Disadvantages of using an ineffective ionizer for asthma and allergies Ionizers cannot remove large particles from the air, including those that cause asthma and allergy symptoms. Ionizers do not destroy odors or gases, including volatile organic compounds (VOCs). Negative ions occur naturally, near waterfalls or after rain. These negative ions can even positively affect humans, animals and the environment because they create oases of clean air. However, ionic air filters aren't that benign.
When released into indoor air and inhaled, ozone is a powerful lung irritant that aggravates allergies and asthma. Ionic air filters not only produce ozone as an undesirable by-product, but they are not even particularly effective in removing others air contaminants. Laboratory tests were performed with air samples of particles and gases in a large semi-furnished chamber and in a field test with an ionizer device installed in an air treatment unit serving an occupied office building. Another recent study on air ionizers in school classrooms reduced particle concentrations and led to some improvements in the respiratory health of 11- to 14-year-old children.
Ionizers had an adverse effect on heart rate variability (a measure of cardiovascular health), meaning that any benefit to the lungs comes at a cost to the heart.