Near indoor plants, temperatures fell by as much as 4.5 degrees Celsius in some studies reviewed by researchers at the University of Surrey. The review also found that greenery can help remove some gases from indoor air, offering clues for how homes and workplaces might be designed to feel fresher and more comfortable.
A team of 35 international experts, led by Surrey’s Global Centre for Clean Air Research (GCARE), brought together findings from studies around the world. Their review, published in Eco-Environment and Health, looked at how indoor greenery affects air quality and temperature. The topic matters because people spend much of their time indoors, where common products can release pollutants into the air.
These pollutants include volatile organic compounds, or VOCs: gases given off by items such as paints, furniture and cleaning products. The researchers found that passive greenery, including potted plants and living walls, can help remove some VOCs. Systems that actively pull air through plants and the materials they grow in were often more effective at removing pollutants in controlled tests.
The review also linked indoor greenery with local cooling. Temperatures near plants fell by about 0.5 to 4.5 degrees Celsius across the studies. That range suggests plants could make indoor spaces more comfortable and may reduce the need for air conditioning. But the effects are not the same everywhere. They depend on factors such as ventilation, light, plant species and the kind of greening system used.
The authors caution that much of the research so far has taken place in laboratories, often in small test chambers and over short periods. Those setups may not show how plants perform in real rooms over months or years. As a result, the review offers a starting point, not a guarantee that any indoor plant arrangement will clean or cool a building in the same way.
The team also says outdoor weather and climate change need closer study. Extreme heat and humidity could change how indoor greenery works. If moisture is not managed well, it could lead to condensation or mold. These risks make it important to test systems in realistic conditions, rather than focus only on their potential benefits.
Professor Prashant Kumar, GCARE’s founding director and co-director of the Institute for Sustainability, said the review brings together research that often examined separate benefits on their own. He said it provides a preliminary benchmark for deciding where and how indoor plants may be most useful, while substantial gaps remain. GCARE researchers Dr. Elisa Valentim Goulart and Dr. Hao Sun also called for better monitoring and modeling.
To help guide future work, the researchers proposed a framework that combines measurements with computer modeling. It is intended to show how indoor greenery performs under different conditions and could help inform building design, management and policy. More real-world testing will be needed before designers can know which systems work best in particular places. For now, the review suggests that plants may do more than brighten a room: used thoughtfully, they could become one part of healthier, cooler indoor spaces.