Improving our knowledge of airborne particulate matter on trains
Previous RSSB research, project T1188, discovered varying levels of pollutants on different kinds of trains.
The Department for Transport’s Science Advisory Council suggested further research into air quality onboard trains. The focus of this research should be on particulate matters (PMs).
The aim of the project was to identify the sources of the PMs found onboard trains and to understand their toxicology. The goal was to find ways to reduce health risks for passengers and staff where necessary.
RSSB teamed up with Imperial College London. A bespoke transportable system was developed to measure air quality onboard trains and take air quality samples.
The project team tested six different diesel train classes on six different routes. These classes were picked based on the T1188 RSSB study, which indicated relatively elevated PM level onboard these trains.
The data collected was analysed to understand the level of PMs present in the trains, and mathematical models were used to determine their possible sources. The results were used to find ways to reduce the health effects on passengers and staff.
The project significantly added to our understanding of PMs onboard trains— both their levels and possible sources.
We can link the metal concentrations back to the likely emission sources. The main source was engine exhaust, but other possible sources could be linked to wheel and rail wear, brakes, lubricant, or pantograph wear. More studies are needed to analyse other sources.
To improve air quality on trains, we can reduce engine emissions, use different brake pad materials, and improve ventilation. Better filtration systems on trains can also help. All these measures can contribute to improving onboard train air quality.