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Cycle under 12mph in cities to reduce pollution inhalation

Study finds sweet spot for fastest travel with least pollutant damage

Cycling at between 12 and 20 kilometres per hour (7.5- 12.5 mph) in cities will minimise your inhalation of air pollution, a new study has found.

Pedestrians should limit their speed to two to six kilometres per hour (1.2 - 3.7 mph) too, to gain the health benefits of exercise without dangerous particle inhalation.

Writing in the International Journal of Sustainable Transportation, Alex Bigazzi, a University of British Columbia transportation expert, calculated minimum-dose speeds (MDS) for different age and sex groups.

Female cyclists under 20, were found to have an ideal speed linked to the least pollution risk of 12.5 kilometres per hour on average on a flat road.

For male cyclists in the same age group, it's 13.3 kilometres per hour.

Ideal travel speeds were at 13 and 15 kilometres per hour for female and male cyclists in the 20-60 age group.

"If you move at much faster speeds than the MDS—say, cycling around 10 kilometres faster than the optimal range—your inhalation of air pollution is significantly higher," Bigazzi told Medical Xpress. "The good news is, the MDS numbers align pretty closely with how fast most people actually travel.

"The faster you move, the harder you breathe and the more pollution you could potentially inhale, but you also are exposed to traffic for a shorter period of time. This analysis shows where the sweet spot is.”

Last year we reported how all 50 of Britain’s worst air pollution blackspots are in London. Each has at least double the EU limit for nitrogen dioxide (NO2), which is generated by emissions from diesel vehicles and linked to asthma and other respiratory problems.

According to data obtained under Freedom of Information, the most polluted street is Marylebone Road, followed by Park Lane, Knightsbridge, the Hammersmith Flyover and the East Ham and Barking Bypass.

While the European Union sets a limit of 40 micrograms of NO2 per cubic metre on average per year, the junction between Marylebone Road and Glentworth Street showed 132 micrograms and all 50 pollution blackspots exceeded 80 micrograms.

Last year, Oxford Street was found to have a peak level of nitrogen dioxide of 463 micrograms and an average of 135. David Carslaw, an emissions researcher at King’s College London, remarked that this was to his knowledge the highest in the world in terms of both hourly and annual mean.

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18 comments

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FatBoyW | 7 years ago
0 likes

Come now, is that an excuse to allow lorries designed in the fifties, that is the 1950s to be on the roads of a 21st century city? No visibility for 4 metres up front! No cameras to cover blind spots. No collision detection/ prevention tech?

I'm sure that if you bought the ban in, allowing electric lorries with proper safety features, they'd soon make them. It's the way California has always pushed things forward.

neccessity being the mother of invention. 

Avatar
gcj replied to FatBoyW | 7 years ago
0 likes

FatBoyW wrote:

Come now, is that an excuse to allow lorries designed in the fifties, that is the 1950s to be on the roads of a 21st century city? No visibility for 4 metres up front! No cameras to cover blind spots. No collision detection/ prevention tech?

I'm sure that if you bought the ban in, allowing electric lorries with proper safety features, they'd soon make them. It's the way California has always pushed things forward.

neccessity being the mother of invention. 

It's hard to think of an excuse not to make blind spot cameras mandatory on HGVs. I'm pretty sure that I could build a system using off-the-shelf components for under £150 and install it within a day (admittedly it'd be a bit rough around the edges, but economies of scale and all that). For a company whose fuel bill alone is in the tens of thousands that's peanuts! Hell, give them it back as a tax rebate.

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cyclisto | 7 years ago
0 likes

I will be ownest, I am not afraid of cars, I am afraid of their exhausts.

 

Air pollution is the No1 risk that cyclists face. Increase in gasoline and diesel price, with the extra money going directly on greener modes of transport would make us all smile. I wouldn't say no also to banning diesel passenger cars from any city centre.

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emishi55 | 7 years ago
1 like

There's also still no cap on PHVs (private hire) - too many roads in London are often full of primarily taxis.

Meanwhile, as if they weren't doing enough damage, cab-drivers are now taking it upon themselves to do their damnedest to scupper TfL consultations for the latest bits of cycling infra:

 

If anyone can respond to these two - one fairly quickly:

Junction of A100 Tower Bridge Road and Tanner Street
Closes 30 Oct 2016

Shepherdess Walk/City Road/Bath Street junction improvement
Closes 18 Nov 2016

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gsavill90 (not verified) | 7 years ago
1 like

Surely anyone that's reasonably fit will not get 'the health benefits of exercise' whilst cycling at 12mph...

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FluffyKittenofT... replied to gsavill90 | 7 years ago
1 like
gsavill90 wrote:

Surely anyone that's reasonably fit will not get 'the health benefits of exercise' whilst cycling at 12mph...

