摘要
欧盟(EU)的'欧洲清洁空气'计划(Clean Air for Europe,CAFE)目前正在对大气质量政策进行修订,这将促使欧盟在2005年中期实行的第六期环境行动计划(Environmental Action Programme)中采取针对大气污染的专题策略。显而易见,对于削减地面臭氧浓度,欧洲控制之外的过程对于满足其未来的长期目标和大气质量方针是至关重要的。观测和模拟结果表明,气候变化与地面臭氧存在着强烈的联系,臭氧浓度很有可能会由于欧洲气候变暖、变干而增加,而且,亚洲发展中国家人为排放的增加也可能提高北半球臭氧的本底水平。北欧几个站点已经观测到臭氧本底浓度的显著增长,尽管其潜在的原因尚未确定。对流层中浓度不断增加的甲烷和一氧化碳之间的光化学合成也可能导致全球范围的高臭氧水平。这些作用可能会逐渐超过欧洲在降低臭氧前体物质排放方面所取得的成就。因此,需要从全球或北半球的角度看欧洲臭氧大气质量政策的修订。
EUs programme Clean Air for Europe (CAFE) is presently revising the policy on air quality which will lead to the adoption of a thematic strategy on air pollution under the Sixth Environmental Action Programme by mid-2005.For the abatement of surface ozone it is becoming evident that processes outside European control will be crucial for meeting long-term aims and air quality guidelines in Europe in the future.Measurements and modelling results indicate that there is a strong link between climate change and surface ozone.A warmer and dryer European climate is very likely to lead to increased ozone concentrations.Furthermore,increased anthropogenic emissions in developing economies in Asia are likely to raise the hemispheric background level of ozone.A significant increase in the background concentration of ozone has been observed at several sites in Northern Europe although the underlying causes are not settled.The photochemical formation of tropospheric ozone from increased concentrations of methane and CO may also lead to a higher ozone level on a global scale.Gradually,these effects may outweigh the effect of the reduced European ozone precursor emissions.This calls for a global or hemispheric perspective in the revision of the European air quality policy for ozone.
