Healthier Air due to the Low Emission Zone

The Low Emission Zone in Leipzig was established in March 2011, allowing only access of Diesel vehicles of Euro4 and higher with few exceptions. The ban of older vehicles and subsequent modernization of the car fleet resulted in slightly reduced PM10 and PM2.5 mass concentrations. However, the mass concentration of black carbon (soot particles) emitted mainly from Diesel vehicles decreased by 60% at the street site. These particles are believed to be most dangerous due to their carcinogenic trace compounds such as polycyclic aromatic hydrocarbons. Furthermore, also the number concentration of ultrafine particles, which can penetrate deep into the lungs, decreased by approximately 70%. Despite modernized Diesel vehicles, nitrogen oxides concentrations did not follow these trends and remained nearly constant. The main achievement of the Low Emission Zone was the improvement of air quality by the reduction of the most dangerous particles.

Impact of sea smell overestimated by present climate models

The formation of sulfur dioxide from the oxidation of dimethyl sulfide (DMS) and, thus, of cooling clouds over the oceans seems to be overvalued in current climate models. This concludes scientists from the Leibniz Institute for Tropospheric Research (TROPOS) from a model study on the effects of DMS on atmospheric chemistry. Until now, models considering only the oxidation in the gas phase describe merely the oxidation pathway and neglect important pathways in the aqueous phase of the atmosphere, writes the team in the journal PNAS. This publication contains until now the most comprehensive mechanistic study on the multiphase oxidation of this compound. The results have shown that in order to improve the understanding of the atmospheric chemistry and its climate effects over the oceans, a more detailed knowledge about the multiphase oxidation of DMS and its oxidation products is necessary. Furthermore, it is also needed to increase the accuracy of climate prediction.