American researchers have discovered that even a brief exposure to very small particles of air pollution near a motorway can trigger asthma symptoms.
The researchers found that tiny particles of air pollution, about one-thousandth the width of a human hair, caused inflammation deep inside the lungs.
These particles are most often released in car exhaust fumes and so levels are high near motorways and other high-traffic areas.
In addition to new considerations for asthma treatment, the study findings may also help epidemiologists further establish the link between surges of pollutants near motorways and worsening asthma symptoms and to pinpoint the amount of ultrafine particle concentrations involved.