Chemicals used to make decaffeinated coffee are contributing to ozone damage

Chemicals used to decaffeinate coffee, produce paint strippers, melt plastics, and purify antibiotics are contributing to ozone depletion over the tropics.

Since the Montreal protocol in 1987, when countries agreed to phase out the use of chlorofluorocarbons (CFCs) and other harmful aerosols, the ozone layer has been healing itself. But a part of it, in the lower tropical stratosphere, has shown signs of depletion in recent years.

Researchers have blamed climate change for this discrepancy, as a warmer atmosphere accelerates the flow of warm air from the tropics toward the poles, depleting the ozone layer in the tropics.

But research by Julián Villamayor at the Institute of Physical Chemistry in Madrid, Spain, and his colleagues suggest that contamination by short-lived chemicals is also to blame.

Very short-lived substances (VSLS) are ozone-depleting chemicals that typically last only six months in the atmosphere. Some, like bromine, occur naturally, while others, like dichloromethane, are produced industrially. They are used for a wide range of applications, including the extraction of caffeine from coffee and as a propellant for aerosols. Although they are known to attack the ozone layer, their use is not regulated by the Montreal Protocol.

These substances are damaging the ozone layer in the lower tropical stratosphere, says Villamayor. “They are so short-lived that they don’t reach the highest levels of the stratosphere, nor the polar regions,” he says. “But they manage to penetrate the stratosphere through very strong tropical convection and they react in the lowest layer of the stratosphere.”

Villamayor and his colleagues used sophisticated climate models to simulate the impact of emissions from all natural and man-made VSLS on the ozone layer, and found that they can account for up to a quarter of the damage to the layer in the tropics in the past. 20 years. Climate change is responsible for the rest.

In the future, uncontrolled human use of VSLS could increase ozone depletion in the tropical stratosphere by 30 percent by the end of the century, Villamayor says.

This could have serious implications for the millions of people who live in the tropical belt, one of the most populated areas in the world, leading to increased rates of skin cancer, lower crop yields and disruptions in the food chain. Marine.

Villamayor says that countries should consider amending the Montreal protocol to restrict the use of VSLS.

Neil Harris of Cranfield University, UK, says the research is sound and agrees that the use of VSLS should face more stringent controls. “There must be a drive to reduce emissions of these compounds, for sure,” he says.