You can watch all four reports of our special Pollution Investigation here:
A major survey has found almost half of our children are worried about the quality of the air they breathe at the school gates.
43% of children between six and 15 are concerned about the levels of air pollution near their school according to the research from the sustainable transport charity Sustrans.
In one rural village in Hampshire - new data shows that peak pollution levels at a busy railway crossing used by hundreds of children are more than three times above the EU's recommended limits.
Our Social Affairs Correspondent Christine Alsford has this exclusive report which begins with footage from the Poisoned Playgrounds campaign from ClientEarth.
More than 950 of our schools are near roads with illegal levels of air pollution according to a recent study.
There's growing concern among parents about the quality of air our children breathe, and if recent scientific studies are anything to go by they have good reason.
The school in the report is in the heart of Southampton. They're doing lots of work to try and reduce the pollution children are exposed to on the school run - but it's an uphill battle.
This school has a ferry terminal opposite the school, with crew ships coming in that you can see from the school windows.
However it's not just in the inner city where air pollution's a problem.
The image below shows the dedicated Safe Route to School if you live on one side of rural Bramley Village in Hampshire.
The barriers here can be down for as long as 36 minutes in any one hour - and that's a big concern for both residents and parents.
It's families like the Nicholsons who are left feeling the effects of queuing traffic on their twice daily walks to and from school.
The danger from the traffic is more immediate whereas the danger from the air pollution you don't really know that's happening and it can build up over time and it might be five, ten years or so before you see the effect of that.
Meaurements gathered by the parish council show at peak commuting times, pollution levels at the crossing are way above EU limits.
Councillor Bruce Ansell from Bramley Parish Council goes through the EU limits for us:
3/4 (76%) of parents and carers say they want extra measures to protect pupils whose schools and playgrounds are in illegally-polluted areas.
Leading scientific experts back wider action too to protect future generations.
Johnathan Grigg from Queen Mary University London and Doctors Against Diesel says the main concern is to protect the youngest generation of children:
While China is banning some diesel cars from its roads this year and countries like Germany and India will outlaw them from 2030, it will be 2040 before this country aims to do the same.