VARIATIONS IN SURFACE OZONE TRENDS OVER EUROPE

Surface ozone data from 20 European stations of differing character (remote, rural, suburban and urban) were analysed for linear trends over a common period of 1978-1988. Pronounced annual and seasonal variations are apparent in the trends in different areas. Relatively few of the trends are statistically significant and there is no dominant region-wide trend. However, there does appear to be some commonality of behaviour on a subregional scale as positive or negative trends tend to be clustered together in some areas. Stations on the maritime fringe of the network generally exhibit negative trends in summer average concentrations, whilst those located further into the continental interior exhibit positive trends. Most of the stations in the network exhibit positive trends in the winter averages. The short-term variability evident in this study reflects the complex controls affecting surface ozone concentration and suggests that it may be misleading to draw conclusions concerning long-term trends from records of limited duration.