Back in Ancient Times, in the 1960s, we were taught about air pollution and how pollutants inhaled into the lungs can cause severe respiratory disease and horrible death.
In 5th grade, I remember students figuring out (back when 2+2=4) that smoke--any kind of smoke--is a pollutant, and so therefore any smoke inhaled into the lungs can be deadly. It's quite elementary.
"In the 1960s, an environmental movement began to emerge that sought to stem the tide of pollutants flowing into the planet's ecosystems. Out of this movement came events like Earth Day, and legislative victories like the Clean Air Act (1970) and the Clean Water Act (1972).....
...In 1963, in an effort to reduce air pollution, the U.S. Congress passed the Clean Air Act, legislation which has been amended and strengthened in the ensuing decades."
Water and Air Pollution — History.com Articles, Video, Pictures and Facts