Studies have made it more clear that microscopic particles are a trigger for asthma attacks, and could work beside pollen to set off severe attacks by inflaming the lungs, he said.
But the latest findings also show particulates are so small that they can sneak through the lungs' natural defences and damage the body's cells,
MAY 4, 2011 Wall Street Journal
Asthma Rates Climb for Children, Adults
Some 24.6 million Americans had asthma in 2009, up from 20.3 million at the beginning of the decade, according to a new report from the Centers for Disease Control and Prevention.
Asthma, a chronic respiratory disease, affected 8.2% of all U.S. residents in 2009, up from 7.3% in 2001, an increase of 12.3%, the CDC said