Portugal is the 11th largest wine producer in the world and the 5th largest in the European Union. The Douro Demarcated Region (RDD) is the wine-growing area where the famous Port wine is produced, responsible for more than 60 per cent of the total value of national wine exports. In the context of climate change (CA), it is important to understand how the distribution of ozone in the lower layer of the troposphere will be affected and how ozone will in turn affect forests and agricultural crops such as vines. It is widely accepted that exposure of crops to ozone results in underdeveloped plants, lower quality produce and lower yields. Recently published studies prove the negative effects of increased tropospheric ozone concentrations on productivity, however, these studies focused mainly on four of the world’s major crops – wheat, maize, rice and soya. On the other hand, the damage caused by ozone has been related to ozone concentrations, with the logic being that higher concentrations are more damaging to plants. However, it is becoming increasingly clear that it is the amount of ozone absorbed by the plant, or internal dose, and not the external exposure that should be used when assessing the risk of ozone.

This distinction is important in a situation where high ozone concentrations are associated with hot and very dry meteorological conditions, as is the case with the AC situation projected for southern Europe. Under these conditions, plants tend to reduce the opening of their stomata in order to reduce water loss, which also reduces ozone absorption. Therefore, when studying the effects of future ozone concentrations on crops, it is necessary to consider not only ozone concentrations, which determine the exposure of crops to ozone, but also ozone deposition on vegetation, which determines ozone flux, i.e. the entry of ozone via stomata. The aim of DOUROZONE is to assess the risk of ozone exposure to vineyards in the Douro Valley in the present and future climate, estimating the concentrations and deposition of ozone in the Douro Valley and then assessing the potential damage in terms of productivity.