<p>Combined radiation exposures are increasingly relevant in medical, spaceflight, and environmental contexts</p>

Completed Metrology Partnership project Metrology for Earth Biosphere: Cosmic rays, ultraviolet radiation and fragility of ozone shield (21GRD02, BIOSPHERE) developed and validated new methodologies to assess how increasing atmospheric ionisation, driven by cosmic rays, solar activity, and human-related emissions, affects the health of both people and ecosystems.

Through observations of multiple solar particle events during the project’s measurement campaigns, combined with experiments and simulations under different atmospheric conditions, the project helped clarify how such events can intensify ozone-depletion reactions and elevate biologically active UV radiation at ground level, while providing valuable experimental data on associated changes in atmospheric ionisation.

Some of the outcomes of the project are outlined below:

Effects of radiation on human cells

This project carried out one of the first systematic assessments of the effects of combined radiation fields – energetic protons and ground-level UVB radiation under ozone-depleted conditions – on normal human cells across molecular, cellular, and cytogenetic endpoints.

A comprehensive dataset was produced documenting the functional, morphological, and molecular changes induced in healthy human cells by combined exposures.

AI model trained on satellite data

The work of the project delivered significant value to industrial stakeholders and operational user communities that depend on reliable space-weather forecasting, including satellite operators, aviation, and space mission planners. By introducing electron flux data into a deep learning framework, a high-performance model capable of predicting the dynamics of the Earth’s radiation belts has been produced.

These advances enhance the ability to anticipate hazardous conditions: predicting the state of the Van Allen Belts (regions of intense radiation trapped by the Earth’s magnetic field) is crucial for satellites orbiting near-Earth, and to aviation and astronaut operations.

Good practice guides

The following good practice guides were published:

• Good Practice Guide for the simulation and estimation of particle fluxes during minimum solar activity, maximum solar activity and the recent Solar Energetic Particle Events.
• Good Practice Guide for comprehensive radiobiological studies of human cell lines to single and combined fields of SCR and UV radiation enabling the establishment of correlations between the radiation type and flux, and changes to cellular parameters (cell death, DNA damage and genomic instability, adhesion, proliferation and gene expression), using established radiation effect models and integrative approaches.

Systematic review

A new systematic review published in the journal Biomolecules Combined Radiations: Biological Effects of Mixed Exposures Across the Radiation Spectrum highlights the biological consequences of combined exposure to ionising and non-ionising radiation, a topic of growing relevance for medicine, spaceflight, and environmental health. The paper- backed by the BIOSPHERE project - synthesises data from 172 studies, spanning decades of research, to assess how mixed radiation fields affect living systems.

The review reveals that combining radiation types often produces synergistic or additive effects on biological endpoints such as DNA damage, cell survival, genomic instability, and stress responses – effects that are stronger or qualitatively different than those from single-type exposures.

By systematically cataloguing these findings, the authors provide an unparalleled resource for researchers and regulators, emphasising the need for standardised protocols and mechanistic studies to better understand health risks associated with mixed radiation exposures.

Given rising interest in space travel, environmental exposure to radiation, and combined therapies in medicine, this review is timely: it underscores potential hazards but also points toward improved risk assessment frameworks. The paper thus marks an important step toward integrating complex radiation-exposure scenarios into radiation protection guidelines, occupational safety standards, and public health policies.

The outcomes of this project advance our ability to evaluate space-weather impacts on the atmosphere and biosphere and support the development of effective environmental monitoring and health-protection strategies.

Project coordinator Faton Krasniqi from PTB said

‘The BIOSPHERE project has shown how metrology can help us better understand complex radiation environments and their effects on the atmosphere, ecosystems and human health. By combining atmospheric modelling, space-weather data, biological experiments and validated measurement methods, we have provided new tools and evidence to support improved risk assessment, environmental monitoring and health-protection strategies. The project’s open datasets, good practice guides, systematic reviews and peer-reviewed publications ensure that these results can be reused and built upon by researchers, regulators and operational users working on space weather, radiobiology, radiation protection and environmental health.’

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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