The Ozone Layer, found in the stratosphere between 10km and【M10】km

above the ground, protects earth from the harmful effects of certain【M1】__

wavelength of ultra-violet (UV) light from the sun, specifically UV-B.【M2】__

Any significant decrease in ozone in the stratosphere would result from an【M3】__

increase of UV-B radiation reaching the earth surface.

Scientists warned for decades that increases in levels of UV-B【M4】__

radiation must cause the increase in skin cancers. 【M5】__

An Antarctic "ozone hole" was discovered in 1985. Since then,

scientists have observed ozone depletion in the middle and higher latitudes.

This year, the biggest ozone hole even recorded was observed over 【M6】__

Antarctica, expanding over the southern tip of South America. 【M7】__

To halt ozone depletion, countries committed themselves to ban the use【M8】__

and production of CFCs through implementation of the 1987 Montreal Protocol.

According to data received from the Cape Grimm Global Atmosphere

Monitoring Station locating in Australia, which measures worldwide CFCs【M9】__

in the lowest layer of the atmosphere, the most common CFCs, such as

like Freon used in refrigeration, have reached zero growth. 【M10】__

This means that these substances are not increasing in concentrations

on the earth's surface. Less common CFCs have begun to decrease in the

last two years.

【M1】