NOx emissions from UK lorries have halved in five years, according to new government statistics.

Department for Transport figures show a 52% fall between 2013 and 2018 as haulage firms have upgraded to cleaner Euro VI lorries.

The Road Haulage Association (RHA) says the trend is set to continue and projects NOx emissions from HGVs will have reduced by more than 80% by the end of 2025.

But the Association in its NOx Emission Assessment warns many operators face an uncertain future as local authorities press on with plans which will see hauliers charged up to GBP100 (US$126) per day to enter clean air zones.

RHA chief executive, Richard Burnett says efforts to improve air quality will fall short until they proportionately target sources of emissions.

“The government is signing off poorly conceived measures which punish hauliers for local authority failures to keep emissions in check,” he said.

“But we’re leading the way – we’ve more than halved our NOx emissions in the last five years and this will only continue as firms upgrade their fleets.”

Lorries and buses account for a small, declining proportion of NOx emissions according to National Atmospheric Emissions Inventory data.

Figures from 2015 show the sectors were responsible for 7.6% of NOx, while the share from other key sources such as passenger cars and combustion in industry were higher reports the RHA.