The given line graph illustrates the amount of nitrogen oxide emissions released by selected four types of vehicles.
It can be seen that the emissions of buses and lorries are higher while remaining two vehicles produce constant and low amounts of nitrogen oxide.
At the starting speed of 10kph, buses produce largest amount of around 40g/km with lorries follow the second place of around 33g/km. With the same speed from above, petrol car and diesel car release smaller amount of over 10g/km and around 7g/km respectively. After that, the emissions produced by four vehicles all have a downward trend. Buses reach the bottom point of emissions, around 26g/km at the speed of 60kph, while lorries meet its lowest point of over 15g/km with the speed 90kph.
Following this, buses emit an increasing amount of gas with faster speed till highest point of over 40g/km at the speed of 130kph. And lotties emission also have a swiftly climb till around 24g/km at the final speed.
When we look closer to other two vehicles, the petrol car have a steady and fluctuate changing amount of emissions produced just around 10g/km. In diesel car, the amount of emissions have a unnoticeable fall to 5g/km at the speed of 70kph and remain unchanged till the final speed of 130kph.
