Environment

Study suggests roadside barriers could deflect harmful exhaust

The barriers should also reduce traffic noise, plus they could be used as a scaffolding for greenery
Imperial College London
The barriers should also reduce traffic noise, plus they could be used as a scaffolding for greenery
Imperial College London

There are currently many projects aimed at reducing the air pollution emitted in automobile exhaust, but in the meantime couldn't we just … redirect that exhaust? A new study suggests a possible means of doing so.

Although vehicle exhaust can be problematic throughout a city, it's particularly harmful to pedestrians walking alongside busy roads. It's especially hard on children since they're closer to the ground, towards which the airborne particulates gradually settle. Additionally, vortexes forming in the air above sidewalks can actually concentrate the exhaust near pedestrians.

In countries such as Germany and the Netherlands, some motorways are already flanked by inwards-curving walls that reflect traffic noise back onto the road and away from homes. Inspired by these – and by the engine-noise baffles used at airfields – Imperial College London's Dr. Tilly Collins envisioned similarly curved roadside barriers that could deflect exhaust back towards the vehicles.

Working with Dr. Huw Woodward, she proceeded to develop simple airflow models that replicated the effect of such structures. According to the university, testing with these models suggested that the barriers would "effectively disperse and reflect pollutants back towards the roads and would very rapidly improve air quality for pedestrians in an inexpensive manner."

As an added bonus, the structures would also reduce the volume of traffic noise reaching pedestrians, plus they could serve as scaffolds for roadside greenery – presumably of the hardy variety.

That said, the structures would likely also reduce visibility both for pedestrians checking for approaching vehicles, and for motorists checking for cross-traffic at intersections. Nonetheless, the scientists believe their findings are encouraging enough that the concept should be explored further.

The research is described in a paper that was recently published in the journal Cities & Health.

Source: Imperial College London

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9 comments
Spud Murphy
Or, we could just shift to EVs...
WillyDoodle
Irrelevant. These smelly conglomerations of junk will be off the road in a few years.
Dirk Scott
We have a lot of these in the Uk. They are called “hedges”. Here in South Wales we have a special type intended to counter the high winds off the Atlantic. They consist of a rock core about four feet in cross section and about five feet high. This is covered with Earth and planted with hawthorn. After a few years it grows to an impenetrable barrier and windbreak. Running for miles and miles these “Welsh banks” form corridors of habitat for wildlife all over the countryside.
Primecordial
In a traffic jam, drivers will stew in their own exhaust
CarolynFarstrider
And where do we think the exhaust gases will then go, in a few hours? Up, spread around, until turbulence brings them down into surrounding areas.... This is not a sustainable solution to problems associated with gaseous emissions from dirty engines, and they have many disbenefits.
michael_dowling
Primecordial: Good. Hit them with ads for EVs.
David F
Another advantage is the barriers will reduce the number of places where drivers can park their car on kerb.
ljaques
Oh, HORSEFEATHERS. The fumes will waft anywhere they want to within 20' of their redirection. This is a total waste of urban money. If they must, invest the money in an EV manufacturer.
buzzclick
Another case of treating the symptoms instead of the problems.