The provided line graph compares four types of vehicles (diesel cars, petrol cars, lorries, and buses) in terms of nitrogen oxide emissions.
It is clear that buses produced the highest amount of nitrogen oxide emissions, with their emissions increasing alongside those of petrol cars. In contrast, emissions from lorries and diesel cars declined as speed increased.
At 10 kph, the amount of nitrogen oxide emissions produced by buses was the highest, 40 g/km, with emissions from lorries following closely behind, at just under 35g/km. However, the emissions from diesel cars and petrol cars were much lower, at just over 10 g/km and just over 5g/km, respectively. At 60 kph, the figure for buses fell to just over 25g/km, whereas that for lorries dropped to just over 15 grams of emissions per km as their speeds increased. At 90 kph, the amount of nitrogen oxide emissions generated by both diesel cars and petrol cars went down slightly, to just under 10 g/km and 5 g/km respectively.
At 130 kph, just over 40 grams and just below 25 grams of emissions were produced per kilometer by buses and lorries. Finally, emissions from petrol cars grew negligibly to just over 10 g/km, with pollutants from diesel cars remained stable, at 5 g/km.