Analysis of trends in NOx and NO2 at 219 monitoring sites across the UK, over six years to December 2021, showing the effects of COVID lockdowns in the context of long-term patterns.
AQC has previously analysed trends in NOx and NO2 concentrations over time across the UK and shown that, once weather effects are accounted for, large improvements have been achieved over the period 2014 to 2020. AQC has also previously quantified the effects of COVID lockdowns on NOx and NO2 concentrations, showing the effects of lockdown severity on weather-normalised concentrations.
In this latest report, the Company brings these strands together to consider long-term trends at 219 monitoring sites, spread across the UK, over six years.
This shows the effect of the first UK lockdowns in the context of long-term patterns. It also shows that, while average concentrations measured since autumn 2020 have been much lower than any recorded prior to the pandemic, the effect of the pandemic in driving these improvements is probably quite limited. The low concentrations recorded over the last 12 months appear more the result of systematic changes, such as the increased use of lower emissions vehicles, than of recent changes in behaviour.
A potential correlation has been observed between reports of elevated van usage and higher measured concentrations in winter 2021. While this does not appear to undermine the overall trend for improving concentrations of NOx and NO2, it warrants further examination in subsequent analyses.
These observations relate to concentrations averaged over a large number of monitoring sites, and patterns at any individual location may be different. However, on balance, this analysis provides good news regarding recent, and likely future, concentrations of NOx and NO2 across the UK, which will be helpful when developing strategies for future air quality management.
View the full report here.
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