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Cities and air pollution

Cities are hotspots for poor air quality and much of the world is rapidly urbanising. Improving mobility and public transport is key to clearing the air, while creating sustainable cities and communities.

The frontline of air pollution impacts

Air pollution is one of the largest threats to public health, our climate and the environment. 41% of cities in the world have air pollution that is over 7 times higher than the WHO’s recommendation. 97% of cities in low- and middle-income countries have unsafe levels of air pollution.

of the world’s population is expected to live in cities by 2050

Countries in Africa and Asia are rapidly urbanising, which means even more people will breathe toxic air and die prematurely.

Cities often have poor air quality due to a combination of factors, primarily stemming from human activities and geographical features. The dense concentration of vehicles, industrial facilities and construction projects are huge sources of emissions. Additionally, the high energy demands of cities lead to the combustion of fossil fuels, releasing pollutants into the atmosphere. Other key sources include burning waste and solid fuels like coal and wood in homes. Some cities’ poor air quality levels are also exacerbated by weather conditions.

Traffic is a huge source of urban air pollution  

Vehicles, particularly those fuelled by diesel, are a significant source of air pollution and greenhouse gas emissions, with transportation accounting for about half of emissions in cities. Much urban growth occurred during the automobile era, with planning focused on the movement of cars rather than people. Congestion problems have been made worse by the growth in home deliveries in recent years. Meanwhile deaths and injuries caused by road traffic take the greatest toll on pedestrians, cyclists and motorcyclists.

At the heart of global street design is road safety, but so is the environment, physical activity, economic health, diversity, equality. The street is the nexus of so many different global challenges.

Skye Duncan, Global Designing Cities Initiative

The need for clean air has driven recent action at national and city level, with the focus on transportation and sustainable mobility – clean air zones, electrification and active travel. Electrification is happening in some cities and significant investments are being made. But electric cars still take up valuable space in cities and create congestion.

Public transport infrastructure is often lacking in cities. Only half the world’s urban population has convenient access to public transportation. Many people depend on walking and cycling to access vital services, education, employment and other opportunities. While such active commuting can support health through increased physical activity, poor air quality can force pedestrians to take alternative routes to avoid the worst exhaust emissions. On very high pollution days, active commuters may need to avoid walking or cycling entirely.

Smarter urban planning for sustainable cities

The UN Sustainable Development Goal 11 (SDG11: Sustainable Cities and Communities) calls for cities to become inclusive, safe, resilient and sustainable. A more coordinated approach across clean air and sustainable urban development can deliver multiple benefits for mobility, health, equity, safety and climate. Cities that address air pollution through well-planned transport systems, walkable streets and green spaces are more likely to support physical fitness, mental health and social cohesion.

As a global public health emergency, air pollution can provide the impetus to prioritise the movement of people, rather than cars. For those advocating a fundamental rethink of how we move around, the need for clean air can be a catalyst for rethinking and redesigning accessible, clean, liveable and safe streets.

When you take away space from cars and give it to people you not only get cleaner air, but you also positively support more physical activity and lower risk of cardiovascular disease. You also provide space for recreation and socialisation – important considerations for mental health.

Jose Siri, Wellcome Trust

Air quality data can be used to measure the health impacts of sustainability mobility and urban transformations and provide the evidence that urban planners and designers need to scale projects. Data is essential to build the evidence base and bring more funding to mobility and urban improvements.

Our work on urban air pollution globally

Breathe Cities is a first-of-its-kind partnership delivered by Clean Air Fund, C40 Cities and Bloomberg Philanthropies. This ambitious initiative supports cities around the world to cut their air pollution and climate emissions. The initiative, which began in London, brings together data, communities and city decision-makers for clean urban air.

We also support C40 Cities’ Clean Air Accelerator initiative. 48 city mayors signed the global clean air cities declaration, in which they committed to working towards the WHO air quality guidelines — a signal that city leaders are taking air pollution seriously.

city mayors signed the global clean air cities declaration

We support the accelerated introduction of clean air policies in cities. In the UK, we supported partners to drive the creation or expansion of eight Clean Air Zones (CAZ) in Bath, Brighton, Portsmouth and the London Ultra Low Emission Zone – with the potential to save millions of lives. In the EU, we pushed the Polish Government to adopt legislation to enable Low Emission Zones (LEZs), with 12 mayors pledging to implement LEZs and Krakow becoming the first LEZ in central and eastern Europe. In Sofia, Bulgaria, the city announced plans to introduce a LEZ, following civil society’s demands for stronger clean air measures that were spearheaded by our partners.

Photo: Heavy traffic during the commuting hours in Jakarta, Indonesia. Credit: Aji Styawan / Climate Visuals