单选题 .  Children who live near a main road are in greater danger of catching pneumonia (肺炎) because pollution from passing traffic damages their lungs. A leading expert in childhood breathing difficulties has made the link between exposure to particles from vehicle exhausts and a child's susceptibility to the chest infection, which can be fatal.
    Professor Jonathan Grigg, an honorary consultant at the Royal London Hospital and academic paedia-trician (儿科医生) at Queen Mary, University of London, made the breakthrough after studying the effect of airborne pollutants on human lung cells. Children whose home is within 100 metres of a main road could be as much as 65% more likely than others to develop pneumonia, he said.
    Although the disease is usually associated with the elderly, it is a significant childhood illness. Every year about 20,000 children and young people under 18 end up in hospital after contracting the condition. Children trader 12 months are the most likely to die. Of the 76 young people under 20 who died in 2008, 29 had not reached their first birthday—20 boys and nine girls—and 23 others were between one and four.
    "The findings strongly suggest that particles pollution is a major factor in making children vulnerable to pneumonia. We've shown a very firm link between the two. The study raises strong suspicions that particles cause pneumonia in children," said Grigg. "This is significant because pneumonia causes many admissions of previously healthy children to hospital." Some children with the disease spend several weeks in intensive care.
    Previous studies have blamed proximity to a main road for children having higher rates of asthma, coughs, ear, nose and throat infections.
    A study this month by the Boston-based Health Effects institute claimed that poisonous emissions from vehicles can speed up hardening of blood vessels, as well as worsening lung function.
    "Strong evidence" suggested that being exposed to traffic fumes can lead to variations in heart rate and other potentially fatal heart complaints, the study said.
    Exposure to the burning of wood or coal, or to tobacco smoke, can also increase a child's chances of pneumonia. One study found that secondhand smoke was to blame for 28.7% of all children under five in Vietnam who were admitted to hospital with the condition.
    Professor Steve Field, chairman of the Royal College of GPs, said: "We have known for some time that pollution causes chest problems, such as asthma, in both children and adults. This new research adds to the weight of evidence about the problems of air pollution, especially from cars, buses and lorries."
    The research underlined the need for Britain to move towards greener forms of transport in order to protect public health from traffic fumes, he suggested.1.  What is taken as fatal by Professor Jonathan Grigg? ______