CHLOROFORM IS DESTROYING OZONE LAYER
- The United Nations announced some much needed, positive news about the environment: The ozone layer, which shields the Earth from the sun's harmful ultraviolet radiation, and which was severely depleted by decades of human-derived, ozone-destroying chemicals, is on the road to recovery.
- The dramatic turn around is a direct result of regulations set by the 1987 Montreal Protocol, a global treaty under which nearly every country in the world, including the United States, successfully acted to ban the production of chlorofluorocarbons (CFC's), the main agents of ozone depletion.
- As a result of this sustained international efforts, the United Nations projects that the ozone layer is likely to completely heal by around the middle of the century
- But a new MIT study, published in Nature Geo-science, identifies another treats to the ozone layer's recovery: chloroform-a colorless, sweet-smelling compound that is primarily used in the manufacturing of product such as Teflon and various refrigerants.
- The research found that between 2010 and 2015, emissions and concentrations of chloroform in the global atmosphere have increased significantly.
- They were able to trace the source of these emissions to East Asia, where it appears that production of products from chloroform is on the rise. If chloroform emissions continue to increase, the research predict that the recovery of the ozone layer could be delayed by four to eight years.
- Chloroform is among a class of compounds called "very short-lived substances" (VSLS), for their relatively brief stay in the atmosphere (about five months for chloroform).
- If the chemical were to linger, it would be more likely to get lofted into the stratosphere, where it would, like CFC's, decompose into ozone-destroying chlorine. But because it is generally assumed that chloroform and other VSLS's are unlikely to do any real damage to ozone, the Montreal Protocol does not stipulate regulating the compounds.
- Last year, research from the United Kingdom reported on the potential threat to the ozone layer from another very short-lived substance, dichloromethane, which like chloroform , is used as feed stocks to produce other industrial chemicals. Those research estimated how both ozone and chlorine levels in the stratosphere would change with increasing levels of dichloromethane in the atmosphere.
- The fact that rise in chloroform stems from East Asia adds further urgency to the situation.
- This region is especially susceptible to monsoons, typhoons, and other extreme storms that could give chloroform and other short-lived species a boost into the stratosphere, where they would eventually decompose into the chlorine that eats away at ozone.
- "There's an unfortunate coherence between where chloroform is being emitted and where there are frequent storms that puncture the top of the troposphere and go into the stratosphere,"
- "Now is the time to do it, when it's sort of the beginning of this trend," "Otherwise, you will get more and more of these factories built, which is what happened with CFC's, where more and more end uses were found beyond refrigerants. For chloroform, people will surely find additional uses for it."
