How well are our cities working?

Here’s some encouraging news for city-dwellers: per person, since 2006, we’ve been consuming less energy and water, producing less waste and recovering more of it, and breathing cleaner air.

This information comes from the State of Australian Cities 2011 report, prepared by the federal government’s Major Cities Unit.

The study, which was first undertaken last year, compiles dozens of indicators regarding population, productivity, sustainability and liveability in urban areas.

Among its varied findings, the report reveals that while inner-city areas have become denser, it’s the outer suburbs that still accommodate most of the population growth.

Despite the gathering sprawl, average commuting times – longest in Sydney (35 minutes) and Melbourne (31 minutes) – remained steady in the decade to 2006.

The report also shows that public transport use is on the rise. The average distance travelled by vehicle peaked early last decade and has fallen slightly since then. Nevertheless, the total “vehicle kilometres travelled” in our cities continues to increase, because we have more people and more freight altogether.

So how should we judge these facts about our cities?

Alan March, senior lecturer in urban planning at University of Melbourne, says the analysis lacks a yardstick. “I don’t see a forward projection there, which is the point of ‘sustain’ in sustainability: a sense of how we’re going to deal with a low-carbon or a low–fossil fuel future,” he says.

He’s also troubled by the scant attention given to inequality and disparities in service provision. “The way cities operate is crucial to the difference between the haves and the have-nots, which is clearly increasing in Australia,” he says, citing, for example, the need for everyone to have a primary school within walking distance.

“I put that under the social sustainability mantle – if you let some people get a long way behind then it’s much harder to bring them back later. In many ways it’s much less efficient.”

And while a reduction in energy, water and waste per person is heartening, it’s the total eco-impact that counts. With a growing population, cutting overall consumption is a bigger challenge. When it comes to housing, that could entail retrofitting and adapting the housing we have, rather than building new.

Dr March argues that governments need to switch investment away from roads and into public transport, and pay heed to other concerns, including habitat loss and the way we feed our towns.

“We need to take our food supply into account,” he says, “particularly all the knock on effects when you relate it to oil-scarce economies and the large distances involved. Food should be weighing more heavily on our minds.”

In the same way, he says, we must assess our cities’ ability to withstand crises. “The evidence is conclusive that we’re going to have more extreme weather events. We’re also becoming increasingly aware of the fragile nature of the world economy.

“One of the big movements in sustainability now is thinking about the resilience of places, not just to natural disasters, but also to things like economic shocks, terrorism, or pandemics,” Dr March says.

“We have very vulnerable single-service systems, like our water and electricity supply. We know they’re not resilient and therefore not particularly sustainable if something goes wrong with one key element of that chain.”

Read this article at The Age online

The eco-standard of houses will be made public at sale or lease

IF you buy a car, you can easily find out its fuel efficiency. But what about a house? The ongoing costs and eco-impacts of existing buildings vary widely, but it’s hard for would-be buyers or renters to know what we’re in for.

In early 2009, state and federal governments agreed that a dwelling’s energy, greenhouse and water performance should be publicised at the point of sale and lease. Since then, however, not much has happened.

The policy is known as “residential building mandatory disclosure”. The name may be uninspiring, but if the reform is handled well, it could prompt a big change in household energy and water consumption.

While the details haven’t been set, the approach will be broader than the current star ratings. As well as the building fabric, it is likely to cover heating, cooling and hot water systems, together with lighting, clothes drying, rainwater tanks and water fittings, and a list of recommended upgrades.

Tim Adams, president of the Building Designers Association Victoria, says the scheme shouldn’t be compared to fuel efficiency in cars; rather, he likens it to a roadworthy certificate.

“We have consumer protection measures in place for all sorts of products. Mandatory disclosure should be seen as a kind of roadworthy check – and in this case we’re talking about protecting investments of several hundred thousand dollars,” he says.

“Unfortunately, we have a large quantity of building stock that was built before any energy efficiency provisions began. This is a way of informing us what the costs will be in our next house.”

