Recently there have been hazy skies and colorful sunrises and sunsets in the Miami Valley. On Thursday, July 22, there was an air quality alert issued by Public Health Dayton and Montgomery County. Both of these phenomena are due at least in part to the wildfires happening in the western United States and Canada. The smoke from those fires has travelled thousands of miles in the atmosphere to Ohio.
WYSO Environmental Reporter Chris Welter spoke with Ohio University Associate Professor of Atmospheric Science Dr. Jana Houser to learn more.
Transcript (edited lightly for length and clarity):
Chris: What has been happening meteorologically?
Dr. Houser: There are currently one hundred and seventy three active wildfires in the United States. They're burning thousands and sometimes hundreds of thousands of acres of wood. All of that smoke and all of those aerosols are deposited upward. They're pumping smoke up thousands and thousands of feet into the atmosphere. So these smoke particles get dispersed over a very large depth of the atmosphere and as a result of that, you have the winds that are blowing through the atmosphere and carrying those aerosols and dispersing them over pretty much the entire United States. Actually, right now, there are air quality issues in a majority of the states in the United States.
Chris: Yesterday there was an air quality alert for the area, so there are health issues related to this as well?
Dr. Houser: Yeah, absolutely. So it is common during the summertime months to have air quality issues. Oftentimes we have relatively high pressure. The air gets kind of stagnant. We don't have a whole lot of winds to mix things up. So any kind of pollutants that are being released at the surface from cars, from your lawnmower, from industrial sources, et cetera, those get trapped in the lower levels of the atmosphere. Plus, the really warm temperatures and the availability of sunlight also causes chemical reactions that can contribute to producing molecules that are hazardous to human health. Now, when you add the smoke to that scenario, you're enhancing any kind of preexisting conditions that might be present even without that smoke. Adding those particulates exacerbates a problem that commonly already is going to occur during the summertime months. So as a result of those particulates, as well as some of the chemicals that can be generated, people with sensitive respiratory systems, with heart disease, with other kind of underlying health conditions, the elderly, very young children, et cetera, can really be affected.
Chris: We’ve seen pictures from all over the area of colorful sunrises and sunsets. Can you explain what is going on with that?
Dr. Houser: If you look up, you notice that the sky looks kind of like this odd milky, white, maybe even like a gray. But you can sort of see the sun through it. It's not really a cloud. What you're seeing is those smoke particles. Another thing that those smoke particles do is that they provide a physical site for water vapor to condense onto. So you don't just have the contribution from the smoke, but then you also are having an increase in condensation in tiny water drops.—we're talking much smaller than raindrops. So they're not precipitating out, but they are visible enough to start to obscure the sky.
What happens at sunrise and sunset is as the sun goes lower in the sky, it's actually the light from the sun is passing through a thicker layer of those aerosols than it is when you're looking vertically up. So if you're looking vertically up, you might be only passing through twenty thousand feet of smoke particles. But when you're looking kind of horizontally, the light is actually passing through a much greater distance because it’s lower on the horizon and it's passing through a more shallow depth of the aerosols for a much longer time. As a result of that, the particular size of those drops and the haze particles are actually going to make that sunlight look orange or red instead of the sort of more traditional, whitish yellow that we tend to see.
Chris: This is the second year in a row that wildfires in the west have affected the weather in Ohio. Is a pattern emerging?
Dr. Houser: We might be sort of on the tipping point of the new normal, so to speak, where we're being impacted by these fires even as far away as Ohio more frequently than we have in the past.
The sort of scary thing is that wildfire season is typically from roughly September, October, and then it kind of dies down into November out west. But we are seeing a scenario where it's occurring earlier and earlier and earlier in the summer. So there's a little bit of concern there that perhaps with climate change impacting the moisture budget and precipitation patterns, we might end up seeing a scenario where these wildfires just kind of continue to really be a problem this time of year and into the early fall season as well.
Environmental reporter Chris Welter is a corps member with Report for America, a national service program that places journalists into local newsrooms.
