In offices, homes, and other indoor areas, poor air quality can both cause health problems and make existing health problems worse. The U.S. Environmental Protection Agency currently ranks indoor air pollution as one of the top five threats to public health. Indoor air pollution results from the release of chemical vapors and the suspension in the air of particulates such as dust and microorganisms.
In response to increasing energy costs and the need to conserve energy resources, buildings and homes have been designed to be more energy efficient. Thus, many offices and new homes have tighter construction, sealing the building from the outside air. This makes it easier for indoor air pollutants to accumulate to dangerous levels. With people spending up to 70–90 percent of their time indoors, long-term exposure to indoor air pollution can cause various health problems. Air pollution can build up in any confined space, but gases from synthetic materials used these days to construct or furnish offices and homes can, among other factors, result in "sick building syndrome." While some people exposed to sick building syndrome will be unaffected, others who are hypersensitive to the pollutants can develop serious symptoms including eye, nose, and throat irritations, allergies, asthma, blurred vision, dizziness, fatigue, headache, skin irritation, nervous system disorders, and upper respiratory and sinus congestion. .
The Plants for Clean Air Council and Wolverton Environmental Services have tested different houseplants for their ability to remove various toxic gases such as formaldehyde, xylene/toluene, and ammonia. Plants absorb volatile organic compounds from the air into their leaves and then translocate them to their root zone, where microbes break them down. Micro-organisms in the soil can use trace amounts of pollutants as a food source. Some organic chemicals absorbed by plants from the air are destroyed by the plant's own biological processes.
