Purification of Indoor Air Quality – Negative Ions & Plants
David Baggs, CEO and Technical Director
With most people spending up to 80% of their time in indoor
environments, be it at home, in the office, at school or
university, it's becoming more and more important to ensure our
indoor environment is a healthy place. This is even more necessary
as buildings become increasingly air tight and ventilation systems
become closed loop as people rely increasingly on air conditioning
in summer time. This closing up of buildings comes at a price
indoor air quality reducing due to emissions from various sources
indoors and nowhere for them to go with the windows closed.
The term "building ecology" has been coined to describe the
interaction between building environments and their occupants
(Levin, 1981). A healthy building is one that does not adversely
affect the health of its occupants or the larger environment and an
integral factor in this interaction is the indoor air quality of a
building or home.
Many studies have shown that indoor air quality can often be
several times worse than the worst outdoor pollution (apart from
sandstorms!) and poor indoor air quality can substantially reduce
health of families and reduce the productivity and general health
and immune system function of workers in the office
environment.
Problem causing emissions can come from outside in the form of
car, truck or industrial pollution or be generated indoors directly
from appliances, décor (such as adhesives, paints, lacquers, vinyl
fabrics and flooring, carpets etc.) building products (such as
particleboard, medium density fibreboard -MDF), cleaning products
and furniture and fixtures (that contain foams, padding, vinyl
fabrics etc) and contain enormous amounts of potential polluting
substances that emit volatile organic compounds or VOCs.
These compounds evaporate out of the materials at room
temperature and can cause a range of serious health impacts ranging
from irritation of eyes, nose and skin, headaches, fatigue, poor
concentration or ability to think clearly, difficulty breathing and
nausea to long term impacts such as liver and kidney disease,
cancer (IARC) and so on with studies showing 5% to 40% of office
workers have been affected, depending on the symptom (Fisk, 1997,
2000). So it is very important to ensure the internal air quality
of all buildings is healthy and clean.

Figure 1: DV1 Air Ioniser for air
purification
Image courtesy of Kempe (Aust)
While the best form of mitigation is avoidance, i.e. eliminating
materials and products that emit VOCs from the home or workplace in
the beginning, there are ways to clean up the air to make it
healthy again. There are mechanical means such as air ionisers that
produces negatively-charged ions which can assist in reducing
airborne and surface borne contaminants and improving bodily
function. These negative ion generators come at various scales for
commercial use (such as DV1 illustrated in Figure 1) or
residential/personal use such as Elanra, among the only ionisers
globally to be officially recognised by government authorities as a
Therapeutic Device, Elanra (shown in Figure 2 left to right as
suitable for large room, small room/personal or individual), is
registered in Australia by the Therapeutic Goods Administration, it
is unique in generating small air ions. Small air ions are,
compared to the medium and large sizes that in effect largely only
clean air and surrounding surfaces, are medically active because
they can be directly ingested by inhalation and pass through
directly into the blood stream where they actively promote a
variety of health benefits including:
- Better sleep
- Easier breathing
- Faster recovery from illness
- Less severity and frequency of colds and flu
- Enhanced oxygen intake
- Increased energy
- Better concentration and learning
- Stress relief
- Improved vascular system
- Removal of airborne pollutants including passive smoke
- General health and wellbeing
- Immune system recovery
- Reduction in Allergy and eczema
- Assisting with Chronic fatigue

Figure 2: Elanra Ionisers -left to right Mark I, Mark II
and Pendant, office, room and personal ionisers -Australian TGA
Approved
Image courtesy of www.negativeions.com
Dracaena
marginate
Image courtesy of Lechusa Planters
One can also take a more natural approach, it is possible to
clean up air by introducing plant-based ecosystems into your indoor
spaces. Before you discount this as sounding to complex or
difficult, realize that it is as simple as bring pot-plants into
spaces and keeping the soil and plants healthy,
Worldwide experience has recently been confirmed in Australia by
research at the University of Technology, Sydney (UTS) that green
plants are an effective way of reducing VOCs in internal air.
The indoor foliage plant species:
- Kentia Palm (Howea forsteriana),
- Peace Lily (Spathiphyllum 'Petite'),
- "Janet Craig' (Dracaena deremensis),
- Devil's Ivy (Epipremnum aureum),
- Queensland Umbrella Tree (Schefflera actinophylla,)
- "Amate' Spathiphyllum 'Sensation', 'Petite' and
- Dracaena marginate
were all tested for their ability to remove VOCs from the indoor
air. All seven plant types studied demonstrated benzene removal
activity at similar rates. Kentia Palms were found to remove
benzene up to 90% from a closed room after 24 hours. When
ventilation was added to a room with a Spathiphyllum 'Petite'
inside, the rate of benzene removal was improved up to 15%.
Studies in Norway
and the Netherlands have shown that health complaints at work can
be significantly reduced by the presence of plants. Whether these
effects are physical or psychological (or a combination of the two)
is uncertain. What is clear, though, is that symptoms associated
with Sick Building Syndrome (SBS) can be dramatically reduced by
the addition of good plant displays.
Spathiphyllum 'Petite' in a sub-irrigated
planter
Image courtesy of Lechusa Planters
Keeping plants healthy is very important to achieve this effect
and the best way to achieve this is with planters that have
sub-irrigation that reduces the frequency that plants need to be
watered and introduces the potential for water savings. The water
is fed into a tube from the top runs down and collects at the
bottom of the planter, and is wick-fed through holes in the
sub-irrigation base. Effectively, water use is determined as the
plant requires, and there is reduced evaporation loss. A water
level indicator is also generally included to indicate water
supply.
Another effective plant based air improvement technique has been
shown to be the "Green Wall". In this system, air is drawn through
a porous wall kept constantly wet and covered with mosses and
ferns, removing low levels of indoor air pollutants. Examples of
green walls are shown here at the New T3 Terminal in Singapore and
the Qantas Club Lounge in Sydney International Airport.

Integrating plants into the office environment has proven to be
an effective, inexpensive, flexible and aesthetically pleasing
biofiltration system that is self-sustaining as long as the plants
are maintained adequately. Not only do they improve the atmosphere
of any indoor environment, they help improve productivity, health
and overall wellbeing of employees or your family.

Sources:
Elanra Ionisers: www.negativeions.com
DV1 Ionisers: http://www.kempeaustralia.com/dv1/
IARC: AGENTS REVIEWED BY THE IARC MONOGRAPHS, Volumes 1-88,
International Agency for Research into Cancer, 2006
R. Wood, IMPROVING THE INDOOR ENVIRONMENT FOR HEALTH, WELL-BEING
AND PRODUCTIVITY, Dept Env Sc., UTS, Sydney.
http://www.plants-in-buildings.com/whyplants.php
B. C. Wolverton, How to Grow Fresh Air: 50 Houseplants That Purify
Your Home or Office
All websites last accessed on 9/4/13.