Is soot in the air from fires bad for our health?

The Wichita Eagle

After the giant Barber County fire in March had burned for a day, the winds started blowing toward the northeast and on March 23 the Wichita sky turned into a scene from a post-apocalyptic science fiction movie and smelled like a citywide barbecue.

On April 4 the scene repeated itself, when an increasingly thick layer of smoke obscured driving in the afternoon, created spectacular sunset scenes in the evening and again gave off the aromatic sense of a mandatory smoked-meat competition that night.

But these were very different kinds of smoke when it comes to your health, according to Baylee Cunningham, air quality specialist for the city of Wichita.

That’s because on March 23 the city saw a couple of hours of decreased air quality but the rest of the day was pretty clean. So when it comes to tracking Wichita’s air quality, according to standards set by the Environmental Protection Agency, Cunningham said, it didn’t exceed an acceptable threshold.

“It looks really, really scary out there when we have grass fires surrounding the city and smoke billowing in,” Cunningham said. “During the Barber County fire we had reports that ash was hitting the ground. That is a scary thought.”

Part of the reason is that some of the ash and soot will be filtered out by your nose and lungs, she said. Often it’s the smaller particles, gases and liquids, about 1/28th the thickness of a human hair, that get deep into your lungs and cause damage.

Cunningham is mostly concerned with ground-level ozone, commonly referred to as smog. When this gets into your lungs for longer periods it can cause throat irritation, shortness of breath and tightness in the chest and can trigger asthma in children.

On April 4, the city’s ozone levels exceeded the EPA’s acceptable threshold of 70 parts per billion. The smoke was blowing from the east and so it likely came from controlled burns in the Flint Hills, where most of the spring smoke comes from, according to Cunningham.

Most ranchers, historians and conservation scientists say that burning farmland and pastureland in Kansas helps protect the prairie grassland and prevent massive fires like the one in Barber County from getting out of hand.

But usually when farmers and ranchers burn their lands it doesn’t affect Wichita’s air quality enough to cause alarm, Cunningham said, because it happens in the spring, before temperatures get too hot. Ozone needs the heat from the sun, so typically the worst air quality days are in the summer.

This year’s air quality has been affected because it has been unusually dry, Cunningham said. But still only one day has reached the threshold that the EPA says is when most people need to start to seriously worry. And every city is allowed three bad days per year, before it starts to count against the city’s official air quality measures.

Even April 4 would not have exceeded standards 10 years ago, because the EPA keeps tightening its health standards as it gathers more evidence about the potential impact, Cunningham said.

The science does not yet tell us how many people or what kind of person will get sick, she said, if the air quality is bad for one hour or eight hours. Healthy people can have symptoms, and people with asthma may not. It just depends.

Cunningham said there are approximately 300,000 people in the Wichita area who could be considered members of a sensitive group, who “have an increasing likelihood of experiencing respiratory symptoms and breathing discomfort if they are active outdoors (exhibit exertion) for a prolonged period of time when ozone concentrations are between 71-85 ppb.”

But she said that typically people experience symptoms only when they do moderate or vigorous exercise outside in the bad air. So on days when the air quality decreases, people can play it safe by staying indoors or not exerting themselves too hard when they do go outside.

People in Wichita can check AirNow.gov to see what the air quality is like, although Cunningham warns that the data comes in on a two-hour delay. So on April 4 at 6 p.m., when the air quality reached its peak ozone level of 109 parts per billion, 39 above the level considered safe, it didn’t show up on the maps until past 8 p.m.

That meant that most people were already home or on their way home before they could get out an official warning.

“From my perspective it’s absurd,” Cunningham said, “because I want to know what the current air quality conditions are.”

Oliver Morrison: 316-268-6499, @ORMorrison

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