Are these enivronmental myths?

Quite the opposite. The real nasties in cigarette smoke are caused by the temperature of the burn. A drawn cigarette burns at some ridiculous temperature, akin to an oxy-acetylene welding torch IIRC. This temperature volatilises a lot of substances that will never get airborne in a normal fire. It also produces a lot of compounds never produced in a normal fire, including a lot of partially oxidised species that are potent oxidising agents themselves. All this gunk goes straight into the lung.

OTOH a smouldering cigarette is just a very low temperature fire. It doesn’t produce anything unusual.