Environment Certain pollutants first form in the air
According to a new study, harmful fine dust particles from traffic and combustion are formed much more slowly than previously assumed. As a result, air pollution spreads further than previously thought.
25.03.2025, 11:24
SDA
This finding improves air pollution models by providing more accurate predictions of particulate matter concentrations, the Paul Scherrer Institute (PSI) announced on Tuesday.
According to the research institute, it was previously thought that particulate matter forms directly at the source. For example, during the emission of car exhaust fumes at the tailpipe. In the new study, however, the research team led by PSI showed that many so-called aerosols are only formed after several chemical reactions in the air. This process can take between six hours and two days.
Particle filters are not enough
Before they form solid particles, the gases produced from car exhaust fumes and the combustion of organic materials, such as toulene and benzene, go through several oxidation stages. The research team estimates in the study that such multi-stage oxidation is responsible for more than 70 percent of all human organic aerosol pollution in Europe.
The results also show that it is not enough to simply reduce the direct emission of particulate matter, for example by using particle filters. Instead, the emission of precursor gases, which only later form solid particles, must also be curbed.
The researchers came to this conclusion in experiments they carried out at the Cern nuclear research center in Geneva. The results were published in the scientific journal "Nature Geoscience".
