Research funded by the Department for Transport and conducted by Rail safety and Standards Board on 6 types of train, has found that air quality levels on some trains, while operating under diesel power, is poorer than desired.

The report published on 16 September 2021has independently concluded that the quality of air on services remains within legal workplace limits. There is already cross-industry research underway to understand the issue and identify short-term and long-term solutions.

However, in response to the report, DFT has asked the RSSB to publish the full findings and has commissioned a review of all the regulations and standards that currently control air pollution and people’s exposure to it on the rail network. This will include on-board services as well as in stations.

The report shows measurements of pollutants including nitrogen dioxide and particulate matter throughout the duration of train journeys. It demonstrates that on-train concentrations of nitrogen dioxide can peak at levels ranging from 1 to 13 times higher than identified next to major central London roads. Peaks most frequently occur when trains are in tunnels or idling in stations.

While this is verified as within legal limits, the government is committed to ensuring passengers and staff can be reassured that the railways meet the very highest standards. This could include updating or strengthening existing railway standards on air quality.

DFT has also commissioned further research, managed by RSSB to help better understand the scale of the air quality issue on board trains and to identify potential causes and solutions. This work will include measuring air quality levels inside a further 8 train classes in service across the country’s rail network.

The work forms part of the broader Air Quality Strategic Framework, which details RSSBs recommended approach for monitoring, modelling and mitigation. Most recently, this has included kicking off a £4.5 million Stations Air Quality Monitoring Network to focus on measuring air quality at train stations across England and Wales and provide high quality and robust data.

Rail Minister Chris Heaton-Harris said:

'The safety of staff and passengers is our absolute priority. While these findings are within limits, I do not believe people should have to accept anything less than the highest levels of air quality.

I have asked the industry to immediately conduct further research and explore all engineering modifications and options to rapidly improve air quality on trains and in stations.

I have also launched a comprehensive review of the current standards and guidance related to air quality on the rail network. If required, we will not hesitate to strengthen legislation to ensure the highest standards of air quality are met and maintained.'

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