The bar chart compares how much air pollutants, namely SO2 and NO2, were recorded on a daily basis in four particular cities in the year 2000.
Overall, while N2O was a dominant pollutant in Los Angeles, that in Beijing was SO2. It is worth noticing that Mexico was the most polluted city among the four, and Calcutta showed the level of these pollutants approximately the same.
In Mexico, the lowest SO2 density was registered at 80 micrograms per m3, which was 33 lower than its minimum N2O counterpart. However, the maximum level of these two pollutants in this city was nearly similar, hovering around 200 micrograms per m3. In addition to this, although the minimum pollutant density of SO2 in Calcutta outnumbered that of N2O, with the respective figures being 47 and 30 micrograms per m3, their contributions at the maximum level did not demonstrate a large disparity, with the difference being only 7 micrograms per m3.
The other two countries, Los Angeles and Beijing, recorded their major pollutants differently. The highest N2O densities in the former were 104 micrograms per m3, tripling its minimum level, whereas the N2O level at this city reached its maximum value of just 10 microgram per m3. However, a reverse place was witnessed in Beijing. Whilst the minimum levels for SO2 and N2O were 25 and 14 micrograms per m3, respectively, their maximum values for these pollutants was fourfold their minimum counterpart.