BUSES are the main culprit behind poor air quality on Oxford's most polluted street, while cars are the main offenders in other hot spots, a new report has shown.

Every year, Oxford City Council publishes a report showing which areas of the city have the worst air quality, with the last one being conducted in September last year.

Now, a report commissioned by the council has shown what kinds of gases and polluting particles plague those streets, and which vehicles are emitting them.

On St Clement's, the street with the worst air quality in Oxford, buses are the main cause of pollution.

But in the other areas where the report found that air quality was poor - Botley Road and Worcester Street - cars were the cause of most of the pollution.

Tom Hayes, who is the councillor for St Clement's ward, said the narrow road, tall buildings and large amount of traffic on the road had a 'canyoning' affect which meant air pollution was more likely to build up.

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My Hayes, also the city council's cabinet member for zero carbon Oxford, added: "For each street in my area, the residents have a particular issue of concern I hear about. On St Clements this is the issue I hear about on a returning basis."

The report by Ricardo Energy and Environment, a consulting firm, found that 69.9 per cent of Nitrogen Oxides on St Clements came from buses through a technique called source apportionment.

Nitrogen Oxides are harmful chemicals emitted from fossil fuel vehicle exhausts.

It also found that more than half of all microscopic pieces of material from car exhausts known as particulate matter also came from buses.

Emissions on the street are currently far above the legal limit for healthy air quality.

But on Worcester Street and Botley Road, privately owned cars created the most pollution, followed by light goods vehicles performing deliveries.

The report was written and data was gathered before emissions took a nosedive during the coronavirus pandemic, so does not account for it.

The report also predicted that if Oxford City Council's plans to create a Zero Emissions Zone in the city centre are put into force, all of these streets would be brought within legal limits for air quality.

The Zero Emissions Zone plans includes enforcing a higher environmental standard for buses as defined by the EU, meaning all buses driving through central Oxford would have to give off fewer harmful emissions.

READ AGAIN about the Zero Emission Zone proposals here

It also includes plans to fine all fossil fuel emitting cars for entering the city centre.

A reduction in emissions noted in the report was described as a 'minor improvement' by the Green Party.

Green city councillor Dick Wolff said: "Rather than seeking to 'lock in' the improvements to air quality witnessed in the last few months, the city council are actually delaying the introduction of a clean air zone in the city centre and for a number of weeks even waived car parking charges. We need to 'build back better' - not return to the same poor air quality."

The Greens have proposed Low Traffic Neighbourhoods across the city, massive improvements to cycle infrastructure, and other measures to reduce car use.

But the Green councillor's claims were denied by cabinet member Mr Hayes, who said the council was committed to 'achieving the cleanest possible air'.

He said: "We are going out to a formal consultation on the ZEZ in October; We were required to postpone it by the global pandemic.

"We couldn't expect businesses who were fighting to survive to prioritise this."

The ZEZ was due to launch this year, but has been pushed back to Summer 2021 because of the coronavirus pandemic.

A bid for £50m of government cash by Oxfordshire County Council could see all buses operating in the city centre converted into electric vehicles.

Poor air quality kills 7 million people a year worldwide.

In the UK, the government ultimately has responsibility for making air quality better, but local councils have a part to play with local air quality management plans.

30/06/20: This article has been updated to include a reply to Green party criticisms of Oxford City Council