Experts see subsequent treaties as reducing the use of CFCs – 1987 The Montreal Protocol—as a landmark environmental achievement. Scientists estimate that this agreement could have prevented it. Millions of skin cancers. Currently, the ozone hole is recovering smoothly.
However, provocative scientific paper A paper published Friday in the journal AGU Advances suggests that the relationship between the ozone layer and human health is more complex than we think. Under certain circumstances, a small depletion of the ozone layer could save lives, the researchers wrote.
“There may be strange and unexpected ramifications that have profound implications for human health,” said Jonathan Buonocore, a professor of environmental health at Boston University and one of the study’s authors. Ta. Authors. “This is a surprise.”
The researchers were initially studying something else. The question was what would happen to atmospheric chemistry if humans injected sulfates into the stratosphere, a controversial strategy to cool the planet.
However, in the process they discovered the following Chemicals change the ozone content in the atmosphere and affect human health. Sulfate chemicals are known to destroy ozone in the upper atmosphere, but the paper says they could also reduce air pollution above the ground.
Ozone (O3) occurs in two forms in the atmosphere. There’s what scientists call “good ozone” in the stratosphere, the layer of the atmosphere between 6 and 31 miles above the Earth’s surface, and “bad ozone” in the troposphere, the atmosphere. layer that reaches the ground.
“Good ozone”, also known as the stratospheric ozone layer, protects the earth from excess substances. Ultraviolet light. Excess ultraviolet rays change DNA, cause skin cancer and eye problems, and harm plants and animals. This is why the world acted quickly to protect the ozone layer in the 1980s.
“That was the wisdom of the protocol,” said Sebastian Eastham, a researcher at the Massachusetts Institute of Technology’s Aviation and Environmental IT Institute and one of the study’s authors. Authors. “We realized that we were doing something to the stratosphere that we did not intend.”
“Bad ozone”, on the other hand, is a tropospheric air pollutant produced by power plants, automobiles, and industrial sites. It can worsen respiratory illness and lead to death. According to one study, 400,000 people In 2019 alone, people died from long-term ozone exposure.
A new paper shows that “good ozone” and “bad ozone” can interact in unexpected ways. As good ozone decreases, more UV rays reach the troposphere, increasing the incidence of skin cancer. However, UV light also catalyzes chemical reactions in the troposphere. This includes reactions involving hydroxides, or OH. Some scientists call this a “chemical reaction.”atmosphere pacman” – Swallow the pollutants. The more UV radiation the OH consumes dangerous pollutants.
Research suggests that this reduction in ground-level air pollution may actually outweigh the increase in skin cancer. According to their research, a small reduction in stratospheric ozone could save between 33,000 and 86,000 lives each year.
Only a few papers, including one from 2018, have revealed this relationship. Found as well A small reduction in the ozone layer could save lives from air pollution.
In an interview, the study’s authors emphasized that the Montreal Protocol remains valuable because it helps avoid catastrophic loss of the ozone layer. “The Montreal Protocol was a great achievement in avoiding a very unfortunate outcome,” Eastham said.
But small-scale changes come with complex trade-offs, Eastham said. For example, the people most likely to die from skin cancer primarily live in developed countries, while those who would benefit from reduced air pollution primarily live in developing countries. “You can’t automatically weigh one person’s loss against another person’s gain,” he says. “These are really difficult policy decisions.”
Atmospheric scientists not involved in the study had mixed reactions. David Fahey, director of the National Oceanic and Atmospheric Administration’s Chemical Sciences Laboratory, praised the authors’ scientific record. Fahey, who co-chairs the Montreal Protocol’s scientific review committee, said that when scientists of this caliber “come together like this, we should stop and pay attention to them.” “It’s high-quality paper.”
But Fahey cautioned that the paper should be read as an early attempt to quantify the effects of geoengineering, rather than the final word.
“This is a shot over the edge,” he said, adding that attempts to incorporate such trade-offs into the Montreal Protocol would be difficult. “Getting the consent of 197 countries is a very difficult task,” he said. “As far as I know, there isn’t really an argument like, ‘Let’s just repair the ozone layer.'”
Ross Sarawich, a professor of atmospheric science and chemistry at the University of Maryland, questioned the study’s findings.
“If you take their paper literally, you might conclude that the Montreal Protocol, which saved the world from massive ozone depletion, is probably having negative effects on human health,” he says. “That would be a very provocative statement.”
Sarawich criticized the researchers for not explaining how sulfate particles could change the meteorology of the atmosphere and, in turn, change some of the chemistry the researchers described. . He argued that the paper ignored how other human actions, such as industrial activity or driving a car, have an impact. Ground-level ozone pollution is even more serious.
“We know that human activities can have a very large impact on surface ozone,” he says. “We’re working on both issues in parallel. I think it’s a strange way of looking at the world to isolate one and look at the impact on the other.”
The paper’s authors, Eastham and Buonocore, emphasized that their aim was not to criticize the Montreal Protocol, but to provide more detailed information about its impact. They also pointed out that the paper focuses specifically on sulfates rather than CFCs. Her CFCs in the atmosphere may have similar effects on terrestrial air pollution, but they were not explicitly studied in this paper.
One way to read this study is to think of it as another warning about how dangerous ground-level air pollution is and how far the world needs to go to clean it up. (Outdoor air pollution is estimated to be large-scale. 4.2 million premature deaths Every year. )
But it also shows that changing just one small element of Earth’s atmosphere, whether due to climate change itself or attempts to limit it, can set off complex chain reactions. ing. And despite years of Earth system science research, researchers still have a limited understanding of what all these changes will look like.
“We start breaking something, and then we apply a fix that breaks something else,” Buonocore says.
