Methods of Air Cleaning – Filtration, Adsorption, Ionization and Free Radical
There are only so many ways that you can “clean” air of particles and volatile organic chemicals (VOC), bacteria, virus and mould. In general these include:
- Ionization to generate charged particles
- Photolysis to generate free radicals
Removing particles from air requires the use of high performance filters, which are aided by ionization which creates positive and negative charged particles which can be attracted to charged collection plates or clump together to fall as “dust”. If sufficient energy is generated, you may also create positively and negatively charged VOC’s. The charged organic compounds can undergo some degree of decomposition, although the oxidation by-products themselves can be as much of a health issue as the original VOC. There is very little real data to show how extensive the decomposition process is with many of these systems. Removing VOC’s and microorganisms can be done in a variety of ways. You can absorb small quantities, in the low parts-per-billion (ppb) range, onto a filtration medium, like activated charcoal which will trap them. You can also adsorb small quantities, in the low ppb range on certain catalytic surfaces. These catalytic surfaces can then be irradiated with selected wavelengths of UV energy to generate reactive oxygen species which decompose the adsorbed material.
The most efficient method to eliminate high ppb and low parts-per-million (ppm) levels of VOC’s, moulds, bacteria, and viruses continuously present in air (and on surfaces) requires the use of high performance vapor phase oxidative air cleansing systems that generate hydroxyl radicals – the process used in nature. Hydroxyl radicals react one million times faster than the next most powerful oxidant, ozone. HGI systems have confirmed their Odorox® products produce concentrations of hydroxyls equivalent to those produced in nature and react effectively with high ppb levels of VOC’s (confirmed by independent third party testing). Other manufacturer’s electric discharge or ionization cleaners (like “Plasma Ionizers”) make claims that they produce hydroxyl radicals in concentrations similar to HGI’s photolysis method but they offer no data. Ionization devices generate positively and negatively charges particles, not free radicals so that their reactions with VOC’s are very different than those for Odorox® systems or those found in nature. There is no evidence that they produce hydroxyl radicals. The ionization process involves electric discharge and is modeled on the Siemens ozonizer patent. It will innately produce considerable amounts of ozone. The only method to be proven safe both in nature and in an independent clinical/toxicological testing laboratory is HGI’s Odorox® multiple UV energy method.