Stratospheric ozone destruction is primarily driven by catalytic chemical cycles involving halogen-containing source and reservoir gases, including chlorofluorocarbons (CFCs), methyl bromide, hydrogen chloride, chlorine nitrate, and related compounds, whose ozone-destroying potential is often enhanced by heterogeneous reactions occurring on the surfaces of polar stratospheric clouds; in contrast, volatile organic compounds (VOCs) and simple hydrocarbons are primarily associated with tropospheric air quality issues, such as photochemical smog and tropospheric (ground-level) ozone formation, rather than with the catalytic halogen-driven chemistry responsible for stratospheric ozone depletion.