London —Despite a programme to stop illegal production, north-east China is using industrial quantities of CFC-11.
The revelation is published in Nature, a peer-reviewed scientific journal. It follows a 2018 pledge by signatories to the Montreal Protocol to hunt down illicit CFC sources.
It is the second time in as many years that CFC production has been reported as coming from East Asia. In 2018, samples collected at monitoring stations in Hawaii flagged the general location.
The latest research triangulates the location of the emission using air samples taken in South Korea and Japan.
These suggest that over half the surge in CFC-11 emissions originates in the provinces of Shandong and Hebei.There could be up to 7000 tonne/year production.
Matthew Rigby, an atmospheric chemist at the University of Bristol, UK is the lead author of the report. He said the result is 'pretty unequivocal.'
Four independent modelling groups analysed have atmospheric circulation patterns in the study. All came identified north east China as the source.