• Question: why can't we breath carbon dioxide?

    Asked by to Anna, Chris, Jane, Iain, Nick on 14 Mar 2014. This question was also asked by .
    • Photo: Iain Moal

      Iain Moal answered on 14 Mar 2014:

      Carbon dioxide makes up less than one thousanth of the air that we breath, but we do breath it in all the time. At this level, it is perfectly safe for us. At higher concentrations, however, it can be toxic to us, because when it dissolved in our blood it can form carbonic acid, and acidic blood is not a good thing. In fact, we make carbon dioxide naturally as part of the respiration reaction, and the very reason we breath is to get oxygen into our bodies and carry carbon dioxide out.

    • Photo: Chris Cole

      Chris Cole answered on 14 Mar 2014:

      Carbon dioxide is toxic to our bodies. It’s as simple as that.

      We need oxygen as it used in important chemical reactions in our bodies which allow us to live.

    • Photo: Anna Middleton

      Anna Middleton answered on 17 Mar 2014:

      Hi jamestheboss
      I guess the basic reason why we can’t breath carbon dioxide is because we never needed to. It is evolution that brought us to adapting to our environment. Our environment consists of air and the components of that. If carbon dioxide was the main component of air (which it isn’t) then, in theory, whatever species were in existence then would have evolved an ability to breath it .

    • Photo: Jane Charlesworth

      Jane Charlesworth answered on 19 Mar 2014:

      We do breathe in carbon dioxide a little bit, because there is carbon dioxide present in air. But we mostly don’t breathe it in because our cells rely on oxygen, not carbon dioxide to carry out all the functions we need to do to live. We actually produce carbon dioxide as a waste product when our cells extract energy from sugar (respiration) and we get rid of it by exhaling.

      You might ask why our bodies haven’t evolved to be able to extract the oxygen atoms from a carbon dioxide molecule and the answer to that is that we don’t need to because there is a plentiful supply of oxygen in the air we breathe.

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