We all breathe in carbon monoxide as soon as we are outside. Already tested. So far you aren't dead from the looks of it.But, if you want to believe that these chemicals are not toxic to the body in any amounts, then be my guest to test this hypothesis.
And walking past someone who has a ciggie, sure passive smoking, but the nicotine if present in the smoke, isn't the killer part to the walker-by.
And yeh we all eat nuts/rice containing trace amounts of cyanide and still not dead.