Air is a mixture of different gases, the most important one is oxygen. Ozone is an allotropic oxygen modification, its molecule consists of 3 oxygen atoms. Ozone comes from the Greek word "ozein". The first who identified ozone was Christian Friedrich Schönbein. The vertical division of the atmosphere is known by the processes present in it and it contains of ; the troposphere, stratosphere, mesosphere and the thermosphere. In the stratosphere, ozone can be triggered by reactions where the equilibrium is first established, followed by vertical distribution. Tropospheric ozone makes only 10% of the total amount of ozone in the vertical column of Earth's atmosphere. Schoenbein's method is based on the oxidation ability of ozone. The aim of this study is to see the level of ozone in Pula before it began with the widespread use of steam engines, before or at the beginning of the industrial revolution itself and the data obtained from that period to compare with today's ozone values, which are the result of technological and industrial progress in the past century. Ozone from the air will oxidize the potassium iodide on Schonbein's paper, thus creating elemental iodine. The value of the Schonbein scale depends on the relative humidity and in the conversion of the Schonbein scale to ppb. Relative humidity measured at the weather station in Pula was used. As for the ozone values at Schoebein's scale for the summer months, the highest ozone value is measured in 7h and the lowest in 21h in June. The average ozone values measured at "Pula Fižela" station from june till august 2015. are higher than the average ozone value in ug / m3 also measured in Pula but in 1878. The highest value of 2015. is recorded at 21h and the lowest at 7h in the morning for summer months.. We conclude that the ozone concentrations from Pula in the 2nd half of the 19th century are lower than the values of ozone obtained by the Bojkov method with constant moisture. There is a potential for further ozone researches.