Mr Adams argues that it will help people better judge the worth of the homes they’re inspecting.

“We’ve been lazy due to the cheapness of coal-fired electricity and natural gas,” he says. “In the future, when energy isn’t as abundant or cheap, we’ll need to be increasingly aware of these issues so we can value houses properly before we buy or rent.”

So how will it work?

In July, the federal government released a regulatory impact statement and sought feedback on different designs for the scheme. It detailed six proposals, ranging from a comprehensive, independent assessment, to an optional, self-assessed checklist.

The scheme’s success will depend on the quality of information required. The more rigorous options would be the most useful for buyers, but cost more upfront.

Some environment groups have criticised the report’s modelling, arguing it failed to factor in the health benefits of higher standards, or the avoided expense of new electricity infrastructure.

In its submission, the Association of Building Sustainability Assessors proposed a hybrid option, in which householders could choose among three tiers. Only people who opt for the most comprehensive version would be eligible to receive the highest rating.

Mr Adams’ association, which also accredits sustainability assessors, supports a system of compulsory self-assessment, at a minimum. The weaker proposals, such as an optional tick list, would be a waste of time. “The information needs to be consistent and people should be obliged to provide it,” he says.

“It’s in nobody’s interests to end up with the status quo. We need to do something about climate change and energy efficiency, so we need to start making some progress.”

Once the various governments agree on the scheme’s design, it will be up to the states and territories to enact the rules.

Read this article at The Age online

Living ponds or pools are good for your garden

WITH the cost of electricity and water rising, conventional swimming pools are becoming more resource-sapping than refreshing.

But landscape designer Phillip Johnson believes there are several smart ways to keep water bodies in our gardens – from natural pools to seasonal ponds and billabongs – if only we think a little differently.

“If you have water in your front or backyard, you’re bringing back habitat and biodiversity. And it helps cool down that space as well,” he says.

The first thing to do, he argues, is to think of stormwater as a valuable resource. Because of climate change, south-east Australia is expected to receive less rainfall overall, but more severe storms.

“Every property and road has been designed to drain water as fast as possible, and that contaminated water gets into our creeks and rivers,” Mr Johnson says. “If you can slow the stormwater, catch it and clean it, whatever leaves your place will be in much better condition.”

To help do that, he designs dry creek beds or swales running from rainwater tank overflows or downpipes. “When it rains, the dry creek bed comes alive and feeds into a billabong, water feature, or natural pool, which works as a reservoir for flood mitigation,” he says.

“In a natural system, billabongs exist on the edge of a creek. When it floods, it fills up this little wetland to the side. They’re really rich in biodiversity and create great habitats for frogs.”

Unlike conventional pools, Mr Johnson’s natural pools don’t rely on chlorine or salt to keep the water clean, but rather, use biological filters to aerate the water. An energy-efficient pump moves the water through a “regeneration” zone. “We learn from nature, where water often passes through river gravels and plants that absorb nutrients,” he explains.

Installing natural pools, and converting existing ones, has become a significant part of his business, but he maintains that you don’t have to spend big bucks or install a complex system. “You can do this yourself, but you’ve got to do your research.”

At her house in Northcote, permaculturalist Kat Lavers took the straightforward approach. She simply dug a hole and dropped in an old bathtub with the plughole blocked.

“We filled it with water from our tank and put rocks in there to create niches and different microclimates for plants that need a shallower depth,” she says.

“We also collected water from a nearby freshwater dam, which contained lots of critters like small shellfish, freshwater snails and maybe even dragonfly larvae. It added a diversity of life into our pond – and that means mosquito larvae don’t breed in large numbers.”

The plants in the pond also help inhibit mosquitoes by aerating the water and reducing the nutrient level. You can grow edible plants there, such as land cress and some kinds of mint. Water chestnuts will thrive in a boggy spot at the edge of a pond.

