BALTIMORE — The state of California has aggressively pursued an eco-friendly agenda, focusing on reducing greenhouse gases in recent years. Ironically, however, researchers from Johns Hopkins have found that the Golden State is actually our nation’s largest emitter of one lesser-known greenhouse gas: Sulfuryl fluoride.
When people hear the term “greenhouse gases,” they usually think of carbon dioxide, methane, and nitrous oxide. When these gases enter the environment, they trap heat in our atmosphere, contributing to the global dilemma collectively known as climate change. While it’s true that the three gases account for the majority of greenhouse gases in the atmosphere, there are many other gases and chemicals at play as well. One of those is sulfuryl fluoride, a common pesticide used against termites and other wood-infesting insects.
On a global scale, the United States is responsible for as much as 17 percent of global emissions of this gas. Incredibly, researchers find that the majority of those U.S. sulfuryl fluoride emissions (12%) originate from just a handful of counties in California.
“When we finally mapped it out, the results were puzzling because the emissions were all coming from one place,” says study co-author Scot Miller, an assistant professor of environmental health and engineering at Johns Hopkins who studies greenhouse gases and air pollutants, in a media release. “Other greenhouse gases like carbon dioxide and methane are found everywhere across the U.S. On our sulfuryl fluoride map, only California lit up like a Christmas tree.”
In collaboration with lead author Dylan Gaeta, a PhD candidate at Johns Hopkins, Prof. Miller analyzed over 15,000 air samples collected between 2015 and 2019 by NOAA Global Monitoring Laboratory scientists. Study authors were also sure to account for other factors like wind speed, direction, and other meteorological variables while tracing the chemicals back to their origins.
This approach led to the finding that 60 to 85 percent of sulfuryl fluoride emissions in the U.S. come from California. More specifically, Los Angeles, Orange, and San Diego counties. This is especially strange, considering California is a national leader when it comes to policies aimed at reducing greenhouse gas emissions. The state even published a comprehensive plan to achieve net-zero emissions by 2045.
“We can now show not only where but also how and why this gas is being emitted,” Gaeta adds. “In order to get to net-zero emissions, we need a complete inventory of what greenhouse gases are out there.”
Originally approved by the U.S. Environmental Protection Agency for use as a pesticide in 1959, sulfuryl fluoride became more popular after countries all over the world agreed to phase out more reactive fumigants shown to be depleting the ozone layer, researchers explain.
Since California has kept thorough pesticide use records, the team successfully attributed the vast majority (roughly 85%) of the state’s sulfuryl fluoride emissions to structural fumigation, which refers to sealing an infested structure with an airtight tent, pumping gas into the tent to kill the pests, and then venting the gas directly into the atmosphere. About 15 percent, meanwhile, came from agricultural and commodities fumigation.
The gas spreads and lingers within the atmosphere for over 40 years, where it contributes to global warming by trapping heat and sending it back down to the Earth’s surface. While average concentrations of sulfuryl fluoride in the atmosphere are low, study authors still caution humans have been emitting the man-made gas for decades at a rate faster than it can break down naturally.
“Without some form of intervention, sulfuryl fluoride is going to keep accumulating in our atmosphere. For most greenhouse gases, California has been very intentional about how it’s going to reduce emissions,” Gaeta notes. “This one has slipped under the radar.”
Typical efforts to reduce greenhouse gas emissions usually focus on carbon because it poses the greatest threat to global warming. However, researchers are still focusing on forming a more complete picture of the risks tied to other greenhouse gases.
Sulfuryl fluoride is one of the few effective treatments for ridding buildings of drywood termites. They’re a common regional pest known to form colonies in high, hard-to-reach parts of wooden structures. It’s also frequently used at shipping ports to kill pests before they can hitch a ride on boats to other parts of the world.
“It really is a double-edged sword. Sulfuryl fluoride is less harmful than the banned fumigants, but it also contributes to global warming,” Prof. Miller concludes. “California’s track record shows that it’s been looking at out-of-the-box, creative ways to reduce its greenhouse gas emissions. I think knowing better what the emissions are and what impact they have will give the state the information it needs to help holistically develop greenhouse gas reduction strategies.”
The study is published in the journal Communications Earth & Environment.
Eco Hypocrisy seems to me a very unfair title lead-in designed only for its sensationalism in that the article shows no such POV within the body of it.