The provided line graph illustrates the amount of nitrogen oxide emissions, being released by a means of vehicles namely buses, lorries, petrol car and diesel car, was measured by speed.
Overall, there was a difference trend in four various vehicles. As can be easily to see that buses which always had a dominant sector in the production of emissions, experienced an upward trend, compared to the figures for lorries and others with a decrease in the former and no change in the latter, ignoring how the speed, respectively.
At 10kph, buses released about 40 g/km while just 35 g/km in that of lorries. Afterwards, the figure for buses’s nitrogen oxide emissions witnessed a sharp drop by around 15 g/km before surging to the maximum level at nearly 45g/km. By contrast, there was a slump constantly in that of lorries from 33 g/km to under 20 g/km at 90 kph and then, the amount of emissions was magnifactured by lorries started to rise by 7 g/km at the last speed.
An opposite trend can be seen in others, there was a remain constant in two kinds of car, including: petrol and diesel cars. Regarding petrol car, this vehicle magnufactured a much higher amount of emissions than diesel car by twofold, at about 10 g/km. During the speed, between 10kph and 130 kph, the quantity of emissions was produced by diesel car always kept the lowest level with a mere 5 g/km.