I went to the airport saturday to take a flight to Cleveland, What is the machine that spits air at you do

I went to the airport saturday to take a flight to Cleveland, What is the machine that spits air at you do?
Really I was affaid the that it was getting fresh with me. Never had a machine ever taken such an interest in me before.
Air Travel - 2 Answers
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1 :
It checks to see if you were handling explosives. It picks up particles
2 :
They're called "puffers" and can detect trace amounts of explosives as small as one-billionth of a gram: http://www.boston.com/news/nation/washington/articles/2006/01/09/tsa_announces_new_airport_bomb_detectors?mode=PF