Diesel fumes health hazard to asthmatics: study

Diesel fumes health hazard to asthmatics: study
The World first hybrid diesel electric double decker bus is driven in London in March 2007. Exposure to everyday pollution from diesel-powered vehicles can be a health hazard for people with asthma impairing their lung function in just a few hours, a new study showed.(AFP/File/Shaun Curry)CHICAGO (AFP) - Exposure to everyday pollution from diesel-powered vehicles can be a health hazard for people with asthma impairing their lung function in just a few hours, a new study showed.
And to carry out the study, the researchers chose an urban environment where millions of shoppers go every year -- Oxford Street in London.
The study, the first to look at the impact of vehicle fumes on the health of asthmatics in a real setting, confirms what asthma patients have been telling their doctors for years -- that this type of pollution aggravates their condition.
It found that after just two hours in that London urban environment with diesel-only traffic, people with mild and moderate asthma experienced increased symptoms, reduced lung capacity and inflammation in the lungs.
When the same group of 60 volunteers spent two hours in a traffic-free part of London's Hyde Park, an inner city park just a few miles away, they experienced some of the same problems but to a far lesser degree.
"Our study illustrates the need to reduce pollution in order to protect people's health," said Fan Chung, a professor of respiratory medicine at Imperial College, London, and one of the authors on the paper.
"Environmental authorities need to ensure that pollution levels remain within recommended levels, and even then the pollution may be harmful to people who are particularly susceptible because they have conditions like asthma."
Writing Wednesday in the New England Journal of Medicine, the researchers reported that the severity of the lung problems seen in the volunteers was linked to the amount of pollution spewed out by the diesel vehicles.
Air quality tests showed there were three times as many ultra fine particulates in the air at street level in Oxford Street than in the air samples taken in Hyde Park.
The researchers believe that particulates (minute particles of dust, dirt, soot and smoke), particularly the tiniest or "ultra fine" ones can interfere with the respiratory system because they are so tiny that they can be inhaled deeply into the lungs. They can also be absorbed into the blood with damaging effects.
The tests also revealed that two noxious gases produced during the combustion process were found at much higher levels in Oxford Street than in Hyde Park.
Nitrogen dioxide was three times higher in the Oxford Street air samples, compared to the Hyde Park samples. Elemental carbon was six times higher.
The researchers said that while the overall impact of the traffic pollution on the volunteers was modest, and their lung function returned to normal by the following day, they were concerned about the cumulative effects of such environmental pollution on people with chronic respiratory conditions.
Chung said asthmatics should be prepared for an asthma attack when they go to high pollution areas and should carry medications to treat symptoms like wheezing and a tightening in the chest area.