“The most obvious benefit of having a pond is beauty, but it goes beyond that,” Ms Lavers says. “It provides a reliable water source for lots of critters – some of them slugs and snails, but also really helpful ones like dragonflies, hoverflies, honeybees and lots of creatures that help to minimise the work you need to do in the vegie garden.”

Climate change heralds an uncomfortable future for Victorians

It’s easy to think of climate change as a far-flung concern, well away from our daily lives. But what are the predictions for Melbourne and Victoria? How will they affect our cities and houses?

Dr Penny Whetton, principle research scientist at CSIRO, says we can expect the average temperature to be 1 degree warmer by 2030, compared to the start of this century. It could get much hotter as the decades go on.

“If we continue the growing trend in global emissions, we’re looking at between two and four degrees warmer by 2070. And then warmer again later in the century,” she says.

Among the most uncomfortable consequences will be heatwaves. “If you think about the severe hot spell in Melbourne in February 2009,” Dr Whetton says, “that type of weather is going to become more frequent.”

Under a high emissions scenario, days over 40 degrees could be three to six times more common by 2070.

Such extremes not only damage infrastructure, such as electricity and rail networks, but also human health. The heatwave preceding the Black Saturday bushfires caused 374 deaths in Melbourne. To limit the consequences, we’ll need to design our buildings for low-energy summertime cooling, not only winter warmth.

Temperature rise is just one part of the change. On rainfall, Dr Whetton says most of the science suggests we can expect less. “But as temperatures increase, when conditions are right for a thunderstorm or a downpour, the atmosphere holds more moisture,” she says.

“We’re looking at longer dry spells and less rainfall, but when rain comes, we’ll have heavier downpours. That’s the pattern for Victoria and most of southern Australia as well.”

Drier conditions overall will make farming more difficult and probably lead to higher prices for fresh fruit and vegies. Bigger storms will cause more flash floods, unless we upgrade our drains and culverts.

Then there’s sea level rise: the predictions for the end of the century vary from about 30 centimetres to around one metre.

“The increase in sea level is due both to oceans becoming warmer and expanding, and to ice on land melting,” Dr Whetton says. “The largest ice sheets that concern us are in parts of Antarctica and Greenland. We don’t know a lot about how rapidly the ice can melt, but sea level rise is likely to continue for many hundreds of years.”

Under its Future Coasts program, the Victorian government is planning for a rise of “not less than 0.8 metres by 2100”. That’ll mean protecting beaches and properties against erosion and storm tides, as well as restricting new development in low-lying places.

But Dr Whetton says we still don’t know what the biggest impacts on cities will be. “We might feel it most through the impact on the hinterland – the climate change predictions are quite a worry for food production in the Murray-Darling basin,” she says.

“It’s likely we will find ways to adapt to a 1- or 2-degree warming, although we don’t know for sure. A 3- or 4-degree warming is going to be significantly more challenging. If we want to avoid the bigger climate change, then it’s not about adaptation. We need to reduce greenhouse gas emissions globally.”

Let insects be your constant gardeners

ANTLIONS, the larvae of lacewings, have insatiable appetites. Luckily, for vegie growers, they’re on our side.

“They look like tiny balls of fluff,” says insect expert Jane Davenport, author of The Garden Guardians, “but they’re really like little crocodiles dashing around the garden, eating aphids and sapsuckers. They suck the juice out of the aphids and stick them on their back, so they smell like the aphids and ants give them a free pass.

“There are all these symbiotic relationships in the vegie patch. Once you’ve got your bug-eyes on and you realise what’s happening, it’s fascinating. ”

She says gardeners have a choice between being a “cure-all” or a “curator”: the former need all manner of pesticides to keep their patch in check, while the later employ bugs to protect their produce.

“If you’re the kind of gardener who uses chemicals, you’re giving yourself lots of work. Good bugs will do it for you for free,” she says. “And there are already so many toxins in our cities, why would you want to add them into your garden as well?

