It’s the end of October, and while there are still a few active fires, it looks like the rain is here to stay. We wanted to review the most recent smoke event and put this wildfire season into context in comparison with previous years.
Ecology's Air Monitoring Coordinator, Jill Schulte, put together these useful maps to look at the frequency and duration of smoke events. She used the daily Hazard Mapping System (HMS) smoke polygons developed by the National Oceanic and Atmospheric Administration’s (NOAA’s) Office of Satellite and Product Operations.
These polygons use daily GOES satellite imagery to categorize the density of smoke as light, medium, or heavy. Polygons categorized as heavy are more likely to indicate the presence of ground-level smoke. To make these maps, the daily heavy HMS smoke polygons during wildfire season were overlaid with 4km grid cells, and the number of days each grid cell intersected (at any part of the grid cell) a heavy smoke polygon were counted.
The first map below shows the average number of heavy wildfire smoke days from 2015-2021—you can really see how different parts of the state have been impacted by wildfire smoke over the years, with some locations experiencing on average over 20 days of wildfire smoke per year.
So how did 2022 measure up?
Another way to put this wildfire season into context is to look at how many Washingtonians were exposed to extended periods of unhealthy air in comparison to other recent smoke events.
The number of people exposed to unhealthy or worse air quality (daily PM2.5 average of > 55 micrograms per cubic meter) in 2022 is comparable to the smoke-filled days of 2017, 2018, and 2020.
One difference between 2022 and previous years is the duration of the smoke event. While the smoke lingered for much longer than we hoped this year, the majority of Washingtonians were exposed to unhealthy or worse air for less than 5 days. A smaller fraction of the state (those located closest to active fires including the areas of Darrington, Leavenworth, and Wenatchee) were exposed to unhealthy or worse air for 10-14 days.
And finally we can take a look at an updated PM2.5 cumulative exposure plot. Last we checked in early October, average statewide concentrations in 2022 were middling compared to those of the last 10 years. A week of heavy smoke makes an impact—an updated analysis below shows that average statewide PM2.5 concentrations are greater than most years in the past decade. Average cumulative 2022 PM2.5 concentrations as of 10/25/2022 are only less than 2017, 2018, and 2020—years with larger fires or smoke that blanketed the entire state for weeks.
Fantastic analysis. SO helpful for putting this year in perspective.ReplyDelete
It'd be great if you're able to comment at some point on what you think the region can expect going forward... and, if the evidence shows that the heavy smoke events of the last few years (since ~2017) are primarily an anomaly... or, cyclical. What I'm not able to tell (and this is the million dollar question) is if our recent events depict a dismal upward trend... or, if the Pacific NW just runs into heavy smoke years every so often (i.e. Mark Twain's quotes about how severe the smoke was during a visit to Olympia have been used as an indicator that recent events aren't all that unusual.)
Thanks! To answer your question about what the region can expect going forward, here are a few articles that may provide insight:Delete
Super. Thank you!Delete
Thanks so much for posting and maintaining this blog. A lot of us don't post and/or ask questions often, but we really do check in often to see if there is a new post. My question above is, is there data for the PM2.5 cumulative exposure plot that goes back more than 10 years and if so how many years back does it go (and where to get it :-)? thanks again.ReplyDelete
There is! Check out EPA's air data site for data information: https://www.epa.gov/outdoor-air-quality-dataDelete
I reside in Leavenworth and we certainly had more than 14 days of unhealthy or worse air. If there are no errors in the analysis then the culprit would be the instrument. I’ve been following air quality locally ever since the August 11th fire start and the permanent installation that .gov pulls data from significantly underreports air quality; there were many days when it would say moderate or USG and you couldn’t see more than a quarter mile through the haze. It also did not correlate well with other regional monitors in Lake Wenatchee, Cashmere, and Wenatchee, or other local PurpleAir monitors. I suggest a review of that official Leavenworth air monitor installation location, calibration, and a data comparison to other area sensors.ReplyDelete
Wonderful analysis otherwise!
Four things to keep in mind: 1) The analysis is based on 24-hour average, and there are days when "Unhealthy" air was sustained during parts of the day, but the daily average did not (the AQI messaging is a 24 hour exposure metric); 2) I reviewed the daily avg independently and see 13 days of Unhealthy or worse in Leavenworth and 8 days in the USG category (many of those USG days had "unhealthy" for certain hours, but not daily avg)... nearby monitors show similar numbers; 3) this analysis does not include purple air monitors; 4) the population in that region is small so the "population exposed" sliver (in millions) is small.Delete
To add to what Farren commented, I'll also note that after every fire season, our air monitoring operators conduct site visits to inspect monitoring instrumentation, perform any necessary maintenance, and ensure that the instruments are operating within acceptable limits. If they do find any issues with the Leavenworth monitor, they will identify and resolve them at that time.Delete
Thanks for the thoughtful and clear analysis/post. Really appreciate seeing the data in context.ReplyDelete
In Brier, after the rain today, I went outside to put away hoses, etc for the winter and the air was very smoky. Is this still from the forest fires or are people burning locally.ReplyDelete
Wildfire smoke is no longer a concern this year. Perhaps some neighbors are using their woodstoves for home heating. It's supposed to get very cold in a few days, so expect woodstove smoke to increase in general. There are areas (not near you) with prescribed burning, ag burning, or even some light wildfire smoldering leftovers... but these are localized and there is no evidence of long-range transport.Delete