Ozone is globally the most important gaseous pollutant causing effects on vegetation. However, while a number of reviews have evaluated the evidence of impacts of ozone on semi-natural ecosystems, none of these has specifically focused on the priorities of the nature conservation agencies. This project provides a systematic risk assessment to identify BAP habitats at greatest risk of impacts ofozone and considers how this risk might change in the future. It identifies key gaps in knowledge, and priorities in terms of conservation objectives. It assesses how policy initiatives might mitigate the possible impacts of ozone on habitats of conservation value in the UK over the next 20-30 years.