There is, however, the small matter of enticing the bugs into your beds. Ms Davenport suggests establishing “an insectary” – a dedicated area where you let the critters have their way – as well as a variety of flowers, so something is blooming all year round.

“For example, ladybirds need something to eat, that’s the thing that attracts them,” she says. “Once you’ve attracted them you want to keep them – they’ll eat pollen if there are no pests.”

Karen Sutherland, from Edible Eden Design, also prescribes petals as a cure.

“Plant flowering herbs and lots of flowers with different shapes – they’ll bring all sorts of beneficial insects to your garden,” she says.

If you’re beginning a vegie patch in an area where there are no established gardens nearby, you can kick-start colonies of good bugs by ordering them in the mail. Another useful hint is to compost your old mulch during the cooler months, and let the chill eliminate the pests.

But what can you do if your leafy greens look grim?

First, find out what you’re up against. “If your plant has a lot of bugs on it, check whether your neighbours and other gardeners have the same problem. If so, then it’s something normal – it’s not because the plant is unhealthy,” Ms Sutherland says.

In springtime, aphids gather to gorge on new growth. “You have to be patient,” she says. “As an interim measure you can squirt the plants with a hose to knock them off.

“I find that if I wait and don’t do anything, ladybirds and praying mantises start appearing and eating the aphids.”

For a more active response, she suggests searching the web for organic pest control tips. You can easily homebrew your own sprays. For white oil spray – to control aphids, scale, mealybug, mites and more – mix four parts vegetable oil and one part detergent, and dilute 1:50 with water.

Above all, spend time in your garden. Ms Sutherland says the diversity of insect life affords infinite exploration, especially for kids. “Praying mantises are hatching at the moment in Melbourne, so if you look very closely in your garden, you might find tiny ones, only one-centimetre long.”

Read this article at The Age online

Despite rebate changes, solar energy is on the rise

Last year, the European Union set a deadline for all new buildings to meet a “nearly zero energy” standard by 2020. It also directed its member countries to make plans to boost the performance of existing buildings.

By comparison, Australian building energy standards are far less stringent.

Maria Wall, from Lund University in Sweden, explains that European homes will have to be super energy efficient, and then meet their remaining needs by way of solar photovoltaic panels and solar hot water.

The EU’s target encourages the installation of distributed (locally generated) electricity production.

“You must start with buildings have very low energy demand and then add the renewables,” she says. “You can’t skip the efficiency, because otherwise you can’t get the equation to reach zero.”

Ms Wall leads a research project for the International Energy Agency, investigating solar energy and architecture. She visited Australia recently to present a seminar on the latest solar technology for buildings.

Under the project, researchers from 15 countries are compiling case studies and developing new design tools. Ms Wall argues that to get the most efficient and affordable results, solar energy must be part of the initial design concept.

She observes that Australia has much greater potential for solar harvesting than northern Europe. “If you’re renovating or building a new house, you should think about renewable energy from the start. Add it now, because it will make you more independent of rising energy costs,” she says. “You have the possibility, so you should use it.”

In Sweden, there are no rebates for solar panels. Here, however, the local industry is coming to terms with yet another change in government subsidies.

The most recent re-jig is a hefty cut in the Victorian government’s solar feed-in-tariff – the rate that panel owners are paid for the surplus energy they put back into the grid.

When the feed-in-tariff was introduced, it offered panel owners a minimum of 60 cents per kilowatt-hour, for 15 years. The new arrangement, called the transitional feed-in tariff, reduces the rate to a minimum of 25 cents, for only five years.

In July, the federal government’s solar credits scheme was also reduced.

Brad Shone, from Moreland Energy Foundation, says it’s very difficult to calculate accurate payback times, given the endless changes to government subsidies, together with the fluctuating price of renewable energy certificates and swiftly rising energy charges.

“It’s still a good thing to put solar on your roof, because you’re increasing the amount of renewable energy in Australia. But it becomes complicated if you’re focussed on the payback,” Mr Shone says. “It’s impossible for an average person in the street to understand the variables.”

