In 1994, the UN General Assembly proclaimed 16 September the International Day for the Preservation of the Ozone Layer, commemorating the date of the signing, in 1987, of the Montreal Protocol in the Vienna Convention on Substances that Deplete the Ozone Layer. Bangladesh has been observing the day since 1990 following signing of the protocol in the same year. In 1930, two French physicists Charles Fabry and Henri Buisson first discovered the ozone layer. The ozone layer is a layer of earth's atmosphere that has relatively high levels of ozone gas. This layer is mainly located in the lower part of the stratosphere.

The closure of the hole in the ozone layer was observed 30 years after the Montreal Protocol was signed. Due to the nature and characteristics of the gases responsible for ozone depletion their chemical effects are expected to continue for between 50 and 100 years. The Ozone Layer which surrounds the earth at a height of about 25km protects life on earth by absorbing some of the radiation from the sun thus preventing harmful ultra-violet (UV) rays from reaching the earth's surface. Decreases in ozone amounts lead to increases in UV radiation. Exposure to UV irradiance reaching the Earth's surface is also affected by the amount of cloud cover and by the altitude above sea level. The increase in UV rays has been linked to an increase in some types of skin cancers, cataracts, lower plant productivity, and deterioration in certain forms of marine life.

Stratospheric ozone is "good" because it protects living things from ultraviolet radiation from the sun. Ground-level ozone, the topic of this website, is "bad" because it can trigger a variety of health problems, particularly for children, the elderly, and people of all ages who have lung diseases such as asthma. Ozone Depleting Substances (ODS) are certain man-made chemicals containing Chlorine and Bromine, which have a high potential to deplete the Ozone Layer through chemical interactions in the earth's stratosphere. Examples of ODS include chlorofluorocarbons (CFCs) used in refrigerators, air-conditioning units foam products, and aerosol sprays and halons used in fire extinguishers.

The Montreal Protocol started life as a global agreement to protect the ozone layer, a job it has done well, making it one of the most successful environmental agreements to date. A united global effort to phase out ozone-depleting substances means that today, the hole in the ozone layer is healing, in turn protecting human health, economies and ecosystems. But, as this year's World Ozone Day seeks to highlight, the Montreal Protocol does so much more - such as slowing climate change and helping to boost energy efficiency in the cooling sector, which contributes to food security. The theme for this year is Montreal Protocol - keeping us, our food and vaccines cool.

By developing cold chain solutions that are more efficient, more climate friendly, and cheaper to buy and operate, cold chains will become more effective and widely available. This will provide producers such as farmers and pharmaceutical providers with access to pre-cooling, refrigerated storage and refrigerated transport - ensuring products such as food and vaccines reach people in safe and good condition.

Not only is ozone crucial for life on Earth but that we must continue to protect the ozone layer for future generations. Earth's ozone layer is healing, after COVID-19 decreases pollutions rate and that really contribute to healing ozone layer. Some expert says that the coronavirus outbreak fastens the recovery of the Ozone layer by decreasing the pollution.

An "unprecedented" ozone depletion in the northern hemisphere has healed, but unlikely due to the impacts of worldwide coronavirus lockdowns, scientists say. The hole had been about three times the size of Greenland. A "record-level" ozone hole over the Arctic - the biggest since 2011, has now closed, the UN World Meteorological Organization (WMO) said. Despite coronavirus lockdowns resulting in a significant reduction in air pollution, some scientist said, the occurrence of the hole healing "was completely unrelated to COVID.

In Bangladesh Ozone depleting substances, all imported gases, were used in pharmaceutical, refrigeration, air-conditioning, readymade garments and aerosol manufacturing industries. As a signatory of Montreal Protocol, a global deal to phase out ODS, Bangladesh along with other developing countries cannot import and use of any kind of ODS gases of chlorofluorocarbon (CFC) group, carbon tetrachloride and methyl chloroform after December 2009 except for essential uses.

Bangladesh was the first among the developing countries, that had completely phased out hydrochlorofluorocarbon-141b gas from the foam sector of the refrigerator assembling industries. With almost 8.2% GDP growth, Bangladesh is experiencing increasing demand for appliances having ODS in air conditioners and refrigerators. Despite the challenges of this increasing demand, Bangladesh did and doing well in the phase out activities of ozone depleting substances and one of the most successful countries.

The phase-out of controlled uses of ozone depleting substances and the related reductions have not only helped protect the ozone layer for this and future generations, but have also contributed significantly to global efforts to address climate change; furthermore, it has protected human health and ecosystems by limiting the harmful ultraviolet radiation from reaching the earth. Let this International Day for the Preservation of the Ozone Layer is an inspiration towards greater ambition on cooling, at the Climate Action. On this World Ozone Day, we celebrate and acknowledge the Montreal Protocol and its Kigali Amendment in its wider efforts to keep us, our food, and vaccines cool!

Professor Dr. Ahmad Kamruzzaman Majumder, Dean, Faculty of Science, Chairman, Department of Environmental Science, Stamford University Bangladesh, Founder and Director, Center for Atmospheric Pollution Studies (CAPS) and Joint Secretary, Bangladesh Poribesh Andolon (BAPA), E-mail: kamrul_sub@hotmail.com