Ammonium Nitrate Chemistry

Ozone Cheats Found

In May of this year scientists reported that atmospheric levels of one of the most important ozone depleting gases, CFC-11, were not declining as quickly as they should be.  Modelling showed that new sources of CFC-11 out of east Asia were required to explain this worrying finding, and that these sources were large: 13 gigagrams per year of extra CFC-11 since 2012.  This was in apparent contravention of the Montreal Protocol, an international treaty ratified by all nations.  As I wrote at the time, possible sources included clandestine production of the banned compound and leaky stockpiles of old material. Reports soon emerged that leaking fridges were probably accounting for some of the emissions increases, and now an investigative piece by the New York Times has reported that factories in rural China are still manufacturing CFC-11 and releasing it to the atmosphere in the production of polyurethane foam.

These new reports are consistent with the initial scientific findings of increased emissions, in that they originate in Asia and they comprise only CFC-11 and not the related chlorofluorocarbon CFC-13. Furthermore, use of CFC-11 for foam production makes more sense than as a refrigerant; cheaper alternatives designed for use in modern refrigeration cycles are available but CFC-11 still makes an excellent polyurethane blowing agent.

It still remains to be determined if these rogue chemical plants can account for most of the new CFC-11 emissions.  However, the production and use of any CFC-11 is a major international incident which needs to be rigorously prosecuted in order to help ensure the ongoing recovery of our planet's protective ozone layer.