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Air Quality Expert Group - Rapid evidence review
Air pollution context and climatology – learning from COVID-19 lockdowns
Nationwide reduction in transport intensity began mid-March, reached a minimum in early April. Major sectors contributing emissions of NOx, VOCs and PM.
The UK has had unusual meteorology in 2020. Post-lockdown - significant Easterly component, with transboundary pollution contributions
Air Quality Expert Group - Rapid evidence review
Significant reductions seen UK-wide in NOx and NO2
Top: Raw data from 225 air quality measurement sites across the UK. Bottom: Same data but corrected to account for meteorological variability
Reproduced from Marner, B., Air Quality Consultants, 2020.
Air Quality Expert Group - Rapid evidence review
o Compared to 2019, PM2.5 higher during lockdown - due to Easterly weathero But using computer models, PM2.5 has been lower in many places compared to a
business-as-usual scenario.o Highlights significant AQ influence of wider European emissions.
Reproduced from: Keller C. and Evans, M.J., University of York andNASA Goddard Space Flight Center, 2020.
Business as usual
2020 actual
Changes in PM2.5 are more complex to quantify
Air Quality Expert Group - Rapid evidence review
Reproduced from: Williams, M., on behalf of the Environmental Research Group, King’s College London, 2020.
Exposure to pollution depends where you live, work and how you commute
o Less commuting reduces exposure in London, but could be offset by higher indoor pollution, for example from additional cooking.
Air Quality Expert Group - Rapid evidence review
Lower NOx emissions in isolation can lead to local increases in ozone
Business as usual
10% lower NOx
Lower NOx & VOC
Forecasts of a Springtime ozone case study under COVID-19 emissions
Forecasts of a summertime ozone case study under COVID-19 emissions
30% lower NOx 50% lower NOx
Lower NOx
o Emphasizes the importance of managing all the key pollutants together with coherent strategy that recognizes the chemical interconnections
Reproduced from: Agnew, P., et al. Met Office, 2020 and Fakes, L. and Evans, M.J., NCAS / University of York, 2020.