Air quality in Barnet has “improved significantly” according to a town hall chief, although recent data has been “severely distorted” by coronavirus lockdowns.

Levels of nitrogen dioxide – which can cause respiratory problems with long-term exposure – fell by almost a quarter during 2020, mainly due to lower traffic volumes and reduced congestion caused by the lockdowns.

The figure is set out in an annual air quality report presented to Barnet Council’s environment committee on Wednesday. The report adds that there has been a “general improvement in air quality across the borough in the past seven years”, mainly down to “increasing numbers of cleaner engines” and more “sustainable transport options”.

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It also reveals there has been a gradual decline in levels of particulate matter, which has been linked to lung and heart problems.

Geoff Mee, the council’s executive director of environment, told the meeting: “This is an extraordinary report, in that there has been a significant improvement in air quality in Barnet over the past few years.”

Although Mr Mee admitted that the pandemic had “severely distorted” the figures, he described the improvement in air quality as a “success story”.

However, opposition councillors suggested the council could do more to cut pollution. Labour environment spokesperson Cllr Alan Schneiderman pointed out that Barnet was the only London borough not to join a London-wide campaign to encourage drivers to switch off their engines when their vehicles are stationary, known as “idling”.

Cllr Peter Zinkin, a Conservative member of the committee, said anti-idling measures were difficult to enforce because once drivers turn their engines off, they stop committing an offence, but when an enforcement officer walks away, they could switch their engines back on again. 

Labour’s Cllr Claire Farrier suggested the council could introduce more 20mph zones to further reduce air pollution. The air quality report states that lowering the speed limit to 20mph around schools would reduce levels of particulate matter. 

Cllr Farrier said: “If that has made a difference, does that mean we should be looking at more 20mph zones elsewhere in the borough, not just around schools?”

Mr Mee said the council did not see any need to change the current policy of placing 20mph zones around schools, adding that the “major problem” was that the zones were “unenforceable”.

At the end of the debate, Cllr Schneiderman proposed that Barnet join the other London boroughs in the campaign against engine idling. Conservative members voted against his suggestion, with the exception of Cllr Laithe Jajeh, who abstained.

Cllr Zinkin called on the council to monitor the impact of the expansion of the Ultra-Low Emission Zone (ULEZ) to the North Circular, warning drivers could make more journeys along the road – which marks the boundary of the zone – to avoid paying the £12.50-a-day charge incurred by travelling inside it.

Fellow Tories backed his proposal, with Labour abstaining. Labour also abstained on the air quality report, claiming it did not go far enough.