Effects of meteorology and human-mobility on UK's air quality during COVID-19.

Efforts to prevent the spread of the coronavirus disease 2019 (COVID-19) pandemic have had profound positive and negative impacts on social and environmental indicators worldwide. For the first time, a scenario of a partial economic shutdown could be measured, and large tech companies published wide-coverage mobility reports to quantify the impacts on social change with anonymized location data. During the COVID-19 pandemic, the UK government has employed some of the strictest lockdown periods in the world, causing an immediate halt to travel and business activities. From these repeated lockdown periods, we have gained a snapshot of life without excessive human-made pollution; this has allowed us to interrogate the interaction between meteorology and air quality with minimal anthropogenic input. Our findings show a warmer 2020 increased the UK's ozone levels by 9%, while reductions in human-mobility reduced UK-wide nitrogen dioxide levels by 25% in 2020, which have remained low during the first months of 2021 despite curtailing/ending of restrictions; and a decrease in particulate matter created by meteorological and human drivers. Regionally, London records the highest NO and O changes, -31% and 35%, respectively, linked to mobility reductions and meteorology.