It's still poison. Check msds.
Just because there is already poison in the air, doesn't mean people can't put more poison in the air.
Just because the poison doesn't kill everyone, doesn't mean it isn't poison.
That's a perspective one can have, for sure. Something that's like 10 orders of magnitude below the known hazard level is not something anyone should raise alarms about to the general public though. Otherwise you'd have to go around policing every little bird that's exhaling CO₂, etc.
acidburnNSA|4 years ago