Table 7.
Comparison of the commonly-used indoor air cleaning technologies reviewed.
| Technology name | Indoor air pollutants removed | Advantages | Disadvantages | Potential development |
|---|---|---|---|---|
| Catalytic oxidation (including PCO) | Gas pollutants: organic, inorganic Airborne microbe. |
Active at room temperature. Can degrade various contaminants (such as aldehyde, aromatics, alkanes, olefins, halogenated hydrocarbons, odor compounds, airborne microbes). Does not need regeneration. |
Can generate harmful by-products such as formaldehyde, acetaldehyde, and acetone. Catalyst may be poisoned, resulting in decreased performance. |
Combined with other air cleaning technologies, such as adsorption and thermal catalytic oxidation, to reduce by-products and enhance performance. |
| Plasma | Gas pollutants: organic, inorganic Airborne microbe. |
Can simultaneously remove gas pollutants, airborne microbe and even particles. High single-pass removal efficiency. |
May produce O3, NOx and other harmful by-products. High voltage and high energy consumption. |
Combined with particle filter to increase filter performance and reduce pressure drop. Combined with catalysts to reduce or remove ozone. |
| Ozone-related | Gas pollutants: organic, inorganic Airborne microbe. |
Can reduce some targeted odors; Can enhance some catalytic oxidation reactions for VOC removal. |
Ozone itself is a harmful pollutant and may react with other indoor pollutants to produce harmful pollutants such as carbonyls, dicarbonyls, carboxylic acids, and secondary organic aerosols. | Combined with catalysts to reduce or remove ozone. |
| Sorption | Gas pollutants: organic, inorganic. | No harmful by-products. Good performance for gas-phase pollutants. |
Must be regenerated after long-term operation. May produce some airborne pollutants. Reactions with ozone may generate gaseous secondary pollutants. |
Dynamic continual or intermittent generation systems need to be developed. |
| Filtration | Particles | Good at removing particles in the range from 0.1 μm to 4 μm. | Used particle filters are sources of sensory pollutants. No evidence of VOC removal by filter alone, except when filter is combined with other materials, such as activated carbon. |
Combined with electrostatic field. |
| UVGI | Airborne microbe | Good for inactivation of some airborne microorganisms (bacteria, fungal, virus). | May generate O3 and dioxin. | – |