Green Stars For Indoor Plants

This article was originally published in the Facility Perspectives Magazine June - August p.86 - 87. 

From home to car to office and back again - we now acknowledge that most office workers spend up to 90 per cent of their lives indoors or in enclosed spaces while commuting. But do buildings create a healthy environment for the people who work in them? Robin Mellon explains.

The Organisation for Economic Cooperation and Development suggests that illnesses - such as asthma and respiratory problems, headaches and allergies - from indoor air pollution are now one of the most acute problems related to building activities around the world. Australia's building industry is increasingly focused on making buildings greener, which means not only ensuring higher standards of environmental performance, but also ensuring developments that improve the indoor environment quality (IEQ) for occupants.

IEQ refers to the quality of the air and environment inside buildings, based on pollutant concentrations and conditions that can affect the health, comfort and performance of the people who live and work in them - including temperature, relative humidity, lighting and acoustics. Good IEQ is an essential component of any building, especially a green building.

CSIRO modeling based on US research into the affects of indoor environment quality on health and productivity has found that improving IEQ has the potential to save Australia's economy up to $21 billion each year. So, good IEQ is nothing to be sneezed at! What's more, creating a better indoor environment can help building owners, managers, occupants, architects and builders to minimise or eliminate the negative health effects, liability, bad publicity, and costly renovations and repairs often associated with IEQ problems.

Improving IEQ involves designing, constructing, commissioning, operating and maintaining buildings in ways that reduce pollution sources and remove indoor pollutants while ensuring that fresh air is continually supplied and properly circulated. The Green Building Council of Australia has been supporting the property industry in the shift to higher performing buildings since it launched the Green Star environmental rating system for buildings in 2003. Green Star evaluates the green attributes of building projects based on nine criteria, including energy and water efficiency, resource conservation, access to public transport and IEQ.

Within Green Star's IEQ category are credits designed to recognise and encourage developments which provide more fresh air, circulate fresh air around the rooms more efficiently, ensure daylight can reach more of the interior, and do not bring harmful chemical compounds into the building in paints, adhesives or carpets.

Volatile Organic Compounds (VOCs) are chemicals which evaporate easily into the air, and are frequently found in carpets and flooring, paints and sealants, and adhesives and fixatives. While many of us love the smell of a freshly painted room or new car, many VOCs can cause irritation, discomfort and what has become known as ‘sick building syndrome'. Since many buildings across Australia, just as across the USA, are built with air-conditioning as standard and so are ‘closed' environments, we have essentially created our own personal gas chambers - a sealed space which we then fill with materials that can have serious impacts upon our health.

Green Star rewards projects which can demonstrate that the products used in the building have low levels of harmful VOCs or do not emit VOCs at all. Green Star also rewards projects which can demonstrate that products and materials used have low levels of formaldehyde - another chemical which can cause eye and skin irritations, headaches, asthma and other breathing problems, and is classified as a probable human carcinogen. New developments around Australia are factoring IEQ into their building designs - introducing lots of fresh air to circulate around the building, and excluding materials and products which off-gas harmful levels of VOCs.

Interior fit-outs and refurbishments are also focusing on ventilation rates and the materials used in renovations. However, many older or existing building owners and tenants have long been concerned that their options may be limited - they can either carry out localised works to improve the indoor environment quality bit by bit, or wait until a major refurbishment of the building is feasible.

Recent research carried out by the National Interior Plantscape Association and Professor Margaret Burchett at the University of Technology Sydney, however, would suggest that help is at hand, and in the form of an inexpensive, sustainable and easy solution. Pots of indoor plants such as Zanzibar (Zamioculcas), Peace Lilies (Spathiphyllum), Mother-in-law's Tongue (Sansevieria) or Parlour Palm (Rhapis) have the ability to ‘scrub' many of the VOCs from the air, cleaning the air we breathe as well as decreasing carbon dioxide levels, increasing oxygen levels and adding to the sense of tranquility with their greenery.

Professor Burchett's work, which has been developed over many years, demonstrates that many of these plants can significantly reduce levels of harmful chemicals by breaking them down and converting them into less harmful substances which can be stored in the soil. Indeed, the research reveals that although the plants put oxygen back into the surrounding air, it is the soil content and size of the plant pot which can dictate the effectiveness of the removal of pollutants. Microbes and bacteria in the soil convert the chemicals into less harmful compounds, and Professor Burchett's work has now shown that increased levels of VOCs can in fact cause the indoor plants to increase their capacity to clean the air. As levels of VOCs in the air rise, many plants can increase their role as air filters.

Professor Burchett's work at UTS has found, for example, that indoor potted plants can reliably reduce total VOC loads by 75 per cent to below 100 parts per billion, the level identified as crucial by the World Health Organisation. This reduction takes place equally well with or without air conditioning, and in light or dark. Furthermore, the new research shows just how effective potted plants can be in removing indoor carbon dioxide and carbon monoxide. Larger indoor plants, in larger pots, can deliver increased benefits when concentrations of pollutants rise.

Further research is being carried out into rates of VOC removal, focusing on particular chemicals and length of exposure to such pollutants. In the meantime, the Green Star credit which recognises and encourages specification of indoor plants for the interior of office buildings or tenancies (found in Green Star - Office Interiors, IEQ category) will continue to play an important role in clearing the air. Projects which can demonstrate that they have introduced a certain number of indoor plants, of a particular size or larger, across the office floorspace can be awarded Green Star points towards their overall rating.

The Green Building Council of Australia has worked closely with Ambius Australia (formerly Rentokil) to ensure that the research behind its rating tools remains relevant and robust, and the credits relating to indoor plants and pollutants recognise and encourage best practice within the Australian market. The message is simple: clean air and healthy spaces are not the preserve of new buildings. Existing buildings can also reduce levels of harmful pollutants, increase oxygen levels and promote a greater sense of wellbeing, by ‘greening' their buildings from the inside out.

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