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).
At a certain point, because of Earth's tilt, the days and nights become exactly the same length and that point is the exact start of spring (or fall - the exact opposite point in the orbit 6 months later). When the orbit reaches the point with the longest day, that's the start of summer. The point with the shortest day is exactly half way around, 6 months later and is the start of winter.