Plants have long been recognized for reducing air pollution in urban settings, and we may see a rise in roadside plantings to protect children from air pollution. Such findings are backed by new research, which demonstrates that “tredges” (trees that serve as head-height hedges) planted around school playgrounds can help protect children from traffic-related air pollution. The recent study conducted by Professor Barbara Maher and her team has shown that selective planting of certain species, such as western red cedars, can significantly reduce air pollution around school playgrounds.
Planting Tredges
In the new study, led by Professor Barbara Maher of Lancaster University, rows of tredges were planted around three Manchester schoolyards throughout the 2019 summer break. The yards were all situated near busy roadways.
The following hedges were planted at the primary schools:
- Ivy hedges at one school,
- Western cedar at another,
- A combination of Swedish birch, inner juniper hedges, and western red cedar at the third.
- And as a control, no tredge was planted in the fourth schoolyard.
Red Cedar Tredges
Professor Maher said:
“Western red cedar tredges work well because this species’ leaves form millions of tiny rough corrugated projections, each of which can bump into the particulates suspended in the air and ‘capture’ them in their ridges, furrows and pores. This takes them out of the local atmosphere and therefore reduces the exposure to these traffic-sourced air pollution particulates of the children and staff in the playground.”
According to an analysis of air quality readings obtained within and outside the yards, the pure red cedar tredges outperformed the other hedges. Specifically, they blocked:
- 26% of the PM2.5 and PM1 microparticles
- 49% of the black carbon particles released by passing traffic.
Additionally, the cedar tredges reduced the intensity of unexpected, acute air pollution surging in the schoolyard. The red cedar’s higher performance is thought to result from the tiny grooves on its leaves, which catch flying airborne particles. After that, the rain washes those particles away, washing them into the ground or down storm drains. Then, as the leaves can gather more debris, the process starts again.
However, the ivy tredges’ waxy leaves were better at blocking some particles than catching and hanging onto them.
Maher concluded:
“Our findings show that we can protect school playgrounds with carefully chosen and managed tredges, which capture air pollution particulates on their leaves. 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 was published on August 20, 2022, in the journal Scientific Reports.
Dangers of Particulate Pollution
It is no secret that motor vehicles are a major source of air pollution, and this can pose a serious threat to our health. In heavily trafficked regions, such as city centres, the risk is especially high. During periods of heavy traffic and congestion, these foul-smelling fumes can fill the air with thick visible smog. Not only do these airborne toxins have an unpleasant odour, but you can actually taste them too! This situation is even worse for children since their developing bodies are particularly vulnerable and susceptible to the harmful effects of air pollution.
The connection between high PM air pollution levels and negative health effects has been known for decades. Early twentieth-century smog incidents such as the Meuse Valley incident in Belgium, the Donora event in Pennsylvania, and the Great Smog of London provide stark examples of how quickly PM levels can dramatically affect public health. In the 1950s, in London alone, over 4,000 people died, and more than 100,000 people faced serious adverse health effects as a result of their exposure to air pollution. Following these devastating events, governments around the world took steps to reduce air pollutants through legislation like the enactment of the Clean Air Act in 1970.
As air pollution laws have taken effect since then, epidemiological studies have continued to show a clear link between PM exposure and increased mortality linked to cardiopulmonary diseases. These studies make clear that even at lower levels of PM pollution, there is an increased risk for ill-health amongst vulnerable populations such as those with existing respiratory or heart issues or among older people or children. This underscores the need for further actionable measures that can be taken to prevent excessive pollutant exposure worldwide.
Air pollution is estimated to account for 2.5% of all deaths in developed countries, making it one of the leading risk factors for mortality globally. Pollutants can cause short-term negative health impacts such as irritation in the eyes, nose or throat; however, long-term exposure has been linked to various chronic illnesses, including respiratory diseases and cancer. Air pollution can even aggravate existing conditions like asthma or allergies and lead to long-term lung damage. Additionally, outdoor air pollutants have been shown to cause hospitalization and premature death due to cardiovascular and respiratory illness as well as cardiopulmonary diseases like strokes or heart attacks. It’s clear that air pollution continues to be a real public health concern around the world, prompting many governments to take action.
Numerous studies have demonstrated that the hazardous effects of air pollution are linked to several serious lung and cardiovascular diseases. However, fewer investigations have investigated the association between air pollution and central nervous system (CNS) disorders. This review aims to explore the evidence supporting PM-induced neurological damage.
Research has established that exposure to polluted air can lead to CNS impairment through a variety of biological processes, such as inflammation, oxidative stress, microglial activation, protein condensation, and cerebral vascular-barrier disruption. Emerging evidence suggests that particulate air pollutants can also cause long-term neurological damage ranging from impaired cognition development in babies and children to stroke in adults later in life. Additionally, recent studies suggest that PM exposure may be associated with an increased risk for Gestational Diabetes which could then lead to some negative physiological implications for prenatally exposed fetuses. Although further research is needed in this field, it is clear that there is strong evidence linking air pollution and CNS diseases, including dementia, depression, ADHD and Parkinson’s Disease, among others
As Microcosm, So Microcosm
The use of roadside vegetation as green infrastructure is becoming an increasingly popular approach to reducing air pollution. Green infrastructure is a term used to describe natural elements such as trees, grass, and other vegetation used to mitigate the environmental impact of urbanization. In addition to providing visual appeal and promoting biodiversity, roadside vegetation is proving to be an effective means of reducing particulate pollution in urban environments.
The benefits of selective planting are not limited to schools, as green infrastructure has been shown to be effective in reducing air pollution in residential areas, along highways, and near industrial sites. While improvement in air quality is certainly a major plus, there are even further improvements beyond reducing particulate pollution.
Studies have repeatedly shown the use of green infrastructure can also help to improve soil quality, prevent erosion, and provide habitats for local wildlife. The use of natural elements can help to create more pleasant environments that promote mental and physical health. With the rising concerns over the impact of climate change and the need for more sustainable practices, green infrastructure is becoming an increasingly important part of urban planning. By integrating natural elements into our built environment, we can create more resilient and sustainable communities that benefit both people and the environment.
