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Cyclists (in Guildford) breathe in more polluted air than motorists finds study

Motorists’ exposure was greater but cyclists’ inhalation rates outweighed that

A new study carried out in Guildford, Surrey, found that cyclists breathed in more pollution than motorists travelling on the same roads.

BikeBiz reports that researchers looked at four types of commuters — cyclists, drivers, pedestrians and bus-riders — to see how much they were exposed to fine and coarse particulate matter.

While they found that pollutant exposure was greater for bus passengers and motorists, the inhalation rates of cyclists and pedestrians meant that respiratory deposition doses (a measure of the number of pollutants left in someone’s respiratory system) were higher.

Past studies indicate deposition to be three or more times greater under moderate activity than when at rest.

The study found that respiratory deposition doses for cyclists for finer particles was 20 per cent higher than for bus passengers and 2.5 times higher than for car drivers (if they have windows closed and air conditioning systems on).

A ten-day study carried out last year found that exposure to fine particulate matter on Bath’s London Road was greater for a taxi driver than for a cyclist.

While high nitrogen dioxide levels were experienced by the cyclist, levels of small particulate matter from diesel fumes – associated with respiratory and cardiovascular conditions – were consistently higher for the taxi driver.

For six of the ten days, the taxi driver involved in the experiment was exposed to pollution in excess of the World Health Organisation’s (WHO) recommended limits, whereas the cyclist’s exposure always remained below.

Professor Gavin Shaddick of the University of Bath explained: “Being in a car is not like being in a sealed box.

“Winding up your windows may give you the perception that the air isn’t coming through the windows and that you might have reduced your exposure to air pollution, but the intakes for the car’s air system are at the front of the car. And the problem is, they’re generally at the level of the exhaust pipe of the car in front of you.”

However, the new study’s lead author Professor Prashant Kumar of the University of Surrey points out that exposure is not the full story.

“Cycling and walking benefits the health of people due to increased physical activity. However, the increased physical activity also means increased inhalation rates and hence the intake of more polluted air.

“Even though some cyclists experience low concentrations of particulate matter, they have significant potential dose when inhalation rates and trip duration are taken into consideration."

The researchers point out that private car commutes contribute to the highest emissions per passenger, thus contributing to increased exposure of those commuting using cleaner modes.

They also suggest that pedestrian and cyclist exposures “could be further reduced by routing pedestrian and cycling paths away from heavily trafficked roadways.”

A 2016 study carried out by scientists at the University of Cambridge and the University of East Anglia modelled the risks and benefits of walking and cycling in varying levels of air pollution around the world. That study found that only in the worst one per cent of polluted cities would the ill effects of poor air quality outweigh the benefits of exercise.

According to a recent report, more than 40 towns and cities in the UK are at or have exceeded air pollution limits set by the WHO.

Alex has written for more cricket publications than the rest of the road.cc team combined. Despite the apparent evidence of this picture, he doesn't especially like cake.

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11 comments

Avatar
Morat | 5 years ago
1 like

Ban diesel! Well, at least for private/light goods vehicles. The effects of particulates and NOx have been ignored too long in favour of reducing CO2 output.

We should incentivise conversion of existing petrol vehicles to LPG as that gives 0 particulate emissions and reduces CO2 output by ~20% overall. Sadly, the biggest opposition to this comes from the SMMT who seem to only back policy which replaces existing vehicles with new ones. Funny that.

And then, of course, electric vehicles for urbanites and hybrids for the countryside.

 

Simples. Can I have the job?

Avatar
cyclisto | 5 years ago
1 like

Do bears shit in the woods? Of course they do and of course the biggest risk when cycling in urbam areas is air pollution, not accidents as very few of us will have a life threatening accident but 100% of us will have our health affected by air pollution. I don't need epidemiological reports when a diesel "green" bluemotion VW or a WVM accelerates leaving a black cloud in front of my face when I hit the pedals hard that has led most of us in losing our sense of smell. Pretending that the problem doesn't exist in order not to discourage other people start commuting on cycle is not option. Our real goal should not be putting more bicycles in the streets but removing as much motor vehicles as possible and the ones that remain try being as safe and low emissions as possible.

Avatar
BehindTheBikesheds | 5 years ago
1 like

Doesn't shallow breathing by those sitting/being sedentary mean more of the crap just sits in the lungs?

All that said I'd rather breathe in what I do than places like Delhi, apparently equivalent to smoking 40+ tabs a day!

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madcarew replied to BehindTheBikesheds | 5 years ago
0 likes

BehindTheBikesheds wrote:

Doesn't shallow breathing by those sitting/being sedentary mean more of the crap just sits in the lungs?

...

In short, no. Shallow breathing means it doesn't get taken as far into your lungs. The air velocity in the alveoli (the little bags where gas exchange takes place) is basically the same regardless of the depth of your breathing, it's just that with bigger breaths larger number of the bags are involved, so there's greater opportunity for particles to be deposited overall

Avatar
grumpyoldcyclist | 5 years ago
3 likes

Feel even better about living in Wales now....

Avatar
burtthebike | 5 years ago
2 likes

All very well, but two things strike me:  why aren't we banning car driving when pollution levels are high, and since cyclists live on average two years longer and suffer less from all forms of illness, the effects of the pollution on them doesn't appear to be too dramatic.

This government has been taken to court for failing to control air pollution, and they still don't seem to be doing anything about it, certainly not investing in the single most effecient way of reducing it; cycle provision.

Avatar
madcarew replied to burtthebike | 5 years ago
1 like

burtthebike wrote:

All very well, but two things strike me:  why aren't we banning car driving when pollution levels are high, and since cyclists live on average two years longer and suffer less from all forms of illness, the effects of the pollution on them doesn't appear to be too dramatic.

