Air pollution: know your enemy - BreatheLife 2030
Network Updates / Nairobi, Kenya / 2018-09-13

Air pollution: know your enemy:

What air pollution actually does and how you can fight the world's top environmental health problem

Nairobi, Kenya
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Sometimes you can’t even see it, but air pollution is everywhere.

Perhaps you think that air pollution doesn’t affect you because you don’t live in a city shrouded in smog. You are most likely wrong. Statistically, nine out of ten people worldwide are exposed to levels of air pollutants that exceed World Health Organization safe levels.

This means that with every breath, you are sucking in tiny particles that attack your lungs, heart and brain. For millions of people across the globe, this is causing a host of problems – illness, lower IQs and death chief among them.

We can’t stop breathing. But we can do something about the quality of our air, and global action is growing at all levels. To have any chance of truly clearing the air, however, we need to know our enemy better and what we can do to defeat it.

What is air pollution and where does it come from?

Air pollution is broken down into ambient (outdoor) air pollution and indoor air pollution. This pollution comes from many sources, the majority of them a result of human activity:

• the burning of fossil fuels, such as coal to generate electricity for homes and businesses, or petrol and diesel to power our cars, buses, ships and planes
• industrial processes, particularly from the chemical and mining industries
• agriculture, which is a major source of methane and ammonia
• waste treatment and management, particularly landfills
• dirty indoor cooking and heating systems, a major problem in the developing world
• volcanic eruptions, dust storms and other natural processes

These sources spew out a range of substances including carbon monoxide, carbon dioxide, nitrogen dioxide, nitrogen oxide, ground level ozone, particulate matter, sulphur dioxide, hydrocarbons and lead – all of which are harmful to human health.

Deaths and illnesses from air pollution are largely down to tiny, invisible airborne particles, known as particulate matter, which can be as small as a molecule. These particles are clumps of poison, containing anything from black carbon (soot), to sulphates to lead. The smallest particles are the deadliest: PM2.5 particles, which are 2.5 microns or less in diameter, and PM10, which are 10 microns or less in diameter. These tiny killers bypass your body’s defences and lodge in your lungs, bloodstream and brain.

How much of this pollution we breathe in is dependent on many factors, such as access to clean energy for cooking and heating, the time of day and the weather. Rush hour is an obvious source of local pollution, but air pollution can travel long distances, sometimes across continents on international weather patterns. Nobody is safe.

What is air pollution doing to us?

Air pollution has been called a major global health epidemic, causing one in nine of all deaths. It also has massive negative impacts on climate change and economies.


In 2016, PM2.5 exposure reduced average global life expectancy at birth by approximately one year.

Around seven million people die each year from exposure to polluted air, both indoor and outdoor. The three biggest killers attributable to air pollution are stroke (2.2 million deaths), heart disease (2.0 million) and lung disease and cancer (1.7 million deaths).

Ambient (outdoor) air pollution accounts for:

• 25 per cent of all deaths and disease from lung cancer
• 17 per cent of all deaths and disease from acute lower respiratory infection
• 16 per cent of all deaths from stroke
• 15 per cent of all deaths and disease from ischaemic heart disease
• 8 per cent of all deaths and disease from chronic obstructive pulmonary disease

Air pollution doesn’t just kill, however. It also contributes to other illnesses, hampers development and causes mental health problems.

One study found that ambient PM2.5 contributed to 3.2 million cases of diabetes in 2016.

Research from the United Nations Children’s Fund (UNICEF) shows that breathing in particulate air pollution can damage brain tissue and undermine cognitive development in young children – with lifelong implications. An estimated 17 million babies under one year old live in areas where air pollution is six times higher than safe limits.

Other studies have linked air pollution to lower intelligence levels, with the average impact equivalent to one lost year of education, and to an increased risk of dementia, with those living closest to major traffic arteries up to 12 per cent more likely to be diagnosed with the condition.

A photo of people wearing respiratory masks during smog in Beijing, China. Photo by Reuters


If you are lucky enough to not suffer the negative health impacts of air pollution, it can still hit you in the pocket. Air pollution creates a burden on healthcare systems, which costs taxpayers money.

Air pollution from energy production in the U.S. caused at least US$131 billion in damage to its economy, including increased healthcare costs, in 2011.

One Oxford University study found that air pollution from cars and vans cost society 6 billion pounds per year.

The European Environment Agency found that emissions from 14,000 industrial facilities in Europe cost society and the economy up to 189 billion euros in 2012.

