Research Paper
by Nicole Bijlsma (2005). Indoor Air Quality - a Dilemma
Introduction
Like
clean water, air is something we all take for granted, but can we
afford to be so complacent? Despite the fact that we inhale some 10,000
litres of air per day (Carola et al 1992), and indoor air is rated
among the top four environmental health risks facing this planet according
to the US EPA, indoor air quality (IAQ) remains largely ignored by
government and Occupational Health and Safety (OHS) authorities. Since
the oil embargo of the 1970s, the term Sick Building Syndrome has
become synonymous with the modern office environment with poor IAQ
being a major contributing factor (Rooley 1995; WHO 1986). The annual
cost of poor indoor air quality to Australians is estimated to be
around $AS12 billion (Brown 1998a) and $US60 billion to US businesses
(Cullen 2002). IAQ has become an important occupational health issue
that has led to increasing numbers of investigations in mechanically
ventilated workplaces worldwide. Since 1971, NIOSH has conducted more
than 1500 non-industrial indoor environmental health hazard evaluations
(Springston et al 2002). Australian studies have been limited (State
of Knowledge Report, State of Environment Report, Seneviratne and
Phoon 1997), but indicate a similar occurrence to other developed
countries regarding sick building syndrome-like symptoms and dissatisfaction
with office air environments. Whilst a large number of pollutants
have been investigated in Australian buildings, many of these pollutants
have not been sufficiently researched to determine exposure levels
for the Australian population (Brown 2004; Environment Australia 2001).
Of concern, is the recent legislative pull towards ‘energy efficient’
building designs and the consequent reduction in air exchange rates.
No doubt this will further adversely impact indoor air quality. Despite
these concerns, no single government authority is currently taking
responsible for indoor air quality in Australia (Brown 2004).
Exposure
of building occupants to pollutants in workplace air, whether industrial
or non-industrial falls within the requirements of OHS legislation
(Environment Australia 2001). Under sections 21(1) and 26(1) of the
Victorian OHS Act 2004 (Australia), the employer and any persons who
has management or control of a workplace, must take every reasonable
action to ensure that the workplace is safe and without risks to health.
According to WorkSafe (2005) this includes an employer, the building
or site owner, and the property manager or lessee of a building or
site where there is a workplace. Brown (2004) states that poor IAQ
has become a liability for employers and building managers who fail
to provide a ‘safe’ working environment. This is also
supported by Ferrari of the Clean Air Society of Australia and New
Zealand (2002) who is concerned that Australia is failing its responsibilities
of a ‘duty of care’ to protect the community. Despite
the employer’s duty of care to take all reasonable practicable
steps to resolve any problems, little guidance is provided by the
OHS legislation on IAQ. What little is available focuses on thermal
comfort (Code of Practice for Workplaces 1988 and Officewise 2001),
and mechanical ventilation systems (AS 1668 and AS/NZS 3666). Most
of the information provided by WorkSafe with regards to offices relates
to ergonomics, manual handling, lighting, noise and thermal comfort
with very little guidance on indoor air quality. This is quite alarming
when you consider that we not only spend up to 90% of our time indoors,
but that “a pollutant released indoors is 1000 times more likely
to reach a person’s lungs than a pollutant released outdoors”
(WHO 1997). Furthermore, indoor air pollution is estimated to be two
to five times worse than outdoor air pollution though the exact figure
varies amongst authors (Cullen 2002; US EPA 2005; Wadden and Scheff
1983). Interestingly, of the hundreds of air pollutants covered by
US laws, only ozone and sulphur dioxide remain more prevalent outdoors
(Ott and Roberts, 1998).
Given
the amount of research now associating poor IAQ with ill health, employers
and building managers can no longer ignore their obligations. But
what then is the role of an OHS authority if not to address the hazards
in the workplace? It appears that OHS authorities have inadvertently
by way of inaction, delegated the issue of IAQ to the building manager
and the ventilation system. Despite their expertise on HVAC systems,
very few have a clear and definitive direction for the proactive management
or control of a sick building beyond ventilation and maintenance (Thomas-Mobley
et al 2005). Furthermore the use of ventilation as a mitigation measure
for air quality problems is not only limited according to Godish and
Spengler (1996), it now widely accepted overseas that the control
of emissions within offices is the most important strategy for achieving
good indoor air quality (Environment Australia 2001). Moreover, there
are no legal obligations on building designers, suppliers of materials
and equipment, builders, building owners and tenants to consider indoor
air quality (BOMA 1994). The Building Code of Australia (2005) for
example offers little guidance on IAQ for offices, referring instead
to the Australian Standards on mechanical ventilation.
When
it comes to IAQ, there also appears to be inherent limitations in
the methodology that underpins hazard identification in OHS risk management.
