Pollution Impacts Asthmatics on Several Levels
Air pollution may impact the lives of asthmatics in more than one way, according to several recent studies. On one level, pollution exacerbates the seriousness of asthma attacks caused by viruses. On another, pollution decreases the effectiveness of asthma inhalers used for relief of symptoms.
About 80 percent of asthma attacks are due to viruses, particularly the common cold virus, according to Anoop Chauhan, MD, a lung specialist at St. Mary’s Hospital in Portsmouth. U.K.
While many asthma attacks suffered by children are caused by viral infections, they are more serious if the child has been exposed to ordinary traffic pollution,” Chauhan noted.
Implicated in the seriousness of attacks is exposure to nitrogen dioxide from vehicles. “It drops the lung function and increases the symptoms after a virus infection by as much as 20 percent,” Chauhan explained.
Researchers measured the personal exposures of 114 asthmatic children over a one-year span and found a strong relationship between nitrogen dioxide pollution and the severity of asthma attacks.
“These effects are occurring at levels of pollution currently considered to be safe by international quality standards,” Chauhan explained in an interview with Patricia Reaney. “So it has an important bearing on what we should set as targets for air quality.”
Perhaps controlling air pollution would reduce the number of severe attacks of asthma, the researchers reported in a recent issue of The Lancet medical journal.
In an earlier study, Fernando Holguin, MD, and colleagues at the University of Pittsburgh, Pa., reported air pollution may reduce the effectiveness of rescue inhalers.
That group studied 85 asthmatic children in Mexico City where air pollution is generally high. They found nitrogen dioxide and ozone were the culprits. An increase of 10 parts per billion in nitrogen dioxide levels decreased inhaler efficacy by about 15 percent, they reported late last year in Chest.
Nitrogen dioxide levels in the U.S. average from 10 to 20 parts per billion, according to the U.S. Environmental Protection Agency.
Nonetheless, inhaled steroids still provided protection against the effects of pollution for those children who regularly used inhaled corticosteroids to help control persistent asthma, Holguin told a Reuters reporter.
These finding are consistent with other studies and may explain why asthmatics are more symptomatic in relation to air pollution, he explained.