The best aroma diffuser uses ionization to help make the air fresher and more pure. Ionization is a process that electrically charges molecules inside the diffuser chamber, which releases an oxygen molecule into the air. Oxygen molecules are highly reactive and they react with things like water molecules and carbon-dioxide molecules in our environment to create negative ions. Negative ions have a calming effect on people because they help balance the body's nervous system by preventing oxidative stress. They also bring down our heart rate and promote a state of relaxation. This helps you sleep better at night when you wake refreshed in the morning. Negative ions also promote a state of relaxed alertness that helps you get out of bed in the morning.