For a start, it does not take into consideration the synergistic effects
of multiple air contaminants commonly found in non-industrial workplaces
within ‘acceptable’ exposure standards. This is surprising
given that unlike industrial workplaces, sick buildings are rarely
due to a single pollutant present in amounts above the exposure limit
(Cullen 2002). Where occupational exposures are covered by OHS legislation
and are specific for certain industries, incidental exposures to the
same contaminants in indoor air from supposedly ‘unrelated’
industries are not covered (CASANZ 2002). For example, despite the
fact that lead dust is an obvious risk to human health, the lead regulations
only apply to workplaces associated with the use of lead (OHS (Lead)
Regulations 2000). As such renovations to older buildings containing
lead-based paint may contaminate the indoor air of offices where people
are working and yet the employer is not obliged to address this hazard
under the lead regulations. The Clean Air Society of Australia and
New Zealand (2002) argue this distinction is arbitrary and does not
protect workers who maybe affected by indoor air pollutants. The US
EPA point out that the use of occupational standards are not appropriate
for use in commercial facilities. As a result of this ambiguity, it
is a widely accepted practice in the US for non-industrial workplaces
to guess what is acceptable by either adopting a % of TLV or establishing
a ceiling target (eg. no more than 10% of employees complain before
action is taken) (Burton 2003). Another limitation in OHS is that
exposure standards do not account for sensitive individuals such as
asthmatics or pregnant women who are likely to make up a significant
proportion of the office environment. Poor IAQ is consequently ignored
in many workplaces or at worse, misdiagnosed by OHS professionals
as psychosocial (Richey 2003).
There
is a growing need for OHS professionals to familiarize themselves
with the issue of poor indoor air quality. Currently most questionnaires
and surveys on IAQ such as the UK Revised Office Environment Survey
(ROES), the Swedish MM Questionnaire, US Building Assessment Survey
and Evaluation (BASE) and the Stockholm Indoor Environment Questionnaire
(SIEQ) tend to focus on the prevalence of sick building syndrome in
a building. These self administered questionnaires are generally lengthy
and time consuming and are impractical to implement in OHS risk management.
In contrast, this audit tool will provide the OHS professional with
a quick and simple tool to assess and investigate complaints about
IAQ from workers whilst also providing them with control strategies
by which to address these. Whilst this tool is by no means an authoritative
tool in diagnosing IAQ issues, it will provide the OHS consultant
with the basics required to determine what hazards maybe involved
and which professionals to engage. The survey may also be used to
determine the effectiveness of any control measures implemented. The
IAQ tool can be found in Appendix 1.
This
paper will explore the complexities underpinning IAQ in a relatively
new (4 year old) mechanically ventilated open plan office and the
various contaminants likely to be involved. Environmental tobacco
smoke is strictly prohibited from this office, so this will not be
discussed as a hazard. This office has a designated OHS representative
who does not have access to any indoor air quality monitoring equipment.
Indoor air is defined by the NHMRC as any non-industrial indoor space
where a person spends a period of an hour or more in any day such
as an office, classroom, motor vehicle, shopping centre, hospital
and home (cited in Environment Australia 2001). CASANZ (2002) consider
indoor air pollution as all those air pollutants that are not controlled
by occupational or ambient legislation in the environment.
IAQ reflects a complex set of factors from building and ventilation
system design, to construction, operation and maintenance; prevailing
climatic conditions, outdoor and indoor pollutant sources and tenant
activities (Environment Australia 2001; ACT Public Service 1995; Brown
2004; Raw et al 1993; Brooks and Davis 1992). This is further compounded
by the following issues:
1. There is no single government authority that is responsible for
indoor air quality in Australia such that there are no definitive
parameters as to what ‘poor’ indoor air quality is.
2. As a result of the multiple parameters affecting IAQ, broad scale
monitoring must be building specific.
3. Human variability regarding susceptibility to various contaminants,
perception of thermal comfort and ability to detect odours makes it
difficult to establish ‘ideal’ IAQ goals.
4. Ventilation rates have changed frequently such that older buildings
may not comply with present legislation.
5. The occupiers themselves often contribute to IAQ problems.
No single authority
There is no single government authority that is currently responsible
for indoor air quality in Australia (Brown 2004). Historically the
realm of indoor air quality has been taken up by varying degrees by
departments of public health, occupational health and safety as well
as environmental government agencies such as the NHMRC. This sporadic
involvement has resulted in the dissemination of information on isolated
issues such as unflued gas heaters and passive smoking (CASANZ 2002).
