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What is air pollution – and why is it dangerous?

Air pollution is a mixture of chemicals, particles and other materials in the air in amounts that could damage the environment or harm the health or comfort of humans, animals and plants.

If you already have lung disease or a heart problem, air pollution makes it worse. Air pollution has also been linked to certain cancers.

Outdoor air pollution

The air outside gets polluted in many ways. Sometimes the pollution comes from natural sources, such as forest fires and volcanoes. But more often, people create pollution through activities that send harmful substances into the air. These activities include:

  • running gasoline and diesel engines
  • generating power (such as smoke from coal-burning power plants)
  • industrial manufacturing
  • agricultural processes (such as managing soil or raising animals)
  • home heating and cooking

Air pollution in your community can be affected by:

  • some types of local businesses
  • local traffic patterns (vehicle type and how heavy traffic is)
  • whether you live in an urban or rural location
  • geography (valleys versus plains)
  • weather patterns (especially wind direction)

Indoor air pollution

Air inside your home can also be polluted. Major sources of indoor air pollution include:

  • second-hand smoke
  • radon from the ground
  • indoor burning of coal or wood
  • chemicals from paint or cleaning products
  • biological pollutants that come from living organisms (mould or dust mites)

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