Ionizers are better at removing smaller molecules, such as bacteria and viruses, so they may not benefit people with allergies or asthma. Ionizers also do not remove particles from the circulation. Instead, they charge them to stay on something else. Unless you constantly clean the hard and soft surfaces of your home, it becomes difficult to remove particles that have fallen to the floor. Ionizers don't require you to change a filter, so they're easier to maintain if you don't mind dusting or vacuuming regularly to clean particles that fall to the floor.
If the presence of ozone isn't a problem for you, they're a viable alternative to air purifiers. Ionizers also purify a larger area than HEPA air purifiers and can remove smaller particles of the air.