Whilst the NHMRC developed ‘interim’ goals for a number
of common indoor air pollutants, these documents were rescinded on
19th March 2002. What little research has been undertaken in Australia
on IAQ, is likely to be conducted by the CSIRO, Environment Australia’s
Air Toxics program, enHealth Council, Department of the Environment
and Heritage and private interest groups such as the Clean Air Society
of Australia and New Zealand. These groups provide general guidance
on IAQ control (Environment Australia 2001). Current responses to
IAQ in Australia are to improve building design (Building Code of
Australia) and make changes to ventilation codes (AS 1668.2). However
the use of ventilation as a mitigation measure for air quality problems
is not only limited according to Godish and Spengler (1996), it now
widely accepted overseas that the control of emissions within offices
from identifiable sources is the most important strategy for achieving
good indoor air quality (Environment Australia 2001).
Multiple parameters
Indoor air quality is influenced by building ventilation rates (construction,
operation and maintenance), pollutant emitting sources (both internal
and external), the occupants and prevailing climatic conditions. It
is not only building specific, but may vary considerably within a
particular building according to pollutant sources present, their
emission rates and the rate of ventilation (Environment Australia
2001). In reality, monitoring individual buildings is not only intrusive
and time consuming, it is very expensive. As such, no such broad scale
monitoring currently exists in Australia with regards to IAQ. An alternative
approach is to identify individual sources of indoor air pollutants
by setting exposure standards as documented by OHS authorities such
as NOHSC, NHMRC and ACGIH, however there are several problems associated
with this. For a start, occupational exposure standards (OES) are
not a measure of relative toxicology, they only apply to long term
exposure (8hr day, 5 day working week), they only consider absorption
via inhalation and consequently they should not be used as a basis
for the evaluation of community air quality (NOHSC 1995). This is
further supported by Meek (1991), who states that the long term effects
of various chemicals has not been evaluated thoroughly. Part of this
may be due to the fact that when the LD50 has been reached in the
test animals, the surviving animals are terminated, so their long
term effects are never established. Furthermore, many indoor air contaminants
have not been assigned exposure standards as there is insufficient
information on the health effects of these substances to allow the
Commission (NOHSC) to assign an exposure standard. On top of this,
OES, like many of the standards and guidelines on IAQ, do not cater
for the presence of sensitive groups such as asthmatics, pregnant
women or an ageing workforce (ASHRAE 2004).
In an office environment, it is rare for a single pollutant to exceed
existing standards and guidelines even when occupants continue to
report health complaints (Cullen 2002; US EPA 2005). Many argue that
it is the cumulative mixture of chemical contaminants present in low
concentrations that are likely to be the culprit (Pollak 1993; Spengler
et al 2001). For example, VOCs in combination may cause irritation
of the eyes and nasal passages even when each are found well below
their nominal irritant threshold (Molhave 1992). Material Safety Data
Sheets used in OHS risk management do not take into consideration
the possibility of interactions: synergism, antagonism or additive
effects arising from chemical mixtures particularly with regards to
indoor air (Kerr 1994; Ng 1999). Furthermore, most ventilatory standards
and guidelines do not consider interactions amongst contaminants in
indoor air (ASHRAE 2004). As such, there are no obligations on the
employer to make any changes to the workplace with regards to IAQ
if they are already compliant with OHS legislation.
The issue of multiple parameters is further exacerbated by the fact
that there are few protocols for monitoring indoor air, such that
results are not easily comparable (CASANZ 2002). Brown (2000) highlights
the need to establish uniformity in the monitoring of chemicals in
workplace air. The lack of standardisation of monitoring methods means
data cannot be compared to indoor air quality goals.
Individual differences
Intrinsic genetic variability is a central problem with regards to
IAQ. For example, large differences in the order of 10 to 100 fold
have been observed with regards to people’s reaction to ozone
(Woolcock Institute of Medical Research 2003; Californian EPA 2005).
Where some people are sensitive to or dislike low levels of contaminants,
others do not object to high levels (Brown 2004). Human variability
is rarely taken into consideration when it comes to ventilation rate
studies. According to Spry (1989), these studies use healthy, young
adults, middle class test subjects and do not take into consideration
workers who may deviate from this (Spry 1989). Brown (2004) argues
that asthmatics are sensitive to a variety of pollutants which act
as inducers and triggers. Considering that one in ten adults have
asthma, this is not a minority (Asthma Foundation 2005). Whilst it
is not economically viable to take into consideration every office
worker’s genotype (age, sex, metabolism, genetics, medical history,
lifestyle, medication and susceptibility to disease…) the adverse
health effects of exposing a population to multiple parameters will
vary enormously. In the ASHRAE Standard 62.1-2004, ventilation requirements
for chemically sensitive people are not taken into consideration.
The need to take individual variances and lifestyle factors into consideration
was highlighted by a study on occupational CO exposure in Adelaide.
