Other Effects of Ozone Depletion
As well as the effects to human health, land plants and aquatic life, which may occur as a consequence of ozone depletion, there are other impacts which could result from prolonged destruction of ozone in the stratosphere. These include damage to polymers used in buildings, paints and packaging, and changes in biogeochemical cycles affecting ground-level pollution (smog), acid rain and even climate change.
Damage to Polymers
Ozone depletion will cause many materials to degrade faster. These materials include PVC (used in window and door frames, pipes and gutters, etc.), nylon and polyester. They are all composed of compounds known as polymers. Synthetic polymers, naturally occurring biopolymers, as well as some other materials of commercial interest are adversely affected by solar UV radiation. Today's materials are somewhat protected from UV-B by special additives. Therefore, any increase in solar UV-B levels as a result of ozone depletion will therefore accelerate their breakdown, limiting how long they are useful outdoors. Shorter wavelength (i.e. more energetic) UV-B radiation is mainly responsible for photo-damage ranging from discoloration to loss of mechanical integrity in polymers exposed to solar radiation.
The use of higher levels of conventional light stabilisers in polymer-based materials are likely to be employed to mitigate the effects of increased UV levels in sunlight. However, it is not certain how resistant such light stabilisers are themselves to increased levels of UV-radiation. In addition, their use will add to the cost of plastic products in target applications. With plastics rapidly displacing conventional materials in numerous applications, this is an important consideration particularly in the developing world.
It is not certain yet how other materials, including rubber, paints, wood, paper and textiles will be affected by increased UV radiation resulting from ozone depletion.
Effects on Biogeochemical Cycles
Increases in solar UV radiation could affect terrestrial and aquatic biogeochemical cycles, thereby altering both sources and sinks of greenhouse and chemically-important trace gases e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulphide (COS) and possibly other gases, including ozone. These potential changes would contribute to biosphere-atmosphere feedbacks that attenuate or reinforce the atmospheric build-up of these gases. Likely effects include an increase in smog in urban centres, and acid rain in rural areas.
Effects on Climate
Whilst increases of UV radiation as a result of ozone depletion may affect the production and removal of carbon dioxide, the main greenhouse gas, ozone depletion itself can influence the global climate. Ozone is also a greenhouse gas, and as well as filtering out the incoming short-wave solar radiation, can absorb much of the outgoing long-wave terrestrial radiation (infra-red radiation). If stratospheric ozone is destroyed, ozone's greenhouse effect is reduced and this could lead to a global cooling, offsetting some of the warming that may be occurring as a result of man-made emissions of carbon dioxide, methane and nitrous oxide. Ironically, when the ozone layer starts to repair itself in the next century as a result of a control on CFCs, this cooling potential will be lost. More significantly, the replacement chemicals to CFCs, the HCFCs, which themselves do not harm the ozone layer, are very strong greenhouse gases, and are further contributing to the potential problem of global warming.