Traffic Pollution Linked to Severe Asthma Attacks

By Patricia Reaney

LONDON (Reuters) - Asthmatic children exposed to traffic pollution before getting a viral infection have more serious asthma attacks, doctors said on Friday.

In children, about 80 percent of attacks are due to viruses -- most of them from the common cold virus.

Researchers at St Mary's Hospital in Portsmouth, southern England have discovered that exposure to nitrogen dioxide (NO2) from vehicle exhausts exacerbates the attacks.

"It drops the lung function and increases the symptoms after a virus infection. It can increase symptoms by as much as 200 percent," said Dr. Anoop Chauhan, a pulmonolgist at the hospital.

NO2 is common but the main sources indoors are gas stoves and, outdoors, traffic pollution.

Chauhan and his team measured the personal exposures of 114 asthmatic children between the ages of 8-11 from non-smoking families over almost a whole year. They found a strong relationship between higher NO2 pollution and the severity of an attack.

With up to 150 million people worldwide suffering from asthma and cases expected to rise by 50 percent every 10 years, Chauhan said the findings reported in The Lancet medical journal could have important public health implications.

"These effects are occurring at levels (of pollution) that are currently considered to be safe by international quality standards. So it has an important bearing on what we should set as targets for air quality," Chauhan said in an interview.

Asthma affects the airways -- small tubes that carry air in and out of the lungs. It occurs when the tubes swell up and go into spasm blocking the free passage of air in and out of the lungs.

People with the illness suffer from coughs, wheezing and shortness of breath. A very severe attack may kill. Colds, the flu, cigarette smoke, pollen, stress and pollution can trigger an asthma attack. There is no cure for asthma but it can be controlled with drugs

"We know viruses trigger asthma exacerbation but this is another step forward because it tells us that pollution makes it (the attack) far worse than it should be," said Chauhan.

"Maybe we should be looking at controlling air pollution to perhaps reduce the number of severe attacks of asthma."