They recorded the mother's home address at the time of birth and the average levels of traffic pollutants (such as nitrogen oxides (NOx), nitrogen dioxide (NO2), and fine particulate matter (PM2.5) from traffic exhaust and non-exhaust sources, including brakes or tire wear) and larger particulate matter (PM10) were estimated Noise levels during the day and night-time traffic were also estimated.
An analysis of the data found that increases in traffic-related air pollutants were associated with 2% to 6% increased odds of low birth weight and 1% to 3% increased odds of being small for gestational age.
But Professor Kevin McConway, emeritus professor of applied statistics at The Open University, warned that The BMJ study could not definitively conclude that it was the air pollution causing low birth weight in these cases. The researchers found that for each 5 microgram per cubic meter increase in PM 2.5, the risk of low birth weight increased by 15 percent.
City air pollution can cancel out the beneficial effects of exercise in older adults, say scientists.
To conduct the study, the researchers recruited 119 volunteers over the age of 60 who were either healthy, had stable COPD, or stable ischemic heart disease.
Participants spent two hours walking along traffic-heavy Oxford Street, which is one the most polluted spots in the United Kingdom, or in Hyde Park.
Going for a brisk walk is one of the best ways for older people to exercise and stay healthy - unless your route takes you along Oxford Street that is.More news: The Latest Chevron Corporation (CVX) Insider Trading Activity
More news: Bank of America Analysts Give Merck KGaA (MRK) a €95.00 Price Target
More news: Hornets' Steve Clifford Takes Leave Of Absence To Address Health
Environmental measurements were also collected, to track pollution levels and volunteers' exposure.
On the contrary those who walked in the park had a noteworthy health improvement in their lung capacity which endured as long as 24 hours compared to those who walked on a polluted street said the benefits were negligible.
In contrast walking along busy Oxford Street had little impact on arterial stiffness and led to only a small increase in lung capacity.
Blood flow also increased after exercise, with decreases in blood pressure and an increase in heart rate.
This is the first study to document these negative effects on healthy people as well as those with pre-existing cardiorespiratory conditions such as chronic obstructive pulmonary disease (COPD) or coronary heart disease.
Walking in Hyde Park reduced arterial stiffness by more than 24 percent in healthy and COPD volunteers and more than 19 percent in heart disease patients.
The authors add that it is possible that stress could account for some of the physiological differences seen between the two settings, with the increased noise and activity of Oxford Street having an effect. Air pollution exposure has been related to growth in hospital recognitions and deaths from cardiovascular diseases, respiratory diseases and lung cancer.
The study found no evidence that exposure to road traffic noise was linked to birth weight but the authors said they "cannot rule out that an association might be observed in a study area with a wider range of noise exposures".