Research suggests nitrous oxide has significant ozone-depleting potential
September 15, 2009
According to a team of US researchers from the National Oceanic and Atmospheric Administration (NOAA), nitrous oxide is the single most important man-made substance reducing ozone in the atmosphere.
Nitrous oxide has now become the largest ozone-depleting substance emitted through human activities, and is expected to remain the largest throughout the 21st century. Nitrous oxide is emitted from natural sources and as a by-product of agricultural fertilisation and other industrial processes. Calculating the effect on the ozone layer now and in the future, NOAA researchers found that emissions of nitrous oxide from human activities erode the ozone layer and will continue to do so for many decades.
The team calculated the ozone-depleting potential (ODP) of nitrous oxide and found it comparable to several currently-controlled substances. Using a well-known atmospheric model, the researchers calculated that while the ODP of nitrous oxide is smaller than that of chlorofluorocarbons (CFCs), it is comparable to many hydrochlorofluorocarbons (HCFCs).
Nitrous oxide bears many similarities to CFCs in that they are both very stable in the troposphere where they are emitted, and when they reach the stratosphere release active chemicals that destroy ozone through chlorine or nitrogen oxide-catalysed reactions. However, while this process has been understood for decades, a focus on CFCs and HCFCs has meant the importance of nitrous oxide has been overlooked.
The researchers suggest that curbing nitrous oxide emissions could help speed up recovery of the earth's protective ozone layer and, since nitrous oxide is also a greenhouse gas, could also be an effective way to tackle global warming.
Print this page