Unfortunately, the layer of good ozone is being destroyed by air pollution. The chief culprits are chlorine and bromine gases. They are released in aerosol sprays, coolants, and other products. Loss of ozone has created an ozone hole over Antarctica. Ozone depletion results in higher levels of UV radiation reaching Earth. In humans, this increases skin cancers and eye cataracts. It also disturbs the nitrogen cycle, kills plankton, and disrupts ocean food webs. The total loss of the ozone layer would be devastating to most life. Its rate of loss has slowed with restrictions on pollutants, but it is still at risk.
Toronto is home to one of the leading manufacturers of aerosol sprays in the country. Because of this, homes in Toronto often spray high levels of aerosol on a regular basis. In Saskatchewan, meanwhile, the local government enacted a ban on aerosol sprays several years ago, so their level of aerosol use is now essentially zero.

Which city, Toronto or Saskatchewan, will be destroying less of the ozone layer?