15 years of research and 5 years of HN discussion. It can always get worse, https://news.ycombinator.com/item?id=29901979

  We could use terahertz spectrum to detect specific molecules and in turn use terahertz frequencies and radios as a way to track specific ingredients in food or pollutants in the air

Is there a PKD sci-fi story about terahertz-radar smart lock breathalyzer (substances, viruses) with conditional door entry/exit rules?