The line graph compares the two pollutant levels measured in micrograms per cubic meter in London, from the year 1600 to 2000.
Overall, both the pollutants, sulphur dioxide and smoke show similar patterns and trends throughout the timestamp. However, the amount of sulphur dioxide is comparatively much more than that caused by the smoke.
From 1600 till somewhere around 1730, the amount of pollution caused due to sulphur dioxide steadily increased, merely above 750 micrograms per cubic meter. It later dropped from this level and plateaued for the next 50 years. The level of pollution by this method then moderately saw an upturn reaching over 800. At the same time, pollution because of smoke surged gradually during this period, reaching at a figure slightly below 500.
After this period, both the forms of pollution saw similar fluctuations in their levels, however, the pattern in smoke is more significantly clear. Starting from 1920, smoke started with up and down trend which was followed by sulphur dioxide in 1930, after touching 500. These pollutants then sank to 0 just before the year 2000.