Quebec is increasingly seeking to densify its cities, among other things, to promote sustainable mobility and better protect agricultural environments. Densification has certain adverse effects on health, but there are also benefits, indicates a recent INSPQ report.
The National Institute of Public Health of Quebec analyzed several studies to provide a portrait of the impacts of densification on health. It looked at physical activity levels and walking, noise and air quality, injury risks posed by vehicles and social interactions.
Poor air quality can result in higher mortality or hospitalization rates, the analysis shows. She says air pollution can affect even healthy people, but those with asthma or other respiratory conditions as well as the elderly and young children are populations at higher risk.
“We know that when we breathe air pollution, there will be health effects such as an increase in the risks of certain cancers, the frequency of heart attacks increases, the number of people who must be admitted to hospital with respiratory problems are also increasing,” listed Patrick Hayes, professor of analytical and atmospheric chemistry at the University of Montreal.
He indicates that there is significant intoxication in air quality for people who live near a source of pollution such as a busy highway. Mr. Hayes points out that there is a very large variation in air quality within the same city depending on the sector.
Furthermore, large cities often have a better public transportation network and a greater proportion of the population travels on foot or by bike.
“There is an effect that will cancel out a little in the sense that total emissions are reduced, but emissions per unit area will increase,” explains Mr. Hayes. There are two effects going in opposite directions, so it’s a question of [savoir] whether reducing emissions has an effect that is greater than the effects of densification. »
Mr. Hayes emphasizes the importance of polluting less, in particular by reducing car travel. However, he adds that certain pollutants are beyond our control. “There are certain sources that we cannot easily control, such as the smoke from forest fires that we saw last summer in Montreal. The frequency and intensity of forest fires are influenced by climate change, […] but it’s not something we can directly control. »
Furthermore, Mr. Hayes indicates that Quebec is rather poorly placed geographically in terms of prevailing wind, which means that the province receives part of the air pollution coming from the northeast of the United States and the Ontario.
The INSPQ report also explored the effects of noise on health. It indicates that exposure to excessive noise can notably disrupt sleep and proximity to car traffic or an airport is associated with “high blood pressure and cardiovascular diseases, a reduction in quality of life and well-being as well as a possible alteration of cognitive development in children.
More social interactions in the city
The quantity and quality of social ties between individuals have positive effects on health, says the report. People with more social connections live longer, while isolation is associated with a risk of depression, cognitive decline, physical inactivity and generally poorer health.
Public spaces – which are generally used more in high-density cities – play an important role in social interactions. These spaces encourage opportunities for spontaneous encounters.
Traveling by public transport, on foot or by bike also leads to more spontaneous encounters.
“We also know that public places, when they are well designed, provide significant psychological renewal,” explains Linda Pagani, professor at the School of Psychoeducation at the University of Montreal. Today, we tend to spend too much time indoors in solitude because of virtual life. We have lost track of how important chance is in life. »
Mme Pagani maintains that social interactions promote a sense of security, decrease anxiety and sadness in addition to increasing a sense of belonging.
“When it’s set up for social interactions and spontaneous encounters, we tend to be very positive towards each other,” adds the professor.
However, she says, crowded situations, meaning being forced to live side by side and crowded on top of each other, can have a harmful effect.
Physical activity
Road traffic inevitably causes collisions, whether between motorists or with pedestrians and cyclists.
According to the analysis, the link between density and road trauma is mixed. “At the neighborhood level of the same city, it is generally the denser neighborhoods that experience more collisions due to the higher number of trips that pass through them. On the other hand, if we compare cities with each other, considering the number of kilometers traveled by car, it is the denser cities that suffer fewer collisions,” we can read in the INSPQ document.
In relation to the level of physical activity, the analysis mentions that “urban sprawl is associated with lower levels of physical activity due to sedentary lifestyle habits associated with massive use of the car”. This may play a role in the development of cardiovascular disease, type 2 diabetes as well as certain types of cancer.
According to data from the Institute of Statistics of Quebec, 48% of the population aged 15 and over does not achieve the recommended level of physical activity per week, which is at least 150 minutes of physical activity. medium intensity for adults.
Getting enough movement has positive effects on mental health and reducing the risks associated with being overweight such as hypertension and cardiovascular accidents.
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