Transport should be a key target for efforts to reduce nitrogen oxide emissions, a new report from a House of Lords committee has indicated. The report, will add to pressure for expanded low emission zones, and a switch to electric or hydrogen vehicles, because those changes would reduce air pollution as well as carbon dioxide emissions.

Several witnesses told the committee that “the shift towards a zero emission vehicle fleet and greater public transport needs to be accelerated to further reduce nitrogen emissions to air”. The report from the House of Lords Select Committee on Environment and Climate Change, titled “Nitrogen: time to reduce, recycle, reuse”, cited evidence that low emission zones had been effective and quoted the Sustainable Nitrogen Alliance’s view that low emission zones should cover more urban areas.

The Lords heard evidence that emissions from the road transport fleet, in the form of nitrogen oxides (NOx) have been falling as it is modernised, but the sector still emitted as much nitrogen to air as agriculture. The committee reiterated recommendations made in its previous report ‘EV strategy: rapid recharge needed’ on electric vehicles.

The Committee was concerned that the government “has historically taken a piecemeal approach to nitrogen management and regulation, with different government departments addressing individual parts of the problem in siloes. This piecemeal approach has led to a largely ineffective regulatory framework, with poor enforcement, lack of clear accompanying guidance, and overlap between regulatory bodies’ remits which have complicated roles and responsibilities.”

It said: “We recognise that measures such as Clean Air Zones (CAZ) and Ultra Low Emission Zones (ULEZ) have been effective urban transport policy measures in reducing nitrogen emissions,” but more needs to be done to incentivise this shift and it raised concerns over gaps in monitoring systems.

It concluded that “while significant progress has been made in reducing nitrogen pollution from transport and industry in recent decades, challenges and gaps remain” and called for on the government to publish a national and cross-sectoral Nitrogen Strategy within two years.