Do Houseplants Clean Indoor Air? 2026 Review Findings

Key facts
Event date	2026-02 (published online February 2026: Oxford ORA record gives 6 Feb, White Rose record gives 19 Feb; White Rose gives the issue date as 15 Apr 2026)
Source published	February 23, 2026
Where it applies	International. The 35 authors are based in the UK, Europe, the USA, Australia, India and Brazil; the findings apply to homes and workplaces generally.
What to do	No action needed. Keep growing houseplants for enjoyment, but don't count on a few pots to clean your air. Ventilation, filtration and cutting pollution at the source still matter most.

A few potted plants won't noticeably clean the air in a normally ventilated room. That's the practical message of a review of indoor greening research published in the journal Building and Environment in February 2026. The authors found that air exchange with clean outdoor air usually outweighs anything plants do, while larger, well-designed plant systems can reduce some pollutants and make rooms feel cooler. The review was led by the University of Surrey's Global Centre for Clean Air Research, with Professor Prashant Kumar as first author (University of Surrey; Kumar et al., 2026).

Key facts

Event: Paper published online in February 2026 (Building and Environment, vol. 294, article 114336)
Source: University of Surrey news release, February 23, 2026
Who wrote it: 35 researchers based in the UK, Europe, the USA, Australia, India and Brazil
Type: A review of existing evidence, not a new experiment
Action needed: None. It changes what to expect from houseplants, not how to care for them

What the researchers did

Rather than running a new experiment, the 35 authors, working through the GREENIN network, reviewed what is already known about indoor plants and indoor environmental quality. They organised the evidence under ten questions in five themes: technical performance, indoor microbes, health and wellbeing, equity and access, and fitting greenery into real buildings. They also built a matrix that rates 26 types of indoor greening, from ordinary potted plants to engineered green walls, against 20 indoor-environment measures, with a rating of how confident the current evidence is for each (paper abstract, Oxford University Research Archive; University of Surrey).

What they found

Ventilation usually wins. The review says that high air exchange with clean outdoor air can outweigh any improvement from plants and, where it's feasible, remains the most effective way to improve indoor air. It cites one estimate that 10 to 1,000 plants per square metre of floor area would be needed to match the removal of volatile organic compounds (VOCs) by typical building ventilation (open-access accepted manuscript).
Engineered systems can do more. Some engineered greening systems can reduce fine particles and VOCs, but how much depends on plant density, lighting and overall design (University of Surrey).
Rooms can feel cooler, but measured changes are small. Larger greening systems can make a space feel up to 2°C cooler, even when the measured temperature stays the same (University of Surrey). At typical plant numbers and ventilation rates, the review reports measured changes in room air temperature of about 0.5–1.0°C or less, and in relative humidity of 2–5% or less (accepted manuscript).
Humidity needs watching. Plants release moisture, but room-scale studies are inconsistent: some found humidity rose and others didn't. The authors note that care is needed to avoid over-humidifying a room, and they treat dampness and mould as risks to manage (accepted manuscript).
The evidence is thin in places. Many older experiments used unrealistic numbers of plants or sealed lab chambers that don't behave like real homes or offices. The authors call for long-term studies in real buildings (University of Surrey; paper abstract).

What to do

Nothing needs to change if you grow plants because you enjoy them. The review doesn't suggest removing houseplants, and it points to possible psychological and comfort benefits (paper abstract).
Don't swap ventilation for plants. Fresh air, from open windows when that's practical, and a kitchen extractor while you cook do far more for indoor air than extra pots. The review notes that effective kitchen extraction can keep nitrogen dioxide from cooking below the World Health Organization's one-hour guideline (accepted manuscript).
Watch moisture in humid rooms. If you keep a lot of plants in a room that is already damp, ventilation matters more, not less.
Be wary of bold air-purifying claims for single plants. Many trace back to sealed-chamber experiments, such as NASA's late-1980s tests in a chamber of less than half a cubic metre, rather than to real rooms (accepted manuscript).

Why this matters for your garden

Houseplants are often sold on air-cleaning promises they can't keep at room scale. That doesn't make them any less worth growing. Our guide to monstera plant benefits separates the real benefits from the myths. If you're adjusting humidity for your plants' sake, our pothos humidity guide explains when a humidifier helps and why airflow matters.

Do Houseplants Clean Indoor Air? What a 2026 Review Found