In recent years, indoor air quality has become a major health concern, especially with the rise of newly renovated homes and office buildings. One of the most dangerous indoor pollutants is formaldehyde (CH₂O), a colorless gas with a strong odor that can cause irritation to the eyes, nose, and throat—and long-term exposure may even increase the risk of cancer. Many people turn to air purifiers as a solution to remove pollutants and improve indoor air quality. But can an air purifier really remove formaldehyde? The answer depends on the type of air purifier and the technology it uses.

What Is Formaldehyde?

           Formaldehyde is a volatile organic compound (VOC) commonly found in indoor environments. It is released from building materials, furniture, flooring, paints, adhesives, and even household products such as cleaning agents and cosmetics. New homes or recently renovated rooms often have higher levels of formaldehyde because of fresh paint, new carpets, and pressed-wood products that continue to “off-gas” for months or even years.

           Exposure to formaldehyde can cause eye and throat irritation, coughing, nausea, skin allergies, and breathing problems. Prolonged or repeated exposure can damage the respiratory system and has been classified by the World Health Organization (WHO) as a human carcinogen. Therefore, reducing formaldehyde levels indoors is essential for a safe and healthy living environment.

How Air Purifiers Work

          An air purifier’s main function is to clean indoor air by removing harmful particles and gases. It works by drawing air through one or more filters, capturing dust, pollen, smoke, bacteria, and other pollutants, and then releasing clean air back into the room. The effectiveness of an air purifier depends on its filtration technology, airflow rate, and the size of the room it covers.

           However, formaldehyde is a gaseous pollutant, not a particle. This means not all air purifiers can effectively remove it. Traditional filters like HEPA (High-Efficiency Particulate Air) filters are designed to capture solid particles such as dust and pollen, but they cannot trap gaseous chemicals like formaldehyde. To remove formaldehyde, additional technologies are required.

Types of Air Purifiers That Remove Formaldehyde

1. Activated Carbon Filters One of the most common and effective methods for removing formaldehyde is through activated carbon (also called activated charcoal). Activated carbon is a porous material with a large surface area that can adsorb gaseous molecules, including VOCs such as formaldehyde, benzene, and toluene. When air passes through an activated carbon filter, the formaldehyde molecules stick to the surface of the carbon particles. However, over time, the filter becomes saturated and must be replaced regularly to maintain efficiency.
2. Photocatalytic Oxidation (PCO) Some advanced air purifiers use photocatalytic oxidation technology, which combines UV light with a catalyst—usually titanium dioxide (TiO₂)—to break down formaldehyde and other harmful gases into harmless substances like carbon dioxide and water. This chemical reaction effectively decomposes VOCs rather than merely trapping them. PCO technology is particularly effective in eliminating formaldehyde, though it requires sufficient light intensity and maintenance of the catalyst surface for consistent performance.
3. Cold Catalyst and Molecular Sieve Filters In addition to activated carbon and PCO, some purifiers use cold catalyst filters or molecular sieve materials. These filters rely on special chemical reactions or adsorption processes to capture and neutralize formaldehyde molecules at room temperature. While these methods are less common, they are often used in combination with other filtration systems for better overall results.
4. Ozone and Plasma Purifiers Certain air purifiers generate ozone or plasma ions to oxidize formaldehyde molecules. Although ozone can break down VOCs effectively, it can also be harmful to human health when present in high concentrations. For this reason, ozone-based purifiers should be used with caution and preferably in unoccupied rooms.

Factors Affecting Formaldehyde Removal

          The effectiveness of an air purifier in removing formaldehyde depends on several factors:

• Filter quality and size: Larger, thicker, and high-grade activated carbon filters perform better.
• Air circulation rate (CADR): The purifier must be powerful enough to process the room’s air multiple times per hour.
• Concentration of formaldehyde: In newly renovated spaces, formaldehyde levels may be too high for an air purifier alone to handle.
• Ventilation: Proper ventilation and temperature control significantly help reduce indoor formaldehyde levels.

Other Ways to Reduce Formaldehyde

            While air purifiers can help, they should not be the only method to control formaldehyde. The best approach is a combination of source control, ventilation, and purification:

• Choose low-formaldehyde materials and furniture when decorating or renovating.
• Open windows regularly to improve airflow.
• Use indoor plants like aloe vera or spider plants, which can naturally absorb some VOCs.
• Maintain a moderate temperature and humidity level, since heat and humidity can accelerate formaldehyde release.

Conclusion

            So, can an air purifier remove formaldehyde? The answer is yes—but only if it’s equipped with the right filtration technology. Air purifiers with activated carbon filters, photocatalytic oxidation, or cold catalyst systems can effectively reduce formaldehyde and other harmful gases in indoor environments. However, users should remember that air purifiers are part of a broader solution. Combining an effective purifier with good ventilation and careful material selection offers the best long-term protection against formaldehyde exposure.

           By understanding how air purifiers work and using them properly, we can create cleaner, safer, and healthier living spaces for ourselves and our families.