Commercial Buildings, Trade-Show Greenery, and Plants for Events

Ahhh…. Breathing clean with plants.

As Americans, we are spending more and more time indoors. Plants can help us bring the outdoors indoors and by doing that help prevent ‘sick building sydrome’ by increasing air quality as well as beautification and noise abatement. 

What do plants do to clean our air?

Plants give off oxygen and take in carbon dioxide during the photosynthetic process. Many studies have shown that plants also remove airborne chemicals from the indoor environment including formaldehyde and carbon monoxide. ALL PLANTS help air quality, but some plants are more effective at removing chemcals than others. According to a study done by NASA scientist, Dr. Bill Wolverton, the top-rated plants are:

Which plants are the top air cleaners? 

  1. Areca palm (Chrysalidocarpus lutescens – recently changed to Dypsis lutescens)
  2. Lady palm (Rhapis excelsa)
  3. Bamboo palm (Chamaedorea seifrizii)
  4. Rubber plant (Ficus robusta)
  5. Dracaena Janet Craig (Dracaena deremensis ‘Janet Craig’)
  6. English ivy (Hedera helix)
  7. Dwarf Date Palm (Phoenix roebelenii)
  8. Ficus alii (Ficus binnendijkii ‘Alii’)
  9. Boston fern (Nephrolepis exaltata ‘Bostoniensis’)
  10. Peace lily (Spathiphyllum sp.)
  11. Corn plant (Dracaena fragrans ‘Massangeana’)
  12. Golden pothos (Epipremnum aureum)

How do the plants clean the air? 

There are two major processes plants employ to clean the air:

  1. Plant leaves can absorb certain organic chemicals and destroy them through ‘metabolic breakdown’.
  2. When plants give off water vapor from their leaves, they also pull air down around their roots.  This supplies their root microbes with oxygen.  The root microbes use other airborne substances like volatile organic chemicals as a source of food and energy.  Naturally-occurring microbes living in the root zone (rhizosphere) can rapidly adapt to a chemical contaminant by producing new colonies that are resistant to the chemical.  As a result, they become more effective the longer they are exposed to the chemical.  

How many plants/what size plants are needed in a home to achieve air cleaning benefits?

The amount of leaf surface area influences the rate of air purification by plants.  Generally, the larger the plant leaf surface area, the higher the transpiration rate and the greater the surface area to absorb airborne chemicals. Without spending a ton of money to determine a particular area’s need for plants a general room of thumb is two plants per 100 square foot area. The more plants you have and the larger the plants the more air purification. 

Is there anything that these particular plants have in common?

The most effective plants in removing airborne chemicals all have high transpiration rates, meaning they move air more rapidly down to the root zone.

Which toxins and gases can these plants help remove from the air?

The Environmental Protection Agency (EPA) has identified as many as 900 volatile organic chemicals (VOCs) in the indoor environment.  Many of the chemicals are similar in structure.  These chemicals include formaldehyde, benzene, xylene, toluene, ammonia, trichloroethylene, acetone, carbon monoxide, methyl alcohol and ethyl acetate.

Is there evidence that more of these toxins and gases build up in the indoors during winter months when the building is closed up?

A tightly sealed building is more likely to have a buildup of toxins regardless of the season.  During winter months, heating of the building dries the air and makes one more susceptible to respiratory ailments.  Plants add humidity to the air as they transpire.

Do temperature and humidity influence the ability of plants to remove airborne chemicals and microorganisms?

Yes.  The transpiration rates of plants are important in removing both airborne chemicals and microbes.  When plants transpire (emit) water vapor from their leaves into the air, they also pull air down to their roots.  Any airborne contaminants are also pulled down into the plant root zone.  Microbes, living on and around plant roots in an area called the rhizosphere, breakdown and destroy the chemicals.  Microbes convert these chemicals into a source of food and energy for the plant and themselves.

Both temperature and humidity influence the transpiration rates of plants. Test results show that plants with high transpiration rates are more effective in removing pollutants from the indoor environment.