By Paul Homewood
Following up the claims of cleaner air due to the lockdown, I thought I would do a few checks.
Our local air monitoring site is Devonshire Green, close to Sheffield City Centre. It is a site I have posted on before.
https://uk-air.defra.gov.uk/networks/site-info?uka_id=UKA00575
DEFRA offer a tool to graph pollutants in various ways, and below are their graphs for daily mean pollution from NO2, PM10 and PM2.5, going back over the last 12 months:
https://uk-air.defra.gov.uk/data/data_selector_service?q=2051795#mid
The general impression on NO2 is that pollution levels have dropped this month, but are similar to much of March and also last August.
Assistance here please. Would we expect NO2 levels to be higher in winter? Logically they would rise during periods of high pressure, due to still air, but the opposite seems to have happened, with levels peaking during February’s storms?
However far more significantly is the apparent upward trend in PMs this month, at a time when supposedly traffic levels have dropped.
This is only one site, so it may be a fluke. And I would appreciate any suggestions of why this should be.
But on the face of it, the lockdown may have reduced levels of NO2, but had no effect at all on PMs.
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April 12, 2020 at 04:15AM
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