With perfumes, spices, incense and personal care products, humans use smells to communicate emotional messages and transform themselves and their environments. As with any skill, practice makes perfect. A trained professional in the perfumery business can name and distinguish some 10,000 odors. A master perfumer can identify 100 different ingredients in a modern scent. Similarly, using smell alone, trained wine tasters can tell you a wine's alcohol content and grape variety, and perhaps even the growing conditions of the grapes.
Estimates vary widely.
This is probably the most sophisticated chemical detector that we know of. You've probably noticed that when you have a cold, your sense of taste is much diminished. Without the sense of smell, it would be hard to tell the difference between biting into an onion or an apple. This is because flavor is based mainly on smell. Our sense of smell is responsible for most aspects of flavor - except for those aspects mediated by taste buds on the tongue.