Greening Cities

Presented by Alexandra de Blas
Saturday 10 January 2004, 7.30am

Alexandra de Blas: So far on the program, we’ve been talking about using more plants on the outside of buildings. But they’ve got an important role to play inside as well.

Dr Ronald Woods is from the University of Technology in Sydney, where a team of scientists has been researching the benefits of indoor plants.

They’ve found that a bit of greenery not only makes the office look better but it helps to detoxify the air and make you feel good too.

Ronald Wood: We’ve been looking specifically at indoor air quality and how the commonly-used indoor plants, like the Peace Lily and Dracenas and Kentia Palms in particular, can make a difference to concentrations of volatile organic compounds that are commonly found in indoor air.

Alexandra de Blas: What are some of the common volatile organic compounds that we may find in houses and our workplacers?

Ronald Wood: There’s a wide range of these chemicals. We’ve looked specifically at benzine, which is an aromatic hydrocarbon, and enhexane? Hydrocarbon. Benzine is a known carcinogen, hexane is a neuro toxin, so we’ve been looking at these as models for a whole range of chemicals, and we know that there’s a mixture of chemicals in the indoor environment and they come from the fixtures and fittings, the furnishings, the paints, the glues, the solvents, the cleaning compounds, the deodorants, all of these cleaners that are used in bathrooms and so on that out-gas small amounts of volatile organic compounds at normal room temperatures.

Alexandra de Blas: And what sort of impact can they have on people?

Ronald Wood: Irritated eyes, skin, sore throat, headaches, even nausea, and in some people this can be even more serious than that and leads to what is commonly called billing-related illness.

Alexandra de Blas: What difference can indoor plants make?

Ronald Wood: Well our work has been investigating how indoor plants can sequester or degrade these common kinds of pollutants, and our findings to date are that it’s a plant-soil microcosm that actually works as a little clean air machine, if you will, and can take concentrations from as little as one part per million, up to even a thousand parts per million, and simply turn them into carbondioxide and water.

Alexandra de Blas: So how does the plant do it?

Ronald Wood: We think that the micro-organisms in the potting media are the first line of response. We also think that the plant systems have a role to play, but that’s yet to be fully investigated, but we know that this system will work equally as well in the dark as in the light, so when the plant is only just holding dark respiration and not photosynthesising, that the system will still work.

Alexandra de Blas: Will any plant do, or are there specific plants that are much better at removing these toxic chemicals from the atmosphere?

Ronald Wood: At this stage we’re still evaluating that particular aspect. We suspect that all commonly-used indoor plants have this capacity to some degree; which ones are better than others we’re not quite at that stage yet. But we do know that a plant needs to be healthy and thriving in the indoor environment.

Alexandra de Blas: You started off looking at benzine and hexane, but you’re looking at other chemicals now; what’s the latest work showing you?

Ronald Wood: This is just in the very early stages. Obviously in the real world, you’re going to have a cocktail of chemicals and it’s going to vary from space to space. But to really get a good handle on this, we’re starting to look at some other commonly-found chemicals such as acetone and some of the synthetic pyrethroids that are used in household insecticide sprays such as promethron. These are suspected to be hormonally active agents, so they could have a potentially severe impact on some individuals’ health and wellbeing. And we’re just starting at the very early stages to do that sort of work.

Alexandra de Blas: To what extent are you actually looking at a cocktail of chemicals together, because that’s often the problem, isn’t it, with chemical research; researchers often just look at one chemical at a time, and not the mixture.

Ronald Wood: We’ve just purchased a sniffer, which is a portable hand-held photolionisation detector. It’s essentially a similar sort of instrument that was previously used in Iraq by the weapons of mass destruction inspectors, and it measures total volatile organic compounds in parts per billion, which is about the equivalent of detecting a sugar cube in Sydney Harbour, so it’s a very accurate instrument and it gives you an instantaneous read-out. So the project we’re commencing will be looking at some offices in Sydney to evaluate the presence-absence of plants, using this equipment.

Alexandra de Blas: Acetone is one of the chemicals that you’re looking at, and that’s nail polish remover, it’s what women all around the country use all the time, and particularly beauticians, where they can work on nails all day, there could be quite high levels of this in the atmosphere. Has this ever been looked at before?

Ronald Wood: Not that we’re aware of with regard to plant material, but certainly there’s an understanding from the United States and Europe that acetone is quite likely to be a hormonally active agent, and as such, can have some health implications for people, particularly women.

Alexandra de Blas: So what sort of health implications could it have? Can it influence the development of a foetus, say?

Ronald Wood: The literature points to the fact that this is potentially a hormonally active agent that can disrupt the normal hormonal activity of people, men and women.

Alexandra de Blas: So many people now work behind computer screens, and what difference can plants make to improving the environment when you’re working behind a computer?

Ronald Wood: There was a study reported last year that was carried out in Holland at the Taxation Office. One of the results was that people who work in front of a Video Display Unit for more than four hours a day in the presence of plants, had up to 12% improvement in their productivity, measured by work output.

Alexandra de Blas: Ronald Wood. Ron’s based at the University of Technology, Sydney, and from where I’m standing right now, that building could certainly do with a bit of external greenery.