Small and densely populated cities have higher death rates than other urban areas: study

A new survey of 919 European cities has found that small towns with high population density are not only less green than low-density urban areas, but they also have poorer air quality (due to higher nitrogen dioxide emissions from vehicles) and higher mortality rates.

The findings, published in The Lancet Planetary Healthfurther emphasize that while compact European cities have significantly lower CO2 emissions, the downside is that they have less green space, making residents much more vulnerable to stronger urban heat island effects. “However, sprawling cities with low population density also face challenges, especially related to longer travel distances, higher CO2 emissions, car dependence, availability of proximal and diverse destinations, and social isolation,” the authors point out.

Because cities are largely concrete jungles and every surface is covered with concrete or asphalt, they absorb and retain more heat during the summer and become hotter than rural areas. The only way to combat the urban heat island effect is to increase green areas such as parks and gardens, and protect and plant more street trees.

“Compact cities have many conceptual advantages in terms of reduced car dependency, walkability, immediate access to services, increased social interactions and a greater sense of community,” the authors wrote in the study. “Yet in their current configuration they are highly densified and likely act as economic hubs attracting large numbers of commuters for education or employment. Moreover, mobility within compact cities is still largely dependent on motorized modes of transport.”

“As our analysis shows, traffic volumes are significantly higher within the compact city type compared to all other urban configurations, which is also in line with the higher nitrogen dioxide emissions observed in these cities,” she added. “In this sense, today’s European compact cities should be understood as being in a state of transition towards an optimal form, a state that currently combines a number of positive characteristics (such as proximity to services) with challenges such as densification, mobility and the management of traffic flows. , poor air quality and insufficient green and natural spaces.”

One of the lead authors, Tamara Iungman, a researcher at ISGlobal, and colleagues proposed a number of measures that could help make compact cities less polluted and cooler for residents.

They explained that in terms of density there may be a maximum of 175 homes per hectare. This way, people won’t feel socially isolated and can still create a sense of community while living in a walkable city with easy access to essential services. The authors say that promoting high-quality public transport and reducing dependence on cars can help reduce traffic and air pollution. One solution they believe will have enormous health benefits is creating car-free neighborhoods in major cities.

“Compact cities can be used to implement new urban models that promote the creation and better use of public spaces for citizens. These approaches include the implementation of superblocks in various parts of Barcelona, ​​Spain, the development of car-free neighborhoods in London and the creation of car-free neighborhoods in Hamburg and Freiburg, with potential positive environmental and health impacts. authors wrote.

Incorporating green spaces when planning infrastructure projects is another crucial solution that more urban areas can adopt.

“Green roofs or facade greening can be introduced in well-sealed commercial areas to reduce surface water runoff. Sky gardens can compensate for the absence of green spaces on the ground floor; street trees reduce CO2 emissions and improve the microclimate; and the introduction of small gardens in public, industrial, educational and institutional spaces can help support biodiversity as part of green spaces in the city,” she added.