Laughing gas is the biggest threat to the Earth’s ozone layer

Laughing gas is now the biggest threat to the earth’s ozone layer and is likely to remain so throughout this century, says a new study. An international team, led by A R Ravishankara of the US National Oceanic and Atmospheric Administration, has found that nitrous oxide, commonly called laughing gas, has replaced chlorofluorocarbons(CFCs) as the potent destroyer of ozone in the Earth’s upper atmosphere. The dramatic reduction in CFCs over the last 20 years is an environmental success story. But man-made nitrous oxide is the ‘elephant’ in the room among ozone-depleting substances. “Right now, nitrous oxide is the most important ozone depleting gas that is emitted. It will continue to be so unless something is done”, Dr.Ravishankara was quoted by the New Scientist as saying. The team calculated the ozone depletion potential of nitrous oxide, to come to the conclusion that is ts threatening the ozone layer which shields Earth from the ultraviolet rays of the Sun, which increases the risk of cancer. Nitrous Oxide (N2O) is produced naturally when nitrogen in soil or water is eaten by bacteria. It then rises into the stratosphere where most of it is broken down into harmless molecules of nitrogen and oxygen by the Sun’s rays. But some of it remains, and can survive for hundreds of years. The compound reacts with high-energy oxygen atoms to produce a deadlier compound nitric oxide (NO. this then goes on to destroy ozone, a molecule made up of three oxygen atoms. Nitrous oxide is also a heat-trapping greenhouse gas in the league of methane or carbon-dioxide, so regulating it would, also be good for the climate”, Ravishankara said. The findings are published in the latest edition of the Science journal.
The New Indian Express, 29th August 2009