In many cities across the UK, pollution levels have dropped significantly, according to statistics from the BBC Joint Data Unit.
But in the three areas of Sheffield surveyed – Tinsley, Devonshire Green and Barnsley Road – only one area saw a clear reduction, with one experiencing an increase.
According to the data, on Barnsley Road in 2019 a reading of 35.5 micrograms of nitrogen dioxide per cubic metre of oxygen was recorded from March 19 to 26.
By comparison, in the week of March 17 to 24 this year – the period where Prime Minister Boris Johnson ordered pubs and non-essential shops to close – a level of 34.6 was detected.
Nitrogen dioxide, or NO2, is a byproduct of burning fuel.
In Tinsley, harmful emissions fell dramatically – from 32.3 to 24.1 – while around Devonshire Green, levels rose from 20.1 to 23.8 over the same period.
By comparison, central Leeds saw a drop from 26.6 to 21.1, pollution in the middle of Nottingham fell from 29.9 to 19.9, Westminster’s reading reduced from 37 to 25.8, while in parts of Derby the level fell from 40.4 to 25.6.
Councillor Douglas Johnson, who represents City Ward for the Green Party, said he would have expected Sheffield’s figures to have demonstrated a bigger drop.
He said the increase on Barnsley Road could be down to its closeness to the Northern General Hospital, while Tinsley’s location near the M1 – much quieter amid lockdown – could explain the change there.
“These are still high levels,” said Coun Johnson.
“It’s when you record levels of 40 or above that it becomes illegal.
“With Devonshire Green, it’s a residential area so it's maybe to do with domestic heating.
“In general, cars are getting cleaner, which may explain the drop generally.”
Meanwhile, Graham Jones, founder of the Burngreave Clean Air Campaign, questioned the figures.
“We do our own monthly monitoring and I would expect Barnsley Road to be in the 40s or even 50s,” he said.
Sheffield Council was approached for comment.