The Moreland Energy Foundation coordinates a solar energy bulk-purchasing scheme for nine councils that are members of the Northern Alliance for Greenhouse Action. Together, they’re aiming to install clean energy systems in 1000 houses throughout Melbourne’s north.

“We’ve taken some of the risk away from householders, by doing all the research,” Mr Shone says. “We’ve found a product we trust at a good price, through a reputable, local installer.”

A 1.5-kilowatt solar electricity system will cost $4690 up front, including the current federal government subsidy.

“The first step is to make all the savings you can by improving your building shell,” he advises. “Solar electricity is the cream on top.”

Read this article at The Age online

Grow green around the gills with backyard aquaponics

Next to a warehouse in Northcote, there’s a long, white greenhouse. Inside, leafy greens and silver perch are growing together.

It’s a community-scale aquaponics system, run by CERES Community Environment Park as part of its Food Hubs project, which aims to create intensive food production sites in the city.

“Aquaponics is a form of gardening where you grow vegetables and fish in a symbiotic manner,” says Stephen Mushin, the scheme’s coordinator. “The fish wastes are converted into nutrients for the plants.

“It uses about one-hundredth of the water of a regular farm, so it’s especially suited to the dry Australian environment. And it’s suited to urban areas because of its space efficiency.”

That means it works well in backyards too: aquaponics is becoming increasingly popular with householders.

“The most exciting thing is that it’s a way of farming some protein at home,” Mr Mushin says.

“A large part of ecological footprint is in the food we buy and the way we dispose of food waste. By harvesting in your garden you can reduce packaging, water consumption and food miles. It puts food production in your face.”

If you buy a ready-made kit, it’ll cost you a few thousand dollars; if you build it yourself, it can set you back just a few hundred. Mr Mushin says well-designed systems require few ongoing inputs – they can run using water from your roof and need only a small amount of power for a pump.

On October 22 and 23, he’s teaching a short course on aquaponics at CERES, together with biologist Dr Wilson Lennard. Over the weekend, participants will construct a system combining a garden bed of 1 square metre, with a fish tank of 1 cubic metre.

Dr Lennard says rainbow trout is the best catch, because it tolerates a broad range of water temperatures. Depending on the species and conditions, the fish can grow from only a few grams up to about 750 grams in a year.

For the garden beds, he says, veggies will grow well in washed river gravel, which is cheap and widely available.

His most important advice, however, is to research well before plunging in. “You have to make sure you know what you’re doing. That’s mostly about looking after the fish – if you get the fish care right then the plants usually look after themselves.”

To keep the system in balance, you’ll need to test the water’s pH several times per week, keep an eye on its temperature and check nutrient and oxygen levels.

“People who have kept aquarium fish before usually have no problems because the principles are the same. If not, then I always suggest starting small to see how you go,” he says.

Dr Lennard specialises in commercial aquaponics, but he says that even on a small scale, it’s an economical option. “You need few fish and very little fish-food to produce enough nutrients for a lot of plants.”

Like normal gardening, he says, aquaponics will get you out and about. “It’s a good way to get back in touch with the planet – we all live such indoor lives nowadays. And it connects you even more to ecology, because it’s an ecosystem approach. It helps people understand water and nutrient flows, and how animals, plants and bacteria interact.”

Read this article at The Age online, or check out this excellent video on CERES Aquaponics, made by SCOUTFILMS:

CERES Aquaponics from CERES Fair Food on Vimeo.

The more you earn, the more you travel and shop, and the worse it is for the environment

Inner-suburbanites have bigger eco-footprints than people who live further out, despite having better access to public transport. It might sound surprising, but that’s one of the glaring results of the consumption atlas produced by the Australian Conservation Foundation.

“We found there’s a very strong relationship between wealth and environmental impact,” says Chuck Berger, from the foundation.

The reasons? Shopping and flying.

