Pollution is, by definition, the contamination of a resource (water, air, soil) with something that is or could be, toxic in effect. Air pollution by that definition is the contamination of our atmosphere with substances that have a negative effect on humans, ecosystems as well as the built environment.
The earliest manifestations of air pollution were probably smoke from burning poor quality coal used for heating in Northern Europe. High concentrations of sulphur dioxide (SO2) and particles, which by inhalation can have serious health impacts, lead to legislation against excessive smoke introduced as early as in the 13th and 14th centuries by Parliamentary Acts in England.
The Industrial Revolution introduced more numerous and larger sources of emissions from various processes, most importantly the burning of coal for energy production. Due to these emission sources, atmospheric levels of pollutants could rise drastically, particularly during temperature inversions under stable high pressure systems over large cities – as was the case during the ‘Great Smog’ in London in 1952. This prompted more strict legislation, starting the modern history of air quality management.