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Mayor of Paris, Anne Hidalgo & Former Governor of California Arnold Schwarzenegger reveal findings of new C40 research on the health benefits of climate and air pollution policies for cities and regions.


Walking or cycling to work, on green & healthy streets, can cut your risk of heart disease by almost one quarter and type 2 diabetes by 15%, and it reduces greenhouse gas emissions.


World Champion Cyclist Peter Sagan sends video message of support.


Paris, France (11 December 2017) — New research by C40 Cities revealed today the scale of the potential health benefits that could be achieved by cities and regions implementing climate action and policies to clean the air that citizens breathe. Anne Hidalgo, Mayor of Paris, and Chair of C40 and Arnold Schwarzenegger, Former Governor of California and founder of R20 – Regions of Climate Action, presented the findings on the eve of the One Planet Summit to be held in Paris on December 12th.


The research, conducted by C40 Cities reveal that:

  • Under the commitments made by Paris in the C40 Green & Healthy Streets Declaration, improvements to the air quality in Paris will avoid an estimated 400 air quality related premature deaths per year and add 21 days to life expectancy on average for every resident in the city of Paris.
  • This will prevent an estimated 1,280 respiratory hospital admissions and 6,350 cardiovascular hospital admissions in Paris each year triggered by air pollution.
  • If all C40 cities reduced their annual average PM2.5 levels by 2.5 µg/m³ – by for example meeting the commitments of the Green & Healthy Streets Declaration and encouraging more people out of their cars – it would potentially prevent more than 45,000 premature deaths each year.
  • Switching from driving to an active commute (walking at a brisk pace or cycling 30 minutes per day, 5 days a week) can deliver the following health benefits for citizens:
    • 23% reduced risk of heart disease,
    • 23% reduced risk of stroke, 
    • 15% reduced risk of type 2 diabetes,
    • 14% reduced risk of depression,
    • 12% reduced risk of breast cancer
    • 11% reduced risk of dementia, and
    • 8% reduced risk of colon cancer
  • An active commute also reduces greenhouse gas emissions and therefore prevents climate change – If 10% of citizens in C40’s North American Cities switch from driving to cycling that would save over 1.6 million tonnes of CO2e per year, equivalent to 180 million gallons of gasoline consumed.

These findings are based on research conducted by C40 Cities Climate Leadership Group with support from Johnson & Johnson on the wider benefits of climate action on air quality and health, and Novo Nordisk in connecting active mobility to climate and health.  


As Mayor of Paris my first priority is to protect the health and wellbeing of Parisians. This research reveals that the policies we are implementing to clean the air we breathe and restrict the polluting diesel and petrol vehicles will add 3 weeks onto the life of every citizen, whilst also preventing climate change,” said Anne Hidalgo, Mayor of Paris and C40 Chair. “If the policies are escalated to cities and regions around the world, the health benefits will affect tens of thousands of people. Now we see just how dangerous those forces who want to prevent the shift to clean and healthy streets really are. Nothing will hold us back.”


“I am proud to stand with Mayor Hidalgo to bring the life and death aspects of our environmental crusade into the spotlight,” said Arnold Schwarzenegger Founder of R20. “As we both know, Governors and Mayors have a duty to protect the health and safety of their citizens, and air pollution is one of the greatest threats to mankind, with over 7 million people dying worldwide every year. Together, through the R20 and C40, we will inspire subnational leaders around the globe to focus on the immediate dangers and health impacts of fossil fuels.”


In April 2017, C40 and R20, organisations representing the most powerful cities, states and regions of the world including Paris, London, Mexico City, California, British Columbia and Gujurat State in India, signed a Memorandum of Understanding to collaborate to tackle climate change. C40 and R20 will collaborate across a range of issues, including accessing finance for climate action projects and supporting the next generation of women climate leaders.


World champion cyclist, and C40 Cities ambassador for cycling cities, Peter Sagan sent a message of support to encourage more people to travel by bike in cities.


– ENDS –




About the research

Full details of the methodology for determining these figures can be downloaded here. Members of the C40 Research team are available for comment on the findings, the methodology and the sources used.


Please contact Josh Harris,


About the C40 Cities Climate Leadership Group

C40 Cities connects more than 90 of the world’s greatest cities, representing 650+ million people and one quarter of the global economy. Created and led by cities, C40 is focused on tackling climate change and driving urban action that reduces greenhouse gas emissions and climate risks, while increasing the health, wellbeing and economic opportunities of urban citizens. The current chair of the C40 is Mayor of Paris Anne Hidalgo; and three-term Mayor of New York City Michael R. Bloomberg serves as President of the Board. C40’s work is made possible by our three strategic funders: Bloomberg Philanthropies, Children’s Investment Fund Foundation (CIFF), and Realdania. To learn more about the work of C40 and our cities, please visit, follow us on Twitter @c40cities or Instagram @c40cities and like us on Facebook at


About the C40 Green & Healthy Streets Declaration

In September 2017, at a ceremony in Paris, 12 pioneering mayors committed to the C40 Green & Healthy Streets Declaration – a series of ambitious targets to make their cities greener, healthier and more prosperous. The committed cities are: London, Paris, Los Angeles, Copenhagen, Barcelona, Quito, Vancouver, Mexico City, Milan, Seattle, Auckland & Cape Town


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