Wickramatillake and Gun (cited in AIOH n.d) discovered that the carboxyhaemoglobin
levels in most of the smokers (unlike the non-smokers), exceeded the
TWA for CO. Furthermore a proportion of workers in the study had narrowed
coronary arteries thereby increasing their susceptibility to CO poisoning.
As such, the authors argued that the TWA for CO is inadequate as it
fails to take into account people who smoke or those predisposed to
cardiovascular disease.
Heating, ventilation & air-conditioning (HVAC) systems
HVAC systems are designed to maintain a good thermal comfort level
by controlling temperature, humidity and air velocity at a reasonable
cost (Spengler et al 2000). This does not always mean maintaining
an ‘acceptable’ indoor air quality; on the contrary, HVAC
systems may contribute to indoor air quality problems if they are
misused or badly maintained as evidenced by the recent legionnaire
outbreaks at the Melbourne Age building, Royal Melbourne Hospital
and the Melbourne Aquarium. Brown (2005) suggests an urgent need to
study ventilation rates in repartitioned offices in Australia and
their impact on IAQ. Inadequate mechanical ventilation in offices
can arise from poor ventilation rate and efficiency, contaminated
outdoor air and, poor maintenance of the existing ventilation system
leading to adverse health effects (Hedge et al 1993). Alterations
to AS 1668.2 have meant that ventilation rates have changed over time.
Brown (2004) observed that in the 1980s, the ventilation rates were
far lower for mechanically ventilated buildings compared with the
present time. Given that the ventilation rate in non-industrial workplaces
is determined by the requirement for the control of odour, it does
not take into consideration emissions from high polluting sources
such as new building materials or those that are likely to be introduced
into the workplace (Brown 2004; ACT Public Service 1995). Fortunately
most developed countries are developing schemes to identify low-emission
building materials, furniture and appliances (Brown 2004). Refer to
Appendix 2 for more information. It is generally acknowledged that
ventilation rates below 10 L/s per person are associated with a worsening
of indoor air quality in office buildings (Seppanen et al 1999). However
there are discrepancies amongst authors as to the impact of increasing
ventilation rates above this figure, with some saying it further improves
IAQ (Seppanen et al 1999; Wargocki et al 2000), whilst others stating
it makes little difference because of other compounding factors (Godish
and Spengler 1996; Hedge et al 1993; Bluyssen 1996). ASHRAE recently
revised its ventilation standard to provide a minimum of 20 cfm/person
in office spaces. Whilst there is an increased prevalence of complaints
regarding IAQ in mechanically ventilated offices, there are other
risk factors apart from the HVAC system which are likely to be involved
(Jaakkola et al 1991).
Occupiers
A common problem contributing to poor IAQ is the occupiers themselves.
People are sources of bioeffluents such as carbon dioxide and VOCs
(body odour), as well as heat and water vapour (Spengler et al 2001).
They also wear personal care products (VOCs) and are carriers of biological
contaminants such as bacteria, dander and viruses. Furthermore the
way in which occupants use the building may also adversely affect
IAQ (ACT Public Service 1995). Changes to the occupancy levels, type
of work and office layout (partitioning) may significantly alter the
effectiveness of HVAC systems such that compliance with AS 1668.2
cannot be assured. Management may also contribute to IAQ problems
if it does not establish a good organizational environment for reducing
stressors that foster complaints about IAQ and for dealing with complaints
should they arise (Spengler et al 2001). However this issue warrants
a research paper in its own right.
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Indoor Air Quality Parameters
IAQ
problems maybe defined in terms of one’s health, comfort and
productivity. The risk factors associated with poor IAQ in an office
are many and varied. Apart from thermal comfort, the office environment
is typically host to particulates and biological contaminants (bacteria,
fungi and viruses) as well as a multitude of chemical contaminants
from personal care products (perfumes, fragrances from aftershave,
moisturisers…), printers, copiers, building materials (solvents
and adhesives in carpets, paints, treated wood products, vapour barriers,
synthetic materials…), furnishings and upholstery, pesticides
(tracked via shoes and ambient air), cleaning solvents, clothing (dry
cleaning solvents) and car exhausts from underground parking garages
(Ilozor et al 2001; Kerr 1994).
The following have been cited causes of or contributing factors to
sick building syndrome:
Thermal comfort - temperature, humidity &
air velocity
The greatest perception of a sick building and consequently poor IAQ
arises from thermal comfort: air temperature, relative humidity and
air velocity.
