Recent nitrogen dioxide levels in Southampton
Researchers from SERG have been collaborating with colleagues at the University of Auckland, NZ to analyse the effects of UK Covid lockdown on the most recent Southampton air quality data. This work has subsequently been submitted to DEFRA in response to a call for evidence.
The analysis suggests that overall
- 2020 was already a ‘cleaner air’ year compared to the 2017-2019 average;
- Covid-19 lockdown appears to be amplifying this trend for NO family pollutant emissions with some days recording up to 92% lower NO2 levels than the 2017-2019 average.
Recent nitrogen dioxide levels in Southampton relative to 2017-2019
However, other days show substantially higher air pollution levels compared to both pre- lockdown and previous years and this is particularly noticeable for levels of PM10 and PM2.5. These periods appear to correlate with certain wind conditions and highlight the importance of meteorological affects and/or pollution sources that are not affected by lockdown. Were it not for these conditions/sources, it seems likely that the lockdown affect in Southampton would be consistent and sustained.
More sophisticated analysis that can control for differing meteorological conditions, variable public holidays (i.e. Easter) and account for other sources of pollutants will be needed to determine the true significance of lockdown affects. SERG are in the process of collating data and developing statistical models that can be used to do this.
Code and regularly updated results at: https://cfsotago.github.io/airQual/