In South East Asia, 220 million children breathe air which is at least six times more polluted than the World Health Organisation’s safe limit, the report found.
A further 70 million children in East Asia and the Pacific and 10 million in the Middle East and North Africa inhale the most highly toxic air.
UNICEF’s director Anthony Lake said air pollution is a major contributing factor in the deaths of around 600,000 children under five each year:
“Pollutants don’t only harm children’s developing lungs – they can actually cross the blood-brain barrier and permanently damage their developing brains – and, thus, their futures. No society can afford to ignore air pollution.”
The UN children’s fund used satellite imagery to identify for the first time how many children around the world are affected by air pollution.
In total, around 2 billion children grow up in areas where outdoor pollution exceeds minimum air quality guidelines, UNICEF confirmed.
The report warns that vehicle emissions, heavy use of fossil fuels, dust and burning of waste all contribute to poor outdoor air quality.
Meanwhile, the use of fuels like coal and wood for cooking and heating in low-income, rural areas leads to toxic indoor pollution.
The report was launched a week ahead of COP22, this year’s UN Climate Change Conference in Marrakech.
UNICEF has called on world leaders to take four steps to protect children in their own countries from pollution.
Governments have been urged to cut back on fossil fuels, increase children’s access to healthcare, taking precautions to minimise exposure, such as ensuring factories aren’t built near schools, and monitoring air pollution.