Air temperature is the most important thermal comfort factor,
however the ‘ideal temperature varies considerably amongst workers
depending upon several factors such as their genetic predisposition
(their metabolic rate), disease states (eg menopausal or hypothyroidism),
pregnancy, clothing they are wearing, the work they are doing, seasonal
variations and so forth. Thermal comfort is also influenced by the
mean radiant temperature of surrounding surfaces which should be approximate
to the air temperature (Comcare 1995; Rooley 1995). Kroemer and Grandjean
(2001), suggest that adjacent areas should not differ from that of
the air by more than 20C or 30C. According to WorkSafe (2001), thermal
differences between the head and feet should be avoided. Temperatures
below 180C are associated with symptoms of colds, chills, flu, restlessness
and reduced concentration (ACT Pubic Service 1995; Kroemer and Grandjean
2001). In contrast, temperatures above 260C are associated with sleepiness,
increased liability to errors, discomfort, headaches and fatigue (ACT
Pubic Service, 1995; Kroemer and Grandjean, 2001). WorkSafe (1988)
suggest a minimum of 180C for an office environment, however this
contradicts the general consensus that the ideal temperature should
vary between 20 to 240C in winter and 23 to 260C in summer (NOHSC
n.d; Comcare 1995; Rooley 1995). Where Kroemer and Grandjean (2001)
provide more narrow limits of 20 and 210C in winter and 20 and 240C
in summer, ASHRAE Standard 55 recommends an air temperature between
20-270C and a relative humidity between 30 and 65%. For purposes of
this research paper, I will follow the recommendations recommended
by NOHSC.
Humidity is the amount of moisture in the air with indoor
humidity generally reflecting the prevailing outdoor humidity. However
internal sources may include cooking (boiling water), showering, washing,
people (exhale water vapour and sweating), humidifiers and plants.
Unlike temperature, people can tolerate a wider range of relative
humidity levels from 30 to 70% without adverse complaints (Brown and
Mathieson 1991). Given that most air-conditioning systems in Australia
do not humidify, dry conditions within offices are common (NOHSC n.d).
As such low humidity (<30%) may lead to symptoms of dry eyes, nose
and throat, as well as increased respiratory illness and static electric
shocks (ACT Public Service 1995). Reinikainen and Jaakkola (2003)
also highlight skin dryness as a problem with low humidity, but dispute
any correlation between eye symptoms and humidity levels. In contrast,
high humidity (>70%) makes a building feel hot and stuffy, and
workers are likely to experience fatigue, headaches, dizziness and
stuffiness (ACT Public Service 1995; Reinikainen and Jaakkola 2003).
Warm, humid conditions pose a further hazard as it provides an ideal
breeding ground for dust mites, moulds and fungi whilst also raising
the level of VOCs. According to Rooley (1995) and ASHRAE Std 55 the
ideal relative humidity range is 30-60%. In contrast, Brown and Mathieson
(1991) suggest the optimum range conducive to health is 45-55%. The
latter argue that beyond these limits, bacterial, viral and fungal
growths are markedly increased. Furthermore, relative humidity has
a significant influence on dust emission from carpets and furnishings
and on static electricity (Brown and Mathieson 1991). With regards
to the indoor air quality tool, I will follow Brown and Mathieson’s
guidelines.
Too little air velocity (<0.05m/s) may produce feelings
of stuffiness whilst high air velocity (>0.2m/s) may cause draughts,
which are a common cause of complaints in office environments (ACT
Public Service 1995; Seneviratne et al 1998). WorkSafe (2001) and
Kroemer and Grandjean (2001) suggest air flow in an office should
be between 0.1 and 0.2 m/s. Rooley (1995) is more specific and suggests
a mean air velocity of <0.15 m/s. In contrast, ACT Public Service
(1995) highlights the need to alter mean air velocity according to
the season; with the ideal being 0.15m/s in winter and 0.25 m/s in
summer. I will adhere to the WorkSafe recommendations in the IAQ audit.
Carbon dioxide
Carbon dioxide is a colourless, odourless gas found in concentrations
of around 350 ppm (0.04% of air). Apart from its presence in air,
CO2 is exhaled by humans and released from the burning of fossil fuels;
the former accounting for the majority of levels found in an office
environment (Erdmann and Apte 2004). CO2 concentrations in office
buildings typically range from 350 to 2500 ppm (Seppanen et al 1999).
CO2 concentrations are a surrogate for ventilation rates, occupant-generated
pollutants (body odour) and to estimate the percent of outdoor air
at the air handling unit (Seppanen et al 1999). Evidence suggests
that the risk of sick building syndrome decreases significantly when
CO2 levels are below 800 ppm (Seppanen et al 1999). According to Erdmann
and Apte (2004), there is a statistically significant association
of mucous membrane (dry eyes, sore throat, nose congestion, sneezing)
and lower respiratory related symptoms (tight chest, short breath,
cough and wheeze) with increasing CO2 levels above outdoor levels.
