Ozone Timeline By SuperScienceKid3 Aug 27, 1840 Ozone mention in a writing by Schönbein Aug 27, 1857 Von Siemens ozone generator developed Aug 22, 1890 Ozone First Identified It was a great day Aug 22, 1920 Ozone measurments begin via the ingenuity of a British Scientist Jan 27, 1956 Hailey Bay Observatory Oct 27, 1994 Ozone in October is less than half its value than it was october 1970 Aug 27, 1995 European scientists conduct SESAME