Our planet has never known a time like this. In 1950 just 30% of the global population lived in cities – today that figure stands at around 54% and is projected to climb to around 66% in the next 30 years or so.
People are attracted to cities because of opportunities for better access to education, employment, entertainment, sanitation and health care. However, with that increase of the global urban population comes greater pressure on natural resources such as water and land, more road traffic and congestion, and associated air and noise pollution and, critically for us, health risks.
The changing global climate may also mean that in the future extreme weather events will become more frequent, and possibly more severe, and the urban heat island effect, in which temperatures in built-up areas are higher than in surrounding rural areas due to the use of materials such as concrete, may push-up temperatures in cities which can increase heat-related illness and ultimately put more pressure on healthcare systems. Taken together these twin issues, a changing climate and rapid urbanization, present an unprecedented challenge to those working in public health.
Our globally changing climate also presents us with significant opportunities to improve health and wellbeing.
But, our globally changing climate also presents us with significant opportunities to improve health and wellbeing. It’s likely that measures to mitigate and adapt to a changing climate will bring about societal benefits.
For example if new buildings are built in a way that keeps them cool in summer and warm in winter (or existing building are retrofitted to achieve improved thermal performance), it’s likely they’ll also use less energy, which will lead to less carbon in the atmosphere and less air pollution, which in turn brings health benefits.
Another example would be walking and cycling more and using public transport instead of cars for short journeys in our cities, which would reduce local air pollution and improve our cardiovascular health by making us more physically active.
Planting more street trees can also benefit the environment and our health and wellbeing by providing shading and other ecosystem services.
However, policies to improve energy efficiency of buildings, promote active travel and plant more trees can also have some unintended negative effects if they are not properly designed and implemented.
For example, good ventilation will be needed in increasingly airtight buildings to keep indoor air clean, cycling routes will have to be designed in a way that reduces the risk of accidents and injuries, and the right tree species should be selected to minimize emissions of pollen and allergens in cities.
One of the key questions being asked is what we can do now to mitigate these future health impacts and maximize the potential benefits
To those of us who work in climate science and public health one of the key questions being asked is what we can do now to mitigate these future health impacts and maximize the potential benefits, and how do we get these positive steps embedded into policy at both the local and the national level? These are questions which the Healthy-Polis initiative is tackling head-on.
What is this initiative?
Healthy-Polis is a consortium of researchers and practitioners from public health agencies, local authorities, universities, companies and non-governmental organizations in Europe, Australia, New Zealand, China, South Asia and other parts of the world, co-ordinated by Public Health England.
Those involved in the work come from a wide variety of backgrounds. Among our membership are environmental scientists, toxicologists, epidemiologists, urban planners, architects, mathematical modellers, engineers and public health practitioners and researchers.
It’s that breadth of experience and expertise that is needed to delve deeper into the complex issues that cities face and collectively come up with evidence based proposals for the best way to protect the health of those living in cities now – and better design and shape the cities of the future.
Environmental health
So far, our consortium has published a number of papers considering various aspects of urban environmental health – but now we have really hit our stride with 12 separate detailed pieces of research on key aspects of our work and an editorial being published in the special edition of the Environmental Health journal.
As for what’s tackled in this issue – there’s a wealth of inter-related topics. From how much the urban heat island effect contributes to death rates in heatwaves through to the health and climate benefits that street trees can provide to urban environments. From ways to reduce the burden of disease from indoor air pollution in Europe through to the effects urbanization is having on health in China at the national, local and individual level.
What’s exciting for me as a scientist who has worked in this field for several years, is the scope of what this initiative can achieve.
What’s exciting for me as a scientist who has worked in this field for several years, is the scope of what this initiative can achieve.
Because our members hail from different parts of the world and bring a wealth of experience, data and expertise, we can report on complementary approaches being undertaken to tackle in a holistic way the different but often interlinked urban health problems.
We can highlight emerging issues and consider what research gaps there are that could usefully be addressed through scientific inter-disciplinary collaboration, and sharing of knowledge and resources.
Ever evolving and changing cities
Of course we know that finding answers to the issues we’re all grappling with is not an easy task. Cities, both old and new, are complex ever evolving and changing systems. Methodological innovation in epidemiology, exposure assessment, risk analysis and urban planning, and standardization of methods across countries, can help address complex environmental health challenges in the context of climate change and sustainable development.
Citizens in different places want to be involved in determining solutions to problems like air pollution, traffic congestion and noise, climate change and extreme weather, municipal waste, and contamination of water and soil. We’re hoping Healthy-Polis will engage scientists, decision-makers and citizens, and pool global resources to highlight what can be done to make our cities even better places to live.
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