Environment Australia (2001) suggests elevated levels may cause headaches
and changes in respiratory patterns but fails to elaborate what this
means. However this contradicts most authoritative sources including
ASHRAE who specifically state that high CO2 levels are not associated
with adverse health problems nor are they a measure of IAQ (ASHRAE,
1999). This is also confirmed by Spengler et al (2000), who suggests
that CO2 levels are only a hazard in the event of a fire where it
may lead to asphyxiation. As a result of this, carbon dioxide will
not be included in the IAQ tool.
Combustion gases
Carbon monoxide is a colourless and odourless pollutant gas that is
created from the incomplete combustion of carbon containing fuels:
petrol, gas, oil and coal. The most common source of CO in offices
used to arise from environmental tobacco smoke, however given the
recent legislative changes, it is now more likely to arise from poorly
located air intake vents enabling motor vehicle emissions to enter.
Combustion appliances are also another possible source. A 1994 Perth
study, detected varying concentrations of CO in office buildings with
underground parking in accordance with peak traffic flow (Pointon
et al 1994). Indoor CO concentrations generally follow outdoor levels
except where combustion sources occur in buildings without adequate
ventilation (Brown 1997). At low concentrations, it may cause fatigue,
difficulty concentrating, poor memory, headache, dizziness, vision
problems, and loss of muscle coordination (Environment Australia 2001;
Spengler et al 2000). People with coronary heart disease are at particular
risk and may experience chest pain (Spengler et al 2000). At higher
concentrations (200 ppm) it may lead to headaches, fatigue and nausea.
Due to its high affinity for haemoglobin, in sufficient concentrations
it can cause convulsions, unconsciousness and death due to oxygen
starvation (Spengler et al 2000).
Indoor sources of nitrogen dioxide are formed from gas-fuelled cookers,
fires, water heaters and unflued gas and/or oil-fired space heaters,
tobacco smoke and to a much lesser extent, motor vehicle emissions
(Spengler et al 2000). Sulphur dioxide is primarily produced from
the combustion of oil and coal and is consequently found ambient air
and unvented space heaters. Their presence in an office, is likely
to be due to motor vehicle emissions entering the building. Both gases
may cause eye, nose and throat irritation, exacerbation of asthma
and an increase in respiratory tract infections (American Lung Association
et al n.d).
Ozone
Ozone is an oxidant gas produced in small amounts by the electrical
discharge of photocopiers, laser printers and ionisers (ACT Public
Service 1995). Whilst the health effects of ambient ozone are well
documented, little research has been conducted on the adverse health
effects of indoor ozone levels in office environments (NEPC 2005).
Ozone concentrations in indoor air are generally lower than ambient
levels (0.04 ppm) except in situations where photocopiers are operated
in areas with insufficient ventilation (NSW EPA n.d). A single photocopying
machine can produce more than 0.1 ppm (London Hazards Centre 1990).
Health effects include eye, nose and throat irritation, headache,
cough and shortness of breath (ACT Public Service 1995). Little is
known of actual levels of ozone in offices, however a combination
of sources and poor ventilation may see them elevated (Environment
Australia 2001).
Radon
Radon (radon-222) is a carcinogenic gas formed from the radioactive
decay of naturally occurring uranium-238. Given radons abundance in
granite, it is a huge concern in the US as its progeny (polonium,
lead and bismuth) is the second leading cause of lung cancer deaths
in the US (US EPA 2004). Studies on radon emissions in Australian
dwellings concluded that nationwide only 2,000-3,000 homes may exceed
200 Bq/m3 (Langroo et al 1990; State of the Environment Report 1996;
Toussaint 1994). Therefore radon emissions in Australian buildings
are more likely to occur as a result of the introduction of granite
containing building materials. No studies have been conducted on radon
gas emissions in Australian offices (ARPANSA 2002). For these reasons,
radon will not be included in the IAQ tool.
Volatile Organic Compounds (VOCs)
VOCs are organic compounds composed of hydrogen and carbon which evaporate
as gases from solids or liquids at room temperature which have been
closely linked with sick building syndrome (Cullen 2002; Spengler
et al 2001). VOCs are ubiquitous and are generally found in higher
levels in indoor air than ambient air (Zhu et al 2005; Bluyssen 1996;
Wallace 1993). Total Volatile Organic Compounds (TVOCs) in non-industrial
indoor environments are normally a complex mixture of 50 to 300 different
compounds (Molhave 1990; Wallace 1991). Potential sources of VOCs
in an office include building materials (adhesives, cabinetry, sealants,
insulation products, paints and coatings, wall and ceiling materials
and wood products), cleaning products, furnishings (furniture, floor
and wall coverings), dry cleaning solvents, environmental tobacco
smoke, office equipment (laser printers, photocopiers, pens, inks..),
HVAC systems, occupants (clothing, bioeffluent and personal care products
perfume, moisturisers, hair spray after shave…), air fresheners,
ambient air sources (from traffic and industry), pesticides, space
heating and cooking equipment (Bluyssen et al 1996; Spengler et al
2000; Franke et al 1997).
