What you can't see...can hurt you.
I'm Lindsay Liepman with the latest health news.
A new study found that ultrafine particles in polluted air may be tied to heart disease.
Ultrafine particles are generated by gas and diesel engines.
They also come from biomass burning like forest fires and energy production.This was the first
study to look at the health effects of being exposed to ultrafine particles over a long
period of time.
The information will help environmentalists help protect public health.