These free radicals were known to be present in the stratosphere, and so were regarded as part of the natural balance—it was estimated that in their absence, the ozone layer would be about twice as thick as it currently is.
Radikal bebas ini diketahui hadir di stratosfer, dan karenanya dianggap sebagai bagian dari keseimbangan alami—diperkirakan bahwa jika tidak ada, lapisan ozon akan menjadi dua kali lebih tebal dari sekarang.