There are several greenhouse gases (GHGs) that are not naturally occurring and are primarily the product of industrial activities. (The exception is nitrous oxide (N2O) which is naturally occurring, but is produced from anthropogenic sources and activities as well.)
Hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6) are also GHGs with high global warming potentials and are typically included in GHG emission inventories.
Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and bromofluorocarbons (i.e. halons) are all substances that deplete the ozone layer and are covered under the Montreal Protocol, but they are also GHGs not typically included in GHG emission inventories.