloft for quite some time. We're heading back to California smoke the rest of this week, but signs are we'll switch back to Canadian smoke next week. We need to get a solid westerly flow off the ocean to really clean us out, but that's hard to find in the summer. We're typically dominated by persistent high pressure in the West in the summer.

The jet stream is up in northern B.C. and the Alaska panhandle now and doesn't come back here usually until later September -- there's a reason our summers are so dry! We may see occasional brief improvements with day to day weather changes but smoky skies will likely be a frequent occurrence until we get into the rainy season.

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