That is a great question, one I had not considered and can not answer. I will have to research it more but in an attempt to find an answer I did stumble upon an article stating that Aloe does improve the supply of oxygen and absorbs formaldehyde, carbon dioxide, and carbon monoxide. According to Earthship., one pot of aloe is equivalent to nine biological air cleaners.
I also would not want to use Aloe from a plant that may contain these toxins, I am wondering do these toxins convert to clean air which the plant "breathes" back into the environment or does the plant become a containment for the toxins.
Ok came back to edit/add to this post rather than start a new post. it seems that YES the toxins are stored in the Aloe plant and that those who grow their own Aloe to use for consumption are consuming the toxins as well. It is recommend that any Aloe grown for consumption be grown in a lead free , pollutant free environment without any pesticides used in the cultivation. Make sure the Aloe is one of the three specific medicinal types of Aloe and is at least three years of age before harvesting leaves for use.