All fuels work by burning. Their combustion in a vehicle engine results in rapidly expanding gases that are used to turn the engine. The motion of the engine is then transmitted to the wheels to make the car or train go or to a propellor or turbofan in the case of a plane.
Combustion of petrol mostly results in carbon dioxide and water vapour with smaller quantities of pollutants such as nitric oxide, nitrous oxides and carbon monoxide.
Different vehicles can hold different numbers of passengers. The Tyndall Centre for Climate Change Research have calculated the amount of carbon dioxide and oxides of nitrogen produced per person per mile for different modes of transport.
|MODE OF TRAVEL||CO2||NOx|
|Tube / Underground||171||0.12|
|Coach / Bus||90||0.3|
(Source: Tyndall Centre for Climate Change Research, 2001)
*You need to bear in mind how the hydrogen was obtained though. For more on alternative fuel choices click here.
Which mode of travel generates the most greenhouse gases per passenger mile?
Assuming hydrogen cars are not yet available in the UK, what are the least and most environmentally friendly ways of getting to Edinburgh from London?
Try this quick quiz to find out how much you know about how travel choices affect the environment or read through the page on alternatives to fossil fuels.