Indoor air quality is an increasing health concern, particularly in India and other
developing countries where people may spend up to 90 percent of their time indoors,
according to the American Society of Horticultural Science. Indoor air can be as
much as 10 times more polluted than outside air in some areas, due to compounds
in paints, furnishings, clothing, and building materials. Don't be frightened--get
some plants! Research shows that many common houseplants and blooming potted plants
can improve your health by helping to fight these pollutants in your home. The ability
of plants to remove chemicals from the air is called phytoremediation. A study conducted
by Stanley J. Kays at the University of Georgia tested 28 species of common houseplants.
The results showed that some ornamental plants can remove volatile organic compounds
(VOCs) from indoor air. Research by the National Aeronautics and Space Administration
(NASA) also confirmed that plants eliminate harmful gases from the air. NASA findings
showed that houseplants were able to remove up to 87 percent of air toxins in a
The influence of interior plants on dust accumulation has also been explored (Lohr
and Pearson-Mims, 1996). Adding plants to the periphery of a room reduced particulate
matter deposition by as much as 20%, even in center of the room many meters from
the plants. The plants were in self-watering containers that watered the plants
from below, and the growing medium surface was extremely dry and dusty. Documenting
that under such circumstance interior plants were associated with reduced dust was
especially important, because it allayed fears that the growing medium in containers
might actually be making interiors dustier.
The American Horticultural Therapy Association says that the benefits of plants
can be seen across many studies in the cognitive, psychological, social, and physical
realms. Some of the psychological benefits include:
- Increased self-esteem
- Improved mood and
sense of well-being
- Reduced stress,
anxiety, and depression
- Increased feelings
of calm, relaxation, and optimism
- Increased sense of
stability and control
One area that has been explored is the effect of indoor plants on stress levels.
Several independent studies have shown that interior plants can help reduce stress
and improve well-being. A study by researchers at Washington State University found
that people in a plant-filled room saw a four-point drop in their systolic blood
pressure after taking a stressful test, compared with a two-point drop in a group
with no plant exposure.
Keeping plants indoors can make you think better. The mental benefits observed during
this research include:
- Improved concentration
- Improved memory
- Better goal achievement
- Heightened attention
Indoor plants have also been linked to a boost in creativity. In a study from Texas
A&M University, workers who were in a room with two potted plants and a bouquet
of flowers generated 13 percent more ideas than workers in a room with sculptures.
Bring more greenery--and less stress--into your home life!
One study documented that foliage plants can raise relative humidity to healthier
and more comfortable levels in interior spaces (Lohr, 1992). The relative humidity
of the air inside buildings is often below the range of 30% to 60% recommended for
human comfort, especially when buildings are being heated. When the indoor relative
humidity is too low, colds are more frequent and wood dries and cracks. In this
study, when plants were present, less than 2% of the space was occupied by the plants,
yet relative humidity was raised from 25% without plants to 30% with plants. Some
people have been concerned that interior plants might increase relative humidity
too much, but this is unlikely to occur: when the relative humidity rises, the rate
of water loss from the plant slows, because water does not evaporate as rapidly
when humidity is high
A study by the University of Agriculture in Norway found that indoor plants can
also help fight colds. The research showed that indoor plants decreased coughs,
sore throats, fatigue, and other cold-related symptoms by more than 30 percent.
Researchers attributed these benefits to the fact that plants help increase humidity
levels and decrease dust in your home.