What Gas Do Green Plants Give Off?


Humans and plants live in a symbiotic relationship, where humans breathe oxygen and plants produce it as a byproduct of photosynthesis. At the same time, humans produce carbon dioxide as byproduct of breathing and plants use carbon dioxide in photosynthesis.

All plant life produces oxygen as part of photosynthesis. image by "Shelter" is Copyrighted by Flickr user: Richard0 (RICHARD OUTRAM) under the Creative Commons Attribution license.


Photosynthesis is the process plants use to synthesize food from carbon dioxide and water. Sunlight is used as a energy source. Photosynthesis releases oxygen as a byproduct.

Peak Production

According to blueplanetbiomes.org, the most favorable temperature for photosynthesis to occur is between 70 to 80 degrees F.


A single mature tree produces 260 pounds of oxygen each year, which is enough for two people annually. A single tree uses 48 pounds of carbon dioxide every year.


Leaves produce 5 ml of oxygen per hour. How much each individual plant produces depends on how many leaves it possesses. A single-leaf plant produces 43,800 ml or 43.8 L of oxygen in a year.

Plant Species

An estimated 230,000 plant species exist on earth. Of these, 23,000 are trees. The remaining 207,000 plant species include flowers, scrubs and grasses.


  • Blue Plant Biomes
  • Tree Facts
  • Plants Making Oxygen

Who Can Help

  • Photosynthesis
  • Other Tree Facts
  • Amazing Tree Facts
Keywords: trees, photosynthesis, oxygen

About this Author

Armed with a Bachelor of Arts in English from East Stroudsburg University, Amy Gouger quit her job as a technical agent in 2009 to embark on her dream of writing full-time. She's served as a ghostwriter and contributed to a number of online outlets including USAToday.com.