What Causes Air Pollution? Common Culprits and Effects

, Staff Writer
Updated April 23, 2021
Coal-fired power plant on river in Wyoming air pollution
    Coal-fired power plant on river in Wyoming air pollution
    PhilAugustavo / E+ / Getty
    Used under Getty Images license

Air pollution is the term for the presence of pollutants in the air. It is harmful to the environment and dangerous to the people and animals who live in it. Find out what causes air pollution and learn about the effects of air pollution.

What Causes Air Pollution?

Any substance that causes harmful effects when introduced to the environment is a pollutant. Many different types of pollutants can cause air to become polluted. They can be organized into four general categories.

Vehicles That Use Fossil Fuels

Vehicles that operate on any kind of fossil fuels are a major source of air pollution. Examples of mobile sources of air pollution include cars, trucks, vans, motorcycles, boats, airplanes, and trains. These mobile sources of air pollution all use gas, diesel or coal as a source of power. Burning these substances produces a significant amount of air pollution. Air pollution from these sources accounts for over half of the air pollution in the United States of America.


Industrial Sources

Vehicles aren't the only source of air pollution related to fossil fuel usage. Fossil fuels, in the form of petroleum and coal, are commonly burned in the daily operation of power plants, manufacturing facilities, oil refineries, and other industrial operations. These are referred to as stationary sources of air pollution. When a particular industrial location emits a large number of pollutants, it is referred to as a point source for pollution.

Area Sources

In the context of air pollution, area sources refers to locations where small amounts of air pollution are generated. It includes cities, non-urban residential areas, farms, light industrial businesses, and non-industrial companies. This term is also used to describe products and processes that produce pollutants, such as paint, household products, adhesives, aerosol cans, pesticides, and more. There usually isn't a lot of pollution associated with area sources when considered individually, but their emissions can add up when considered in aggregate.


Natural Sources

Catastrophic natural events that cause pollutants to be spewed into the air can also be sources of air pollution. Volcano eruptions and forest fires are examples of these types of events. They can have a significant impact on air quality, though the effects are usually short-lived. So, while problematic, these sources of air pollution don't lead to long-term, ongoing air pollution.

Ways Air Pollution Can Affect People

Air pollution is known to cause serious health problems for people.

  • irritation to the skin, nose, eyes, or throat
  • respiratory illnesses such as bronchitis, pneumonia or emphysema
  • other types of serious illness, including heart disease and cancer
  • damage to vital organs such as the kidneys and brain

How Air Pollution Impacts the Environment

Air pollution can also have significant harmful effects on the environment.

  • returns to the ground by falling, then pollute land and water
  • forms acid rain (occurs when sulfur dioxide and nitrogen oxide combine with water and oxygen)
  • contributes to global warming
  • negatively impacts wildlife (birth defects, diseases and reduced birth rates)

Examples of Air Pollution

Air pollution is a significant problem anywhere it occurs. Review a few examples of places identified as having among the most polluted air.

  • The country of Bangladesh has higher levels of air pollution than any other country in the world. In the capital city of Dhaka, the concentration of lead in the air is more than ten times higher than what is considered acceptable. Air pollution is responsible for nearly 200,00 deaths each year in Bangladesh.
  • In 2020, Hotan, China had a higher level of air pollution than any other city in the world. The air is so polluted there that people are encouraged to avoid all outdoor exercise and wear a mask outdoors at all times. Residents are encouraged to keep their windows closed and to run an air purifier at home.
  • India is home to 21 of the top 30 cities in the world with the highest levels of air pollution. In a single year (2019), more than 1.6 million deaths in India were directly attributable to air pollution.
  • According to the American Lung Association, the top three metropolitan areas for air pollution in the United States are in California. They include the Fresno, Bakersfield and San Francisco metropolitan areas. Statewide air quality monitoring indicates that around 90% of California's residents breathe in some measure of unhealthy pollutants each year.

Learn About Other Types of Pollution

Air pollution is just one of several types of pollution. Now that you have learned about it, take some time to explore a few other types of pollution. Start with water pollution. Then, move on to studying land pollution. You'll be much more knowledgeable about environmental science once you become familiar with all of these types of pollution.