Beijing has been turning a blind eye to manufacturers in northeastern China – big and small – who are spewing large quantities of ozone-depleting gases into the atmosphere.

This is the conclusion of a study by Western universities, which noted that the move contravenes an international treaty which China signed and vowed to adhere to.

Annual emissions from northeastern China’s Liaoning, Jilin and Heilongjiang provinces of the banned chemical trichlorofluoromethane, or CFC-11, have increased by about 7,000 tonnes since 2013, scientific journal Nature reported.

Emissions of CFC-11 are the main substance causing rapid depletion of the stratospheric ozone layer, which protects humans and all other species from the sun’s ultraviolet radiation.

The chlorofluorocarbon was widely used in the 1970s and 80s as a refrigerant and to make foam insulation, until the 1987 Montreal Protocol banned CFCs and other industrial aerosols that can dissolve the ozone layer 10 to 40 kilometers above the Earth’s surface, especially over Antarctica and Australia. The treaty marked a steady decline in the use of CFCs since then.

But Matt Rigby, an atmospheric chemist at the University of Bristol, who is a lead author of a related thesis, found last year that the pace of CFC-11 reduction worldwide stalled between 2013 and 2017, likely due to new, illegal emissions.

CPCs seem to be coming from China’s Shandong and Hebei provinces. Photo: University of Bristol

Another lead author, Park Sun-young of Kyungpook National University in South Korea, said an international team of atmospheric scientists gathered additional data from monitoring stations in Taiwan and Japan and did not find evidence of increased emissions from Japan, the Korean Peninsula or any other country – but there were “spikes” in pollution when air arrived from industrialized areas in China, such as those in the nation’s three northeastern provinces.

The team also ran computer simulations that confirmed the origin of the CFC-11 molecules to nail down the exact origin.

Also, reports published last year by the Environmental Investigation Agency (EIA), a non-government group, fingered Chinese foam factories in the coastal province of Shandong and the inland province of Hebei as the source of new CFCs.

But the Chinese Ministry of Ecology and Environment has categorically denied that new CPC-11 emissions were from China. It claimed that law enforcers had been conducting surprise checks around the country and said that any factory found of using the ozone-depleting gas would be shut down.

The ministry said cut-price Chinese insulation in its home construction industry should not be blamed for the massive rise in emissions of the gas, claiming that such practices were common in developing countries.

’18 Chinese firms culpable’

But a 2018 BBC report noted that researchers from the EIA contacted foam manufacturers in 10 different provinces across China and their discussions with executives in 18 such companies led them to conclude that the chemical was used in the majority of the polyurethane insulation these firms produced.

One seller of CFC-11 estimated that 70% of China’s domestic sales used the illegal gas, as CFC-11 is better quality and much cheaper than the alternatives.

China’s polyurethane foam makes up about a third of global production, so when manufacturers there predominantly use an ozone-depleting substance it will set back the decades-long global efforts to close the ozone hole.