In Europe, tropospheric ozone pollution appears as a major air quality issue, and ozone concentrations remain potentially harmful to vegetation. In this study we compared the trends of two ozone metrics widely used for forests protection in Europe, the AOT40 (Accumulated Ozone over Threshold of 40 ppb) which only depends on surface air ozone concentrations, and the Phytotoxic Ozone Dose which is the accumulated ozone uptake through stomata over the growing season, and above a threshold Y of uptake (PODY). By using a chemistry transport model, we found that European-averaged ground-level ozone concentrations (− 2%) and AOT40 metric (− 26.5%) significantly declined from 2000 to 2014, due to successful control strategies to reduce the emission of ozone precursors in Europe since the early 1990s. In contrast, the stomatal ozone uptake by forests increased from 17.5 to 26.6 mmol O₃ m⁻² despite the reduction in ozone concentrations, leading to an increase of potential ozone damage on plants in Europe. In a climate change context, a biologically-sound stomatal flux-based standard (PODY) as new European legislative standard is needed.

在欧洲，对流层臭氧污染似乎是主要的空气质量问题，臭氧浓度仍然可能对植被有害。在这项研究中，我们比较了两种在欧洲广泛用于森林保护的臭氧指标的趋势：AOT40（累积臭氧阈值40 ppb）仅取决于地表空气中的臭氧浓度，而植物毒性臭氧剂量即累积的臭氧吸收量在整个生长季节通过气孔，并且高于吸收的阈值Y（PODY）。通过使用化学迁移模型，我们发现欧洲平均的地面臭氧浓度（− 2％）和AOT40指标（− 26.5％）从2000年到2014年显着下降，这是由于成功的控制策略减少了臭氧前体的排放自1990年代初开始在欧洲上市。相反，尽管减少了臭氧浓度，但仍为₃  m ^-2，导致欧洲工厂对臭氧的潜在破坏增加。在气候变化的背景下，需要一种基于生物的气孔通量标准（PODY）作为新的欧洲立法标准。