The smells in an environment contribute to atmosphere, welcome and comfort. One friend who is blind told me that smell could provide the most potent sensory information which either made her want to stay or leave. Cooking smells, smell banks housed in a collection of jars or bottles, and herb gardens in pots can transform spaces, atmosphere and mood. These can be added to any space at not much cost. The last feature I will include in this is sound.
Most environments are already full of sound.
When you add sound to your environment do it wisely, bearing in mind the possible impact it may have. Poor design decisions here can lead to enormous discomfort. Consider children who are vision impaired. Consider children with autism. These children may experience daily changes in their vision and hearing.