The main source of these halogen atoms in the stratosphere is photodissociation of man-made halocarbon refrigerants , solvents , propellants , and foam-blowing agents ( CFCs , HCFCs , freons , halons ) .
The main source of these halogen atoms in the stratosphere is photodissociation of man-made halocarbon refrigerants ( CFCs , freons , halons . )