Ozone layer recovery could be delayed by 30 years
Rising global emissions of some chlorine-containing chemicals could slow the progress made in healing the ozone layer.
A study found the substances, widely used for paint stripping and in the manufacture of PVC, are increasing much faster than previously thought.
Mainly produced in China, these compounds are not currently regulated.
Experts say their continued use could set back the closing of the ozone hole by up to 30 years.
Scientists reported last year that they had detected the first clear evidence that the thinning of the protective ozone layer was diminishing.
The Montreal Protocol, which was signed 30 years ago, was the key to this progress. It has progressively helped governments phase out the chlorofluorocarbons and the hydrochlorofluorocarbons that were causing the problem.
However, concern has been growing over the past few years about a number of chemicals, dubbed "very short-lived substances".
Dichloromethane is one of these chemicals, and is used as an industrial solvent and a paint remover. Levels in the atmosphere have increased by 60% over the past decade.
Another compound highlighted in this new report is dichloroethane. It's used in the manufacture of polyvinyl chloride or PVC, a light plastic widely used in construction, agriculture and elsewhere.
For a long time, scientists believed that both these compounds would decay before getting up as far as the ozone layer.
However, air samples analysed in this new study suggest this view may be mistaken and these destructive elements are getting there quicker and doing more damage than thought.
"We believe that if we carry on with these emissions we'll delay the recovery of the layer," said Dr Oram.
"At the moment an average date for ozone recovery could be about 2050 but there are studies that say this could be delayed by 20-30 years depending on future emissions of things like dichloromethane."
