Which websites is best for looking at smoke distributions?
My wife and I had a plan to go hiking today, of course with our cute border collie/mutt “Georgie”. But where to go given the wildfire smoke. I compared the AirNow Fire and Smoke map with the Purple Air map. I was surprised at what I learned and it changed my decision about where or even whether to go hiking today!
The smoke was not too bad near our home in Seattle (AQI category of “yellow” or PM2.5 ~ 15 µg m-3). Normally this level of smoke would not stop me from going outside and hiking/biking or whatever. But knowing that the smoke was worse aloft (above ground level) and likely worse in Eastern Washington, I did not want to leave Seattle, only to drive into a huge smoke cloud up in the mountains. So being a smart air quality person, I checked the AirNow Fire and Smoke Map (https://fire.airnow.gov). This is a great resource that a number of government agencies have developed. It incorporates the most current air quality data from both the official air quality stations as well as from the Purple Air (PA) network of low cost sensors (LCS) installed by thousands of individuals (https://map.purpleair.com). Importantly, the LCS data must be corrected and I recommend to use the EPA correction equation when you use this data. The AirNow scientists did a great job of incorporating the Purple Air data into the Fire and Smoke map and this gives us a much better understanding of the spatial distribution of smoke.
The first figure below show the distribution of smoke that I saw today on the Fire and Smoke map. Looks like the smoke is pretty uniform across the region and smoke up in the mountains (Snoqualmie Pass) is no worse than in Seattle. Looks good, get those hiking boots out! But I also decided to look at the PA map. This is the second figure below. The color is similar and uses the EPA Air Quality Index scale (https://www.airnow.gov/aqi/aqi-basics/). But whereas the Fire and Smoke Map shows only the exact AQI colors (green, yellow, orange, red, etc), the PA map shows gradients between those colors. Now a different pattern emerges. While both the Fire and Smoke and PA maps report the exact same value for PM2.5 at Snoqualmie Pass (currently 32 µg m-3), its clear that the smoke steadily gets worse as one goes towards the mountains. This makes sense both because the pass is closer to the fires and at higher elevation. Since we would start hiking there and go to even higher elevation, its likely that the smoke is pretty bad today along our intended hiking route. So I guess today is a day for a local bike ride and catching up on home choirs!
By the way, if you are interested in smoke, a number of scientists will be speaking on this at the American Geophysical Union meeting in December on smoke topics. My talk there is titled “The Smokiest Cities in America”. Can you guess which locations are at the top of this list? Stay tuned to find out!
