The even more sophisticated array hood models also supply a feature that maintains the hood running on a 10-15 min timer after you're done cooking, in order to cleanse the last traces of odor as well as then silently turn off.
The hot, moist, greasy effluent stream created by food preparation is sucked in and also tired outside, rather than letting it blow right in your face. Any type of cook that spends a significant quantity of time in the kitchen environment will attest to the difference between food preparation in comfort, and needing to sustain a steam bath for several hrs.
Range hoods fix this issue by eliminating the polluted air to the outside (ducted installation) or cleansing it with a series of filters (ductless/ recirculating setup). Besides the obvious benefit of maintaining the kitchen air odorless, array hoods supply numerous other, much more subtle, benefits.