History of Ozone: From Discovery to Global Action
The story of ozone is a fascinating journey that began with simple chemical curiosity, evolved into a global environmental crisis, and then became a symbol of international cooperation. Here are the major milestones in the history of ozone:
1839: Discovery and Naming
Ozone was first discovered in 1839 by the German-Swiss chemist Christian Friedrich Schönbein. While working on the electrolysis of water and electric arcs, Schönbein noticed a "strange" and "pungent" odor forming in the air. He realized that this odor belonged to a new substance and named this gas "ozone" based on the Greek verb "ozein" (to smell). This odor is the clean but metallic smell perceived after lightning during stormy weather.
1865: Determination of the Chemical Formula
Schönbein had identified ozone, but he hadn't fully deciphered its structure. In 1865, Jacques-Louis Soret showed that ozone is an allotrope of normal oxygen and consists of three oxygen atoms (O₃).
1857–1893: First Generator and First Applications
In 1857, Werner von Siemens designed the first ozone generator. In 1893, ozone began to be used to disinfect drinking water in a water treatment plant in the Netherlands. This was one of the first major industrial-scale applications of ozone.
World War I: First Medical Trials
Ozone's powerful antiseptic properties were tested during World War I for disinfecting wounds and treating gangrene. Figures like Dr. Albert Wolff took the first steps towards using ozone in the medical field.
1913: Discovery of "Good Ozone" – The Ozone Layer
Scientists studying the Sun's spectrum noticed that some UV wavelengths did not reach the Earth's surface. Charles Fabry and Henri Buisson proved that ozone in the upper atmosphere absorbed these harmful UV rays, protecting the planet. Thus, the existence of the protective "ozone layer" was scientifically established.
1920s: Measurement of the Ozone Layer
British meteorologist G.M.B. Dobson developed the first instrument capable of measuring the thickness of the ozone layer from the ground. Today, atmospheric ozone levels are still expressed in "Dobson Units" (DU).
1950s: Recognition of "Bad Ozone"
Chemist Arie Haagen-Smit showed that the main component of photochemical smog observed in large cities was ground-level ozone, formed by the reaction of pollutants with sunlight. This clarified the distinction between "good ozone" (the protective layer in the stratosphere) and "bad ozone" (a pollutant at ground level).
1974: CFCs and the First Major Warning
Mario Molina and Sherwood Rowland published a groundbreaking paper suggesting that chlorofluorocarbon (CFC) gases, used in sprays and refrigerants, could break down the ozone layer when they reached the stratosphere. This work would later be honored with a Nobel Prize.
1985: Detection of the "Ozone Hole"
The British Antarctic Survey team announced that they had detected a massive thinning of the ozone layer ("ozone hole") over Antarctica. This finding caused great shock and concern among the global public.
1987: Montreal Protocol – Global Solution
Under the leadership of the United Nations, the Montreal Protocol was signed, gradually prohibiting the production and use of ozone-depleting substances. Today, the Montreal Protocol is considered one of the most successful international environmental agreements in history and has played a critical role in the slow recovery of the ozone layer.
Conclusion: Science, Crisis, and Cooperation
The history of ozone is a powerful example of how science's journey, starting with curiosity, shed light on a global environmental crisis, and how concrete solutions could be produced through international cooperation. The protection of the ozone layer is a symbol not only of the planet's future but also of how science can be used for the benefit of society.