A study published in the British Medical Journal has suggested that exposure to traffic pollution in London during pregnancy is linked to a low birth weight. A team led by Imperial College London looked at more than 540,000 births in Greater London between 2006 and 2010. Their analysis found higher levels of traffic-related air pollutants were associated with an increase of up to 6% in the chances of babies being born with a low birth weight.
The study pointed to an improvement in air quality in Beijing during the 2008 Olympics as an example of what can be done to improve pollution levels.
A second study, also involving Imperial College London, found that air pollution in the city can cancel out the benefits of exercise in older adults. It found that short-term exposure to traffic fumes greatly reduced the positive impact of walking on the heart and lungs. For this research, 119 volunteers aged over 60 walked for two hours in a quiet part of Hyde Park and also a busy section of Oxford Street. The study found that the Hyde Park walk was beneficial but the Oxford Street one didn't do much to improve the participant's health.
The study was published in The Lancet and funded by the British Heart Foundation.