As cities continue to expand, green spaces are becoming increasingly important for residents’ health and environmental protection. Parks, public gardens, roadside trees, urban forests, recreational grounds and other areas covered with vegetation are not simply decorations for cities.
Studies show that having more trees and green spaces in urban areas can contribute to both physical and mental health.
The World Health Organization (WHO) says more than 55% of the world’s population lives in urban areas, a figure that could rise to 68% by 2050.
As more people move to cities, there is a growing need for urban planning that combines buildings and infrastructure with the preservation and development of green spaces.
Cecil Konijnendijk, an expert in urban forestry and environmental planning, developed the 3-30-300 principle, which recommends that everyone should be able to see at least three trees from where they live, have 30% tree canopy coverage in their neighbourhood, and live within 300 metres of a park or large green space.
Green spaces help the brain relax
Cities can expose people to various factors that affect brain function and mental well-being, including noise, overcrowding and heavy traffic, which can increase stress and mental fatigue.
The WHO says green spaces can provide people with opportunities to relax and reduce stress.
A meta-analysis found that a 10% increase in green space was associated with a 3.7% reduction in the risk of depression, anxiety and psychological distress.
Possible explanations include the fact that green spaces provide opportunities for relaxation, walking and physical exercise, while reducing exposure to urban noise and congestion and creating opportunities for people to meet and socialise.
A study conducted across 18 countries and involving more than 100 million people found an association between greater exposure to green spaces and lower levels of cardiovascular disease.
Parks and trees can encourage physical activity
Cities with parks, walking paths, playgrounds and well-designed recreational areas can provide residents with more opportunities to walk, run, cycle and engage in other forms of physical activity.
The WHO says green spaces can provide safe places for exercise and recreation.
This is important because insufficient physical activity is associated with various health conditions, including cardiovascular disease, diabetes and obesity.
Trees can help reduce urban heat
The WHO says temperatures in urban areas can be 3°C to 5°C higher than in rural areas because of the urban heat island effect.
Extreme heat can have serious health consequences, particularly for people living with cardiovascular disease, diabetes and respiratory conditions.
The WHO estimates that between 2000 and 2019, heat exposure was associated with approximately 489,000 deaths each year globally.
Vehicles, industries and other urban activities can also contribute to air pollution.
The WHO identifies air pollution as one of the major health challenges in cities, with large numbers of urban residents exposed to polluted air.
Trees and other vegetation can help remove some air pollutants and trap particulate matter and dust.
A single tree can absorb up to 150 kilograms of CO2 per year, potentially contributing to cleaner air and helping reduce respiratory health risks such as asthma.
