Experiments with Plants …
The National Aeronautics and Space Administration was instrumental in determining that house plants improve the quality of air that we breathe while they were researching ways to clean the air in space stations. Scientists discovered that there were 300 volatile organic chemicals in the air occupied by the crew. Dr. B.C. Wolverton, a research scientist, headed a team that experimented with plants to determine which were best at purifying the air. In 1996 he published the results on 50 plants in his book “Eco Friendly House Plants”. The following information is largely taken from his findings. 

How Plants Clean The Air …

Because most houseplants evolved in the under canopy of tropical or subtropical forests, they have unusually high rates of photosynthesis to allow them to thrive in dim light. This trait works to our advantage when dealing with indoor environments.

The studies confirmed that houseplant leaves, roots, soil and microorganisms work together in a symbiotic relationship to removal chemical pollutants:

• Air pollutants are absorbed through microscopic openings in the leaves called stomata. Through translocation, the movement of substances through the plant to the root zone, toxins are removed from the air to the soil and broken down by microbes. Some chemicals, however, are destroyed by the plant’s own biological processes without involving the action of soil microbes.
• Water vapor is emitted into the air from plant leaves through a process called transpiration. Convection air currents set up by leaf transpiration transport toxins to the root zone. Effective toxin transportation can be increased if the lower leaves of houseplants are removed so that as much soil as possible is in contact with the air.
• Soil microbes biodegrade the toxins into a source of food for the microbes and the plant. Varied populations of microorganisms live in the soil. They are responsible for, among other things, making nutrients available to plants and detoxifying the soil. They are highly adaptive, having the ability to mutate to cope with environmental changes. It is important to note that, since research has shown that microorganisms become more adept at detoxification the longer they are exposed to toxins, the longer we are able to keep our houseplants, the more successful they will be as Clean Air Plants.
• While most plants photosynthesize in daylight, some plants, including most succulents, orchids and bromeliads, act in the opposite manner, opening their stomata at night. Therefore, with a well-balanced selection of houseplants, it is possible to purify continuously the indoor environment – day and night!