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Learn about outdoor air and pollution

What is in the air we breathe?

Air is the name for the mixture of gases that surround the Earth. It is what we breathe into and out of our lungs everyday.

It is made up mostly of nitrogen and some oxygen. It also has small amounts of other gases including carbon dioxide (CO2) and water vapor. 

The air is approximately 78 percent nitrogen and 21 percent oxygen.

What is outdoor air pollution? 

Pollution is the introduction of harmful materials into the environment. 

Air pollution is, then, the presence of substances above the natural level in the air. Polluted air can often be harmful to the environment and to humans. 

What is the Carbon cycle?

The Earth’s atmosphere (the air on our planet) is amazing. The gases are part of near-perfect cycles. One of these is known as the carbon cycle.

As part of the carbon cycle, plants can convert carbon dioxide (CO2) in the air into sugar. This is known as photosynthesis. CO2 can also be locked up in sedimentary rocks, dissolved in the oceans, or absorbed by plants.


The burning of fossil fuels (such as oil and gas) creates more carbon dioxide in the air, faster than it can be removed naturally. Human intervention, the things we do as humans, can affect the natural environmental cycles.

How can we positively and negatively impact our air?

There are so many things that can affect the air on our planet both in a good way and a bad way. Can you guess what is the best thing? Here’s a hint. They grow outside and have green leaves. 

Positive ways we can impact our air 

  • Trees help to stop air pollution directly
    Trees are incredible! They clean the air. Trees remove carbon dioxide (CO2) through photosynthesis. Trees can also reduce other air pollutants such as nitrogen dioxide (NO2) and particulate matter (PM). They do this in the process of photosynthesis.

  • Trees help to stop air pollution indirectly
    Trees create shade and therefore help to keep an area cool. Because it is cooler in the shaded area, there is less need for air conditioning units, meaning less electricity is used. This reduces the amount of greenhouse gases used.
  • Less fossil fuel, more renewable energy
    Using renewable energy such as solar power, wind power or hydropower is better for the environment, including our air! The burning of fossil fuels, such as coal, petroleum, natural gas and oil, release carbon dioxide (CO2) and other greenhouse gases into the air. 
  • Biking to work, taking public transport
    68% of the whole of the United States petroleum usage (a fossil fuel) is used in transportation such as driving a car. The burning of fossil fuels to power cars is bad for the environment. By biking to work or using public transport, we can reduce how much fossil fuels are used to power transportation. This is better for the environment.

Negative ways we can impact our air 

  • Using energy made from fossil fuels
    When fossil fuels are burned, they release carbon dioxide and other greenhouse gases. This is bad for the environment. Greenhouse gases trap heat in our atmosphere. This makes them huge contributors to global warming and climate change.
  • Methane from cattle
    Methane is a colorless, odorless gas which is produced by many things, including cows as they digest food. A huge 50-65% of total methane (CH4) emissions come from human activities, as we mass produce cows for food amongst other things. Methane affects our environment negatively as it traps heat in the atmosphere, contributing to global warming.
  • Forest fires
    Unfortunately, forest fires are more common because of global warming. As global warming increases the Earth’s temperature, this causes longer droughts and dries out the forests. They can catch fire more easily, and burn for longer. 
  • Volcanoes
    When a volcano erupts it releases carbon dioxide (CO2) into the atmosphere. However, volcanoes only release 2% of CO2 from all human activities, which is quite small in comparison. Sometimes however, huge volcanoes (such as Mount Pinatubo) can erupt which will create a huge amount of particles and other gases being released into the atmosphere. 
Sources
  1. https://www.britannica.com/science/air
  2. https://climatekids.nasa.gov/10-things-air/#:~:text=So%20what%20is%20air%2C%20exactly,dioxide%2C%20neon%2C%20and%20hydrogen.
  3. https://www.nationalgeographic.org/encyclopedia/pollution
  4. https://www.ncbi.nlm.nih.gov/books/NBK368034/
  5. https://www.who.int/health-topics/air-pollution#tab=tab_1
  6. https://edu.rsc.org/feature/how-do-trees-clean-our-air/4010864.article
  7. https://www.eia.gov/energyexplained/oil-and-petroleum-products/use-of-oil.php
  8. https://www.nationalgeographic.com/environment/energy/reference/fossil-fuels/#:~:text=When%20fossil%20fuels%20are%20burned,global%20warming%20and%20climate%20change.
  9. https://www.epa.gov/ghgemissions/overview-greenhouse-gases#methane
  10. https://climate.nasa.gov/faq/42/what-do-volcanoes-have-to-do-with-climate-change/