Plants

Call me crazy, but I just did a quick search and found this....very interesting!!

"Plants Actually Clean the Air!

Contact: Diane Relf, Extension Specialist, Environmental Horticulture

August 1996

Many questions have been raised about the quality of the air we breath, both inside and outside of our homes and businesses. Problems with "sick buildings," smog, and heat-island effects compound the feeling of doom from the greenhouse effect and global warming. As scientists scramble to find remedies for such problems, we as consumers can do our part to improve the quality of air around us, while also adding value to our buildings, landscapes, and communities by adding indoor plants, trees, and other plant materials.

Through an in-depth study sponsored by NASA, it was determined that indoor plants in a closed, controlled environment were able to extract pollutants from the air. The foliage of indoor plants was capable of removing low levels of pollution, while plant roots, assisted by an activated carbon filter, removed air pollutants at higher concentrations. Amazingly, these filters around plant roots removed and biologically degraded pollutants before they accumulated -- an advantage over advanced-technology carbon filters which removed pollutants from the air, but required proper, careful disposal. Indoor air pollution, a problem resulting from intense energy-efficiency in buildings, consists of particles and gases trapped in building air which is not circulated or filtered properly. The NASA research demonstrated that plants reduced air pollution from gases, such as formaldehyde and benzene. Further research is determining the efficacy of indoor plants in cleaning up larger particle common indoor air pollutants, such as asbestos; pesticides; carbon dioxide, carbon monoxide, and other gases; chemicals from detergents, solvents, and cleaning fluids; fibers released from clothing, furnishings, draperies, glass, carpets, and insulation; fungi and bacteria; and tobacco smoke.

Outside our homes and offices, air pollution takes on a different aspect as it affects our entire existence with global warming. As much of the population has moved to urban areas, problems with smog and the urban heat island effect have become big air quality problems. High temperatures favor smog conditions where cities become enveloped in a cloud of noxious gases causing respiratory and other health problems. A third of the present smog problems is related to the heat-island effect, causes by internal build up of heat in cities from radiant energy absorbed onto pavement, asphalt, and concrete, such as roads, buildings, and parking lots. This is compounded by car emissions and other carbon released from heating, locomotion, or steam generation (0.8 lbs carbon released for every kilowatt of peak power produced).

Urban forestry has brought attention to trees as air pollution remedies since trees and other plants directly absorb carbon in their life-dependent process, photosynthesis. By taking in carbon dioxide and converting it to oxygen during photosynthesis, trees naturally remove excess carbon from the air. During photosynthesis, tree foliage also removes from the atmosphere other chemicals, such as nitrogen oxides, airborne ammonia, some sulfur dioxide, and ozone, that are part of the smog and greenhouse effect problems. Trees also affect air quality by acting as collection sites for dust and other air particles. Leaf surfaces collect dust particulates on their leaf surfaces until washed to the ground during a rainstorm. Therefore, dust counts can be reduced by 75 percent downwind of urban plantings, and fumes and bad odors can be intercepted by trees or masked by the more-pleasing smells of the trees or shrubs.

"Bad air" conditions, most common in urban locations, can be improved by increasing the amount of trees in urban areas to act as natural air filters. Through photosynthesis and evapotranspiration (natural plant processes) air is filtered through the tree, cleaned, cooled, and released back into the atmosphere. Of course, a tree's ability to offset carbon emissions is determined by average tree size, canopy cover, health, and age, but large trees can help lower annual carbon emissions in the atmosphere by 2 to 3 percent. An 80-foot beech tree has been shown to remove daily carbon dioxide amounts equivalent to that produced by two single-family dwellings. Indirectly, trees also affect air quality through energy savings. Trees strategically planted to shade homes can generate a 10 to 50 percent savings in cooling expenses and 4 to 22 percent savings of heating costs (as wind breaks), although the extent of savings is determined by tree type, planting location, and climatic vacations. This reduces the amount of carbon-based fuels used, therefore reducing emissions that reduce air quality.

Despite all of today's present technology, it seems that foliage plants and trees may be the best means of improving outdoor air quality. They are capable of removing gas and particulate pollutants from the air, reduce energy expenditures, lower air temperatures, and make our communities more attractive places to live."