Daily minimum and maximum air pollutant levels in four major cities

The bar chart illustrates the daily minimum and maximum concentrations of sulphur dioxide (SO2) and dinitrous oxide (N2O) across four major cities in the year 2000.

Overall, Mexico exhibited the most significant air pollution levels among the four cities, recording the highest figures for both pollutants. Conversely, Los Angeles and Calcutta generally maintained lower levels, although Los Angeles showed a notable disparity between its minimum and maximum dinitrous oxide readings.

Regarding sulphur dioxide, Mexico reported the highest range, with levels spanning from 80 to 200. Beijing followed with a maximum of 130, despite a relatively low minimum of 25. Calcutta showed moderate levels between 47 and 59, while Los Angeles recorded the lowest sulphur dioxide concentrations, peaking at only 10.

In terms of dinitrous oxide, Mexico again led with values between 113 and 207. Los Angeles, while having minimal sulphur dioxide, displayed a substantial range for dinitrous oxide, rising from 39 to 104. Beijing and Calcutta showed more stable, lower figures for this pollutant, with maximums of 54 and 52 respectively. Overall, the data highlights that Mexico faced the most severe air quality challenges in 2000 compared to the other three cities.