“People tend to think greenhouse pollution is mainly created by electricity use and driving, but those direct impacts add up to about one-third of our average impact on climate change,” Mr Berger says.

“The other two-thirds comes from the emissions created in producing food and the goods and services we purchase – everything from clothes and electronic goods, to furniture, flights and eating out.”

Using the consumption atlas, you can find out the environmental impact of the average person in your suburb or town, displayed by way of greenhouse emissions, water consumption or land use.

If you want to reduce your spending, you can start by signing up to Buy Nothing New Month, throughout October. It’s the second year of the campaign, which targets over-consumption by promoting alternatives such as buying second-hand, repairing old goods, renting, or taking up hobbies rather than shopping for leisure.

For his part, Mr Berger advocates sharing, whether within the household, among neighbours, or by using community facilities. “Libraries and public swimming pools are classic examples, but there are also new models such as car-share schemes which are taking off in some inner-city areas,” he says.

Dr Samuel Alexander, lecturer at University of Melbourne and founder of the Simplicity Institute, says there’s another confronting message behind the consumption atlas: regardless of the differences between suburbs, nearly all Australians are consuming more than the planet can sustain, if all humanity lived that way.

“As a culture more broadly, if we’re going to take ecological issues seriously, then almost all of us have to rethink our consumption habits – even people who are by no means wealthy,” he says.

Greener Homes voluntary simplicity from Michael Green on Vimeo.

He maintains that the answer doesn’t just lie with technology. All over the world, greenhouse emissions have continued to rise, despite the fact that many production methods have become progressively more efficient.

On the household scale, Dr Alexander says, we must be wary of a similar trap.

“You have to be very careful that the benefits of efficiency improvements aren’t redirected into commodities that have similar impacts. For example, if we save money on power bills by insulating our houses, we shouldn’t use it to buy more plane tickets, but instead, say, to buy a water tank.”

Dr Alexander is conducting an ongoing survey of people who have chosen to live more simply, adopting lower-income, lower-consumption lifestyles. So far, nine out of ten respondents say they’re happier for the change.

He says his findings are consistent with sociological research suggesting the link between consumption and wellbeing weakens once we reach a basic level of material security.

“The core philosophy of voluntary simplicity holds that it’s not about deprivation or sacrifice, but rethinking your lifestyle in a way that you consume less but you live more,” he says. “By limiting your consumption, you’re able to direct more time and energy to non-material pursuits such as time with your friends and family, creative activities and relaxation.”

Read this article at The Age online

Householders can help scientists research climate change

ONE spring afternoon, take a walk in your street and look around. Are there any purple flowers on the neighbour’s jacaranda tree? Can you see a welcome swallow – with its distinctive forked tail – perched high on the wires?

These observations might sound idle, but they could help scientists understand the way climate change is influencing our birds and bees.

“Climate change isn’t just about hotter weather,” says Richard Weatherill, from Earthwatch Institute. “But so far we don’t know much about how changes in temperature, rainfall and more extreme storm events are affecting the behaviour of our plants and animals.”

Together with and the Bureau of Meteorology and the University of Melbourne, the institute has developed ClimateWatch, a website that aims to fill in some of those gaps, with the help of the public.

Over 2500 people around the country have begun monitoring the behaviour of common species of birds, plants, insects, mammals, frogs, reptiles and spiders – both native and introduced – and recording their observations online.

The study of the timing of natural cycles is known as phenology. Because of the changing climate, it’s expected that spring and summer will come earlier. But what might that mean?

Last year, a study by the University of Melbourne showed that a one-degree increase in the city’s temperature had led to the common brown butterfly emerging from its cocoon ten days earlier than it did in the mid-twentieth century.

Mr Weatherill says that while such a change might sound innocuous, it could have far-reaching results – such as those demonstrated by a similar website in the UK, called Nature’s Calendar.

“Researchers found that butterflies were emerging and birds were nesting earlier, but there was a mismatch: where the young chicks would have fed on the caterpillars, they were no longer available,” he says. “That kind of impact starts to cascade in the ecosystem.”

