The Breathe Green Science
At Breathe Green Design, we greatly value the power of science and respect rigorous scholarship. We also freely admit that there is much yet to know, and perhaps much we will never know... Below please find our takes on the status of peer-reviewed research in fields relevant to our work and mission. We hope you find this helpful!
Improving Indoor Air Quality
The Problem:
The air inside our homes is killing us.
In our indoor environments, especially those that are well-insulated, and climate-controlled, life-threatening gaseous chemicals are becoming even more concentrated in the air we breathe.
These chemicals include volatile organic compounds (VOCs), such as formaldehyde, benzene, ethylene glycol, and toluene, as well as carbon monoxide, ozone, and radon. These toxins in our home, school, and office air have thousands of sources, from paint, furniture, and carpet off-gassing, to air fresheners, cleaning products, gas stoves, and vehicle exhaust.
Some health effects may show up shortly after a single exposure or repeated exposures to a pollutant. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue…Other health effects may show up either years after exposure has occurred or only after long or repeated periods of exposure. These effects, which include some respiratory diseases, heart disease and cancer, can be severely debilitating or fatal. It is essential to try to improve the indoor air quality in your home even if symptoms are not noticeable (EPA, 2021).
Unfortunately, almost all US homes have these indoor pollutants, and VOCs are a global issue. The EPA estimates that US average indoor VOC levels are 2-5 times higher than those outdoors, with the highest concentrations in the Northeast and Midwest and in newer, more airtight construction everywhere. Asthma, COPD, migraine headaches, and chronic fatigue syndrome are some of the serious ailments linked to indoor pollution from VOCs and from elevated levels of radon, ozone and CO2.
The Breathe Green Solution:
Plants clean the air we breathe and the water we drink.
A Breathe Green space turns your home into a more healthful physical environment. Researchers have long documented the role of plants in removing harmful toxins from the air, though much debate remains over the extent of the benefits indoor plants bring. The first strong evidence of this benefit comes from the work of NASA scientists. After discovering dangerous gaseous chemical levels in Skylab, the first space station, plants were used to remove dangerous levels of indoor VOCs, quite rapidly and effectively (see Wolverton, Johnson, & Bounds, 1989), Since then, hundreds of scientific studies have been conducted to examine this phenomenon. Some researchers, such as Cummings and Waring (2020), argue that the role of indoor plants in indoor air purification is insignificant, unless the number of plants is quite large, while others, such as Kim and colleagues (2018), maintain that “A plant-based removal system for volatile organic compounds (VOCs) appears to be a low-cost, environment-friendly solution for improving indoor air quality.” The scientific consensus seems to reflect the sentiment that, “In general, indoor plants have great potential to purify the air regardless of time of day or the foliage” (Han & Ruan, 2020).
The key takeaways:
Creating Comfortable, Energy-Efficient Environments
The Problem:
The thermal comfort range of humans and of many indoor plants is quite similar. Humans are most comfortable at humidity levels between 30% and 50%. Indoor humidity levels from late fall through early spring often average less than 20% in colder climates, however, and the central heating systems common in the US and Europe often lower relative humidity to 10% (Gubb et al., 2018). Low indoor humidity, especially common in winter, leads to a host of health problems, including sinus infections, viral infections, nosebleeds, asthma, headaches, and dry, cracked skin (Mayo Clinic, 2021). Mechanical remedies for low indoor humidity, such as humidifiers, bring their own problems, however, which include bacteria, mold, maintenance issues, and high energy use.
The Breathe Green Solution:
Plants create a comfortable level of humidity, naturally, and moderate indoor temperatures in both winter and summer.
Indoor plants, when placed to create temperate micro-environments, help keep us warmer in winter and cooler in summer, while increasing humidity levels. Plants provide a natural way to increase indoor humidity, without mechanical intervention. Although certain indoor plants, such as spider and jade, are particularly effective at increasing indoor humidity (see, for example, Kerschen et al., 2016), all plants make indoor spaces more comfortable through the process of evapotranspiration. Plants give off moisture through their leaves, and the plants that are most effective at adding humidity also (happily for us humans!) take CO2 out of the air at higher rates (Deng & Deng, 2018). Fortunately, plants are best at increasing indoor humidity when it is lowest–when we need it most!
The positive effects of plants on indoor humidity are dramatically increased with proper lighting. A Breathe Green Space can raise relative humidity from an uncomfortable, unhealthful 20% to 30%+, without any need for additional equipment, expense, energy use, or effort. Nguyen, Bui, & Pham (2021) found that plants can reduce indoor summer temperatures by about 20 Fahrenheit. When coupled with the beneficial 10 F increase in winter temperatures from indoor plants, a Breathe Green Space provides an average savings of 15% on heating and cooling costs, plus a more comfortable environment, year-round, for your entire family.
The key takeaways:
Increasing Productivity
The Problem:
The increasing demands–and distractions–of modern life and technology, coupled with sterile, artificial environments, have left us often unable to concentrate fully on tasks at hand. These barriers to productivity and effectiveness are made worse by polluted air, as Zhang and colleagues (2021) have demonstrated. Poor indoor air quality is associated with substantially decreased mental performance, especially in those with other respiratory or health issues (Satish et al., 2012). In particular, higher indoor concentrations of CO2 can lead to large lapses in memory, concentration, and accuracy. Indoor spaces without plants can develop substantially high carbon dioxide levels, especially in well-insulated homes or offices, sapping our energy and causing us to lose focus (Bell & Hanes, 2013).
