POLLUTION levels have worsened in three major York roads - Gillygate, Lawrence Street and Holgate - according to a new report.

The air quality progress report for City of York Council said the authority had a legal duty to improve air quality, and good progress had been made over the past year with the implementation of many measures towards this aim.

And between 2012 and 2013, there were reductions in annual mean concentrations of nitrogen dioxide at locations including Fishergate, Fulford, Nunnery Lane and Bootham, and there was a pronounced fall in Heworth Green.

However, it was a different story in three other parts of the city, “Over the same period, increases in annual mean concentrations of nitrogen dioxide were observed at Lawrence Street, Holgate Road and Gillygate,” it said.

“The increase observed at Lawrence Street in 2013 meant that this site breached the annual mean nitrogen dioxide objective for the first time since monitoring commenced at this site in 2004.”

High concentrations were also found along Rougier Street and George Hudson Street.

The report by the authority’s environmental protection unit says last summer’s trial closure of Lendal Bridge affected the way traffic moved around the city centre but, while pretrial air quality data existed, it was difficult to quantify precisely the impact of closure on air quality because it was heavily influenced by prevailing weather conditions and subject to seasonal variation.

However, for the purposes of the trial evaluation, an assessment was currently being made using computer modelling of changes in emissions resulting from changes in vehicle flows, and this would be reported later.

Green councillor Andy D’Agorne said the council’s actions to tackle pollution should be examined by a cross party scrutiny committee, which could explore which measures had had the most impact so far, before a new action plan was agreed.

He also suggested signs should be installed requiring bus drivers to switch off their engines while waiting at stops in pollution hotspots such as Rougier Street, where the enclosed nature of the area and concentration of buses exacerbated the problems.

“It has been estimated that poor air quality results in more premature deaths in York than the combined impact of obesity and road collisions,” he added.