The severe air-pollution episodes that affected Europe this spring (see, for example, go.nature.com/si6mhu and go.nature.com/1b7ygf) highlight the need for effective policy measures and management strategies, given the persistence and potential global reach of such acute events.
Reducing particulate matter, ozone and greenhouse gases is essential to mitigate air pollution as well as climate change, so policies need to be coordinated. For example, climate policy encourages use of fuels such as diesel (because its combustion releases less carbon dioxide per kilometre than petrol) and biomass, which offsets most of its own carbon release as it grows. However, both fuels generate harmful particulates.
For now, the factors that triggered Europe's latest air-pollution episodes and influenced their duration and spread must be investigated. This insight will aid the development of much-needed cross-border policies that are based on sound scientific advice.