Wildfire Season Off With a Bang
Wildfire in California; photo taken on May 12, 2021 by “CALFIRE_Official” (flickr; Creative Commons Attribution-NonCommercial 2.0 Generic license; image cropped from original).
by Julia Hubbard, PRI Climate Intern
August 4, 2021
August 1st marks the official start to the U.S. wildfire season, but we are already experiencing its effects in full force. Most of these wildfires are concentrated in the western U.S., where dry vegetation coupled with worsening droughts has created the perfect conditions for large fires.
But if the wildfires are thousands of miles away, why should we on the east coast be concerned? How could those fires affect us?
Maybe you’ve looked up at the sky these last few weeks and noticed a haze, or even witnessed the brilliant orange sunsets of late. These are both caused by smoke from the western fires, carried eastward within the polar jet stream, an atmospheric “current” full of fast moving winds, traveling west to east.
Figure outlining location of Polar and Subtropical Jet Streams. Image source: National Air and Space Association (NASA) (public domain).
Smoke particles can easily become entrapped in the strong current, allowing them to travel thousands of miles.
Figure outlining Fine Aerosol Optical Thickness forecast (including aerosols caused by wildfire smoke) on 7-21-2021. A higher optical thickness indicates more smoke in the air. Image source: National Air and Space Association (NASA)
But this isn't just a change in the sky, but also an increase in particulate matter. Particulate matter (PM) is a combination of tiny solid particles and drops of liquid in the air, and increasing levels of PM can lead to poor air quality. PM is typically classified by size; smoke particles generally fall between 5 and 2 micrometers (or PM10 and PM2.5), and when people inhale smoke, it can cause breathing troubles, especially for sensitive groups.
So, we have good reasons to be concerned about wildfire smoke. But here in the eastern U.S. and down at ground level, are we really being exposed to smoke from western wildfires? Over the last few weeks, we have been able to measure and document spikes in particulate matter (specifically smoke-sized particulates) here in the Ithaca area.
Graph showing PM2.5 and PM10.0 concentration over the month of July at the Cayuga Nature Center in Ithaca, NY. Image by Julia Hubbard.
The graph above was taken using a sensor located at the Cayuga Nature Center that measures PM levels, overall air quality, CO₂ concentrations, and meteorological parameters. We were able to map increases in particulate matter (the orange and blue) during times where the haze was visible (such as from July 19-22). This is consistent with smoke forecasts, created by NASA, outlining the areas of the country where wildfire smoke may be present, such as in the figure below.
Map illustrating current fires (flame symbol) and suspected fires (gold dots) in North America on 7-22-2021. The gray represents areas where wildfire smoke is present. Image source: US Air Quality Index.
While we may not have to worry about active wildfires here in New York to the degree that people are experiencing in the western U.S., that doesn’t mean we aren’t experiencing any effects from the western wildfires. Smoke causing increases in particulate matter can cause poor air quality and may be harmful to sensitive groups of people, and is certainly noticeable to all of us.