Chemoreceptor is a specialized sensory receptor cell, which responds to a chemical substance and generates a biological signal.
The type of chemoreceptor responsible for our sense of smell is called olfactory receptor. It is also known as odorant receptor, these are found in a small patch of tissue high inside the nose. These cells directly connected to the brain.
Erosion is brought about by the forces of nature or human activity: water, wind, earthquakes, mining, quarrying, etc. In the desert, there is very little water that can cause weathering or erosion, so the most probable answer is wind or maybe even animal activity.