Monday, August 7, 2017

Rapid Worsening of Air Quality over Puget Sound Today

Air quality declined very rapidly today as temperatures rose back into the mid-80s.   Not only was the degradation obvious on air quality sensors, but visibility clearly worsened during the day.  To illustrate, here are two images from today (top) and yesterday (bottom) from the Seattle Panocam at 4:50 PM.  Much worse today.


Take a look at the small particulate measurements (PM2.5 concentrations) from some local reporting stations (graphic from Puget Sound Clean Air Agency).  Huge rise during the day today at Seattle, Tukwila, and Tacoma...with air quality today comparable to August 3/4.    Really nasty and unpleasant out, with a number of folks complaining to me about coughs and sore throats.


Why did the air quality get so bad today, something that several of us were forecasting two days ago?

 First, the low level winds over western WA switched from onshore (southwesterly and westerly) to northerly and northeasterly, thus bringing in the smoky air from the wildfires in BC.  The time/height cross section of winds/temperatures above Seattle illustrates this change.

Another major change was greater vertical mixing.  With less cool marine air near the surface, the inversion aloft, which acted as a barrier to the smoke aloft, was weaker and that allowed surface heating to mix the air in the vertical.   That is why the air quality declined during the day...vertical mixing was bringing down more and more smoky air.

Levels of PM2.5 particulates of 60-90 micrograms per cubic meter, what we saw this afternoon, are definitely unhealthy for vulnerable populations and ruin our typically great views of the water and mountains. Tomorrow should be more of the same.

Yesterdays smoke aloft really messed up the Blue Angels presentation, with the aircraft quickly disappearing into the muck as the rose vertically.  And when I flew into Sea Tac on Friday evening, the scene below was other worldy (see below).  




19 comments:

  1. We need to send a health cost bill to Canada...
    This smoke is really bad for health.

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  2. meh. I've been hiking and biking as usual and I feel great.

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    1. Good for you. My three year old daughter has asthma and this is terrifying.

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  3. Ronnie - sort of like how they billed us for sending them our acid rain?

    In reality a few days of smoke like this is not "bad for health". It would take months and probably years of daily exposure before it would have any long-lasting effects on a person's health.

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    1. But people with impaired lung function are at risk, including my dad. At hospital they told us they've seen quite a few people in the ER during the last week.

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  4. Cliff, interested in your thoughts on this study released today, which apparently the National Academy of Sciences has signed off on. Thanks.

    "Government Report Finds Drastic Impact of Climate Change on U.S."

    ://www.nytimes.com/2017/08/07/climate/climate-change-drastic-warming-trump.html?hp&action=click&pgtype=Homepage&clickSource=story-heading&module=first-column-region&region=top-news&WT.nav=top-news

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  5. Is it ok to open windows when air quality is this bad?

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    1. Common sense tells me that if you open them the air out side will come in.

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    2. I think it depends on how vulnerable you are, and how much it affects you. If you have a cough best to avoid exposure.

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    3. I would think that since the smoke is rather high, the poor air can't really make it inside. Besides, I'm in the lowlands.

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  6. Cliff, how high is the smoke? If I was to go up in the mountains would I still be affected?

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    1. It was very smoky at Mt Rainier on Saturday.

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    2. It's pretty high up there. A friend just sent me a photo on Monday from about 6000 ft up on the Ptarmigan traverse in the North Cascades. They were surrounded by smoke.

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  7. Seconding Idiophonic's question.

    I'm planning a trip into the mountains (Central Cascades) beginning a week from today. Is there a way to see forecasts of the maximum smoke elevation in mountainous terrain?

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  8. 16 years of fireline smoke. Passed a CPET test with flying colors. :) as well as many others.

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  9. Just got back from a roadtrip from Phoenix to Seattle through the beautiful scenery of the mountainous west. The scenery was gone by the time we reached northern Utah. The smoke is thick from Pocatello to Puyallup.

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  10. I was on Hurricane Ridge (5200') in ONP over the weekend and the haze was higher than the ridge and visibility was very limited. I suspect it would be the same via the webcams at MRNP.

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  11. Hey Cliff! Any idea when the smoke will clear from the Chelan area?

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  12. Remember our Mount Saint Helens... we effected the planet! How can we help our neighbors to the north?

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