摘要：a c k g r o u n d: Short-term exposure to ozone has been associated with increased daily mortality. The shape of the concentration–response relationship—and, in particular, if there is a threshold—is critical for estimating public health impacts. oB j e c t i v e: We investigated the concentration–response relationship between daily ozone and mor-tality in five urban and five rural areas in the United Kingdom from 1993 to 2006. Me t h o d s: We used Poisson regression, controlling for seasonality, temperature, and influenza, to investigate associations between daily maximum 8-hr ozone and daily all-cause mortality, assuming linear, linear-threshold, and spline models for all-year and season-specific periods. We examined sensitivity to adjustment for particles (urban areas only) and alternative temperature metrics.re s u l t s: In all-year analyses, we found clear evidence for a threshold in the concentration–response relationship between ozone and all-cause mortality in London at 65 μg/m3[95% confidence inter-val (CI): 58, 83] but little evidence of a threshold in other urban or rural areas. Combined linear effect estimates for all-cause mortality were comparable for urban and rural areas: 0.48% (95% CI: 0.35, 0.60) and 0.58% (95% CI: 0.36, 0.81) per 10-μg/m3increase in ozone concentrations, respec-tively. Seasonal analyses suggested thresholds in both urban and rural areas for effects of ozone during summer months.co n c l u s i o n s: Our results suggest that health impacts should be estimated across the whole ambient range of ozone using both threshold and nonthreshold models, and models stratified by season. Evidence of a threshold effect in London but not in other study areas requires further investigation. The public health impacts of exposure to ozone in rural areas should not be overlooked
关键词：concentration–response function; daily mortality; ozone; U.K. population
