Nepedia
Back to Discover
Advanced Reader
🌍

Air pollution

earth science Maturity 9-11 climate Next article →

This article covers sensitive topics: climate. Parents can manage visibility in Parental Controls.

Air pollution is the presence of substances in the air that harm humans, living beings, or the environment.

Air Pollution-Causes&Effects
Air Pollution-Causes&Effects

These substances, known as pollutants, can take several forms. They may be gases, such as ozone or nitrogen oxides. They can also be tiny solid or liquid particles called aerosols.

Portrait of Global Aerosols
Portrait of Global Aerosols

Pollution occurs both outdoors and indoors. Outdoor pollution often stems from industrial processes and transport. Indoor pollution frequently comes from household activities like cooking or heating. This issue is a major global challenge because it affects health, nature, and the economy.

Pollutants are classified by how they enter the atmosphere. Primary pollutants are produced directly by a source. Examples include carbon monoxide from car exhausts or sulfur dioxide from factories.

Air pollution by industrial chimneys
Air pollution by industrial chimneys

Secondary pollutants are not emitted directly from a source. Instead, they form in the air when primary pollutants react with each other or with other parts of the atmosphere. Ground-level ozone is a common secondary pollutant. It forms when nitrogen oxides and volatile organic compounds mix in the presence of sunlight.

SMOG-DAMAGED PLANT AT THE STATEWIDE AIR POLLUTION RESEARCH CENTER, UNIVERSITY OF CALIFORNIA. PLANT - NARA - 542686
SMOG-DAMAGED PLANT AT THE STATEWIDE AIR POLLUTION RESEARCH CENTER, UNIVERSITY OF CALIFORNIA. PLANT - NARA - 542686

This process often creates photochemical smog in large cities.

Pollution de l'air
Pollution de l'air

There are many distinct sources of air pollution. Transportation is a major contributor, especially road vehicles. These vehicles produce nitrogen dioxide and other emissions. Petrol and diesel engines release about half of their pollutants through exhaust gas. The other half comes from non-exhaust emissions like tire and brake wear.

Electric Rickshaws
Electric Rickshaws

Industry and construction also release significant amounts of dust and gases. For example, cement production is a major source of particle pollution. Agriculture is another massive source. Cattle emit methane during digestion, which contributes to ground-level ozone.

BurningOffFieldsInTheEveningInSouthGeorgia
BurningOffFieldsInTheEveningInSouthGeorgia

Additionally, the overuse of nitrogen fertilizers releases ammonia. Ammonia can react with other pollutants to form fine particulate matter.

Indoor air pollution is a specific and serious concern. As of 2023, over 2.3 billion people in developing countries rely on polluting fuels. These include firewood, agricultural waste, coal, or charcoal for cooking.

Fish smoking in Ghana
Fish smoking in Ghana

This type of pollution is particularly dangerous for women and young children. In some developed nations, wood stoves are a primary source of urban particulate pollution. Other indoor risks include biological materials like mold and pollen, or fumes from cleaning products. Even building materials can be a source, as some emit formaldehyde.

Natural events can also significantly impact air quality. Volcanic eruptions release sulfur dioxide and particle pollution into the sky.

Air pollution by industrial chimneys
Air pollution by industrial chimneys

Dust storms can carry pollution over vast distances. For instance, dust from the Gobi Desert can reach Hawaii. Wildfires are another major natural source of fine particles. These fires are becoming more common and severe due to climate change. Even vegetation plays a role, as certain trees emit gases that can raise ozone levels.

The consequences of air pollution are vast and measurable. It is a significant risk factor for diseases like asthma, heart disease, stroke, and lung cancer.

How-many-people-die-from-air-pollution-1-1
How-many-people-die-from-air-pollution-1-1

Particulate matter is considered the most deadly type of pollutant. Each year, air pollution kills between 7 and 8 million people. This has a massive economic impact as well. The World Bank estimates that premature deaths and lost productivity cost the global economy over $8 trillion annually.

Share of deaths from indoor air pollution, OWID
Share of deaths from indoor air pollution, OWID

Beyond humans, pollution damages ecosystems. Acid rain, caused by sulfur dioxide, can damage forests and erode structures.

Pollution - Damaged by acid rain
Pollution - Damaged by acid rain

History shows that laws and technology can help manage these risks. The 1956 Clean Air Act in Britain and the 1963 US Clean Air Act were effective national responses.

DARK CLOUDS OF FACTORY SMOKE OBSCURE CLARK AVENUE BRIDGE - NARA - 550179
DARK CLOUDS OF FACTORY SMOKE OBSCURE CLARK AVENUE BRIDGE - NARA - 550179

On an international level, the Montreal Protocol successfully helped almost eliminate ozone-depleting chemicals.

Today, many strategies aim to reduce pollution. These include using electric vehicles, renewable energy, and industrial scrubbers. Improved waste management and clean cookers also help protect the air we breathe.

607 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (26)
File:Athlone cooling towers demolition 2010-08-22.gif
Athlone cooling towers demolition 2010-08-22.gif
File:Air pollution by industrial chimneys.jpg
Air pollution by industrial chimneys.jpg
File:BurningOffFieldsInTheEveningInSouthGeorgia.jpg
BurningOffFieldsInTheEveningInSouthGeorgia.jpg
File:Agbogbloshie,_Ghana_2019.jpg
Agbogbloshie,_Ghana_2019.jpg
File:Fish smoking in Ghana.jpg
Fish smoking in Ghana.jpg
File:Dust storm approaching Stratford, Texas.jpg
Dust storm approaching Stratford, Texas.jpg
File:Air Pollution-Causes&Effects.svg
Air Pollution-Causes&Effects.svg
File:SMOG-DAMAGED PLANT AT THE STATEWIDE AIR POLLUTION RESEARCH CENTER, UNIVERSITY OF CALIFORNIA. PLANT - NARA - 542686.jpg
SMOG-DAMAGED PLANT AT THE STATEWIDE AIR...
NASA - Human Fingerprint on Global Air...
File:Pollution de l'air.jpg
Pollution de l'air.jpg
File:Air Quality (PM 2.5) Regional Overview.svg
Air Quality (PM 2.5) Regional Overview.svg
File:Share-above-who-pollution-guidelines (OWID 0948).png
Share-above-who-pollution-guidelines...

+ 14 more

More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.