Each air purifier type uses a different technology to target specific indoor pollutants. Knowing how each one works makes it easier to match the right purifier to your specific needs. The sections below explain all five types clearly.
HEPA air purifiers
HEPA (High Efficiency Particulate Air) purifiers use a dense fibre filter to capture particles as small as 0.3 microns with up to 99.97% efficiency. They are highly effective against dust, pollen, mould spores, and pet dander — making them the go-to choice for allergy and asthma sufferers. HEPA purifiers are widely used in homes, hospitals, and laboratories.
How it works: Air is drawn through the HEPA filter where fine particles become trapped in the fibre mat. The cleaned air is then released back into the room. No chemicals or ions are involved — just mechanical filtration.
Ionic air purifiers
Ionic air purifiers release negatively charged ions into the air. These ions attach to airborne particles like dust and pollen, causing them to clump together, become too heavy to remain airborne, and fall to the floor. They operate quietly and consume less power than most other purifier types, making them suitable for offices and living rooms.
How it works: The ioniser generates a stream of negative ions. These bond with positively charged particles in the air, weighing them down so they settle on surfaces rather than being inhaled.
Carbon air purifiers
Carbon air purifiers use activated carbon filters to absorb odours, gases, and volatile organic compounds (VOCs) released from paints, cleaning products, and cooking. They are particularly effective at removing smoke and chemical smells, making them a strong choice for kitchens, bathrooms, and spaces where odours linger.
How it works: As air passes through the activated carbon filter, pollutant molecules bond to the carbon's porous surface through adsorption. The filter does not physically block particles — it chemically traps gases and odours.
A buying caveat worth noting: carbon filters do not capture fine particulate matter like dust and pollen. For comprehensive coverage, look for models that combine a HEPA filter with an activated carbon filter — this addresses both particles and gases in a single unit.
UV air purifiers
UV air purifiers use ultraviolet (UV-C) light to kill bacteria, viruses, and other airborne pathogens. As air passes through the purifier, the UV light disrupts the DNA of harmful microorganisms, neutralising them before the air is returned to the room. UV purifiers are common in medical settings and can be a useful additional feature in homes and offices.
How it works: The UV-C light source is housed inside the purifier. When air circulates through, the light damages the genetic material of pathogens, preventing them from reproducing or causing infections.
Ozone air purifiers
Ozone air purifiers generate ozone (O₃) molecules that react with and break down pollutants, odours, and microorganisms in the air. They are powerful at removing strong odours and are used in industrial settings and for targeted odour removal in residential spaces.
How it works: The purifier produces ozone, which oxidises pollutants and neutralises them. However, ozone in high concentrations can be harmful to human health — these purifiers should only be used in unoccupied spaces or under controlled conditions, and are not recommended for continuous residential use.
