Air Quality onboard trains report

[Snow1964]

Published 5th June
Air Quality onboard trains

This report is a response to the Rail Safety and Standards Board (RSSB) report on the Analysis of air quality on board trains (T1188).

The content of this report is the responsibility of the DfT Science Advisory Councilalone and does not represent the views of the Department for Transport (DfT) or DfTministers.

Appears there are high concentrations of NO2 when IETs use diesel mode

An unexpected feature are some high transient and journey mean concentrations of NO2 encountered using the Class 800 bi-mode trains when working in diesel mode. These indicated significantly elevated concentrations when averaged over the full journey length.

This seems worthy of further investigation since the Class 800 is a relatively new train that includes a selective catalytic reduction (SCR) exhaust gas aftertreatment. NO2was also consistently elevated on other train types, such as Class 755 and 230. PMwas seen at elevated concentrations (relative to outdoors) on other train types, prevalent on older trains without abatement technologies such as diesel particulate filters (DPF), but also on some that included DPF. Concentrations of PM in this study were broadly in line with the types of values reported previously in literature.

Some readings exceeded World Heath Organisation (WHO) recommendations

3. Concentrations of PM were frequently higher inside trains than would be experienced outdoors, sometimes exceeding the WHO 24-hour indoor guideline for both PM2.5 and PM10. The values reported were however broadly within the range of interior concentrations reported previously in literature. It may be worthwhile to follow up with additional analysis to identify links between PM and known causal factors such as type and effectiveness of engine aftertreatment system, type of braking system, interior air exchange rate and passenger occupancy level.

summary is mentioning move away from diesel powered trains

A net zero transition away from diesel powered trains would eliminate the risk of elevated NO2 inside carriages. Further indoor and outdoor air quality benefits arise from rail electrification (catenary or fuel cell) since all-electric trains also emit less PM when compared to diesel alternatives. Nonetheless, the performance of all future propulsion technologies and carriage ventilation systems (including positioning of air intakes) should be evaluated for their effects on interior air quality.

Air quality onboard trains: a response to the Rail Safety and Standards Board report

www.gov.uk

 

[kkong]

LNER made a detailed presentation of this topic some months ago.

It is available on the IMechE's YouTube channel here.

 

[Mitchell Hurd]

I wondered why there were times I could smell catalytic in the vestibules on the GWR IET's. Never could smell fumes on other DMU's in the corridor.