Oxford exhaust emissions assessment project begins
Work has started on a project to assess vehicle emissions in Oxford.
Oxford City Council said although overall pollution had fallen there were some "hotspots", such as St Aldates, where bus numbers have increased.
Equipment is being used to shine an infrared beam across some roads in the city to detect the exact breakdown of exhaust gases.
The research, which is being carried out by experts from King's College London, is being funded by Defra.
The city council said it was working in partnership with Oxfordshire County Council and the bus companies to reduce harmful emissions, but said more needed to be done.
The authority added it was "keen to find out as much as possible about why pollution happens and how we can address it".
The technology has been developed by the University of Denver, Colorado.