Lingering wildfire smoke impacting local air quality
You may still notice a milky haze over Mid-Missouri as July comes to a close, and the wildfires bringing this smoke to our skies are burning over a thousand miles away.
As of early Wednesday, nearly 50 wildfires are burning in Oregon and Washington state, and more than 1.8 million acres have been scorched in the last week. Over a dozen more fires are raging across the border in British Columbia.
Dense smoke has led to very unhealthy to even hazardous air quality in recent days in Washington, Oregon, and Idaho. That smoke soared into the upper atmosphere and reached the jet stream, spreading the haze hundreds to thousands of miles southeast and impacting air quality all the way to the eastern seaboard.
Much of the smoke remains in the upper atmosphere, so air quality impacts are lower in the Midwest and East. Air quality sensors report moderate air quality across the Upper Midwest, down to the Deep South and over the East Coast.
Josh Vander Veen, the air quality analysis chief at MoDNR, explained some of the local impacts from the smoke. "So here in Missouri, the impacts we feel from wildfire smoke can be from very small particulate matter that can be harmful for people to breathe in." He says, adding, "Wildfire smoke can also contribute to ozone formation, which also can be harmful for people to breathe in as well."
Ozone levels haven't been as much of a problem this year, though. "So for ozone, it looks like the air quality index is good." Vander Veen said. "In 2023, we really experienced some significant ozone effects here in Missouri. And really all over the country. We've not noticed that as much this year."
Particulate matter, or PM2.5, is a different story. "For PM 2.5, it is significantly moderate across the state. The Saint Louis area is more in the good range, but the rest of the state is more in the moderate." He says.
That level of air quality can affect people with asthma or other sensitivities. "The moderate range is more for unusually sensitive people who need to be more careful about spending time outside, try to make activities shorter and less intense." Vander Veen explains. "Really, for everybody else, that's okay to be pretty active outside on a day like today."
Luckily, the smoke isn't as dense as we've seen in recent weeks. Wildfires that ignited in Canada in mid-July produced thick smoke that dropped air quality to hazardous levels for much of the northeast U.S. for several days. That smoke eventually drifted down to St. Louis by July 20th, when air quality readings dropped to unhealthy levels for sensitive groups, with PM2.5 concentrations over 140.
Though it does cause air quality concerns, the smoke has also produced brilliant sunrises and sunsets. Particulate matter from wildfire smoke reflects the usual blues and greens that reach our eyes during the day, instead allowing more reds and oranges through. The effect is most noticeable at dawn and dusk when the sun is low, because the sunlight has to pass through more of Earth's atmosphere.
Look to the skies around 8 p.m. to see the sun turn into a fierce red ball on the horizon, then wait until nightfall to catch a glimpse of the yellow-orange full moon.
Vander Veen also recommends visiting airnow.gov, the official U.S. government air quality monitoring site that features an interactive map and alerts. The Missouri Department of Natural Resources also provides air quality data across the Show-Me state on their website.
Wildfire smoke will continue drifting over the area for a few days as the upper-level pattern remains mostly fixed, though clouds and rain later in the week will shroud the hazy skies from late Thursday through Saturday.
