How Effective Are Air Purifiers In Your Home? | Talking Point | Full Episode

Summary

The episode examines whether household air purifiers are useful, particularly amid concerns about COVID-19 spreading through the air. Sales surged during the haze and pandemic, but the program stresses that an air purifier is not a substitute for other precautions.

COVID-19 and HEPA filters

Dr Glory Joy Tan says transmission was understood to occur mainly through respiratory droplets and contact, although airborne spread could happen in certain crowded, enclosed settings. A HEPA purifier may help remove particles if air passes through it repeatedly, but it should be treated as an added measure—not a “magic bullet.”

Indoor pollutants

Experts describe three broad categories of indoor pollutants:

• Particles, such as dust
• Gases from sources including cooking and household products
• Biological contaminants, such as mold and bacteria

Vacuuming can send fine particles back into the air if the machine does not filter them effectively. A water-filter vacuum was recommended as one way to reduce this.

Choosing a purifier

The experts favor a conventional HEPA filter, optionally paired with activated carbon. Carbon filters can absorb some gases and odors, but may deteriorate in Singapore’s hot, humid conditions.

They caution that UV light can harm eyes and skin, while ionizers and ozone generators can produce ozone that may affect lung function.

Home test

In a bedroom used by a family with asthma, an air-quality inspector measured conditions before and after a purifier was used. After one hour, several readings—including dust, bacteria, mold, and benzene—fell.

However, total volatile organic compounds remained high, at nearly four times the stated guideline, likely due largely to household products. The family also reported fewer sneezing and asthma symptoms after using the purifier for a week.

Ventilation

An indoor-air expert emphasizes bringing outdoor air into the home and promoting cross-ventilation, such as by opening windows and using a fan when conditions allow. Air-conditioner filters generally do not remove fine particles.

Research cited in the program also found that carbon dioxide in an air-conditioned bedroom could reach up to six times outdoor levels. The expert advises airing rooms thoughtfully, since warm, humid outdoor air meeting cold surfaces can cause condensation and encourage mold.

The program concludes that a suitable HEPA purifier can improve indoor air quality, but ventilation and attention to pollution sources remain important. The presenter says he plans to use his own purifier again.

Presenters and Contributors

• Steven Chia — presenter
• Dr Glory Joy Tan — infectious-disease specialist
• Professor Tham Kwok Wai — indoor-air-quality researcher
• Professor David Chong — indoor-air-quality researcher
• Joey Fung — independent air-quality inspector
• Professor Chandrasekhar — indoor-air-quality consultant
• Muhammad Jufri Ahmad Bajuri — participant in the home test