Air quality on Tube

MQT on 2011-09-14
Session date: 
September 14, 2011
Question By: 
Mike Tuffrey
Liberal Democrats
Asked Of: 
The Mayor


Further to MQ2441/2006, what dust levels in milligrams per metre cubed (mg/m3) have been recorded on the London Underground each year since 2006/07, and has any further analysis been carried out of their potential health impacts?


Answer for Air quality on Tube

Answer for Air quality on Tube

Answered By: 
The Mayor

Officers are drafting a response which will be sent shortly.

Written answer received on 29 September 2011:

As the figures below show, the levels of tunnel dust remain stable compared with those last reported in the previous Mayor's answer to question 2441/2006. All readings are less than 1/3 of the Health and Safety Executive limit for general dust, and exposure remains safe for both staff and customers.

Year Dust level in milligrams per metre cubed (mg/m3)

2004/5 0.753 to 1.447 2005/6 0.050 to 0.910 2006/7 0.130 to 1.440 2007/8 0.060 to 1.140 2009/10 0.030 to 1.270

There is no measurement for the year 2008/9, as measurements are taken every 12-18 months. Dust levels vary by location which is why a range is given. The results for 2010/11 are expected in October.

No further analysis has been carried out on potential health impacts since the authoritative study (Assessment of Health Effects of long-term occupational exposure to tunnel dust in the London Underground) produced by the Institute of Occupational Medicine (IOM) in 2003/4. This report concluded that tunnel dust was highly unlikely to be harmful to human health. London Underground focuses on minimising dust levels as far as reasonably practicable and, monitoring them annually, as recommended in the IOM report.