The Central Line offends every fiber of my being.

Of London’s vast array of tube lines, it’s at once: the hottest, most polluted, the busiest, and the second loudest. It’s a sultry experience begrudgingly shared by a sultry crowd. Too often have I found myself trapped between a swell of people and the grimy metal skin of a downturned train door, inhaling a toxic stew of dead cells and dirt. It also happens to be my new daily commute1.

The Central Line is utterly loathsome. But it’s far from the only place in London.

Case in point.

Some time ago, a troll posting on an internet forum blithely suggested, alongisde a list of real touristy things, that walking the length of the Rotherhithe Tunnel was “an absolute must” for anyone visiting London. For those not in the know, it’s a tunnel for vehicles between Limehouse on the north side, south to Rotherhithe. There’s a pedestrian walkway on one side.

I’ve long since favoured pursuing ‘off the beaten track’ ‘hidden gems’ over their more well trodden counterparts (Atlas Obscura, ilysfm), and as fate would have it, the Rotherhithe tunnel was right on my doorstep. Boom.

Gleefully, I floated the idea to a friend who turned out to be just as gullible as me. Double boom.

We packed our bags and descended naively into the dank, tubular cavern from the North side, waving goodbye to sunny skies and entering into the belly of artifical light below the Thames. The Victorians designed the tunnel to include curves at either end. The logic was that horses wouldn’t bolt on seeing natural sunlight (i.e, an escape route).

It was everything one might think it would be. Unfortunately, we gave the odyssey in question zero thought whatsoever.

It’s perhaps the only time I’ve known the taste of intense pollution. Like the merry family of Central Line pollutants but on high dose steroids. I vividly recall the heaviness of the air, the vulnerability of my throat and lungs, the metallic stench of petrol and diesel strangling my nasal cavaties into light headed submission. A thin, greasy lining of soot formed deadpan on the surface of my face and arms.

We almost immediately realised this was one of those dumb ideas that shouldn’t have made it past the drawing board. But, due to some combination of embarrassment to suggest quitting and stubborn male bravado, we persisted. Adventure – amongst other more sinister things – was in the air.

By the time we decided to turn back, a sign indicated we’d gone past ~800 yards, or: halfway. Onwards we went and through the otherside to freedom. Despite the venture surely bringing any natural death forward by some number of days, it was a hilarious lesson in not believing everything you read online.

You’re probably wondering, how does this relate to climbing? Is all this some overdrawn prelude prior to preaching about the adverse health impact of chalk particulate matter endemic to indoor climbing gyms? Actually, no. At least, not yet.

This storied quest through the tunnel happens to be the same day I went bouldering for the first time in my life.

(Though, apparently not my first time climbing as this picture evidences. Just look at 12 year old me absolutely rocking some classic Converse. To think I just bought new climbing shoes when I could’ve pulled these from the top drawer).

First time climbing

Not so far from the other side of said tunnel is the Arch Climbing Wall in Bermondsey, which in a past life played residence to the art of one Damien Hirst. A great space. A little hot during summer days and a little cool in winter. But nonetheless.

Of the folks who went that day, flatmates and comrades alike, I’m the only one that’s stuck with it enough to crush v7s at will2. Or rather, I remember my utter glee bouncing up and down the wall. I remember the awe of seeing strong climbers ascend impossible routes. I remember the sense of community, the positive energy folks wielded.

It was the bees knees, and I wanted in.


Now that’s out the way, here’s the educational part.3 4 5 6 7

Just how polluted is the Undergound?
It depends! Old, deep tube lines like the Central, Northern, and Victoria lines are the worst offenders due to poor ventilation.
Right. How bad are they really?
Pollution takes many forms. One lens to think about airborne pollution is the size of the particle, for example PM2.5 (a super tiny “particulate matter” that penetrates deep in the lungs). Some parts of the Underground expose you to 20x that of “typical” roadside air. It’s estimated >9000 Londoners die prematurely as a result.
That’s quite scary! Good thing I only hang out in climbing gyms.
Not so fast. A study from 2012 showed that climbing gyms PM2.5 concentration can be even worse! Long term effects of inhaling that particular stew are largely unclear – climbing gyms first got going in the late 1980’s – but it can certainly cause lung irritation and pulmonary problems.
Does that mean climbing gyms are even more polluted than the Underground?!
No! Pollution is a loaded term and there different particulates have different effects. PM2.5 particles like iron oxide, carbon, and metallic and mineral oxides, VOCs, NO2, CO2, etc. Parts of the underground are almost certainly more damaging to you than in the long run than climbing gyms.
Still scary though, should I stop climbing forever?!
Now you’re being silly. Just make sure to go to modern gyms with powerful filtering systems or good ventilation. Consider using liquid chalk, or do what the author of this blog isn’t cool enough to and go climb outdoors instead. Also, try not to go too much on the Central Line!
Thanks little bee 🐝
Thank you, Monsieur Tortoise 🐢

  1. Here’s to re-appropriating PTSD to instead stand for Public Transit Stress Disorder↩︎

  2. Editors note, he’s done one super soft v7 and won’t shut up about it. ↩︎

  3. UK Gov (2018) | Comittee on the medical effects of Air Pollutants ↩︎

  4. Heather Ann Walton et al. (2015) | Understanding the Health Impacts of Air Pollution in London ↩︎

  5. Financial Times (2019) | London Underground: the dirtiest place in the city ↩︎

  6. Stephan Weinbruch et al. (2012) | Reducing dust exposure in indoor climbing gyms ↩︎

  7. Berkley Almand-Hunter et al. (2014) Dust exposure in indoor climbing facilities ↩︎