Diesel fumes can irritate lung tissues
The study is the first offering what is said to be conclusive evidence that particles from diesel exhaust reach, and are taken up by, cells that reside on the deepest part of the lung.
The level of particles was significantly higher in children living on a main road, although there was no difference in the proportion of these particles in children of different ages.
PM10 are tiny particles - less than 10 micrometers in diameter - and their small size allows them to penetrate deep into the lung, where they can aggravate respiratory disease.
Many deaths
The government has estimated that there are 24,000 deaths of adults a year, which can be attributed to the inhalation of PM10.
Dr Grigg said: "This research, which shows particles in cells that are known to cause lung injury, supports epidemiological studies which demonstrate an adverse effect of particles on the respiratory health of children.
"PM10 are one of the most damaging pollutants and can penetrate far into the lungs - causing inflammation, coughing, respiratory symptoms and even permanent damage.
"This biological evidence is very important in furthering our understanding of air pollution and its effects."
Damage
Dr John Harvey, of the British Thoracic Society, said: "This research is clear evidence that current levels of air pollution are damaging the lungs of children across the UK.
"We urge the government and other bodies to fund long-term studies so we can further probe avoidable causes of lung damage in children - and find solutions.
"We owe it to future generations to help them breathe easier."
The research is published in the British Thoracic Society journal Thorax.