Average annual NO2 concentrations at roadsides in the UK 2000-2023
The average concentration of nitrogen dioxide (NO2) measured at roadside sites in the United Kingdom was 21.8 micrograms per cubic meter air (µg/m3) in 2023. NO2 concentrations plummeted more than 25 percent in 2020 as traffic levels dropped as a result of COVID-19-related lockdowns. Although NO2 concentrations rebounded in 2021, they have since continued to decline.