Oldham's pollution levels have dropped by 50.6% since lockdown began.
Meanwhile, at Manchester Piccadilly they have dropped by 41.9% and at Sharston by 54%.
Those percentages are measured from the average daily nitrogen dioxide emissions - which is what is released from car exhausts and is one of the serious air pollutants.
The difference is a trend that has been seen across the UK since the Prime Minister, Boris Johnson, asked people to work from home and lockdown began.
Analysis by the BBC Shared Data Unit found an even larger drop in air pollution since the first day of lockdown on 23 March compared to that time last year – halving at some of the most polluted sites, including readings in London, Glasgow, Bristol and Oxford.
Daily readings from air quality monitoring stations since March 17 were compared to the same period last year, accounting for weekdays.
