"Around the world, whenever airborne particles increase, so do deaths from heart and lung diseases. Now new evidence is emerging that some particles may be more dangerous than others. A growing body of research – much of it in New York City – suggests that breathing nickel and other metals may put acute stress on the lungs and heart, resulting in illnesses and deaths at particulate levels below national standards."
"Heavy Metal: Some Airborne Particles Pose More Dangers Than Others"
Source: EHN, 12/17/2009