Due to the Covid-19 crisis, the Quadrennial Ozone Symposium QOS2020 has been postponed to 3 - 9 October 2021. It will be entirely online.
The International Ozone Commission was established in 1948 as one of the special commissions of the International Union of Geodesy and Geophysics, who represent the entire community of geophysical scientists around the world. The purpose of the IO3C is to help organize the study of ozone around the world, including ground-based and satellite measurement programs and analyses of the atmospheric chemistry and dynamical processes affecting ozone.
You can find the IO3C as well on 
Press Release: The International Ozone Commission, on the 33th anniversary of the Montreal Protocol, reports successes and remaining challenges for understanding ozone layer recovery
September 16th is the International Day for the Preservation of the Ozone Layer, celebrating the 1987 anniversary of the Montreal Protocol on Substances that Deplete the Ozone Layer. The Montreal Protocol is the globally ratified treaty that controls the production and consumption of ozone depleting substances (ODSs) and many replacements for these substances.