Ozone (O3) is a dangerous air pollutant when it penetrates the small pores on leaves called stomata. These small "mouths" allow the gas exchanges that are fundamental both for the photosynthesis of the plant and for their release of oxygen and water vapour. Given the centrality of these aspects in all natural and artificial ecosystems, the correct assessment of risk thresholds for vegetation caused by O3 is the subject of numerous and accurate studies and research.

In addition, in the pilot cities of the VEG-GAP project, the analysis of the effects of O3 concentrations on vegetation is particularly focused, since the Mediterranean climate promotes the production of tropospheric O3 due to a sustained photochemical activity driven by hot and sunny summer conditions. O3 enters through the stomata of leaves where it undergoes oxidation reactions, forming reactive oxygen species and causing damage to biomolecules, including cell membranes, proteins and DNA, and leading to reduced plant growth.

Now, thanks to the study published in issue no. 287 of the prestigious international journal Environmental Pollution, in which the CREA partner in the VEG-GAP project, Silvano Fares, has collaborated on the conceptualisation and methodology, these risk threshold assessments will be able to benefit from new data and approaches, which can investigate how, for example, for some tree species (the evergreen Quercus ilex) it is possible to speak of a "memory effect" in their response to O3 that can last beyond one season.

Specifically, the study compared tests carried out with different approaches to improve the accuracy of risk threshold simulations. This allowed the identification of the most appropriate formulation for a holm oak (Quercus ilex) forest growing in a Mediterranean climate, where O3 concentrations are relatively high and seasonal droughts are common.

The research was made possible thanks to the Castelporziano Scientific Commission, the Multidisciplinary Centre for the Study of Coastal Mediterranean Ecosystems and the Management of the Castelporziano Estate. However, his team wanted to give explicit recognition to VEG-GAP, mentioning it as one of the international, European, national and regional projects that actively supported their study and allowed it to be widely and freely disseminated throughout the scientific community.