Federal health officials are tracking clusters of serious health issues among mostly young people. Analysts have linked these lung conditions and breathing problems with vaping. But some health officials suspect certain unlicensed vaping substances that included contaminated liquids. The Exchange on Wednesday gets the latest on what we know and what we don't about vaping. As of Tuesday, Aug. 20, N.H. health officials said they were not aware of any cases in the Granite State but they are