Research published on 14 November shows that London’s low-emission traffic zone has modestly reduced residents’ exposure to diesel engine pollution, but the better air quality has not brought improved lung health among children. The results suggest that while air pollution levels may be reduced by low emission zones, extra measures are needed to deliver air clean enough to improve health. WHO says that in addition to the pollution problems caused by diesel vehicles, nitrogen oxide - which has been linked to asthma and impaired lung development in children - has become a major problem. Professor Chris Griffiths, who co-led the research, said, ‘In many areas of London, air pollution still remains a major issue’.