Regional strategies and cross-border co-operation to control ozone pollution

In many European cities, air pollution is currently perceived as a local problem mainly related to road transport and certain industrial processes. However, some of the air pollution problems that UK local authorities are currently facing are related to air pollutants formed outside their geographical boundaries. For example, ground-level ozone episodes occurring in Sussex and Kent are often attributed to emission sources in continental Europe. Although there are international agreements in place for transboundary pollutants like ozone, relevant regional control strategies are lacking. A number of studies have recently focused on the formation, trends and spatial patterns of ozone pollution in different geographical areas making use of photochemical grid and/or trajectory models, emission inventories and field observations. Some of these tools may be applicable to the Trans Manche region. An analysis of monitoring data from five stations in England showed decreasing numbers of ozone episodes, but persistently high background levels, with some of the highest values observed at rural locations near the south east coast. Ozone concentrations in coastal areas on both sides of the Channel were highly correlated during recent episodes, probably due to the common origin of the sampled air masses. For this reason, co-operation between UK and French authorities is needed in order to optimise strategies for controlling regional ozone pollution.