NAME: ground–level ozone (O3)

DESCRIPTION:

There are two types of Ozone. The stratospheric ozone is occurring naturally in the earth’s upper atmosphere, where it forms a protective layer against the sun’s harmful ultraviolet rays.
The tropospheric ozone, also called ground–level ozone, is formed close to the surface of the earth in a chemical reaction between oxides of nitrogen (NOx) and volatile organic compounds (VOC) under direct sunlight. Those pollutants are emitted by cars, power plants, industrial boilers, refineries and chemical plants.

HEALTH IMPACTS:

Ground–level ozone is responsible for breathing problems. In the long term ozone can also cause heart diseases.

Icon Heart Icon Lung

Berlin’s ozone has its ups and downs

Ozone – present EU law VS. recommended healthy level by WHO

The blue area shows levels exceeding the present politically negotiated limits for ozone set by EU law and the green one shows the levels recommended by the World Health Organization (WHO) for the least harmful set levels of ozone for human beings.

The recommendation by WHO is, as seen in the graph, lower than the law stipulated by EU. Additionally WHO does not recommend any exceedances above the 100 µg/m3 as the maximum daily 8–hour mean. EU, on their hand, accepts exceedances to 120 µg/m3 as the maximum daily 8–hour mean, on up to 25 days per year, averaged over the last 3 years.

Ozone – from 2005 until 2018

The highest measured 8–hour mean level per year is displayed in the graph.
To be observed is that the recommendation by WHO (maximum daily 8–hour mean of 100 µg/m3) is being exceeded every year.

Additionally, to be seen in the bar chart is Berlin’s amount of yearly exceedances of the EU level. Until now Berlin has been managing to be, with one excepion, below the accepted 25 exceedances per year, averaged over the last 3 years that EU allows.

All together, this means that Berlin has never been close to reaching the recommended healthy levels of ozone set by the World Health Organization (WHO).

Insight

The daily maximum 8–hour average ozone concentration show how much the weather influence the fluctuation in ozone between the different years. Although emissions from the main sources of the precursor substances (traffic, power plants, industrial plants, commercial and private use of paints, varnishes and solvents) has almost halved in Berlin and in Germany since 1990, ozone has not decreased to the same extent. This is due to the non–linear relationship between nitrogen oxide (NOx) emissions and ozone formation and to the fact that ozone is transported over long distances, including international borders. The lowest concentration of ozone is to be found at the point of formation e.g., main streets (since 2018 measured on Leipziger Straße) and the highest in the outskirts of Berlin. Especially the measuring stations located in Friedrichshagen and Marienfelde are recording high values because of the dominating west by north west winds bringing Berlin’s ozone out over the city’s eastern and southern parts.
The present long term trend in Berlin is that the average amount of ozone per year is increasing.