Introduction

          Our family is planning to go to Australia later this year. Naturally, I decided to browse the Internet to learn more about this country and the adventures it offers. It turned out that Australia is a beautiful place with a huge variety of exciting outdoor activities. I also learned that Australia, unfortunately, has the highest rate of skin cancer (1:30) in the world (http://www.healthinsite.gov.au/topics/Cancer_Statistics). This fact made me think about the ozone depletion and the related threat to people in different countries.

          Atmospheric ozone plays a vital role in protecting the life on Earth from harmful solar ultraviolet radiation. Since 90% of all ozone is located in the stratosphere (from 8-12 to 48-50 km), stratospheric ozone receives constant attention from many scientific, industrial and government organizations. Canadian government, for example, supports the maintenance of WOUDC database (World Ozone and Ultraviolet Radiation Data Center, http://www.msc-smc.ec.gc.ca/woudc). WOUDC collects and systematically stores all ozone measurements from different instruments worldwide, and anyone can use these data for free.

         A discovery of the Antarctic ozone hole back in 1980s (http://www.antarctica.ac.uk/Key_Topics /The_ Ozone_Hole/) caused worldwide panic and fear. The Montreal Protocol (http://hq.unep.org/ozone/Montreal-Protocol/Montreal-Protocol2000) specified that production and consumption of compounds that deplete ozone in the stratosphere should be phased out by 2000. However, in spite of all efforts in reducing the emission of ozone-destroying chemicals into the atmosphere undertaken by so many countries, the recovery of the ozone layer is yet to come. Even the stabilization of current ozone levels is very uncertain and has yet to be confirmed.