The line graph illustrates the nitrogen oxide emissions generated by four distinct vehicles.
Overall, it is clear that the nitrogen oxide emissions produced by buses moderately climb, while lorries’ nitrogen oxide emissions significantly decrease. It is also noticeable that petrol cars and diesel cars experience no change in their nitrogen oxide emissions.
Regarding buses, the nitrogen oxide emissions at 10 kph are the largest, at 40 g/km, before remarkably falling to around 26 g/km between 10 kph and 60 kph, which hits the bottom. Then, the figure witnesses a noticeable rise to 44 g/km at 130 kph. At 10 kph, lorries’ nitrogen oxide emissions start at 33 g/km, before dramatically declining to nearly 18 g/km. After that, the nitrogen oxide emissions emitted by lorries slightly rise to 26 g/km at 130 kph.
In terms of petrol cars and diesel cars, there are around 10 g/km and 6 g/km of nitrogen oxide emissions being emitted at 10 kph, respectively. The figure for petrol cars remained constant at nearly 10 g/km from 10 kph to 130 kph, whereas diesel cars’ nitrogen oxide emissions slightly dropped from 6 g/km to 5 g/km and remained the same all over the speed (between 10 kph and 130 kph).