An analysis of the spatial patterns of human health related surface ozone metrics across the UK in 1995, 2003 and 2005

Abstract Maps of a range of human health related surface ozone metrics for the UK have been generated using empirical measurements based models for the years 1995, 2003 and 2005. These years have been chosen to illustrate two recent years with higher and lower photochemical ozone contributions (2003 and 2005) and a year with higher photochemical ozone contributions combined with higher urban NO emissions (1995). A comparison of monitoring data with a transect of mapped values for London suggests that the empirically generated maps include a reasonably realistic description of the regional ozone concentrations and of the urban decrements of ozone concentrations. Estimates of the health impacts associated with ozone have been calculated from the mapped concentrations and are highly dependent on the metric chosen and thus on the implicit assumptions concerning the threshold concentration for effect (0, 70 or 100 μg m −3 ). The year of maximum health impact is also dependent on the metric used. Estimated derived from the annual mean of the daily maximum of the running 8-h mean concentration with a cut-off of 0 μg m −3 vary little from year-to-year, while the greatest impact was estimated to be in 1995 for annual mean of the daily maximum of the running 8-h mean concentration with a cut-off of 100 μg m −3 . Estimates derived from the annual mean of the daily maximum of the running 8-h mean concentration with a cut-off of 70 μg m −3 were greatest in 2003, reflecting the fact that this metric (closely related to the SOMO35 metric adopted for European scale integrated assessment modelling) is influenced by both the magnitude of summer photochemical ozone episodes and the extent of titration with local NO emissions (the urban decrement). The models used should be applicable across much of NW Europe and other locations where there is little or no urban scale photochemical generation of ozone.