Without action, the costs will rise. A study by the Organisation for Economic Co-operation and Development showed that the annual global welfare costs of premature deaths from outdoor air pollution are projected to be US$18-25 trillion in 2060. In addition, the costs of pain and suffering from illness are estimated at around US$2.2 trillion by 2060.


Air pollution doesn’t just impact human health and economic growth. Many of the pollutants also cause global warming. Take black carbon, which is produced by diesel engines, burning trash and dirty cookstoves. Black carbon is deadly, but it is also a short-lived climate pollutant. If we were to reduce the emissions of such pollutants, we could slow global warming by up to 0.5°C over the next few decades.

Methane, a large percentage of which comes from agriculture, is another culprit. Methane emissions contribute to ground-level ozone, which causes asthma and other respiratory illnesses. It is also a more potent global warming gas than carbon dioxide – its impact is 34 times greater over a 100-year period, according to the International Panel on Climate Change.

Where is air pollution worst?

Air pollution is a problem across the globe, but it disproportionately affects people living in developing nations. For example, the 3.8 million people who die each year from indoor air pollution are overwhelmingly from countries where people living in poverty are forced to cook, or heat their homes, with dirty fuels in poorly ventilated indoor spaces.

According to the World Health Organization’s air quality database97 per cent of cities in low- and middle-income countries with more than 100,000 inhabitants do not meet air quality guidelines. In high-income countries, the proportion is 40 per cent.

Delhi, India and Cairo, Egypt have the worst PM10 pollution levels out of the world’s megacities (over 14 million people), but Argentina, Brazil, China, Mexico and Turkey all have cities in the top-ten list of most-polluted places.

You can find out how your city is doing here.


What is being done about air pollution?

A global movement to address air pollution is growing. BreatheLife – a global network headed by the Climate and Clean Air Coalition, the World Health Organization and UN Environment – is running cleaner air initiatives that cover 39 cities, regions, and countries, reaching over 80 million citizens.

By instituting policies and programmes to curb transport and energy emissions and to promote the use of clean energy, cities are proving to be focal points where change that improves the lives of the most people possible is happening. From Accra to Mexico City, local governments are implementing plans to improve air quality. And change is happening. The World Health Organization in 2018 found that more than 57 per cent of cities in the Americas and more than 61 per cent of cities in Europe had seen a fall in PM10 and PM2.5 particulate matter between 2010 and 2016.

The rise of renewable energy is also set to make a big difference, with investment in new renewable sources outstripping fossil fuel investments each year.

What can I do?

We are all part of the problem. Business, public buildings and households account for around half of all PM2.5 and carbon monoxide emissions. But this means we are all part of the solution. By making small changes to our lives, we can all play our part in clearing the air.

For instance, by reducing consumption of meat and dairy products, individuals can contribute to cutting harmful methane emissions. There is a wide range of other areas where people can make a difference when it comes to reducing air pollution.

Manage waste

Compost food and garden items. Recycle non-organic trash if available. Reuse grocery bags and dispose of remaining trash by local collection. Never burn trash, as this contributes directly to air pollution.

Cook and heat clean

Burning coal and biomass (e.g. wood) contributes to indoor air pollution when used for cooking and outdoor air pollution when used for heating. Check efficiency ratings for home heating systems and cookstoves to use models that save money and protect health.

Move mindfully

Use public transportation, cycle or walk. Consider switching to a hybrid or electric if you must drive. Diesel vehicles, particularly older ones, are large contributors of black carbon, which are carcinogenic for health and damaging to our climate.

Rethink your energy use

Turn off lights and electronics not in use. Use energy-efficient equipment. Rooftop solar panels may be an option to generate hot water and power.

Call for change

Call on local leaders to adopt national air quality standards that meet WHO guidelines. Support policies that strengthen emissions standards and provide incentives for purchase of cleaner vehicles, low-energy appliances and energy-efficient housing.

Watch our short animations for more information: 

>I don’t drive during rush hour

>I walk to work

>I drive an electric vehicle

>I compost my waste

>I recycle my waste

>I don’t burn waste

>I use renewable energy to power my home

>I use clean energy to cook

>I check my air pollution levels

>I turn off lights and electronics not in use

This article originally appeared here on the UN Environment website. 

These videos and more are available in the BreatheLife Video Library

Banner photo by CIFOR, CC BY-NC-ND 2.0