What is not well known
In an experiment for The Jeremy Vine Show on BBC Radio 2, Tim Johns tried to find out how much airborne particule matter he was being exposed to in different locations and on different modes of transport, using a portable monitor lent by researchers at King’s College. “The higher the reading, the less healthy it would be.”
[How much diesel pollution am I breathing in?, Tim Johns, BBC, 4 March 2016]
Walking around in Bedford my readings rose to 1.7 and a Saturday afternoon spent driving around town gave me a reading of 2.1.
The researchers at King’s College say one of the worst environments for diesel exposure can be when you’re sitting in your car in slow-moving traffic (although some modern cars are now excellent at filtering out pollution).
On my commute [to London], cycling to and from the train station in Bedford gave me a reading of 3.7.
Cycling to and from the office at the other end in central London, my exposure rose to 6.5. That’s a stark reflection of the far higher level of traffic in central London and other major cities.
But my biggest surprise was on my train journey. Diesel-powered trains like the one I commute on are found on many major routes across the UK. The East Coast Main Line north of Edinburgh, the Great Western route through to Cornwall, and London services to Sheffield and Nottingham are just some examples.
The average reading I got on-board my air conditioned [diesel] train was 8.5. A researcher from King’s College conducted an experiment to mirror mine on his train journey from London to Exeter and came out with similar results.
My time spent standing on the station concourse at London St Pancras, waiting for my train, produced a reading of 13.2.
So it turns out that during the 80 minutes I spend sitting still on a train every day I am being exposed to more diesel fumes than when I’m walking or cycling down a street full of traffic in London. On the day I took an electric train instead, my reading was only 2.4.
[…] My highest reading of the week came from a journey I took with a black cab in the capital. We spent most of the journey crawling in traffic – the windows were down – and I got a reading of 19.9.
[…] There’s one other astonishing measurement I recorded which I haven’t mentioned yet. On the London Underground my device gave me a reading of 77.8. But this wasn’t caused by diesel fumes – other particles found underground can skew the reading.
“The device measured ‘black particles’, which, above ground would primarily be black carbon from diesel,” says Barratt. “But below ground most of it is oxidised iron coming from the tracks. It’s well known that the Tube is a dusty environment, but what is not well known is how toxic the specific kind of particles that we breathe while travelling underground are.”