Last summer's extraordinary heat waves, and the "Fridays for Future" movement, have once again fueled the climate debate and had a significant impact on the "green wave" of this year's parliamentary elections. This is very welcome, because with every IPCC report, the future scenarios of global climate change are darkening.

Worldwide, more than 40% of CO2 emissions are emitted by the generation of electricity and heat. Immediately afterwards, mobility comes in second place with just under 25% of emissions. In addition to CO2 emissions, the total number of non-volatile particulate matter (soot) is also increasing every year. Unfortunately, a strong trend from coarse dust (PM10) to ultra-fine dust (nanometer range) has been observed for quite some time. An aircraft engine, for example, but also diesel engines, emit particles in a median size of about 60-110 nm. These nanoparticles reach the finest ramifications of the human lung almost unfiltered and from there pass through the blood-air barrier into our bloodstream. What health effects nanoparticles have is currently the subject of in-depth studies. The suspicion of a carcinogenic effect has arisen from numerous long-term studies. It is therefore agreed that nanoparticle emissions should be minimized as a matter of principle.

As by-products of fuel combustion, other pollutants are also produced, such as carbon monoxide (CO), unburnt hydrocarbons (UHC), nitrogen oxides (NOx) and, in some cases, large quantities of sulphur dioxide (SO2) in shipping and aviation. It is known that unburnt hydrocarbons in combination with soot nanoparticles have a cytotoxic effect on lung tissue. Likewise, CO, NOx and UHC are considered as source materials for the secondary formation of greenhouse gases such as ozone. However, SO2 also has a significant effect on the environment, as it has a highly hygroscopic effect after an initial oxidation stage and a) thus influences cloud formation and b) strongly supports the formation of aerosols.

Today, air traffic is responsible for about 6% of the global CO2 equivalent footprint. However, IATA expects passenger numbers to double by 2035, and with the simultaneous electrification of the rest of the transport industry, the percentage of emissions from aviation will increase significantly. It is therefore of utmost importance to investigate the effect of the future aviation industry on the climate and the environment in order to contribute to the reduction of emissions.

In order to investigate the impact of air traffic, the continuous development of a framework for an atmosphere-biosphere-chemistry model should be aimed at. This would enable the ZHAW to investigate the influence of aviation on
(a) local air quality, focusing for example on the local contribution of air traffic to secondary toxic irritants (e.g. ozone, peroxyacetyl nitrate, etc.) and
b) to study the climate in more detail, focusing on the calculation of the production of secondary formed greenhouse gases, cloud and aerosol formation
c) In addition, this project offers the opportunity for capacity building, which will enable the participation in future multinational cooperation in EU research projects.