These then react with the ozone molecules, resulting in their removal. CFCs have a lifetime in the atmosphere of about 20 to 100 years, and consequently one free chlorine atom from a CFC molecule can do a lot of damage, destroying ozone molecules for a long time.
exists and is an alternate of . In the northern hemisphere of Earth, Fall begins on the Autumnal equinox (22-23 September) (in Persian calender it will begin at the first day of Mehr) and ends on the Winter solstice (21-22 December). In the southern hemisphere of Earth, Fall begins on the Autumnal equinox (20-21 March) and ends on the Winter solstice (20-21 June).
Seasons are fundamental to how we understand the climate and the environment, but for hundreds of years academics have argued that their specialist field is the one which defines official start of autumn. In meteorological terms autumn begins on September 1, as each season is defined as a three-month period. Astronomers base the date of the seasons upon celestial events, in this case the autumnal equinox, when night and day are roughly equal length.