Monday, September 21, 2020

Phew, glad we're done with that. Now what's next?

No doubt everyone breathed easy yesterday when air quality in the whole state returned to Good. How long will it stay that way?

The map of monitors above shows Moderate or Unhealthy for Sensitive Groups air at several locations in Clark, Klickitat and southern Yakima counties. These are due to smoldering fires nearby. Even though fires are not puffing smoke like they were, low- buoyancy plumes are still draining some smoke into nearby cities. 

These kind of relatively low grade and relatively localized impacts will continue on and off through late Tuesday. "Low grade" compared to last week, that is. A weak system tonight won't help a whole lot but a strong, wet front early Wednesday will show the smoke who's boss and knock back the fires. Impressive 24-hour total precipitation ending 5PM Wednesday, as per the average of all ensemble models at UW.

Two weaker storm systems are expected Thursday and Friday, bringing more good news to smoke- weary Washingtonians. However calmer, dryer conditions under high pressure are possible Sunday onward so lets not pop the champagne cork yet. 

Friday, September 18, 2020

Slow improvement still happening, plus more data showing WA population exposed to smoke

Forecast update

The Olympic Peninsula has pretty much cleared out now, and several Puget Sound area sites are trending downward. Rain is helping a bit, but the weakening inversion is helping most. Still on track to see mostly Good to Moderate air in western WA by tomorrow

Just for kicks, take a look at how some sites in the Olympic Peninsula responded yesterday when a low pressure system offshore initially helped ventilate the area and then dragged in smoke from Oregon fires. Who said smoke dynamics aren't complex!

Most monitors in eastern WA have been pretty static today (read: Unhealthy to Very Unhealthy air) but cross Cascade winds are starting to pick up and will eventually make their way into the Columbia Basin overnight. Eastern WA will start seeing seeing improvements on Saturday, reaching Good to Moderate by Sunday

We're nearly theredone for now. Don't be fatigued with the health precautions.

FYI, Ecology's air monitor in Yakima will be taken offline later today due to renovations happening at the host facility. But our staff proactively installed a temporary monitor in Union Gap, so there is no gap (no pun intended, honest!) in data coverage. Data should start appearing on the above map very soon. 

Population exposed to smoke (written by Ecology's Andrew Wineke)

As an agency dedicated to protecting air quality in our state, we’ve been trying to wrap our minds around not just what the numbers are this hour, but what the longer impacts of this kind of smoke storm may be. 

As we’ve moved from one record-poor air quality day to the next, we’ve shared some charts and analyses as we work through those questions. One important takeaway is that more Washington communities have been exposed to more hazardous levels of particulate pollution than we’ve ever seen since we began monitoring for PM2.5 (the most concerning type of particulate pollution found in wildfire smoke) back in the early 2000s.

Geographic extent is just one way to look at it, though. Sometimes, we have quite serious wildfires that don’t affect many people – either because of helpful weather patterns that blow the smoke away, or simply because they are burning in thinly populated regions.

Ecology researcher Beth Friedman looked at how many Washingtonians have been exposed to extended periods of unhealthy air, compared to other recent smoke events. Looking at the smoke exposures this way helps us contrast this year’s smoke storm with other major events like 2018, where smoke from Canadian wildfires bathed much of our state with a longer period of less-intense air pollution. 

So how does 2020 measure up when we account for populations in smoke- impacted areas? It may not surprise you that 2020 is a stinker: The number of people exposed to very unhealthy or worse air quality for a week or more is practically off the charts compared to 2018, 2017, or 2015. 

Or if you want to include the Unhealthy category in the comparison:

Clearly, this has been an incredibly bad week for Washington’s biggest cities – and it hasn’t been a walk in the park for our less populated areas, either. 

Thursday, September 17, 2020

The worst is behind us but it ain't over yet

So when will it be over?

Western WA: Early Saturday

Eastern WA: Saturday night

Why so long?

