Swamp Stomp
Volume 17, Issue 42
Wildfires produce large clouds of smoke. No one knows what the smoke clouds are made of unless a sample is taken directly from the cloud and tested. This is exactly what was done during the Rim Fire in Yosemite. A NASA DC-8 passenger plane and an Alpha fighter jet each flew through the plume with in-flight labs, that scientists created to measure exactly what the fire was producing.
Though the obvious answer is that fire creates smoke, not all smoke is made up of the same gases. The only way to tell the difference is to study the particles they ferry along. “That’s what you’re actually seeing when you see a smoke plume, you know the big white smoke plume. That’s sunlight bouncing off the little particles,” says Bob Yokelson, an atmospheric chemist at the University of Montana. What makes up smoke matters to human lungs and the climate—which is why Yokelson’s team and NASA’s Alpha jet crew are busy planning their next flights for late summer.
It is not easy to make a lab fly. It can take over a year for teams of scientists to design and assemble custom gas and particle measurement systems. Not only does to these finicky, temperamental machines have to work at a range of temperatures and pressures, they also need to neatly replace a row of plane seats or get even smaller.
The Alpha jet was converted from a fighter jet in 2010. Before this could happen, it had to be quieted down for civilian airspace, and equipped with sensors to measure trace gases in the atmosphere: ozone, carbon dioxide, methane, and formaldehyde. As its two pilots follow a fire’s smoke, the sensors continuously measure the air, according to Laura Iraci, the NASA chemist who runs the experiments. After a two or three hour flight, they land back at the airstrip with data cards full of numbers to analyze.
When Yokelson and his team outfit a jetliner like the DC-8 that flew to the Rim Fire, they get to renovate the plane’s interior. “We’ll take out every other row of seats, and bolt down instruments in their place, so now you have the scientist sitting in front of an instrument and they can monitor the data as we’re sampling the atmosphere,” he says. This summer, their team is getting a C-130 jet ready for its close-up–test flights, set for September.
Airborne studies like these have highlighted that wildfires burn dirtier than the ones that are carefully lit and contained in the forest. More particulate matter is produced by the bigger logs and wetter material. Also as fires smolder longer, they can actually start to release a serious amount of methane, which traps more heat in the atmosphere than carbon dioxide.
Both Yokelson and Iraci have lots more questions about what else fires dump into the atmosphere, and how the airspace changes throughout the course of a fire. Once the planes are ready again, they are headed for more smoke. The accurate field measurements are the key to good air quality and climate change models. The EPA would love to predict how wildfire pollutants might descend on neighboring cities and states. “We’re really optimistic that our data can provide sort of truth, so they can continue improving their models,” says Iraci. It may take a season or two to pump new data in, but predicting air quality around wildfires could get a lot better in the next few years.
Source: Wilhelm, Menaka. “The Tricked-Out Research Planes That Fly Through Wildfires.” Wired. Conde Nast, 25 July 2017. Web. 31 July 2017.