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Banned Chemical Responsible For Antarctic Ozone Hole

After considering a number of possible causes, researchers concluded that CFC emissions must have increased after 2012.

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Emissions of a banned chemical most responsible for the giant Antarctic ozone hole are on the rise, according to a study which suggests that an international treaty that required an end to its production in 2010 is being violated.
Ozone Hole Representational Image. Pixabay
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Emissions of a banned chemical most responsible for the giant Antarctic ozone hole are on the rise, according to a study which suggests that an international treaty that required an end to its production in 2010 is being violated.

Trichlorofluoromethane, or CFC-11, is the second-most abundant ozone-depleting gas in the atmosphere and a member of the family of chemicals most responsible for the giant hole in the ozone layer that forms over Antarctica each September.

Once widely used as a foaming agent, production of CFC-11 was phased out by the Montreal Protocol in 2010.

The new study, published in the journal Nature, documents an unexpected increase in emissions of this gas, likely from new, unreported production.

“We’re raising a flag to the global community to say, ‘This is what’s going on, and it is taking us away from timely recovery from ozone depletion,'” said Stephen Montzka, scientist at the US National Oceanic and Atmospheric Administration (NOAA).

“Further work is needed to figure out exactly why emissions of CFC-11 are increasing and if something can be done about it soon,” said Montzka.

CFCs were once widely used in the manufacture of aerosol sprays, as blowing agents for foams and packing materials, as solvents, and as refrigerants.

Though production of CFCs was phased out by the Montreal Protocol, a large reservoir of CFC-11 exists today primarily contained in foam insulation in buildings, and appliances manufactured before the mid-1990s. A smaller amount of CFC-11 also exists today in chillers.

Since CFC-11 still accounts for one-quarter of all chlorine present in today’s stratosphere, expectations for the ozone hole to heal by mid-century depend on an accelerating decline of CFC-11 in the atmosphere as its emissions diminish – which should happen with no new CFC-11 production.

Emissions of a banned chemical most responsible for the giant Antarctic ozone hole are on the rise, according to a study which suggests that an international treaty that required an end to its production in 2010 is being violated.
Chemical Emission is the main reason of the hole in Ozone layer above Antarctica. Pixabay

Despite the increase in CFC-11 emissions, its concentration in the atmosphere continues to decrease, but only about half as fast as the decline observed a few years ago, and at a substantially slower rate than expected.

This means that the total concentration of ozone-depleting chemicals, overall, is still decreasing in the atmosphere. However, that decrease is significantly slower than it would be without the new CFC emissions.

Precise measurements of global atmospheric concentrations of CFC-11 made by scientists at 12 remote sites around the globe show that CFC-11 concentrations declined at an accelerating rate prior to 2002 as expected.

Then the rate of decline hardly changed over the decade that followed. Even more unexpected was that the rate of decline slowed by 50 per cent after 2012.

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After considering a number of possible causes, researchers concluded that CFC emissions must have increased after 2012.

This conclusion was confirmed by other changes recorded in NOAA’s measurements during the same period, such as a widening difference between CFC-11 concentrations in the northern and southern hemispheres – evidence that the new source was somewhere north of the equator.

Measurements from Hawaii indicate the sources of the increasing emissions are likely in eastern Asia. More work will be needed to narrow down the locations of these new emissions, Montzka said. (IANS)

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According To Study, Ozone Exposure At Birth May Up Asthma Risk

Exposure to ozone (O3) -- a common air pollutant -- at birth may increase the risk of developing asthma by age three, a new study suggests.

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Medical Doctors With a Caring Heart
Medical Doctors With a Caring Heart. Pixabay

Exposure to ozone (O3) — a common air pollutant — at birth may increase the risk of developing asthma by age three, a new study suggests.

The study, presented at the 2018 American Thoracic Society International Conference, showed that 31 per cent of the participants developed asthma, 42 per cent had allergic rhinitis and 76 per cent had eczema.

“Our findings show that the hazard ratios for ozone measured at birth as a single pollutant showed statistically significant higher risks for development of asthma, allergic rhinitis and eczema,” said lead author Teresa To from The Hospital for Sick Children (SickKids) in Canada.

The study also found that 82 per cent higher risk of developing asthma was associated with each 10 parts per billion (ppb), or ppb increase in exposure to ozone at birth.

For the study, 1,881 children were recruited who were followed from birth to 17 years of age, on average.

Childhood asthma can trigger COPD in later life. IANS

 

According to the researchers, children are at a higher risk because their lungs and other respiratory organs are smaller, and they spend more time in outdoor physical activities that make them breathe faster and more deeply.

The research team took annual average concentrations of pollutants from fixed monitoring stations.

Development of asthma, allergic rhinitis and eczema were determined based on any records of health services used for these conditions.

The researchers adjusted for variables such as parental history of asthma and early home exposure to pollutants.

Earlier, some studies have shown that ozone depletes antioxidant activity and increases indications of inflammation in the respiratory tract fluid lining and affects lung growth.

Also Read: Exposure to Traffic-Related Pollution Poses Threat of Asthma in Kids

“Air pollution isn’t only one or a few countries’ problems, but rather a global public health concern,” said To, also a professor at the University of Toronto.

“While there are individual actions one can consider to reduce exposure to air pollutants, it also requires action by public authorities at the national, regional and international levels,” she noted. (IANS)