Measured UK Air Quality responds to severe changes in activity during 2020

Abstract:

Human activity around the world changed substantially during 2020 due to government responses to a global crisis. In the UK people were asked to work from home where possible on the 16^th of March before entering a period of “lockdown” on the 23^rd of March. During this lockdown period all non-essential travel was prohibited, and outdoor activity was limited to once per person per day. Many of these restrictions impacted activities that are considered antagonists for air quality, such as road transport. We examined NO₂ and O₃ measured by the UK’s Automatic Urban and Rural Network, focusing on those located in urban environments. Data between January 1^st and May 31^st in 2020 was compared to the previous 5 years as a means of assessing any changes in air quality as a result of the lockdown.

Significant reductions in NO₂ concentrations were observed at sites across the UK, with a median reduction of 45 %. However, O₃ concentrations saw a median increase of 11 %. These perturbations were also reflected in the number of exceedances in UK air quality objectives and EU directive limits for both NO₂ and O₃.

This behaviour during 2020 may provide insight into how urban areas may change over the coming years; through the increased adoption of electric vehicles and a likely move to more remote working. Places where O₃ is no longer considered a dominant air pollutant, such as London, may need to consider its resurgence during transition to NO₂ reducing technologies and lifestyles.