TfL Ref: 2367-1920

Thank you for your request received by us on 6 November 2019 asking for information about the oxygen, CO2 and dust particulate levels on London Underground’s Central Line between Bond Street and Notting Hill Gate stations.

Your request has been considered in accordance with the requirements of the Environmental Information Regulations and our information access policy. I can confirm that we hold some of the information you require. You asked:

Are oxygen, CO2 and dust particulate levels on the Central Line between Bond Street and Notting Hill Gate, on the trains, platforms and passages to the ground level in accordance with all legal and recommended safety requirements?

I can advise that whilst we do not measure Oxygen or CO2 at these particular station locations, monitoring data for respirable dust taken inside a Central line carriage travelling between White City and Stratford in December 2018 recorded with a photo optical meter, demonstrated that the levels recorded do not exceed the recommended limit. Respirable dust level at this section was recorded as 0.534mg/m3.

The workplace exposure limits set by the Health and Safety Executive are 4mg/m3 – eight hours time weighted equivalent. The Institute of Occupational Medicine recommends 1mg/m3 – an eight hour time weighted equivalent. Therefore the levels recorded do not exceed either the legal or recommended limit.

We routinely monitor and undertake dust surveys across other parts of the London Underground network to evaluate staff and customer exposures to respirable and inhalable dusts.

We are committed to maintaining the cleanest air possible for our staff and customers when using the Tube. As mentioned previously, London Underground continues to operate well within the Health and Safety Executive exposure limit in spite of the increased demand, higher level of service and increased level of upgrade and maintenance works being delivered in recent years.

The main pollutants we measure on the London Underground are respirable dusts (PM 4.0) and specific metals. The source of these are track, wheel and brake wear. We do not routinely measure surface pollutants such as NOx, Ozone etc, as these are not generated inside the network. The air in tunnels is very different from that found on the surface, where pollution is mainly due to vehicle exhaust emissions. While particulates found above ground are known to be carcinogens, those on the Tube are not known to have that effect.

However, to ensure that dust levels remain low and within acceptable levels, London Underground has a stringent cleaning regime. We are working hard to make the Underground environment cleaner and we invest £60m every year on cleaning trains, stations and tunnels.

If this is not the information you are looking for, or if you are unable to access it for any reason, please do not hesitate to contact me.
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Yours sincerely

Jasmine Howard
FOI Case Officer
Information Governance
Transport For London