Whilst bioeffluent and occupant related emissions may account for
a large share of VOC emissions according to Batterman and Chi-ung
(1995), it is generally acknowledged that the major source in an office
arises from building materials and furnishings (De Bellis et al 1995;
Bluyssen 1996). VOC emissions from building materials may differ widely,
with low emissions from MDF product, higher for particleboard and
highest for laminated office furniture as a result of the adhesives
used (Brown 1999). In addition to being primary sources of VOC emissions,
building materials can also affect the transport and removal of indoor
VOCs by sorption. As such, VOC concentrations maybe elevated during
the life of the building (Tichenor et al 1988; Bergland 1988). High
temperatures and humidity levels may also increase evaporative emissions
of VOCs (US EPA 2005a). This explains why the number and rate of emissions
of VOCs varies greatly amongst buildings. The issue is further complicated
by the fact that building materials with few emissions may act as
sinks which absorb VOCs and recontaminate indoor air over a long period
of time (Berglund et al 1987; Brown 2002).
VOC levels in an office environment will vary according to surface
area of the material per volume of space, volatility, emission rate
(ASTM 1997; Walton 1997), age of material (the newer it is the greater
the emissions) (Tichenor et al 1988; Sheldon et al 1988), environmental
parameters (temperature, air exchange rate and relative humidity),
chemical reactions within the source and pressure differences in the
building envelope (eg insulation) (Spengler et al 2001). New buildings
may contain airborne VOCs up to 100 times greater than ambient air
(Sheldon et al 1988). Little investigations have been conducted on
VOC levels in Australian buildings (Brown 1996).
The adverse health effects of VOCs differ depending upon their chemical
structure. Where benzene and vinyl chloride are carcinogenic, the
aldehydes such as formaldehyde are potent sensory irritants and commonly
irritate the skin (rashes), eyes, nose and throat, and upper respiratory
tract leading to sneezing, painful burning sensation, asthma (Sissell
2004), and upper respiratory cancers (Cain et al 1986; Anderson and
Molhave 1983; Godish et al 1990; Broder et al 1988; US EPA 2005).
Headache, fatigue, sleepiness, dizziness and nausea have also been
reported (Sterling et al 1986; Dally et al 1981; US EPA 2005). Pressed
wood products bonded with urea formaldehyde continue to be the major
source of formaldehyde exposure in office environments (Spengler et
al 2000). Renovations to the ground floor of a two storey office building
in Melbourne resulted in complaints of strong odours, nausea and headaches
in office workers on the second floor despite the fact that the levels
had separate ventilation systems (Brown 2002). These symptoms persisted
for the duration of the renovations. Identical symptoms were also
reported in an office located on the sixth floor of a building in
Melbourne’s CBD, which was eventually traced to the opening
of a dry cleaning business on the ground floor (Brown 1998).
VOCs can be very difficult to detect, separate and identify when testing
IAQ. Even when identified, only a small fraction of VOCs are regulated
through exposure limits. According to Kerr (1994), these limits only
consider the effects of a high concentration of one specific chemical
and assume no other exposures occur simultaneously. The issue is further
complicated by the fact that there is increasing evidence that chemical
reactions between ozone and unsaturated hydrocarbons (such as styrene)
at levels commonly found in indoor air, can produce a variety of aldehydes
which may affect human health (Zhang et al 1994; Wescler and Shields
1997). Peak emission of volatile organic compounds (VOCs), particulates
and biological contaminants into the office air is often associated
with activities like vacuuming and cleaning (CASANZ n.d; Brown 2002).
Cleaning products are common sources of VOCs (Franke et al 1997).
Total VOC results help provide an indication of overall ventilation
efficiency (Springston et al 2002).
Particulates
Particulates arise from both within the office and from the ingress
of ambient air. Sources include dust (which in itself is a combination
of any of the following), dirt, skin cells from the occupants, pet
hair and dander, fibres from clothing and furnishings, particles from
insects, fibrous building materials, laser printers and photocopy
dusts, combustion appliances (gas), food, motor vehicle and industry
emissions, as well as biological contaminants such as viruses, bacteria,
mould spores, pollen and mites (Kemp et al 1998; Baechler et al 1991).
