Air pollution in the UK has recently re-emerged as a major policy problem. Insights from the agenda-setting literature are used here to explain the extent to which air quality has become a national political issue, and a local issue in London. The article explores the development of a problem stream in which scientific experts and non-governmental actors have since the late 2000s, provided evidence related to the economic and particularly health costs of air pollution, and increasingly framed the problem as urgent. Key focusing events have also contributed to increasing media coverage and public concern. Explanations are offered for the limited policy response at the national level compared to London. The research is based on primary data which includes 16 elite interviews with key actors, manifestos from London Mayoral and UK general elections, and local and national government policy documents. In London there is broad cross-party consensus and relatively high public concern, and a mayor acting as a policy entrepreneur, able to build upon pre-existing congestion charging policy. In contrast, at the national level there is a shared understanding that air pollution constitutes a problem, but less consensus on its scale amongst the public and across political parties, fragmented policy making and responsibility for the issue and little agreement on the appropriate policy response.

英国的空气污染最近已重新成为主要的政策问题。在这里，来自议程设定文献的见解被用来解释空气质量在多大程度上已经成为国家的政治问题和伦敦的地方问题。本文探讨了自2000年代后期以来科学专家和非政府行为者在其中出现的问题流的发展，提供了与空气污染的经济，尤其是健康成本有关的证据，并日益将这一问题视为紧急问题。重点关注活动还有助于增加媒体报道和公众关注。与伦敦相比，在国家层面对有限的政策回应提供了解释。这项研究基于主要数据，包括对主要演员的16次精英访谈，伦敦市长宣言和英国大选的宣言，以及地方和国家政府的政策文件。在伦敦，有广泛的跨党派共识和相对较高的公众关注度，并且市长担任政策企业家，能够在现有的拥堵收费政策基础上发展。相反，在国家一级，人们普遍认识到空气污染是一个问题，但公众和各政党在空气污染的规模上共识不足，政策制定和责任分散，对适当的政策应对措施也未达成共识。