A study published last week investigated the effects of gases known as VSLS (Very Short-Lived Substances) on the ozone layer over the tropics. Despite only lasting up to six months in the atmosphere, these chemicals — used in the decaffeination of coffee, for example — are not regulated for use.
The ozone layer — which protects the planet from ultraviolet radiation from the sun — has been severely affected over decades by the use of substances such as chlorofluorocarbons (CFCs). In 1987, the signing of the Montreal Protocol made countries commit to cutting the production of these chemicals, applied in refrigeration systems and aerosols. Since then, the hole that formed annually over the poles has been regenerating – but that doesn’t mean that ozone is completely free of threats.
Portions of this protective layer in the tropics have been showing signs of a drop in ozone concentration over the last few years. Scientists thought the reason for this was climate change: a warmer atmosphere leads to a faster flow of the substance towards the poles. As much as this process actually occurs, it is not the only culprit, as short-lived pollutants would also be affecting ozone availability.
Among the chemicals reported by the study are a number of halogenated organic compounds – which have chlorine, bromine or iodine. These substances are applied for various purposes, such as removing caffeine from coffee, purifying antibiotics and as aerosol propellants. Despite their negative effects, they have never had their use regulated.
According to calculations carried out by the researchers, the impact of VSLS on the ozone layer in the tropics accounts for a quarter of the loss of the substance in the region, while the remainder is associated with climate change. The scientists suggest that countries consider amending the Montreal Protocol to answer this question.
Source: Nature Via: NewScientist