The same goes for walking at less than 3.7mph.

I mean, I thought the whole point of 'good' exercise is that you should get a little bit out-of-breath? Which is probably precisely the point at which pollution gets further into your lungs.

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FatBoyW replied to gsavill90 | 7 years ago
2 likes

gsavill90 wrote:

Surely anyone that's reasonably fit will not get 'the health benefits of exercise' whilst cycling at 12mph...

surely this is flat out on a boris bike!

 

Cracking point about cabs and buses, they should all be all electric and hgvs should only be allowed into central London between 1 and 4 in the morning.

 

so obvious but no real appetite.

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atgni replied to FatBoyW | 7 years ago
0 likes

FatBoyW wrote:

hgvs should only be allowed into central London between 1 and 4 in the morning.

 

so obvious but no real appetite.

People aren't overly keen on construction operations at those times though are they.  Loading and unloading might be a bit costly if they can only arrive and depart between 1 & 4am but can't be loaded before 8am due to noise restrictions.  So only 1 load a day for most tight london sites, might take a while to get anything built then.

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wycombewheeler | 7 years ago
7 likes

How about banning single occupancy vehicles from zone 1 to save everyone from pollutant damage?

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tritecommentbot replied to wycombewheeler | 7 years ago
2 likes

wycombewheeler wrote:

How about banning single occupancy vehicles from zone 1 to save everyone from pollutant damage?

 

From all city centres, world over. Or charge a huge levy, say £30.  With a £5 reduction per occupant.

Sensor tech, and mobile phone tech together can make it largely unmanned. Drive around in Norway and the tag on your car charges you electronically as you pass bridges etc. Just an extension of that, but with additional individual GPS tagging and a bit of monitoring to catch people trying to spoof it.

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kie7077 | 7 years ago
4 likes

" the most polluted street is Marylebone Road, followed by Park Lane, Knightsbridge"

Park lane, no buses there, just lots of black cabs, anyone who is serious about pollution in London will do something about the diesel black cabs, london buses, HGVs and LVGs that spew out disgusting levels of pollution without ever being spot-checked.

If terrorists were killing 4000 Londoners each year you can bet heaven and earth would be moved to stop them. F*** all effective is being done to stop London pollution.

 

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bikebot | 7 years ago
2 likes

One to remember, it's a great excuse 

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burtthebike | 7 years ago
5 likes

Interesting, but isn't this looking at it from the wrong end of the telescope?

The important thing is to reduce the pollution, not to limit exposure to it.  Would have been more useful if it had pointed out that if we all cycled/walked, used public transport, pollution would be greatly reduced and we could all heave a sigh of relief without worring about it killing us.

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OldRidgeback | 7 years ago
1 like

Actually fumes tend to build up in vehicle cabs.

If you really want to commute on the road but reduce your exposure to exhaust pollution, you're probably best on a motorbike or an electric bike.

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Jackson | 7 years ago
7 likes

Interesting research but are these researchers aware of the competing findings from LTDA's scientists? The sweet spot is actually to not cycle at all (cycling causes pollution). The recommended solution is to travel at 8.98mph (avg central London traffic speed) in a mostly-empty two tonne diesel cab.

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ooldbaker replied to Jackson | 7 years ago
1 like

Jackson wrote:

Interesting research but are these researchers aware of the competing findings from LTDA's scientists? The sweet spot is actually to not cycle at all (cycling causes pollution). The recommended solution is to travel at 8.98mph (avg central London traffic speed) in a mostly-empty two tonne diesel cab.

I've seen other studies (a bit more reliable than the LTDA) that say the exact opposite. Nothing to do with the speed of travel but to do with the exact position. The very worst position being directly behind the preceeding vehicle's exhaust pipe.Just where taxi drivers spend their entire working day. Polution levels fall quite drastically as you move to one side of the vehicle in front.

Ride level with the wheels or just outside the line taken by the vehicle and you get a small fraction of the fumes.

Being inside a vehicle offers next to no protection. A bike has many more options about the routes that can be taken and I often avoid sitting in traffic even if it means getting off the bike for a hundred metres or so.

The above study compares the polutants ingested at different speeds it doesn't say it takes into account the other benefits of going faster like improved fitness.

I really wouldn't worry too much about polution on a bike.

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tritecommentbot | 7 years ago
2 likes

Move slowly guys or die sooner. Tragic.

Any word on the effects of face masks or breating through a buff?

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Jackson replied to tritecommentbot | 7 years ago
4 likes

unconstituted wrote:

Move slowly guys or die sooner. Tragic.

Any word on the effects of face masks or breating through a buff?

The masks aren't going to filter out NO2 or particles PM10  and below. Hence I'd suggest the chief effect is giving your fellow cycle commuters a fright when you show up next to them at the lights looking like Bane from Batman. 

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