“If it’s not save to breathe…”: let us count the ways

Inspired by a post on facebook, I thought I’d respond to this image, which is doing the rounds:

If it's not safe to breathe...

If it’s not safe to breathe…

There are lots of reasons why it might be safe to eat something, but not to breathe it. These are all conjecture, but not fanciful:

  1. Some things are safe to ingest, but not safe to inhale. Airborne mould spores might be a good example. (Edit: A better example, suggested by David Edwards, is flour, eg, Bakers’ Asthma)
  2. Someone breathing a spray will absorb whatever is being sprayed in much greater concentration than someone who eats some of the liquid after it’s landed on a surface. You would not inhale the spray from an air freshener, but you probably wouldn’t throw away the apples just because a little of it landed on them.
  3. Inhalation is a much more direct route to the bloodstream than ingestion. Ingested substances are acted on by numerous things (saliva, stomach acid, bile, etc) before being absorbed.
  4. The substance being sprayed might be hazardous to health, but might break down into harmless substances by the time it’s harvested. This is the way some of domestic cleaning products work, which are sometimes quite harmful to aquatic life but which are designed to break down before they reach watercourses.
  5. The substance might not be absorbed into the plant, and might therefore be washed off the produce by the time it is eaten. A bit like airborne particulate pollution from burning fossil fuels.
  6. The substance might be absorbed into the plant, but not in sufficient concentration to be dangerous. A bit like green potatoes  which contain (poisonous) solanine. But not so much that using up the odd old potato will do you any harm.

There are probably more. I haven’t thought about it very much.

There are definitely serious, legitimate questions about the way modern agriculture works and how we should produce enough food to feed everyone. But pictures like this one oversimplify the issues, superficially appeal to people’s misconceptions about science and technology, and do not help to advance the debate.