--- title: "What gas do humans breathe out when they exhale?" description: "What gas do humans breathe out when they exhale?" author: "Baishakhi Ghosh" published: 2023-09-22 updated: 2023-11-27 canonical: https://answers.mindstick.com/qa/100587/what-gas-do-humans-breathe-out-when-they-exhale category: "general knowledge" tags: ["general knowledge"] reading_time: 1 minute --- # What gas do humans breathe out when they exhale? ## Answers ### Answer by Saumya Mishra When [breathing](https://www.mindstick.com/blog/299751/what-causes-breathing-problems) out, man exhales [carbon dioxide](https://yourviews.mindstick.com/view/tags/carbon-dioxide). CO2 is a waste [product](https://www.mindstick.com/articles/324746/promotion-of-product-and-services) made by the cells in the body when they burn food to produce energy. The body’s blood carries CO2 to the [lungs](https://www.mindstick.com/blog/299507/the-effects-of-air-pollution-your-lungs) where it is exchanged for oxygen from the air that we inhale through breathes. **Carbon dioxidе (CO2) gas molеculе** The composition of exhaled air is not the same as that of inhaled air. The exhaled air comprises about four percent carbon dioxide while the inhaled air comprises roughly **0.04% carbon dioxide**. Exhausted air includes about **fifteen percent** [**oxygen**](https://www.mindstick.com/blog/301144/how-to-choose-the-right-oxygen-concentrator) while inspired air includes just around **twenty-one percent of oxygen**. The number of breaths we do depends on different factors which include level of activity, metabolism, and overall health. During [exercise](https://www.mindstick.com/articles/332292/why-exercise-is-the-top-treatment-for-anxiety-and-depression), our bodies produce more CO{2} than when resting. People who have some medical diseases such as asthma and COPD may have even more CO2. CO2 is a greenhouse gas and it traps heat within the [atmosphere](https://www.mindstick.com/news/2058/robin-wordsworth-re-creates-the-atmosphere-of-ancient-mars). It can also [contribute](https://www.mindstick.com/news/2332/japan-will-contribute-500-million-to-the-startup-rapidus-for-manufacturing-processors) to [global warming](https://www.mindstick.com/news/1871/artic-ocean-has-been-warming-four-times-quicker-than-the-rest-of-the-world) and subsequent [climate change](https://www.mindstick.com/articles/333790/africa-s-first-carbon-removal-plant-can-be-the-solution-of-climate-change). However, CO2 is naturally present in the earth’s atmosphere, and plants need it for photosynthesis. --- Original Source: https://answers.mindstick.com/qa/100587/what-gas-do-humans-breathe-out-when-they-exhale Copyright © MindStick Software Pvt. Ltd. This Markdown version is provided for developers, AI systems, and offline reading.