Why might smell be slightly different between the right and left nostril?

The smell is different because the left nostril go to the left side of your brain which tends to deal with language and words, while the right nostril go to the right brain which deals with emotions. Scientists found that each side of your brain did process the information from each nostril differently. When odours came in through the right nostril, it smells more pleasant because the right side of the brain deals with emotions.

Hope this helps,

kwrob