TABLE 1.

Air purifier technologies and their characteristics [46].

Machineries	Advantages	Disadvantages
Electrostatic filters	‐Able to remove airborne particles, viruses, and odours	‐Maybe is not as useful as traditional filters
	‐Relatively longer lifespan
HEPA filters	‐Powerful in removing 99.97% of 0.3‐μm particles	‐Short perdurability
	‐No ozone production or other harmful byproducts	‐Ineffective in removing viruses, harmful gases, and odours
Photo‐catalytic oxidation	‐Viruses and gases are effectively removed	‐Ineffective in removing airborne particles
		‐Ozone production
Ultraviolet light	‐Effective in sterilising air that passes UV lamps via forced air	‐Airborne particles could not be removed