Environment

Study shows how planted "tredges" can protect children from air pollution

Study shows how planted "tredges" can protect children from air pollution
Tredges consisting of western red cedars were shown to work best
Tredges consisting of western red cedars were shown to work best
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A close look at the western red cedar's particle-trapping leaves
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A close look at the western red cedar's particle-trapping leaves
Tredges consisting of western red cedars were shown to work best
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Tredges consisting of western red cedars were shown to work best

It has long been known that plants can help mitigate air pollution in urban environments. New research reinforces such findings, showing that "tredges" planted around schoolyards can help protect children from traffic-derived airborne particles.

In the study, which was led by Lancaster University's Prof. Barbara Maher, rows of tredges (trees serving as head-height hedges) were installed around three Manchester schoolyards during the summer holidays of 2019. All of the yards were located next to busy roads.

One of the schools received ivy tredges, another got western cedar, and a third received a mix of western red cedar, Swedish birch and an inner juniper hedge. A fourth schoolyard, which served as a control, was left without a tredge of any sort.

When air quality readings taken within and outside of the yards were analyzed, it was found that the pure red cedar tredges performed best. More specifically, they blocked 49% of black carbon particles, along with 26% of PM2.5 and PM1 microparticles emitted by passing traffic. The cedar tredges additionally helped lessen the severity of sudden acute spikes in air pollution occurring within the schoolyard.

A close look at the western red cedar's particle-trapping leaves
A close look at the western red cedar's particle-trapping leaves

It is believed that the superior performance of the red cedar is due to tiny corrugated projections on its leaves, which trap passing airborne particles. Those particles are subsequently washed out by the rain, going into the soil or down storm drains. The process then begins over again, as the leaves are able to collect more particles.

By contrast, the smooth waxy leaves of the ivy tredges did physically block some particles, but they weren't nearly as good at actually trapping and holding onto them.

"Our findings show that we can protect school playgrounds with carefully chosen and managed tredges, which capture air pollution particulates on their leaves," said Maher. "This helps to prevent at least some of the health hazards imposed on young children at schools next to busy roads where the localized air quality is damagingly poor, and it can be done quickly and cost-effectively."

The research is described in a paper that was recently published in the journal Scientific Reports.

Source: Lancaster University

4 comments
4 comments
guzmanchinky
Or you could, you know, get rid of the pollution? Electric cars and nuclear power are already here, we just need to use it...
Dave Holland
Hey guzmanchinky maybe we could walk and chew gum at the same time?
Hopeful
Hedges should be planted along all highway barriers or other utilitarian walls with a bit of nearby soil. Low cost, look better, hard to put graffiti on, discourage climbing, probably help reduce noise and generally help the environment. They don't really need maintenance and they're easy to replace if construction is required. Not too many drawbacks.
fluke meter
You have to keep in mind that cars cause a number of different pollutions. the carbon dioxide from an ICE car isn't at all harmful locally to people - its harmful when massively accumulated and affecting the atmosphere (at least as I understand it) - but there are other pollutants. Diesel is known to have a fair number of particle pollutants. In addition to combustion related pollutants there is also noise and tire particles. Apparently the tire particle production is both very harmful and also much higher than combustion. This article says 2000X. Also - generally (at least currently) EVs weigh more than ICE which will probably tend to mean higher tire wear and more road damage. That being said I concur myself - Nuke and EV is great - but please lets join the fight in reducing (significantly) this very real and barely discussed pollutant which still exists with EVs.

https://blog.therainforestsite.greatergood.com/tire-pollution/
https://www.cnn.com/2021/06/07/business/electric-vehicles-weight/index.html