This report is submitted in response to the request for evidence issued by the Government’s Air Quality Expert Group (AQEG) in April 2020. The basis of the work carried out has been to examine the hourly average concentrations of nitrogen dioxide, total oxides of nitrogen (NOx), ozone, PM10, PM2.5 and carbon monoxide at a total of 40 monitoring sites (listed in Table 1) across the UK from 1 January to 19 April 2020, compared with the corresponding long term hourly average concentrations at each site. The majority of these sites are in the AURN but some data have also been examined from the London Air Quality Network, Air Quality in Scotland and from sites at Heathrow and Birmingham Airports. These sites cover all the main description categories and were selected because they mainly had long term (ideally 10+ years) datasets to calculate the long-term average concentrations of the various pollutants. For the purposes of this study the date for the start of the lockdown is taken as Monday 23 March 2020.
Not all the pollutants mentioned above are measured at all the sites. The inclusion of the Heathrow sites made it possible, albeit to a very limited extent, to include data for PM1 and Black Carbon (BC) and from sites close to a major airport. A further caveat must be given: at some of the sites there have been equipment changes and this might reduce the validity of comparisons. Finally, at some sites data are not available for all pollutants for all of the period under consideration.
For further reading please download the report …observations-on-air-quality-in-the-uk-during-the-covid-19-lockdown-april-2020