Ozone (O3)
The transport of goods in Germany is often still carried out with climate-damaging diesel locomotives. This is to change in the future: Old diesel locomotives are to be replaced with more environmentally friendly ones.
The ozone layer, which envelops the earth in the stratosphere at a height of 20 to 30 kilometres, protects living creatures from the sun's harmful ultraviolet radiation. It is barely thicker than 3.5 millimetres. At the poles, especially in Antarctica, a hole in the ozone layer forms, which was attempted to be counteracted by banning chlorofluorocarbons (CFCs) in 1987. Without the protective ozone layer, the energy-rich ultraviolet rays of the sun would reach the earth directly and damage the cells of animals, plants and humans. Life in the upper layer of the oceans would then also be damaged.
Ozone pollution is especially likely to occur in summer. Ozone also has adverse effects on plants, especially leafy plants, which absorb the ozone through their stomata. If they are exposed to the gas over a long period of time, it reduces the growth of hardwoods and can affect the quality of crops, leading to crop losses.
Ozone is formed from nitrogen oxides and other volatile organic compounds during intense solar radiation. These precursor substances originate primarily from road traffic. Ozone is formed near the earth's surface especially on hot summer days with heavy traffic. Here, ozone affects the health of living organisms. In humans, too high a concentration causes complaints such as irritation of the respiratory tract and eyes as well as headaches. High ozone concentrations are particularly harmful to the lungs during physical exertion such as sports or hard work. For this reason, the EU has set limits for the harmful gas: If the ozone content remains below 110 micrograms per cubic metre of air per hour, it is not considered harmful to humans. From an ozone hourly average of 180 micrograms per cubic metre of air, the population is informed; from 200 micrograms, humans experience symptoms; from 360 micrograms, there are serious health risks. Last year, the information threshold was exceeded several times in Germany. If ozone levels are too high, there is also the threat of driving bans, as is already the case in France during particularly hot summers.