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Politics : Foreign Affairs Discussion Group -- Ignore unavailable to you. Want to Upgrade?

To: XBrit who wrote (96420)	4/26/2003 9:36:05 AM
From: maceng2	Read Replies (1) \| Respond to of 281500

do you happen to know what distance of travel through ordinary air A few centimeters stoller-eser.com <<Alpha particles don't get very far in the environment. Once emitted, they travel relatively slowly (at approximately one-twentieth the speed of light) due to their electric charge and large mass. They lose energy rapidly in air, usually expending it within a few centimeters. Because alpha particles are not radioactive once they have lost their energy, they pick up free electrons and become helium. Alpha particles also cannot penetrate most matter they encounter. Even a piece of paper, or the dead outer layers of human skin is sufficient to stop alpha particles. How can alpha particles affect peoples health? The health effects of alpha particles depend heavily upon how exposure takes place. External exposure (external to the body) is of far less concern than internal exposure, because alpha particles lack the energy to penetrate the outer dead layer of skin. However, if alpha emitters have been inhaled, ingested (swallowed) or absorbed into the blood stream, sensitive living tissue can be exposed to alpha radiation. The resulting biological damage increases the risk of cancer; in particular, alpha radiation is known to cause lung cancer in humans when alpha emitters are inhaled. The greatest exposures to alpha radiation for average citizens comes from the inhalation of radon and its decay products, several of which also emit potent alpha radiation.>>