The line graph depicts the nitrogen oxide emissions of four distinct vehicle types—petrol cars, diesel cars, buses, and lorries—across various speeds ranging from 10 kph to 130 kph.
Overall, the nitrogen oxide emission trends vary between vehicle types, with buses and lorries displaying fluctuations as speed increases, while petrol and diesel cars maintain relatively stable emissions across all speeds.
The nitrogen oxide emissions from buses begin at 40 g/km at 10 kph, then decline significantly to 25 g/km at 60 kph. Subsequently, they rise again to nearly 45 g/km at 130 kph. Lorry emissions start at 33 g/km at 10 kph, then decrease to approximately 17 g/km at 90 kph before experiencing a sharp increase to 25 g/km at the highest speed of 130 kph.
Conversely, petrol and diesel cars exhibit consistent nitrogen oxide emissions throughout the assessed speeds. The petrol car emits 10 g/km, whereas the diesel car emits a lower 6 g/km.
In summary, the line graph reveals considerable variations in nitrogen oxide emissions among the four vehicle types, with buses and lorries demonstrating notable fluctuations across speeds, while petrol and diesel cars display steadier trends. The petrol car exhibits higher emissions than its diesel counterpart, with the latter producing 4 g/km less nitrogen oxide.