You can watch all four reports of our special Pollution Investigation here:
How do we tackle the problem of air pollution at our school gates?
In a special series, tests we carried out found pollution was worse in cars than walking to school. This report by Christine Alsford investigates the ways in which we can all breathe in less Black Carbon, decreasing the chances of health problems:
It's school drop-off time outside Windmill Primary School in Oxford.
Pupils are timing how long drivers linger with their engines running, polluting the air they breathe.
There is growing awareness among the younger generation about the risks of vehicles idling at the gates.
This project is aiming to change the behaviour of parents who don't have modern vehicles that automatically cut out when they come to a halt.
The country's first so-called moss tree sculpture was recently installed - a giant plant designed to purify the air in the city centre.
Could putting them at every school gate make a difference?
Steve Guppy- Scientific Officer, Southampton City Council says it's not a bad idea:
Travelling on two wheels rather than two feet means children travel through any pollution sources more quickly and reduce exposure.
In countries like China - where the problem is far worse - children wear protective masks on the school run. Would that be effective here?
Paul Morozzo- Clean Air Campaign, Greenpeace says cheap masks have no effect on our health:
Some local authority areas are already issuing fines in exclusion zones specifically set up to deter parents from driving to school.
Others are closing roads to vehicles completely at peak school run times.
It could be that within a few years solutions that sound radical and far reaching now, will just become the accepted norm.