Smoke from the wildfires in B.C. and Eastern Washington obscures the Seattle, 20 August 2018. Photo: Morgan Palmer / KIRO-TV

By Umair Irfan
21 August 2018(Vox) – Ash and smoke are choking Seattle’s air for the second week in a row, as wildfires smolder in the Cascades and in British Columbia.As of Tuesday morning, the Air Quality Index in Seattle was at 181, a rating classified as “unhealthy.” In parts of the city, the index rose as high as 220, which is “very unhealthy.” Other parts of Puget Sound, like Port Angeles, Washington — 80 miles from Seattle — saw the AQI rise to 205.To put it in perspective, an AQI of 150 is roughly equal to smoking seven cigarettes in a day. That means residents should avoid being outside and exerting themselves, particularly people with heart and lung problems, the elderly, and children.The air quality in Seattle this week has been worse than in Beijing, one of the world’s most notoriously polluted cities. The flames from some of the massive wildfires that have raged from Alaska to New Mexico have destroyed homes and taken lives, but the smoke and ash in the air are one of the most insidious threats to health. Since nearly 2 million acres have burned in the United States this year from 109 fires in 12 states ranging from Alaska to New Mexico, many regions are affected.Wildfires have ignited in the Pacific Northwest before, but usually Seattle’s weather quenches flames and clears smoke pretty quickly.That the region has remained so hot and dry this year, allowing smoke to linger, is highly unusual, Andrew Wineke, a spokesperson for the state Ecology Department’s air quality program, told Q13 Fox. But it also happened last year. “The trend is clear. You see the number of forest fires increasing, and so there’s going to be wildfires,” Wineke said. “There’s going to be smoke. It’s going to be somewhere.” [more]

Breathing Seattle’s air right now is like smoking 7 cigarettes. Blame wildfires.Satellite of smoke over Washington state from wildfires in British Columbia and Weastern Washington, 21 August 2018. Photo: NASA Worldview

By Cliff Mass
20 August 2018
(Cliff Mass Weather and Climate Blog) – Folks were surprised how quickly the air quality deteriorated Sunday afternoon, rapidly going from moderate air quality to unhealthy conditions with a profound loss of visibility.     Things improved over night around Seattle, but then went downhill today–with the worst hourly smoke levels on record (back several decades).
Let me show you and explain the fascinating and complex situation we are in.Here is a plot of the particulate levels (PM2.5) at the Puget Sound Clean Air Agency Duwamish site from last Tuesday to 3 PM today (Monday).   You can see the rapid surge of smoke yesterday afternoon, followed by a sudden fall in yesterday evening.  And then it started rising again this morning, reaching a peak now that is far higher that either yesterday or last week.

Graph of the particulate levels (PM2.5) at the Puget Sound Clean Air Agency Duwamish site from Tuesday, 13 August 2018 to 3 PM on Monday, 20 August 2018.   Graphic: Puget Sound Clean Air Agency

In fact, this hourly smoke level is the highest on record at this site (going back roughly two decades) and higher than anything last summer–the plot below is the proof!

Graph of the particulate levels (PM2.5) at the Puget Sound Clean Air Agency Duwamish site from 29 June 2017 to 20 August 2018. Graphic: Puget Sound Clean Air Agency

Yesterday, as the winds aloft turned northerly and northeasterly, the huge reservoir of smoke in British Columbia and eastern Washington surged southward overhead, but air quality did not decline immediately.As the surface warmed, the lower atmosphere started to mix, higher and higher, eventually tapping the smoke aloft and bringing it down to the surface.  That is what caused the air quality to rapidly degrade. […]As illustrated by the EPA AirNow graphic, although it is smoky over Puget Sound, it is crazy bad in Port Townsend and Port Angeles, as well as areas along the eastern slopes of the North Cascades where the numbers are in the 200s. Extraordinarily unhealthy. [more]

Another Surge of Wildfire Smoke Hits Puget Sound: The Worst on Record