Western WA: Encouraging reductions at Olympic Peninsula monitors today and smaller improvements since yesterday in the Puget Sound lowlands. But strong winds off the Pacific are MIA so we have take what the lighter, shifty winds with a little rain (minions!) dish out. These minions are bringing disorganized, mixed results. Some smoke from Oregon fires are now being transported to western WA due to a wind shift, and even though a lot of that smoke is still aloft, it delays the already slow scrubbing process. Expecting Good to Moderate air in much of western WA by Saturday. 

However Clark county and the Columbia River Gorge might continue to see Very Unhealthy air through tomorrow at least because of the proximity to fires, and their relief will be later on Saturday.

Eastern WA: The last 3 runs of the more pessimistic models have continued to show good ventilation across the Columbia Basin on Saturday, so there is good confidence this wont be a busted forecast. This will not immediately erode away all the smoke stuck in valleys, so it needs some time to do it's thing. By Sunday morning most of the air should be Good to Moderate, except very close to fires. 

So how bad did it get?

Some of our readers asked to see a comparison of the # of successive days we were exposed to Very Unhealthy or Hazardous air. Dr Beth Friedman constructed the following plot to answer this question. 

All of 2020's days were from the last week or so. Sadly this wasn't the worst run of bad air for our friends in Chelan and Okanogan counties. 

Note: Monitors did not operate during all of the last 3 years are in the following 3 counties, and they are not included in the above plot. Their stretch of bad days was:







No data



No data

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 But it is nearly over now and we don't see an immediate return to terrible air next week, so hang in there Washington!

P.S. Don't throw open your windows to air out the house the moment air quality improves. With these minions around, it is best to wait a few hours to be sure there is a sustained improvement. 

Understanding your Air Quality numbers

 As our coastal sites turn green this morning and we start to see hope for clean air for the rest of us later today and tomorrow, I thought I’d take a minute to clarify some common misconceptions regarding air quality numbers, where they come from and what they mean to you.  The two indices, Air Quality Index (AQI) vs. Washington Air Quality Advisory (WAQA), have created a lot of confusion.

Both AQI and WAQA are a unitless index calculated from a given concentration of air pollution. There are several different measured pollutants that affect air quality: PM2.5, ozone, NOx, CO, and SO2. PM2.5 is the most commonly measured and generally the one of most concern in Washington state, especially during wildfire smoke episodes. Although all these pollutants can affect AQI and WAQA values, I’m only going to focus on PM2.5 in this post.

State and Federal government run air quality maps ( and use the same air quality monitors and data to determine air quality in your area, but they use a different index to represent what that air quality means for your health.

So, why are there two different indices?  Although we assign breakpoints to the different categories, air quality is a spectrum. Every person will be affected by poor air quality differently.  These are general guidelines and the breakpoints are based on statistical assessments of how large numbers of people respond to varying levels of poor air quality. EPA studies have assigned risk at a certain point, while Washington state toxicology research found more protective levels would better serve our community. Looking at the breakpoints in this table, a PM2.5 concentration equal to 50 ug/m3 is considered unhealthy by WAQA standards, but unhealthy for sensitive groups when using the AQI scale. You are not a statistic and may be adversely affected at moderate levels, or perhaps you can go hiking without difficulty when conditions are unhealthy for sensitive groups.  For individual health concerns, your best bet is to consult your doctor.

AQI and WAQA health risk categories are based on a 24-hour exposure. The number you see on the map is updated hourly and represents the previous hourly average weighted by the air quality observed over several hours before. For example, if the air quality is green all morning and a nearby building catches on fire, smoke may affect the monitor for one or two hours at unhealthy (red) levels, before returning to green. The monitor may only show unhealthy for sensitive groups (orange) during those two hours since the exposure time was so short. As we observed at the beginning of this smoke event, heavy smoke rolled into some areas very quickly and air quality went from good to hazardous in 30 minutes. The map will not update that value until the hour of data collection is complete and may take another hour or two to catch up to instantaneous air quality. Both airnow and the state maps have the option to look at the actual hourly PM2.5 concentration from the previous hour. Those numbers will be the same on both maps.

The second question we often get is “who is more trustworthy? My air quality app, a third-party air quality reporting site, airnow, or the state air quality map”? It is important to understand all these sites are using the same data, if they are using actual air quality measurements. We don’t often know how third-party apps and websites calculate the AQI or interpret our data. In that sense, we consider EPA and the state map to be the gold standard as we are directly involved in collecting the data, making sure it’s valid, and reporting the concentrations.


