In school, we learnt the role trees and plants have in producing the oxygen we breathe.
We came to understand that forests do more than produce oxygen, they also capture and remove vast amounts of carbon dioxide (CO2) from the atmosphere via photosynthesis and other natural processes[i]
Then, as we began spending more and more time in cities, we discovered that the benefits of plants could creep past the tree line and inside our cities and buildings. Not only could they capture CO2 and transform it into oxygen, plants could also remedy some typically modern problems, like the urban heat island effect[ii] and sick building syndrome[iii].
Now, we are finding out that it isn’t the plant alone delivering these benefits but the microcosm around it. And doesn’t it seem obvious? The natural world is symbiotic, nothing is wasted and no process results in a dead end. But let’s pause for a minute before we unpack the science and explore why air quality matters in the first place.
Why air quality matters
Good air quality is essential to our health and wellbeing. On average, a person inhales about 14,000 litres of air every day. The presence of contaminants in this air can adversely affect people’s health.[iv]
Some of the main culprits we’re breathing in include particulate matter (PM), ozone (O3), CO2, sulphur dioxide (SO2), nitrogen dioxide (NO2) and benzo(a)pyrene (BaP). In high concentrations, these gaseous chemicals can lead to headaches, eye, nose and throat irritation, asthma, reduced lung function and cancer, chronic obstructive pulmonary disease, cardiovascular disease and reproductive problems. Infants and older people, as well as those with diabetes, pre-existing respiratory and heart conditions are all particularly vulnerable.[v]. In fact, air pollution is the world’s largest single environmental health risk, causing one in eight deaths in 2012.[vi]
Beyond adverse health effects, poor air quality is also a significant economic issue. A 2016 World Bank study found air pollution cost the global economy about $225 billion in lost labour income and about $5 trillion in welfare losses each year. That is about the size of the gross domestic product of India, Canada, and Mexico combined.[vii]
The call is coming from inside the house
At home and indoors now, the CSIRO has estimated that the cost of poor indoor air quality in Australia may be as high as $12 billion per year.[viii]
Gaseous pollutants and volatile organic compounds (VOCs) are emitted from everyday objects found indoors like carpets, soft furnishings and electronic equipment. Even the greenest office fit-outs, VOCs are introduced through human activities and pollutant sources including deodorants, perfume, computers and printers. Left unchecked, these build to make us sick and impair cognitive function.[ix]
Given that Australians spend more than 90 percent of their time indoors where pollutant concentrations can equal or exceed outdoor levels,[x] we must address indoor air quality urgently. The effect spreads beyond the health of individual building occupants and hurts us all: socially, economically and, of course, environmentally.
Getting back to the science
‘People who work in well-ventilated offices with below-average levels of indoor pollutants and carbon dioxide (CO2) have significantly higher cognitive functioning scores – in crucial areas such as responding to a crisis or developing strategy – than those who work in offices with typical levels’.[xi] How much higher? Well, researchers found that the largest improvements occurred in crisis response (between 97 and 131 per cent improvement); strategy (between 183 and 288 per cent) and information use (between 172 and 299 per cent). Imagine the value of that kind of improvement in your workplace? Or in schools or hospitals? Amongst only some of the things, ‘a breath of fresh air’ or two could deliver improved test scores, more effective project execution and better surgical outcomes.
Taking a closer look
Microbiological testing by scientists at the University of Technology Sydney (UTS) in 2007 found that soil microorganisms were the primary agents removing volatile organic compounds (VOC) from the air.[xii] Microorganisms, part of the potted-plant microcosm, broke down organic matter in the soil, while the plants worked to nourish the species-specific root-zone microbial communities.
This was the ‘first demonstration of removal of gaseous-phase VOCs by in situ soil microorganisms. These studies showed that the potted plant microcosm represents a self-regulating biofilter and phytoremediation unit of indoor air.’[xiii] This is cool because it shows the symbiotic loop at work. It is neither the plant, nor the microorganisms, but both working together to absorb, breakdown and dispel PM, CO2 and all the other nasties floating in the air around us. Unlike even top-of-the-line HVAC systems, these plants don’t just sequester the bad stuff, they use it so there is no filter to dispose of or replace.
