Human beings are in the midst of a dramatic revolution in how we perceive scent. Prior to the 1800’s, most people worked outdoors, lived on farms and were engaged in agrarian work. Starting in the 1800’s, people began to migrate to cities to work in factories and offices. Today, modern humans spend 90 percent of their time living and working indoors. At the same time, we started introducing artificial scents into our homes and offices and now the vast majority of scent compounds we inhale come from synthetic fragrances such as fabric softener, detergents, soaps, shampoos, new carpeting and furniture.