What is Green Infrastructure?
Green infrastructure describes how plants, trees and other vegetation features are incorporated into the built environment in cities. This includes roadside trees, shaded streets and light-coloured roofs.
Urban greenness has many benefits for both the environment and human health, not to mention beautifying effects on communities.
How does it affect health?
With increasing levels of urbanization, Canadians tend to be less and less connected to the natural environment. In order to build cities that support the health of all residents, green space needs to be prioritized. Canada’s Chief Medical Officer of Health identified green spaces as one factor that are essential for neighbourhoods to promote a sense of community, belonging and build strong and supportive social networks. Ensuring there are green spaces in our cities that everyone can access helps boost everyone’s physical and mental health, makes our communities more resilient to climate change and cleans the air we all breathe.
Greenness and green spaces can have a positive impact on human health, including reducing your risk of early death and death from cardiovascular disease. Canadians who live in areas with higher levels of greenness within 250 to 500 metres of their home have a reduced risk of dying prematurely from one of the six most common causes. This holds true even when you consider the health impacts of air pollution, population density and individual behaviours such as smoking. And the more green space you have nearby, the greater the health benefits.
Green space further promotes physical activity, leading to even more health benefits. Many people undertake some form of physical activity – walking, running, cycling – as an inherent part of experiencing natural environments. Having green space along urban streets also makes active transportation more enjoyable, encouraging more people to use their own energy to get around instead of using a car. Including more physical activity in our daily routine and leisure time helps reduce the risk of a number of chronic conditions while also boosting our mood and promoting better mental health.
Having pleasant green spaces in your community encourages residents to spend more time in nature, which promotes better mental health. Those with regular exposure to nature have an increased ability to cope with stress, improved productivity, reduced job-related frustration, increased self-esteem and increased life satisfaction. Having attractive greenery nearby creates a space where residents want to spend time relaxing and recovering from the stresses of city life.
Urban green space provides cooler, cleaner air for neighbourhoods and cities by cleaning pollutants from the environment. Trees capture common air pollutants to improve the quality of the air we all breathe. Trees also significantly relieve heat stress at the street level and within neighbourhoods scale, particularly during heat waves and hot times of day. In Toronto, neighbourhoods with less than 5% tree cover make five times as many heat-related ambulance calls than neighbourhoods with more than 5% cover. Marginally increasing tree cover in neighbourhoods that have less than 5% coverage could reduce heat-related ambulance calls by 80%.
Green spaces also promote better social cohesion, connectedness and a sense of belonging. People who connect with nature feel less isolated and less focused on themselves because they have the opportunity to interact with others in their community.
Who is affected?
Though greenness has many health benefits, they are not equally distributed. Low-income populations in Vancouver, Montreal and Toronto are more likely to live in neighbourhoods with low levels of greenness while high income populations are more likely to live in neighbourhoods with high levels of greenness. However, low-income populations have the most to gain from public green spaces.
In communities without green space, low-income populations have more pronounced death rates from any cause, in particular from heart disease, compared to their higher income neighbours. By contrast, communities with more exposure to green space don’t experience as extreme disparities in mortality rates. Inequalities in mental well-being are smaller among urban dwellers with good access to green areas, compared with those without easy access.
Green space can also help vulnerable populations more easily manage life transitions by creating space for meaningful social interactions. Social contact is known to be important for health and well-being, especially for older people, who go through significant life transitions, and for whom social isolation can increase their risk of death. Green spaces can alleviate some of the negative impacts of such transitions on personal well-being. For example, older adults who participate in group-based outdoor activities gain structure and routine, meaningful social interaction and develop a sense of achievement, pride and ownership.