A study has revealed thousands of London primary school children are exposed to dangerous pollution from red routes, with 9 per cent of primary schools in Hackney and Islington located near the major roads.

Data from a new study by Environmental Defense Fund Europe (EDFE) shows 47,500 primary pupils attend schools near red routes, which are major roads marked with red lines telling vehicles they cannot or are restricted from stopping along them.

The red routes form a network of major roads, controlled by the Mayor of London, which make up 5pc of roads in the capital but up to 30pc of the city's traffic, according to Transport for London (TfL).

Oliver Lord, head of policy and campaigns at EDF Europe, said: “Kids in London have been breathing illegal levels of air pollution for far too long, and not just in the city centre.

"Exposure to air pollution at a young age can irreversibly stunt children’s lungs and create health problems for the rest of their lives."

Hackney and Islington councils have taken action on air pollution however, by implementing school streets and low traffic neighbourhoods (LTNs).

Hackney lobbied for the expansion of the TfL's Ultra Low Emission Zone in 2015, now set to take place this autumn, and Islington was the first UK council to publish air quality data from outside schools last year with its latest figures showing air quality has improved outside most of its schools.

Cllr Mete Coban, Hackney's cabinet member for energy, waste, transport and public realm, said: “This report is a reminder of the urgency with which we need to act if we’re to tackle London’s air quality crisis".

Hackney Council has rolled out "extensive" schools monitoring networks, School Streets and plans for a programme to introduce green screens at primary schools across the borough to deal with the crisis.

Cllr Rowena Champion, Islington council’s environment and transport chief added: “We know it is really important that children have clean air to breathe at the school gate, and we rapidly accelerated our School Streets programme last year to help achieve this.

"School Streets bring real benefits to schools, parents and children, creating a much better environment outside schools, and making Islington a greener place to live."

The EDFE study reveals primary schools within 100m of red routes are exposed to 25pc higher levels of toxic and polluting nitrogen oxides (NOx) than the average London primary school.

The air pollution which surrounds these schools is, according to the study, on average over legal limits set by an EU 2008 directive, which stated NOx levels should average no more than 40 micrograms cubed or μg/m3 in any calendar year.

Exposure to the gases - which come from vehicle exhaust fumes, factories and other sources - impacts the health of people, animals and the environment and, despite the UK no longer being a member state, it may still face financial penalties for its non-observance of the EU obligations when it was a member.

EDFE's research has led to calls from environmental campaigners ahead of the mayoral elections in London for all candidates to commit to safeguard the expansion of the ULEZ and to transform the red routes network.

Hackney council says air quality at its schools on red routes has improved over recent years and the expansion of the ULEZ will improve the "picture further".

Cllr Mete added: "But it’s really important to emphasise that the number one cause of pollution in the borough is road transport.

"We will continue to do all we can to protect school children from poor air quality, but the best thing local people can do is leave cars at home if they can, and walk, cycle or take public transport wherever possible.”

The council adds that proximity to a road is not always an indicator of increased pollution as other factors can affect levels, such as physical barriers like walls and trees.

Information on air quality at Hackney schools can be accessed in the council's Air Quality Status Report on pages 25-41.

For more information about improving air quality around schools visit Islington's Clean Air Toolkit for Schools.