Unknown synergistic effects

The various issues arising fro the pollution of Earth's atmosphere by a number of substances are often closely interrelate, both through chemistry and through potential control strategies. For example, chlorofluorocarbons (CFCs) both destroy ozone and are greenhouse gases; conservation of fossil fuels would contribute to addressing both acid rain and climate change problems; ozone depletion in the lower stratosphere and increasing aerosol concentrations have a cooling effect, which may be partially offsetting, and hence masking, the full extent of the enhanced greenhouse effect.