You are absolutely correct @drwon because human and imagine the population breath our carbon and it shows where there's lots of carbon humans still exist but that shouldn't take the fact that other poisonous gas aint out there that's why this same humans are affected because of pollution from these toxic fumes. But what i feel is that as humans shouldn't be considered alone as living because plant needs this carbon for survival too but not the toxic ones we tend to generate one way or the other. Thanks for sharing Dr.