By Iyad Kheirbek, C40’s Programme Director for Air Quality
Air pollution is a public health crisis. The vast majority of people are breathing polluted air, increasing their risk of early death, hospitalisation and chronic health problems. Dirty air causes 43% of deaths from lung disease, for example, and leads to the early deaths of over seven million people a year globally.1 Our exposure begins before we’re born, increasing the risk of premature birth, low birth weight and more. Throughout our childhoods, over 90% of us are exposed to fine particulate matter (PM2.5) concentrations above the safe level established in the World Health Organization (WHO) guidelines, affecting our health over our entire lifetime.2 In turn, this affects cities’ economies through higher healthcare costs, lower productivity and liveability, reduced tourism and more.
While the most severe air pollution levels are experienced in many of the world’s fastest developing regions, nearly all cities in every region are affected. In November 2019, a very visible public health emergency hit Delhi; as concentrations of dangerous PM2.5 reached 40 times the safe level, schools were closed, flights cancelled and Delhi’s Chief Minister Arvind Kejriwal referred to the city as a ‘gas chamber’.3 In California, the air pollution implications of climate change became clear as wildfires near Los Angeles caused PM2.5 concentrations to spike. In Africa, where hundreds of thousands of people already lose their lives due to poor air quality,4 pollution levels are rising and there is a lack of basic data available to properly manage the problem. Even in more advanced cities, air pollution continues to pose significant risk. Pollution episodes in major cities such as Paris and Mexico City, for instance, have prompted strict control measures like banning vehicles from entering the city. Recently, the economic burden of PM2.5 in the United States has been estimated to top 800 billion dollars annually.5
Solving this crisis presents massive opportunities for cities. Importantly, as many of the sources of air pollution are also sources of greenhouse gas emissions, targeted action to address both crises can bring rapid, local health benefits as well as longer-term, global climate benefits. These health benefits will far outweigh the costs of control. For example, the benefits of clean air programs established by the United States Clean Air Act of 1990 exceed their compliance costs by a factor of around 30 to one.6 The health benefits from air pollution improvements associated with the Paris Agreement targets are estimated to be 45% to 145% higher than the costs of the interventions, demonstrating a substantial return on investment even without accounting for reduced climate-related damages.7
The good news is that city leaders already have a proven set of tools which can be deployed to improve air quality and make their cities more liveable, and economically prosperous. Air quality monitoring can identify the levels and sources of air pollution to inform improvement strategies, engage the public, track progress, and enforce clean air policies. Cities can capitalise on new technologies to do this, including a new generation of air quality monitoring and satellite-based methods. By implementing a tailored suite of actions to reduce emissions from transport, buildings, industry and waste, cities can tackle their air pollution problems and simultaneously mitigate climate change.
When these interventions are prioritized and properly resourced, cities can quickly see significant progress. Across 74 Chinese cities, for example, PM2.5 levels dropped by a third from 2013 to 2017 after the national and city governments introduced strict control measures.8 In New York City, between 2009 and 2017, PM2.5 and sulphur dioxide (SO2) levels fell by 30% and 96% respectively, as combined efforts by federal, state and city authorities reduced emissions from sources such as power plants, motor vehicles, and heating fuels used in buildings.9 In Mexico City, the comprehensive air quality management plan PROAIRE led to a 30% decline in ozone concentrations and nearly 90% decline in SO2 concentrations from 1990 to 2017.10 In October this year, 35 cities announced the C40 Clean Air Cities declaration, recognizing clean air as a human right and pledging to work together towards meeting the WHO air quality guidelines. These cities have committed to establish baseline air quality levels and set ambitious reduction targets within two years, begin implementing new policies and programmes to address their top sources of air pollution by 2025, and ensure the robust foundations of effective air quality management exist within their cities. These targets, approaches and interventions can be adopted by cities around the world.
Spotlight On: Clean Air Cities aims to provide city leaders and practitioners around the world with information, tools and practical experience from other cities on improving urban air quality. This collection of resources explains the problems air pollution causes for cities and citizens, the link with climate action, and effective approaches to create healthier cities.
You can find:
- Why clean air is vital for your city’s health and prosperity, a brief explanation of how air pollution impacts people’s health and cities’ economies.
- A blog from Pallavi Pant and Katherine Walker of the Health Effects Institute and the world-leading State of Global Air report, outlining the current state of air quality in countries and cities around the world, the progress made so far, and what needs to happen next.
- Win-Win: Why cities should tackle climate change and air pollution together, which sets out the synergies and shared solutions.
- Air quality data for your city in our Air Quality Data Explorer.
- Six impactful actions cities can take to improve their air quality, including setting targets and developing effective sectoral interventions on the main sources of air pollution globally.
- Low and middle income countries’ urban air pollution solutions, which looks at tackling the leading sources of air pollution in African and Asian cities.
- How to set standards and monitor air quality, which includes advice for cities at the very start of their monitoring journey as well as those seeking to establish more advanced monitoring networks.
- A guide to ‘hyperlocal’ air quality monitoring, which uses new innovations in sensing technology to create a detailed map of the air that people across the city are breathing. You can also watch a short video from the Environmental Defense Fund (EDF), authors of this guide and a global leader in hyperlocal monitoring. We are excited to share that EDF will also be taking your questions about hyperlocal mapping over the coming weeks – to take part, send in your question(s) by Wednesday, 18th December 2019, and we’ll get answers to you the following week. Please note you need to be logged in to your Knowledge Hub account to participate.
- How to design and implement a clean air or low emission zone, which draws on successful examples from around the world.
- A blog from Irene Burga, Air Quality Advisor with the City of Los Angeles, who explains LA’s approach to reducing emissions and the measures currently being implemented through its Green New Deal. Famed for its cars and congestion, Los Angeles has almost halved its air pollution since the 1970s though vehicle emissions standards and more, and is now ramping up efforts to deliver cleaner air for its citizens. This includes major investments to shift Angelenos out of their cars.
- We have the power to move the world: A mayors’ guidebook on sustainable transport, which sets out approaches and advice from cities implementing some world’s most ambitious substantiable transport policies. https://www.c40knowledgehub.org/s/article/Introducing-Spotlight-On-Clean-Air-Cities?language=en_US