This government has been taken to court for failing to control air pollution, and they still don't seem to be doing anything about it, certainly not investing in the single most effecient way of reducing it; cycle provision.

We have to apply epidemiological caution to that. We don't have good figures (and probably won't get) for mortality, or even all life disease figures for people who regularly commute to work by bike through our current traffic and pollution levels, because we haven't been doing that for 50+ years yet. We will probably know in 20 - 30 yrs time if in fact modern cyclists' lifestyle benefits outweigh the disease risks of modern traffic. I would like to think so. And partly, it's not just the years in your life.....

Avatar
burtthebike replied to madcarew | 5 years ago
0 likes

madcarew wrote:

burtthebike wrote:

All very well, but two things strike me:  why aren't we banning car driving when pollution levels are high, and since cyclists live on average two years longer and suffer less from all forms of illness, the effects of the pollution on them doesn't appear to be too dramatic.

This government has been taken to court for failing to control air pollution, and they still don't seem to be doing anything about it, certainly not investing in the single most effecient way of reducing it; cycle provision.

We have to apply epidemiological caution to that. We don't have good figures (and probably won't get) for mortality, or even all life disease figures for people who regularly commute to work by bike through our current traffic and pollution levels, because we haven't been doing that for 50+ years yet. We will probably know in 20 - 30 yrs time if in fact modern cyclists' lifestyle benefits outweigh the disease risks of modern traffic. I would like to think so. And partly, it's not just the years in your life.....

"Cycling towards health and safety" Mayer Hillman, pubished by the BMA I believe.  Over twenty years ago.

Avatar
madcarew replied to burtthebike | 5 years ago
2 likes

burtthebike wrote:

madcarew wrote:

burtthebike wrote:

All very well, but two things strike me:  why aren't we banning car driving when pollution levels are high, and since cyclists live on average two years longer and suffer less from all forms of illness, the effects of the pollution on them doesn't appear to be too dramatic.

This government has been taken to court for failing to control air pollution, and they still don't seem to be doing anything about it, certainly not investing in the single most effecient way of reducing it; cycle provision.

We have to apply epidemiological caution to that. We don't have good figures (and probably won't get) for mortality, or even all life disease figures for people who regularly commute to work by bike through our current traffic and pollution levels, because we haven't been doing that for 50+ years yet. We will probably know in 20 - 30 yrs time if in fact modern cyclists' lifestyle benefits outweigh the disease risks of modern traffic. I would like to think so. And partly, it's not just the years in your life.....

"Cycling towards health and safety" Mayer Hillman, pubished by the BMA I believe.  Over twenty years ago.

Yep, I've read it, but the point was:

We don't have good figures ...for people who regularly commute to work by bike through our current traffic and pollution levels,

Traffic pollution of carcinogens and other poisons is at the highest level it's ever been (particulate matter is down a bit), so figures that Mr Hillman based his excellent argument on are now 30 - 50 years out of date. You couldn't argue that 50 yr old figures of traffic can be applied to today's streets. 

I wasn't disagreeing with you, I just said that: "We have to apply epidemiological caution to that"

I also said "...(maybe) modern cyclists' lifestyle benefits outweigh the disease risks of modern traffic. I would like to think so"

 

 

Avatar
burtthebike replied to madcarew | 5 years ago
0 likes

madcarew wrote:

We have to apply epidemiological caution to that. We don't have good figures (and probably won't get) for mortality, or even all life disease figures for people who regularly commute to work by bike through our current traffic and pollution levels, because we haven't been doing that for 50+ years yet. We will probably know in 20 - 30 yrs time if in fact modern cyclists' lifestyle benefits outweigh the disease risks of modern traffic. I would like to think so. And partly, it's not just the years in your life.....

"Cycling towards health and safety" Mayer Hillman, pubished by the BMA I believe.  Over twenty years ago.

[/quote]

Yep, I've read it, but the point was:

We don't have good figures ...for people who regularly commute to work by bike through our current traffic and pollution levels,

Traffic pollution of carcinogens and other poisons is at the highest level it's ever been (particulate matter is down a bit), so figures that Mr Hillman based his excellent argument on are now 30 - 50 years out of date. You couldn't argue that 50 yr old figures of traffic can be applied to today's streets. 

I wasn't disagreeing with you, I just said that: "We have to apply epidemiological caution to that"

I also said "...(maybe) modern cyclists' lifestyle benefits outweigh the disease risks of modern traffic. I would like to think so"

[/quote]

You're right of course, but there have been many other more recent analyses of cyclists' health, all of which have concluded pretty much the same as Hillman, some saying that the effects are much more beneficial.   Since these have been done under modern conditions, the effect or lack of effect on cyclists, seems proved, and vehicles were much more polluting twenty years ago, even if there are more of them now.

Whatever, the benefits of cycling are proven in pretty much all conditions.  https://travelwest.info/project/ee-147-can-air-pollution-negate-the-heal...

Avatar
Rich_cb replied to madcarew | 5 years ago
2 likes
madcarew wrote:

We have to apply epidemiological caution to that. We don't have good figures (and probably won't get) for mortality, or even all life disease figures for people who regularly commute to work by bike through our current traffic and pollution levels, because we haven't been doing that for 50+ years yet. We will probably know in 20 - 30 yrs time if in fact modern cyclists' lifestyle benefits outweigh the disease risks of modern traffic. I would like to think so. And partly, it's not just the years in your life.....

Recent study so pretty up to date pollution levels.

Big decreases in illness and death amongst cyclists compared to drivers.

250,000 participants too so very high quality evidence.

https://www.bmj.com/content/357/bmj.j1456

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