The horizontal bar charts illustrate the daily average of low and high levels of air pollutants in four major cities in the year 2000.
Overall, Mexico City has an equal proportion of both pollutants, NO2 and SO2, in its air, which is the highest amount among other cities, while Los Angeles has the lowest amount of nitrogen dioxide and sulfur dioxide in its air.
Specifically, the maximum SO2 in Los Angeles’s air was lower than other cities, while NO2 was ten times higher than SO2 in Los Angeles. Only Calcutta was a city that never exceeded the 100-microgram limit. Beijing’s maximum SO2 was four times more than its minimum SO2.
In Mexico City, the SO2 level was 200 micrograms and the NO2 level was 207 micrograms, which is double Los Angeles’s maximum NO2 and Beijing’s maximum SO2. The minimum NO2 in Mexico City was 113 micrograms, and the minimum SO2 was 80 micrograms.