Partnership project makes progress towards protecting the Earth’s fragile ozone shield

Developing the first metrological framework to assess the impact of cosmic rays and human activity on the ozone layer

One of the most significant − yet unexplored − ecological challenges facing EU member states and beyond is the impact on human and environmental health of the increasing atmospheric ionisation. This is caused by extra-terrestrial radiation, cosmic rays and solar UV radiation, boosted by anthropogenic emissions.

Metrology Partnership project Metrology for Earth Biosphere: Cosmic rays, ultraviolet radiation and fragility of ozone shield (21GRD02, BIOSPHERE) aims to develop the necessary tools, methodologies and measurement infrastructure needed to evaluate the mutual impact of cosmic rays and biologically active UV radiation on the Earth’s biosphere. The work will support EU policy makers with scientific assessments and information that have the potential to substantially improve policies on climate, health and anthropogenic emission activities.

First measurements on ethanol

Combined theoretical and experimental studies on the elastic scattering of electrons on ethanol were performed for the first time in the energy range of 30–800 eV. Ethanol is of current interest in the field of climate physics because it is one of the most promising future sources of renewable energy that can be made from various plant materials. Owing to its lower global warming potential, this biofuel is increasingly replacing traditional fossil fuels.

The growing use of ethanol as an energy carrier, however, is causing a rise in the concentration of volatile organic compounds in the Earth’s atmosphere. Electron-collision-induced dissociation processes of these compounds, initiated by primary as well as secondary cosmic rays, can lead to the production of reactive species which may impact the ozone balance in the upper atmosphere. For the quantitative description of these processes, comprehensive electron interaction cross sections of ethanol are needed – and are provided by the new measurements.

These project results have been published in the European Physics Journal in the paper Combined experimental and theoretical study on the elastic electron scattering cross sections of ethanol.

Project coordinator Faton Krasniqi from PTB said

‘With a series of experiments already successfully conducted, the project is collecting data to quantify the effects of the combined cosmic and UV field on the fragmentation of atmospheric molecules and biological damages in human cells. These data will allow us to assess and expand the current knowledge of how these combined fields affect the ozone dynamics and the associated potential for acute and chronic health effects.

Implementation of electron scattering data into simulation codes for the propagation of space through the atmosphere leads to refined radical, ion and slow electron production rates, which would then make it possible to estimate how effective the cosmic ray model is compared to the photochemical model in depleting the ozone layer.’

This Metrology Partnership project has received funding from the European Partnership on Metrology, co-financed by the European Union Horizon Europe Research and Innovation Programme and from the Participating States.

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