Lynda Chambers, from the Bureau of Meteorology, says the breadth of the observations by householders in ClimateWatch will reveal some of the cascading effects in Australia for the first time.

“For example, for the pollination process we need to know what is happening both with the plant and with the insects that pollinate it. We’ll get an idea of how the ecosystem is changing, rather just a single species.”

She says the fact that the climate acts as a trigger for animal and plant behaviour has long been known. “Indigenous people knew the season was changing and food sources would become available, in large part, because they saw an indicator species – a particular plant would flower and that would be a sign that the fish would start appearing. It’s not something new, but we’ve become disconnected from how these things happen in the world,” she says.

Now, because of climate change, re-discovering knowledge about the timing of natural cycles has become especially important. But Dr Chambers says the benefits of all these observations won’t only accrue to the scientists.

“It’s easy to slip into the city mode of life where we go to the shops to buy our food and goods and we tend to forget that there’s a natural system lying behind it all providing these services,” she says.

“We forget plants and animals change their behaviour with the seasons. It can be fascinating to observe them.”

Read this article at The Age online

Greenery can revive the atmosphere at home

IF you live in a city or suburb, it’s likely the trucks and traffic sometimes make you gasp for breath. But Professor Margaret Burchett, from the school of environment at University of Technology, Sydney, warns that we can’t close our doors on poor air quality.

“According to the World Health Organisation, urban air pollution kills two to three million people around the globe every year,” she says. “But the amazing thing is that our air is more polluted indoors than outside.”

While Australian cities aren’t among the world’s smog-ridden worst, our population is overwhelmingly metropolitan. Eight out of ten of us live in urban areas, Professor Burchett says – and we spend nine out of every ten hours indoors.

In addition to the fossil fuel emissions that blow in from outside, indoor air typically comprises extra carbon dioxide, thanks to gas appliances and our breath, together with elevated levels of air toxics – volatile organic compounds (VOCs) from glues and synthetic materials.

“Inside our homes we have lots of petroleum-based products such as plastics, carpets, furnishings and electronics that are ‘off-gassing’ toxics,” Prof Burchett says.

These contaminants can cause health problems such as headaches, asthma, loss of concentration, wooziness and nausea.

But here’s the good news: we can freshen the air by bringing greenery into our buildings, places that Prof Burchett describes as “the most arid environment on Earth”.

Her team has been researching the way vegetation improves indoor air quality. They’ve found that pot plants can reduce the presence of VOCs by three quarters and diminish carbon dioxide levels by a quarter. “Plants help clean the air, there’s no doubt about that,” she says.

When it comes to vanishing the VOCs, it doesn’t matter what kind of indoor plant you choose – so long as you take good care of it. To reduce carbon dioxide levels, however, the more lush the foliage, the better.

“The bacteria in the potting mix are what takes up the toxics,” she explains. “The plant nourishes the bacteria, and the bacteria do the uptake. If you keep the plant healthy, it will keep its micro-organisms healthy and they’ll do the job – they’re the same bacteria that suck up oil spills, so this is just an entrée for them.”

In her living room, Prof Burchett has four pot plants (she had six, but two died recently while she was travelling – such calamities even befall the experts). Over- and under-watering are the most common ways to kill them, so she recommends testing soil moisture with your finger or a chopstick. To avoid mould growth, make sure you remove dead leaves and flowers.

“Have as many plants as you can, keeping in mind their level of shade tolerance,” she suggests. “Half a dozen will make a significant difference to your air quality and also to how you feel.”

Prof Burchett has been working with psychologists to study the wellbeing effects of plants in offices and schools.

“They lift the spirits,” she says. “They’re good for us psychologically. We’ve found that students perform better on memory and creative thinking tests. In offices, we found that one plant made all the difference in reducing in feelings of stress and hostility.

“When we’ve got greenery around us, it relieves our tension and fatigue.”

Read this article at The Age online