The graph compares the amount of air pollutants among 4 cities in 2000 through the average minimum and maximum figure in a day. It is measured by unit micrograms per a cubic meter.
Overall, Mexico city is likely to be the most polluted among 4 cities as the levels of air pollutants are always the greatest. In addition, while minimum and maximum levels of SO2 respectively are higher than that of N2O in Calcutta and Beijing, the opposite was true for Los Angeles and Mexico city.
Beginning with two big cities in Asia, while the amount of SO2 per a cubic meter is between 47 and 59 in Calcutta, the range of SO2 in Beijing is wider significantly with the highest being 100 which is 4 times greater than the lowest. In addition, Calcutta and Beijing has a proximate figure of max N2O with 52 and 54, respectively, while Calcutta is double greater than Beijing which is 14 microgram per a cubic meter.
Regarding two big cities in North Africa, while the figure in aspects of air pollutant in Mexico city are certainly higher than others with the greatest SO2 being 200, Los Angeles is the lowest. However, Los Angeles is the second greatest N2O which is only lower than Mexico city with more than 200.