3 June 2025
Blog Global

Air Pollution: Sources, Impacts, and Solutions for Cities

Air pollution is one of the biggest threats to our health, our climate, and our cities—driven largely by human-made sources like transport, industry, and waste. With most of the world’s population living in urban areas, cities are at the frontlines of the crisis—and key to delivering real, rapid solutions.

Air pollution is one of the biggest threats to our health, our climate, and our cities. Today, 41% of cities in the world have air pollution that is over 7 times higher than the World Health Organization’s recommendation. Without urgent action, the costs will continue to rise — in lives lost, health systems strain, and economic damage.

But it does not have to be this way. There are solutions. With investment and collaboration, cities can be at the forefront of delivering those solutions so that everyone who works, lives in, or visits them can breathe cleaner air.

 

What is air pollution?

Air pollution refers to harmful gases and particles in the air that change its natural composition. The World Health Organization (WHO) identifies common sources as household burning of fuels such as coal and wood for cooking and heating, motor vehicles, industrial facilities, and forest fires. Worldwide, most major sources of air pollution are man-made and involve the burning of fossil fuels or biomass. 

Two common air pollutants are PM2.5 and nitrogen oxides (NOx). PM2.5 refers to tiny particles floating in the air — like bits of dust, smoke, ash, or soot. Nitrogen oxides are gases that form when fossil fuels like coal, petrol, or diesel are burned and mix with oxygen in the air.

Pollution doesn’t stay put. Wind and atmospheric reactions can transport pollutants far from where they originated, transforming them along the way. For example, areas downwind from power plants or cities can experience smog or haze.

Highlights

Air pollution threatens health, climate, and economies—but most sources are human-made and can be tackled through targeted action.
There are a range of solutions to reduce air pollution, from shifting to cleaner transport to improving how we handle waste.
Breathe Cities supports local leaders and communities to reduce pollution and create healthier, thriving urban environments.

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Sources of Air Pollution

Air pollution originates from a variety of sources. In cities, most of these are human-made, meaning they can be solved through targeted action. These sources can be grouped into four main types:

Mobile sources

For example, vehicles such as cars, buses, planes, boats and trains.

Area sources

These include agricultural areas and wood-burning fireplaces.

Point sources

Power plants, factories, construction sites, waste landfills and oil refineries emit large amounts of pollution from fixed locations.

Natural sources

Events like wildfires, wind-blown dust, and volcanic eruptions can contribute to pollution. These are typically short-term, but the intensity of wildfires is increasing due to climate change.

Why does air pollution matter?

The consequences of air pollution are significant, impacting everything from human health to our economy and the climate.

It contributes to serious illnesses like asthma and heart disease, fuels climate change, affects people differently depending on where they live or work, and costs the global economy trillions each year.

 

Why cities?

With 68% of the world’s population expected to live in urban areas by 2050, cities are at the frontlines of the air pollution crisis. But they also hold the tools to tackle it. From transport and energy to waste and buildings, there are so many ways to clean the air in our cities. When cities act, the results are real and rapid: cleaner air, better health, resilience to the climate crisis, stronger communities, fairer outcomes for the people who need it most and a healthier world for future generations. That’s why Breathe Cities partners with local leaders, communities and experts to drive bold action where it counts the most.

What Can Be Done?

Reducing air pollution is a win-win strategy for our climate, health, people and our economy. Solutions vary, but can include:

Monitoring Air Quality

Tracking air pollution levels and identifying where the pollution comes from can help cities take targeted action to clean the air.

Reducing and Recycling Waste

Burning trash releases toxic particles, so changing how we manage waste and boosting recycling can help cut this down.

Improving Transportation

Transitioning to electric vehicles and public transport reduces mobile-source emissions.

Regulating Industry

Implementing stricter controls on emissions from power plants and factories limits emissions.

Promoting Clean Energy

Shifting from fossil fuels to renewable energy lowers pollution and greenhouse gas emissions.

Community Action

Raising awareness of the impact of air pollution and calling on local leaders to take action to clean the air can help drive change.

The role of initiatives like Breathe Cities

The Breathe Cities initiative works across 14 cities globally to address air pollution. By supporting local governments, working with communities, expanding air quality data, and sharing lessons learned, the initiative aims to reduce pollutants, improve public health, and inspire more cities to take action.

Together, we can create healthier, thriving communities.