I have borderline severe COPD presumably from my days in the military. The chemicals and minerals we worked with could be responsible, I worked with horrible stuff up to and inducing nuclear whizz bangs.

But for most people I believe its due to the plastic microbeads in our food, these beasties are in the entire food chain from bottom to top and it seems that humanity will have these things inside us for all time.

I hope I am wrong in saying this.