qSince
1995, the atmospheric concentrations of many of those halocarbon gases that are both
ozone-depleting and greenhouse gases (e.g., CFCl3 and CF2Cl2), are either increasing more slowly or decreasing, both in response to reduced emissions under the
regulations of the Montreal Protocol and its Amendments.
qTheir
substitute compounds (e.g., CHF2Cl and CF3CH2F) and some other synthetic
compounds (e.g., perfluorocarbons (PFCs) and sulphur
hexafluoride (SF6)) are also greenhouse gases, and their concentrations
are currently increasing.