Cold, still weather in mid January brought pollution problems to most mainland UK cities. Pollution signatures from diesel engines were clear as traffic exhaust built up close to roads and then spread across city centres and into residential areas. Moderate nitrogen dioxide was initially measured alongside busy roads in Glasgow, Oxford and London on Friday the 13th followed by moderate airborne particles on Saturday 14th. Gentle winds and lower traffic volumes provided some respite on Sunday 15th before the episode intensified at the start of the working week.
The worst affected areas were Leeds where airborne particles reached very high alongside Headingley Lane in the north of the city, and Stockton-on-Tees where there was very high pollution alongside the A67. High levels of airborne particles also affected Bristol, Chesterfield, London and Southampton. Winds picked up again on late Tuesday, bringing an end to the episode for the UK, but pollution problems then followed across Paris and northern Germany as the settled weather moved eastwards.
On 31 January polluted, cold easterly winds caused moderate and high air pollution across most of England.
Scientists from UK universities, along with teams from the US and Switzerland, will be analysing in detail January's air pollution around London as part of the Clearflo project. Another 5-week study is planned during the Olympics.