Wednesday, September 16, 2020

Since this is the era of big data, lets compare our plight with those from far and wide

There are claims that we've been exposed to the worst air in the world. True? Fair comparison? Let's investigate that without belittling the terrible air quality conditions we've all had to endure for at least a week now.  

Here's a map of global air quality right now. It uses all available measurements worldwide and uses machine learning methods for spatially interpolation. US west coast is in baaad shape. Worst ranked cities right now are all in our neck of the woods. 

But to do a proper apples-to-apples comparison, we should compare our air during our "bad" season with the "bad" seasons in other places, not our bad against their better times. So lets leverage data from the US State Department's (DoS) air quality monitors around the world. These are easily obtained from one place and have a pretty good quality control regime. 

I've pooled PM2.5 data from the ten highest embassies which recorded data for at least two years anywhere between 2012- 2019. These are: New Delhi & Kolkata (India), Dhaka (Bangladesh), Ulaanbaatar (Mongolia), Kampala (Uganda), Kathmandu (Nepal), Jakarta (Indonesia), Chengdu & Shenyang (China), and Manama (Bahrain). You can see more details about their air quality here. "Normal" conditions were defined as the range between monthly lower and upper quartiles, since the median passes right in the middle of it. This is also known as the interquartile range, or IQR.

The above figure shows how air quality in Seattle, Spokane, Vancouver, Omak and Yakima have varied from 1 Jan- 15 Sept 2020, against the backdrop of IQRs at ten embassies. As can be seen, the overseas cities experience terribly compromised air quality primarily in the winter months. Right now is their "better" season. Even though we spiked right to the top of the AQI chart this week, bear in mind that:

  • All these overseas locations see concentrations that are higher than their own IQRs 25% of the time. Or put another way, they record even higher concentrations for 3 months of the year.
  • Our air will not remain this bad for several months. Most WA sites have experienced some improvement already and we're still on track to clear out in the Friday- Saturday timeframe. 
  • In spite of our wintertime temperature inversions and woodsmoke concerns, we're still in far better shape at that time of year.

Moral of the story: yes its bad here now. Many others have it worse for much longer. Folks who live in these environments and our diplomats serving there can offer us some coping tips. 

Tuesday, September 15, 2020

Where's the smoke coming from now?

One key thing that we need to get smoke out of the air is to stop putting smoke into the air. So where is the smoke coming from now? Here in Washington we have some active fires although the map of Washington below is somewhat misleading as only a few of the fires shown are producing significant amounts of smoke. Three fires in the state were listed as showing moderate fire behavior today including the Big Hollow, the Inchelium Complex, and the Cold Springs fires. The others including Whitney, Fish, Apple Acres, Pearl Hill, Sumner Grade, Customs Road, Babb, Manning Road, and Evans Canyon are listed with minimal fire behavior so they are not smoke free but are unlikely to be making significant contributions to our impaired air quality outside their local area.

But to the south in Oregon there are numerous very large fires that are actively burning and sending smoke north to Washington. The northern group of fires including Riverside, Beachie Creek, and Lionshead, plus a few small ones nearby have a combined size of nearly 500,000 acres and are burning in heavy timber, slash, and brush fuel types. But that’s not all, numerous other large fires stretch the length of the Oregon Cascades and into California. Recent wind conditions have been moving smoke from these fires to the north and right towards us. The smoke layer has actually resulted in cooling many of the fires somewhat although as the smoke begins to thin out somewhat the fires are expected to become more active. More smoke, less fire, less smoke, more fire? It sounds like an unfortunate cycle. 

But on the horizon, arriving Thursday and lasting until Saturday, there is a prediction for enough rain in the Oregon Cascades to tamp these fires down considerably. Will they go out? No. And the farther south in Oregon you go, the less the rain will result in significant suppression of the fires. But the hard work of the firefighters combined with an assist from the weather gods should result in a pretty decent reduction in smoke production by later this week. Let’s hope so!