Ionic propulsion, air conditioners, hair dryers, wind and more like the ionosphere stay around there trying to show that ions are a relevant, perhaps the main cause of activity. In a world composed by atoms and molecules, some of them can gain or lose extra electrons causing a measurable modification in their behavior.
Ions, like in the dichotomy of a usual magnet, have two possibilities with opposite sign. Anions are the negative representation while cations the positive one. Atoms with equal number of electrons and protons are neutral, but in some circumstances there's a lack of electrons or extra, broking the calm and creating a change in both physical and chemical properties of the atom. The same with molecules but the complexity goes to the top.
Water, air are perhaps a good example of theoretically neutral molecules for the daily intake.
Ionizing radiation appears when the energy is capable of interacting with the atom or molecule promoting the loss of electrons, those not prone to leave it easily. When this occurs, the chemical bonds of the molecules are endangered. Ordered from less penetrating to more —or less dangerous to a higher risk— are alpha, beta and gamma radiation.
These concepts are important to be aware of what's surrounding you all the time. For having the concept clear, ions are charged particles, meaning not electrically neutral.