Complex sentence: The first category includes several greenhouse gases (e.g. CO 2, CH 4, N 2 O or CFCs), whilst the latter encompasses species with a lifetime equal to or less than a few months.
Split into simpler sentences: The first category includes several greenhouse gases (e.g. CO 2, CH 4, N 2 O or CFCs). The latter encompasses species with a lifetime equal to or less than a few months.