Kids' asthma may be made worse by where they live... right down the street... from heavy traffic.
A new study from the University of Southern California estimates that at least 8-percent of childhood asthma cases in los angeles county can be attributed by traffic-related pollution at homes within 250 feet of a busy road.
Experts say there's also preliminary evidence that urban air pollution might also affect chronic obstructive pulmonary disease, heart disease and lung cancer.