Changes in Personal Exposure to Fine Particulate Matter (PM_2.5) during the Spring 2020 COVID-19 Lockdown in the UK: Results of a Simulation Model

Objectives: Policy responses to the COVID-19 pandemic in 2020 led to behaviour changes in the UK’s population, including a sudden shift towards working from home. These changes may have affected overall exposure to fine particulate matter (PM_2.5), an air pollutant and source of health harm. We report the results of a simulation model of a representative sample of the UK’s population, including workers and non-workers, to estimate PM_2.5 exposure before and during the pandemic. Methods: PM_2.5 exposure was simulated in April and August 2017–2020 for 10,000 individuals across the UK drawn from the 2011 nationwide census. These data were combined with data from the UK’s ambient PM_2.5 monitoring network, time use data and data on relevant personal behaviour before and during the first stage of the pandemic (such as changes in smoking and cooking). Results: The simulated exposures were significantly different between each year. Changes in ambient PM_2.5 resulted in regional and temporal variation. People living in homes where someone smoked experienced higher exposure than those in smoke-free homes, with an increase of 4 µg/m³ in PM_2.5 exposure in 2020. Conclusions: Changes in PM_2.5 exposure were minimal for most individuals despite the simulated increases in cooking activity. Those living in smoking homes (estimated to be around 11% of the UK population) experienced increased exposure to PM_2.5 during COVID lockdown measures and this is likely to have increased mortality and morbidity among this group. Government policy should address the risk of increased exposure to second-hand smoke in the event of future COVID-19-related restrictions.