The Breathe Green Solution:
Plants, once again, come to the rescue! This time, they aid our brains to function at their highest level: plants make us smarter!
Just having a few plants in a room significantly increases our ability to focus more deeply, be more productive, learn more effectively, and feel happier (Lee et al., 2015). The improvements in air quality that your plants bring also enable us to excel on important, involved, and complicated tasks. Whether you want to understand a set of complex ideas, complete a major project, or learn a new language, a plant-rich environment will help you do so, and you’ll experience more joy along the way! Workers who took occasional three-minute “plant breaks” at their desks were 12% more productive than those who did not interact with plants (Adamson & Thatcher, 2018) , and those in offices with plants had significantly lower blood pressure (Kubota et al., 2017).
The key takeaways:
Reducing Stress & Anxiety
The Problem:
The Breathe Green Solution:
Having plants around us decreases our stress and anxiety levels. That’s a good thing!
Recorded human history begins with agriculture; only when we started to grow plants–for food, clothing, shelter, and ornamentation–did we create more complex societies and culture, as we now understand it. Plants do much more for us than provide our nourishment; they also care for our emotional health. Plants in our surroundings can reduce the effects of stress and allow for faster physiological and emotional recovery from stressful situations, including surgery (Ulrich, 1984).
Colorful and fragrant plants in the workplace promote positive attitudes and reduce the numbers of sick days taken (Larsen et al. 1998). In a detailed experimental study, Kubota et al. (2017) demonstrated significant reductions in both objective measures of stress (heart rate, blood pressure) and subjective ones (surveys, self-reporting) when aromatic and attractive plants were introduced into the workplace.
Meet your deadlines. Enjoy the journey. Be more energetic. Let plants help!
The key takeaways:
Enhancing Mental and Emotional Health
The Problem:
Clinical Depression. Anxiety. Bipolar Disorder. Suicidal Ideation. Insomnia. Anorexia. These mental health problems are all becoming far more common in the developed world, a result of the stressful societies in which we live. The World Health Organization (2022) estimates that now more than a quarter of a billion people worldwide suffer from major depression alone. As terrible as these numbers are, they are mirrored in the widespread unhappiness and pessimism for the future that afflicts too many of us around the globe today, even if we are otherwise healthy. Mental health issues are debilitating themselves, but also are primary contributors to significant physical ailments, including heart disease, diabetes, and strokes (CDC, 2022) . Poor mental health makes us significantly less productive (Goetzel et al., 2003) and weakens our social bonds(Roberts & Burleson, 2013).
The Breathe Green Solution:
Green, restorative environments can improve our mental health and make us happier.
We’re of course not suggesting that plants can cure serious mental illness. That said, an overwhelming body of research confirms what we already intuitively know: we are happier and healthier when we share space with plants. The benefits for our mood, energy level, and sociability are significant. A recent study in Australia (Koh et al., 2017) found that coronary patients had substantially lower rates of post-surgical depression, and were released earlier from the hospital, when flowering plants were placed in patients’ rooms.
The key takeaways:
Promoting Human Curiosity & Connection to the Natural World
The Problem:
For all but the past several decades of our history, most humans have lived outside of urban areas: in other words, as part of, and with, nature. As of 2015, however, a majority of the human race now lives in cities–an accelerating trend–and far too few of us have sufficient access to green spaces we need for recreation and rejuvenation. Many of us are thus left with feelings of isolation, unhappiness, and detachment, which impair our thinking across several dimensions (Kaplan, 1995). Human beings are socially and biologically “wired” to respond positively to lush, green environments. The high cognitive demands of modern life and work, coupled with lack of access to natural settings, decreases cognitive function, including problem-solving, memory, and creativity (Valtchanov & Ellard, 2015).
The Breathe Green Solution:
We were meant to live alongside plants…
Our creativity, learning, and drive to experience new things are all boosted by the presence of plants, especially those with distinctive or colorful foliage. Studente, Seppala, and Sadowska (2016) found that plants in classrooms greatly increased visual creativity. Lichtenfeld and colleagues(2012) identified the substantial impact of the color green on a wide range of creative tasks. More recently, Elsadek & Liu (2021) showed that simply viewing flowering plants provided “A significant increase in alpha relative waves in the prefrontal and occipital lobes, and a significant increase in parasympathetic nervous activity” (p. 1429). Alpha waves indicate a mind at rest, freed from stress and distractions, and open for creative problem-solving; parasympathetic nervous activity promotes calm, rational thinking and supports physical and mental relaxation. Similarly, Johnsen and Rydstedt (2013) found that the natural environment was (by far) the most effective for regulating our emotions, not only for sustaining positive, and limiting negative, feelings, but also for enabling a more creative, solution-oriented mindset.
The key takeaways:
Technological progress has made the human condition better in so many ways. Losing our connection to the natural world, however, increases stress levels, hampers our sense of mental well-being and drains our creative, problem-solving abilities. Incorporating a Breathe Green space into your home or office can reconnect you with the healing, inspiring power of Mother Nature.
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