A Protective Ozone Layer

"The ozone layer must be replenished so as to provide long-term protection against harmful UV radiation."

The ozone layer of the atmosphere protects life on earth by filtering out some of the harmful ultraviolet (UV) radiation from the sun. Thinning of this layer therefore poses a threat. In humans, it increases the risk of conditions such as skin cancer, suppression of the immune system and eye cataracts.

Thinning is a result of the release into the atmosphere of substances which destroy ozone. These include chlorinated compounds that are to be found for example in fridges, air conditioning systems and foam plastics.

Since 1987 there has been an international agreement called the Montreal Protocol, which requires signatory states to ban and restrict the use of ozone-depleting substances. The measures taken have been very successful. Thanks to the Montreal Protocol, emissions of these substances are now falling. So too, with certain exceptions, are levels of ozone-depleting gases in the atmosphere. Most current evidence suggests that the ozone layer is no longer thinning, and there are even signs that it is set to increase in thickness again.

What are the challenges?

Many ozone-depleting substances remain in the atmosphere for a long time. Although emissions of most of them have been reduced or halted altogether, it will therefore be several decades before their thinning effect on the ozone layer is eliminated.

The thickness of the ozone layer is difficult to determine, partly owing to its natural variability. It is also affected by climate and furthermore, some greenhouse gases have the ability to destroy ozone. Rising emissions of nitrous oxide, for example, could delay ozone recovery.

International efforts under the Montreal Protocol must continue, to further reduce production and consumption of ozone depleters. It is also important to ensure that new substances of this kind do not end up on the market. It is also vital that Sweden continues to implement measures against such emissions at the national level. This includes becoming better at treating ozone depleting substances from end-of-life products. This primarily requires improving information and supervision. This especially applies to treatment of CFCs and HCFCs from building and demolition waste.

Specifications for A Protective Ozone Layer

The environmental quality objective A Protective Ozone Layer aims to ensure that:

  • the turning point regarding depletion of the ozone layer has been reached and the start of recovery is observed,
  • concentrations of chlorine, bromine and other ozone-depleting substances in the upper atmosphere are below the level that has a negative impact on the ozone layer.