The line graph illustrates the changing pattern of London pollution rates between 1600 and 2000, expressed as micrograms per cubic metre.
Overall, there were notable shifts in pollution by sulphur dioxide and smoke in a 4-century period. Both sulphur dioxide and smoke pollution shared a similar start, at below 250 micrograms in 1580. However, the level of sulphur dioxide climbed gradually between 1650 and 1700, and reached a peak of over 750 micrograms between 1700 and 1750, remaining at the same level between 1800 and 1900, with the exception of a slight decrease between 1750 and 1800. Eventually, the proportion of sulphur dioxide pollution plunged to zero in 2000 compared to 1900. Comparatively, smoke pollution, lower than sulphur dioxide, displayed a steady upward trend between 1600 and 1800, accounting for 250 micrograms to reach a peak of almost 500 micograms between 1850 and 1900. Surprisingly, a dramatic decrease occurred between 1900 and 1950, with the pollution level plummetting to zero in 2000.
It can be understood that there was a trend towards dramatic declines in the pollution rates of sulphur dioxide and smoke in the final period, with both pollution levels initially going up from 1600 to 1900, then dropping significantly to the upcoming year 2000, at which point there were no pollutions reported at all.