Could Living Park Benches Help Us Fight Air Pollution?

The UK’s capital city has a major air quality problem, but officials just installed a state-of-the-art living park bench at London’s Piccadilly Circus that the makers say could improve air quality as much as planting 275 trees.

The living park benches, dubbed CityTrees, have the usual seating area we would expect from a bench but, rising up from their backs, the benches also have high walls extending four meters that contain around 1,682 pots of specially chosen mosses.

When set up, the mosses and their bacteria get to work extracting particulate matter from the atmosphere, which may include things like soot and dirt, as well as other pollutants. Particulate matter is particularly damaging to humans as it is small enough to circulate in our bodies and can cause a variety of health problems.

In terms of the CityTrees’ capacity, figures show that each unit can remove around 240 metric tons of CO2 from the atmosphere per year. They also remove about 250 grams of particulate matter.

Those figures might not sound that impressive when compared to the capacity of a forest of trees, but the benches are doing this in about one percent of the total space it would take to have the same filtration power from trees.

What’s more, the benches also have some added benefits:

  • They can collect data on air quality by exploiting onboard sensors and internet connectivity.
  • They are solar powered.
  • At about £17,600 ($24,833) per unit they aren’t cheap, but the makers behind the trees, German engineers Green City Solutions, say that buyers can recoup initial investment through selling ad space on the sides of the units, and that they could cut costs on environmental monitoring.
  • Maintenance can be relatively painless as CityTrees can be designed to resist graffiti and other attempts at vandalism.

London isn’t the first city to install a CityTree. You can find them in Glasgow and Newcastle in the UK and other cities throughout Europe.

Here’s an interview with one of the makers behind this initiative talking about what their hopes for the project are.

Opinion on the trees has been largely positive, but some have said they are not convinced, and that CityTrees are unlikely to make a massive dent in city air pollution.

This is true, they are going to be cost-prohibitive during financially difficult times, and may not provide the immediate payoff that environmental research says we need.

In fairness to the makers of CityTrees though, they don’t appear to claim this will be a magic bullet. In fact, the initiative is clearly meant to be one tool in a wider revolution of re-engineering our city spaces to make them more environmentally- and health-friendly.

So how effective are CityTrees?

We don’t have independent data on their wider cost-effectiveness versus environmental impact, but there is at least some science to back that mosses may be a key tool for fighting city pollution and something that we should explore.

A study released in 2017 says that mosses are among a class of so-called “bioindicator” species that can tell us the state of their surrounding environment. If the mosses survive and are healthy in a given location, that is generally a good sign that things like nitrogen pollution in their host region is fairly low.

If the mosses begin to sicken and die, nitrogen pollution may be high.

That study could not measure air purity with the mosses, because the test site’s air was actually too clean. However, other data shows that when mosses encounter different quality environments, they will exhibit physical changes accordingly.

Mosses appear to hold a lot of promise as a largely unobtrusive tool for helping us regulate air quality. CityTrees also have one other thing going for them: they add a much needed bit of green to our often far too gray cities.

So will these benches soon be popping up in a park or city sidewalk near you? That remains to be seen, but this is a good illustration of how so-called “green engineering” holds a lot of promise.

Attempts have already been made to turn city structures like bridges and even office buildings into living gardens that can work to clean our air and remove CO2, so this idea seems entirely in keeping with that and, I hope, will be something city planners can keep in mind as we attempt to move toward a more environmentally friendly future.

Image Credits: Air Pollution Image via Thinkstock, CityBench photo via Instagram.

59 comments

Peggy B
Peggy B3 months ago

TYFS

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Marie W
Marie W7 months ago

Thank you for sharing

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KimJ M
KimJ M11 months ago

tfs

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KimJ M
KimJ M11 months ago

tfs

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KimJ M
KimJ M11 months ago

tfs

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KimJ M
KimJ M11 months ago

tfs

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KimJ M
KimJ M11 months ago

tfs

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Sue H
Sue Habout a year ago

Not exactly pretty but every little bit helps.

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Chad A
Chad Andersonabout a year ago

Interesting and creative idea.

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S M
S Mabout a year ago

I would feel very crowded sitting on that bench and a looming presence! :0

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