Read More: Air Quality and Public Health Crisis

Globally, nine out of ten people now breathe polluted air. Each year poor air quality causes approximately 400,000 premature deaths across Europe, while air pollution kills 7 million people worldwide. Fine particulate matter (PM2.5), suspended dust that, when inhaled, can cause chronic obstructive pulmonary disease, bronchial asthma, stroke, heart disease and some cancers, is the air pollutant driving the most significant health problems and premature mortality.

In the Republic of Ireland, air pollution causes 1,300 premature deaths each year according to the EPA, and the authority’s State of the Environment Report, published in October 2020, again warned of serious health implications from fine particulate matter in air.

A recent Dublin based study demonstrated how the concentration of PM in the city was significantly lower on streets with mature tree canopy compared those streets with no trees. This is due to the increased amount of surface area on which deposition can occur and trees ability to alter the dispersion rates of pollutants. As low income areas are much more likely to have little or no tree canopy cover, the associated health impacts of the current ecological crisis are disproportionately felt by people living in these neighborhoods.

Ireland also has extremely high levels of Nitrogen Dioxide (NO2) within urban environments caused largely by the emissions from diesel vehicles. Though transformative shifts in private and public transport are urgently required, careful investments in urban street trees will help reduce adverse physical health impacts of NO2 while this transition gathers momentum.

Additionally, there is growing evidence of the positive impact a diverse tree canopy cover has on our mental health. A recent study has shown that adults living in neighbourhoods with a tree canopy of 30% or more had 31% lower odds of developing psychological distress. There are also more subtle health benefits which are discussed further in the benefits section.

Though the evidence is overwhelming, the current sporadic and poorly managed urban tree canopies do not provide our citizens with sufficient mental or physical health benefits.

Further Reading:

9 out of 10 People Worldwide Breathe Polluted Air: https://www.who.int/news/item/02-05-2018-9-out-of-10-people-worldwide-breathe-polluted-air-but-more-countries-are-taking-action

Investigating the effect of trees on urban quality in Dublin by combining air monitoring with i-Tree Eco model: https://www.sciencedirect.com/science/article/pii/S2210670720305771

Psychological benefits of greenspace increase with biodiversity: https://royalsocietypublishing.org/doi/10.1098/rsbl.2007.0149

Urban trees found to improve mental and general health: https://phys.org/news/2019-07-urban-trees-mental-health.html