How much cleaner was the air during the first month of lockdown?

30 June 2020

Nitrogen dioxide pollution in Cheltenham was down an average of 45% in April 2020 compared to April 2019. The fall was even higher at busy roads, between 50% and 60%. These results come from the 12 nitrogen dioxide (NO2) monitoring sites run by Leckhampton with Warden Hill Parish Council – and they are replicated in studies from other monitoring networks across the UK and Europe.

Air pollution scientists conclude the fall in NO2 is directly correlated with reduced traffic during the lockdown.

But there is a twist to this story. Pollution from particulates (PM2.5 ) actually increased in April 2020, compared to the previous three months. This result was also reported widely by pollution monitoring bodies across the UK and Europe. Scientists at Kings College London reported that this was due to a combination of factors, primarily highly abnormal wind conditions predominantly from the east and south east, bringing in industrial and agricultural pollution. It was also the sunniest April on record – and high pressure has the effect of trapping particulates.