Air pollution halved in some UK cities on the first day of the lockdown to tackle the coronavirus pandemic.

Air Quality News analysed Department for Energy, Food and Rural Affairs (Defra) monitoring data for nitrogen dioxide (NO2) in London, Leeds, Manchester, Cardiff, Edinburgh, Liverpool, Bristol and Newcastle, comparing yesterday (March 24) with the same day last year (March 26).

Edinburgh saw the largest drop in concentrations from a daily average of 74µg/m3 im 2019, to 28µg/m3 yesterday, as regular commuters worked from home and only essential workers were permitted to travel into the Scottish capital to do their job.

London Westminster also saw a massive decrease in NO2 emissions, from 58µg/m3 in 2019 to 30µg/m3 yesterday.

Despite the fall in transport emissions, Transport for London (TfL) has relaxed penalties around air pollution. From Monday it suspended London’s Ultra Low Emission Zone (ULEZ) until further notice to make it easier for key workers to travel to work and for supermarkets to receive stock.

Whilst Liverpool and Leeds both saw sizeable drops in NO2 levels, other cities saw a more modest reduction.

Defra’s monitor at Manchester Picadilly recorded a daily NO2 level of 37µg/m3, down from 44µg/m3 last year, whereas Bristol fell from 35µg/m3 to 30µg/m3.

The hourly data showed that rush hour was still a busy for time for commuters despite the lockdown. Manchester peaked at a significant 77µg/m3 whereas Birmingham topped out at 57µg/m3.

Both Oxford and Birmingham have this week announced delays to their respective Zero Emission Zone (ZEZ) and Clean Air Zone (CAZ) due to the pandemic.

The mean averages for each city studied are below, courtesy of Defra.