Invisible Volatilization - Methyl Chloride and Ozone Layer Effects

Invisible Volatilization - Methyl Chloride and Ozone Layer Effects

Methyl chloride (chloromethane) is a type of volatile organic compound (VOC) involved in ozone depletion, and was once widely used in industrial applications and as an agricultural fumigant. For a long time, its environmental impact has been overlooked amidst the focus on CFCs and CFC regulations. However, a 2000 survey by the National Institute for Environmental Studies revealed that methyl chloride occurs naturally in tropical forests and along coastlines, making it clear that the impact of naturally occurring sources should be considered in addition to conventional man-made emission sources.

In the same year, the Japan Meteorological Agency announced that ozone depletion over Antarctica had reached 96.22 million tons, the largest ozone hole ever recorded. The impact of methyl chloride has begun to be pointed out as a factor in the failure of the ozone layer to recover even after CFC controls. 232 tons of methyl chloride emissions were reported annually in Japan in the 2020s, and the relationship between industrial emissions and naturally occurring emissions is being closely watched in particular. In the future, along with emission control, it will be necessary to monitor fluctuations in natural occurrence due to climate change and promote comprehensive countermeasures.