Schoolchildren in Wales are not being protected from air pollution, a leading health charity has said.
The British Lung Foundation (BLF) found more than 40 per cent of Welsh councils did not have any air quality monitors outside schools. This prompted the charity to launch a petition calling for urgent action from the UK and Welsh governments.
The Welsh government said it was "firmly committed to improving air quality across Wales."
The BLF said Wales already had some of the highest rates of lung disease in the UK and exposing children to more polluted air would only make it worse.
The charity's Freedom of Information request to Welsh councils found:
Seven out of 17 councils which responded had not placed any air quality monitors within 10m (33ft) of a school
In the five areas identified as having unsafe levels of particle pollution - Cardiff, Chepstow in Monmouthshire, Newport, Swansea and Port Talbot - only six schools had nearby monitors
Three councils - Caerphilly, Denbighshire and Pembrokeshire - did not consider schools to be a priority when placing air quality monitors
"Children's lung health is particularly vulnerable to air pollution, yet they are not being protected by the government's air quality monitoring guidance," said Joseph Carter, head of BLF Wales.
He said the UK Government needed to bring forward a new clean air act and the Welsh Government needed to change its guidance to councils to make sure it monitored air quality outside schools.
Head teachers' union NAHT Cymru is supporting the BLF's petition.
Rob Williams, the union's director of policy, said, "Schools leaders in Wales strive to create safe and happy environments for children. However, they cannot address the potentially dangerous levels of pollution around their schools."
A spokesman said the Welsh Government was "firmly committed to improving air quality" and provided guidance to councils to help them fulfil their responsibilities for reviewing local air quality.
"We recently launched a consultation on this subject which recognises the immediate and long-term health benefits to be gained by reducing pollution exposure across Wales alongside action on localised pollution hotspots," he added.
(Also see: London pollution death toll may hit 2,500 this year: survey)