Over the last few years, the team at UTS have built on this research and tested the ability of plants and plant substrates to modulate indoor air quality. In fact, they have helped my company Junglefy test and quantify the ability of our new ‘Breathing Wall’ to clean the air. What they have found is pleasing – not just for Junglefy, the living infrastructure industry, or even the built environment – but for everyone. It’s that when the operational characteristics of our Breathing Wall were identified and measured like for like against contemporary mechanical filtration systems, the removal efficiency was comparable. They noted that while ‘the removal efficiency detected was lower than conventional in-room air filters, development of the device has the potential to improve the system.’[xiv] I am pleased with this and am looking forward to perfecting this plant-based solution for optimal indoor air quality.
The low hanging fruit
For now though, the research take-away we can all use immediately is that potted plants or ‘PPM represents an adaptive, self-regulating, portable, flexible, low-cost, sustainable and beautiful biofiltration and bioremediation system for IAQ.’
You don’t need a greenhouse teeming with ferns and flowers to improve indoor air quality, in fact, you can reap the rewards with a few potted plants in each room. It is a simple solution – one we learnt in the same school science lab I mentioned above – and it can be integrated into existing fit-outs and new builds, from homes and offices, to schools, shopping centres and hospitals. All you need is a good light source and the plants will go to work with the magic of photosynthesis.
But maybe you’re feeling ambitious? Pair a large-scale green wall with a good quality HVAC system and you can create an indoor environment that enables occupants to flourish mentally, physically and emotionally[xv] You’ll reduce sick building syndrome[xvi] improve test scores and see financial return on your investment.[xvii]
How good is that?
Featured image: 485 La Trobe Street, Melbourne – Australia’s largest Junglefy Breathing WallTM , Photo credit: Junglefy
[i] US Environmental Protection Agency. (2010.) ‘How does green infrastructure benefit the environment?’ fact sheet.
[ii] Department of Environment and Primary Industries for the State of Victoria, Growing Green Guide: A guide to green roofs, walls and facades in Melbourne and Victoria, Australia, Melbourne, 2014
[vi] World Health Organization (2014.) News release: 7 million premature deaths annually linked to air pollution
[vii] The World Bank and Institute for Health Metrics and Evaluation, University of Washington, Seattle. (2016.) The Cost of Air Pollution: Strengthening the Economic Case for Action. p.vii
[viii] Brown, S.K. (1998.) ‘Beating the $12 Billion Cost of Polluted Air’. CSIRO Press Release, Ref 98/55.
[ix] Allen,J. G., MacNaughton, P., Satish, U., Santanam, S., Vallarino, J., Spengler, J.D. (2015.) ‘Green buildings and cognitive function’, Environmental Health Perspectives. Harvard T.H. Chan School of Public Health, Center for Health and the Global Environment.
[xii] Tarran, J., Torpy, F., Burchett, M. (2007) ‘Use of living pot-plants to cleanse indoor air – research review’. Faculty of Science, University of Technology Sydney, Sydney, Australia.
[xiii] Tarran, J., Torpy, F., Burchett, M. (2007) ‘Use of living pot-plants to cleanse indoor air – research review’ P.2-3 Faculty of Science, University of Technology Sydney, Sydney, Australia.
[xiv] P.J. Irga., N.J. Paull., P. Abdo., B.P. Huynh., V. Avakian., T. Nguyen., F.R. Torpy. (2016.) Developing the Junglefy Breathing Wall for enhanced indoor air quality remediation. Plants and Environmental Quality Research Group. Report prepared for Junglefy Pty Ltd. University of Technology Sydney, Australia. p.4
[xv] Beatley, T. (2011.) Biophilic Cities: Integrating nature into urban design and planning, Island Press. p.3
[xvi] Torpy, F. (2013.) Sick building syndrome: how indoor plants can help clear the air, University of Technology Sydney
[xvii] J.F. Dwyer, E. Gregory McPherson, Schroeder, W. Herbert, R.A. Rowntree. (1992.) ‘Assessing the benefits and costs of the urban forest’, Journal of Arboriculture, 18(5): September 1992, p.229