Lavender is used due to its tendency to ease breathing and stimulate the immune system.
Lemon is good for both of these things but it also gives you an energy boost and helps relieve tension and stress. Myrrh is a gum/resin and like other woods and resins is good for breathing and opening up the airways but in a more gentle manner than Eucalyptus.
Peppermint is a stimulant which will help alleviate that tired, groggy feeling.
Chamomile and
Geranium both have calming and soothing effects and can help turn an uncomfortable allergy attack into a manageable inconvenience.