Before revision: Historical observations From as early as the 1200s , air pollution became increasingly prevalent, and a predominant perception in the 13th century was that sea-coal smoke would affect one's health.Calendar of Close Rolls, 35 Ed.
After revision: Historical observations From as early as the 13th century , air pollution became increasingly prevalent, and a predominant perception in the 13th century was that sea-coal smoke would affect one's health.Calendar of Close Rolls, 35 Ed.