Researchers detected a surprising rise in levels of chlorofluorocarbons between 2010 and 2020 using a monitoring network that includes the Jungfraujoch research station in Switzerland. Credit: Shutterstock
Topics: Chemistry, Civilization, Climate Change, Environment, Global Warming
From my resume: “I eliminated ozone-depleting materials using Failure Mode and Effects Analysis (FMEA) and Taguchi Methods of Quality Engineering – using an L16 Orthogonal Array – in the Poly Silicon etch processes substituting out CFCs in manufacturing processes.” How I did it: I substituted our CFC with Sulfur Hexafluoride and Nitrogen (SF6/N2). On the negative photoresist product, the CFC over-etch was 50 seconds. For the positive photoresist, CFC had a 25-second process. I was able to reduce each product line to two seconds, increasing throughput, and the process increased die yields. It is possible to balance the positive impact of product improvement and the environment. I did it in the 90s, so the following report is disappointing.
The Montreal Protocol, which banned most uses of ozone-destroying chemicals known as chlorofluorocarbons (CFCs) and called for their global phase-out by 2010, has been a great success story: Earth’s ozone layer is projected to recover by the 2060s.
So atmospheric chemists were surprised to see a troubling signal in recent data. They found that the levels of five CFCs rose rapidly in the atmosphere from 2010 to 2020. Their results are published today in Nature Geoscience1.
“This shouldn’t be happening,” says Martin Vollmer, an atmospheric chemist at the Swiss Federal Laboratories for Materials Science and Technology in Dübendorf, who helped to analyze data from an international network of CFC monitors. “We expect the opposite trend. We expect them to slowly go down.”
At current levels, these CFCs do not pose much threat to the ozone layer’s healing, said Luke Western, a chemist at the University of Bristol, UK, at an online press conference on 30 March. CFCs, once used as refrigerants and aerosols, can persist in the atmosphere for hundreds of years. Given that they are potent greenhouse gases, eliminating emissions of these CFCs will also have a positive impact on Earth’s climate. The collective annual warming effect of these five chemicals on the planet is equivalent to the emissions produced by a small country like Switzerland.
It’s highly likely that manufacturing plants are accidentally releasing three of the chemicals — CFC-113a, CFC-114a, and CFC-115 — while producing replacements for CFCs. When CFCs were phased out, hydrofluorocarbons (HFCs) were brought in as substitutes. But CFCs can crop up as unintended by-products during HFC manufacture. This accidental production is discouraged by the Montreal Protocol but not prohibited by it.
‘This shouldn’t be happening: levels of banned CFCs rising, Katherine Bourzac, Nature