Recent research has shed light on the significant benefits of incorporating houseplants into indoor spaces, particularly in the context of improving air quality by reducing airborne nitrogen dioxide (NO2).

This pollutant, stemming from fuel combustion, has been linked to respiratory illnesses.

The findings underscore the simplicity, affordability, and effectiveness of using potted plants as a viable option for diminishing NO2 levels in both residential and office settings.

Chemist Pfrang, affiliated with the University of Birmingham in the United Kingdom, emphasized the diversity of the chosen plants, stating, "The plants chosen were all very different from each other, but they all showed strikingly similar abilities to remove nitrogen dioxide from the atmosphere."

In controlled experiments, each plant was placed in a test chamber with NO2 levels equivalent to those found in residences near busy roads. Within a mere hour, these plants managed to eliminate roughly half of the nitrogen dioxide present.

Extrapolating these outcomes to an office environment equipped with five plants (occupying 15 cubic meters), the researchers estimated a 20 percent reduction in nitrogen dioxide levels in poorly ventilated spaces. For larger spaces, such as 100 cubic meters, the projected reduction in the pollutant was 3.5 percent. However, the potential for accommodating more plants in larger areas could lead to a more substantial reduction.

Significantly, this reduction was consistent across varying conditions, including light and dark settings, as well as dry and moist soil—an observation distinct from previous studies on CO2 de-carbonization where environmental conditions played a more significant role. Pfrang noted a divergence in the process used by plants for nitrogen dioxide uptake compared to that for CO2.

In extended experiments, there was no indication that plants released nitrogen dioxide back into the atmosphere. However, the specifics of this process remain unknown and warrant further investigation.

It is noteworthy that a previous study challenging the idea that houseplants improve indoor air quality focused on volatile organic compound (VOC) pollutants rather than nitrogen dioxide. The challenge in such studies lies in the constant influx of new air and pollutants in real-world homes and offices, as opposed to the controlled environment of a laboratory.

Nevertheless, the current research incorporated calculations for larger areas and different ventilation scenarios. Future research is anticipated to delve deeper into the specific mechanism through which plants eliminate nitrogen dioxide, with potential comparisons to the effectiveness of "green walls"—entire walls adorned with vegetation that might offer superior air-cleaning capabilities.