On the 5 and 6 March air pollution reached the maximum value of 10 on the UK’s air pollution index – levels where the public are advised to reduce strenuous outdoor physical activity. The easterly air flow that bought cold weather to the UK during March also brought particulate air pollution from traffic and industry across Europe which combined with local air pollution from our own cities. Yorkshire, Warrington and Birmingham were the worst areas affected on 5 March. The area with index level 10 then expanded on 6 March to include Middlesbrough, the whole of North West England and Belfast.
The situation was made worse by cold temperatures – leading to increased pollution from power generation and heating – and still nights that allowed air pollution to build up in our cites. Cold temperatures also meant that many nitrate and volatile organic carbon particles remained in the atmosphere, whereas on hot sunny days these would simply evaporate.
Particulate pollution at index level 10 is more than twice the World Health Organisation guidelines. In 1961, future West German Chancellor Willy Brandt demanded that the “sky above the Ruhr be made blue again”, making air pollution an election issue and setting in train a cleanup of one of Europe’s most polluted industrial areas.
Air pollution has changed since the sixties but with an estimated annual health cost of around £15bn in the UK, there is a big economic and public health prize from cleaning the air.