New research by the University of Surrey found that air pollution levels in bike trailers on school or nursery runs was between 14 and 18 per cent higher than for the cyclist.
The study, published in the Journal of Hazardous Materials Advances and run by Surrey's Global Centre for Clean Air Research (GCARE) showed that on journeys typical of school or nursery runs the average concentration of coarse air pollution particles was significantly higher than at the cyclist's height.
Researchers found that particle concentration in trailers was 18 per cent higher than at the cyclist's height during afternoons, when parents typically collect children.
Higher concentrations of pollution were also seen during peak morning periods and at traffic lights.
The university took measurements on over 80 school runs, covering 176km, and assessed differences in exposure concentrations in trailers compared to at the cyclist's height.
Use of a bike trailer with a cover reduced children's exposure to pollutants by half during peak morning hours.
Air pollution is a leading cause of death in children under the age of five.
"It is unfortunate that the very people who help minimise pollution by cycling rather than driving can be exposing their children to higher levels of pollution," founding director of GCARE Professor Prashant Kumar said.
"I would encourage adults pulling bike trailers to use covers in heavy traffic. With the use of electric-assisted cargo bikes growing rapidly in Europe, it's crucial traffic planners ensure road infrastructure is designed to enable safe use of sustainable transport options."
The impact of lockdown measures on air pollution levels was also noted, with a 91 per cent reduction in concentration of fine pollution particles when schools were closed.
Researchers have already committed to trying to secure funding to build a database of bike trailers under diverse traffic and environmental factors.
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As someone that regularly tries to cart their kids around (not yet school age, so no school run) I'm not really sure what the takeaway is to this research.
fwiw, I try and minimise the amount of time I spend on roads as best I can as I don't like the idea of them being around cars, which in my opinion is the far greater danger.
As with most research papers - "More research is needed".
Easy fix; just put respirator masks on kids.. they can leave them on all day for premium status enabling pandemic protection.
https://www.3m.com.au/3M/en_AU/p/d/v000170733/
No shock, particulate pollution is heavy and will obviously decrease the higher one goes above ground level. Another excellent argument for imposing restrictions on car use, especially at peak school times.
What would be interesting would be a study comparing the pollution experienced by children in trailers with children inside cars, isn't it generally acknowledged that it's actually worse to be inside a car?
I was thinking much the same. And isn't the reason that it's worse in cars because you are basically at exhaust height, which I guess would be the same with a trailer? But hopefully the fact you are better ventilated in a trailer would mean it was not as bad as in a car.
Or in other words:
Cars cause pollution that's toxic, especially to children....
More specifically, it's diesel engine pollution that's the killer.
Aren't PM2.5s significant in petrol car exhaust too?
And brake / tyre / road wear, which tends to be worse in electric vehicles, due to the weight.
Petrol ain't good just cos diesel's worse..
Hmm. Seems iffy to me.
Firstly 18-20% at what concentration? All concentrations could have been well under recommended max levels for instance.
Secondly what about actually in situ in the airways? My hunch is the cyclist is equal or worse because they are breathing harder, though in this experiment they used an eBike .
edit:
Having looked at the paper what's not mentioned is that higher concentrations the difference disappears.
Also massive variability in the concentrations which doesn't help form any conclusions.
Short version - sample size is too small to say anything interesting - imo.
One really interesting result is that the kids and adults peak exposures were at opposite ends of the journey.
Also it's worth bearing in mind that the whole science of claiming that air pollution causes premature deaths is murky and not particularly statistically rigourous. It's a public health boondoggle to reduce pollution that is best taken with a pinch of salt.
That's not to say they aren't right to reduce pollution for all our sakes - just be careful about reading too much into the numbers. Cause of death statistics are bloody complicated science. See COVID deaths as the latest example.
Variance seems to have been higher at lower concentrations. In the highest quartile, both cyclist and trailer were, on average, exposed to ~75μg/m³; In the lowest, the cyclist received about 50μg while the trailer had ~60μg.
Can't find similar for UK/EU, but in the US the EPA defines 55.4 as the dividing point between 'Moderate' and 'Unhealthy for sensitive groups'.
I couldn't find an explicit guide either. The UK limits are 25 and 40 but these are daily averages which assuming a lot of the time it's near zero allows for some pretty massive spikes.