Occupants and their activities are a common source of particulates
with cooking and in particularly, grilling, toasting and deep frying,
as well as vacuuming being significant sources (Kemp et al 1998; CASANZ
2002). According to Tan et al. (1995) and Raw et al (1993), the primary
source of suspended particulate matter in commercial buildings is
due to poor housekeeping practices and improper maintenance procedures
and schedules. Toxic particles such as asbestos, glass fibres, pesticides,
plastics, tobacco smoke/soot, lead and so on, are unlikely to be a
cause of concern in a smoke free and relatively new mechanically ventilated
office. Renovations to older or adjacent buildings however may expose
workers to lead dust, asbestos and/or synthetic mineral fibres which
will warrant further investigation.
Research on particulates in office environments has generally focused
on the number and size of airborne and surface particulates, and to
a lesser degree, the qualitative properties of dust. Elevated respirable
particulates (PM10) are associated with a range of adverse health
effects including worsening of existing asthma, attacks of chronic
obstructive pulmonary disease, increased hospital admissions for cardiovascular
disease in patients with pre-existing heart disease and death (Donaldson
et al 2001; CASANZ 2002; Pope 2000). Ultrafine particles (PM0.1) in
an office are ubiquitous and may arise from laser printers, fax machines,
photocopiers, laminator, gas cooking, cleaning solvents, vacuuming,
peeling citrus fruits, humidification, tobacco smoke, vehicle emissions
(diesel) and from outdoor air (Spengler et al 2001; Keady and Mainquist
2000). Because they weight almost nothing, they stay airborne for
a long time, and easily move from one area of a building to another
(Keady and Mainquist 2000). There is more research suspecting ambient
ultrafine particles to be directly related to hospital admissions
for respiratory disease such as asthma and bronchitis and cardiovascular
disease such as stroke and heart attacks (Stone and Donaldson 1998).
Headaches, eye irritation, sore throats, chest pains and fatigue may
also be associated with ultrafines in non-industrial settings (Spengler
et al 2001). Whilst the mechanism by which ultrafines affect the lung
are unclear, it is known that they induce adverse health effects independent
of larger particles (PM2.5) and other air toxics (Kreyling et al 2004).
Furthermore levels found in non-industrial environments generally
comply with ASHRAE 62.1 and AS 1668.2 and yet preliminary studies
indicate that their large surface area leads to oxidative stress in
susceptible individuals at these ‘acceptable’ levels (Donaldson
et al 2001). Unfortunately air filters in HVAC systems that comply
with AS 1324 only focus on the % of volume of dust removed which is
biased towards larger particles which form the largest proportion
of mass. Smaller particles such as the ultrafines are generally ignored
and are not addressed even with the use of HEPA filters. More research
is required on this.
A recent European review of 70 papers concluded that there is inadequate
scientific evidence to support that indoor mass or number concentrations
of airborne particulate matter are associated with health risks in
office environments (Schneider et al 2003). However, this study excluded
microorganisms, dust mite and pesticides from their investigations.
In contrast research into indoor surface pollution and into the components
of dust reveals a clear relationship to health effects. According
to Gyntelberg et al (1994), biologically active components in dust
(fungi, bacteria, endotoxins, mites and histamine liberating properties)
and absorbed organic gases and vapours appear to contribute to respiratory
symptoms observed in sick building syndrome. More specifically, they
observed a strong correlation between gram-negative bacteria in indoor
dust and the incidence of sore throat, fatigue, heavy headedness,
headache, dizziness and poor concentration; TVOC were associated with
lack of concentration, and dust containing allergenic material correlated
with headache and general malaise (Gyntelberg et al 1994).
Biological contaminants
Despite the fact that microbes such as fungi, bacteria and viruses
are ubiquitous, they are not likely to be a concern in a mechanically
ventilated office unless conditions enable them to thrive. Respiratory
tract infections are far more likely to occur in offices with inadequate
ventilation and/or stagnant water such as from flooding, plumbing
or roofing leaks, and dirty or poorly maintained air handling systems
(Environment Australia 2001; American Lung Association et al n.d).
Symptoms that may arise are malaise, exacerbation of asthma, increased
respiratory tract infections, cough, chest tightness, nose and throat
irritation (American Lung Association et al n.d). Legionella bacteria
is one such opportunistic organism and will grow in any water based
system where the water is warm (30-450C) and contain nutrients such
as sediment, sludge, scale and organic matter (such as building materials)
(Gelder 2001). Most outbreaks in Australia have been associated with
contaminated drift from air-conditioning cooling towers entering the
building via the air conditioning system with small systems particularly
susceptible after a period of shutdown (Broadbent et al 1994). With
an incubation period of up to 10 days, Legionnaire’s disease
presents itself as severe pneumonia possibly leading to respiratory
failure and death in 20% of people (Environment Australia 2001). Early
symptoms include anorexia, malaise, myalgia and flu-like symptoms
(Department of Human Services 2004). In contrast, Pontiac fever results
in influenza-like symptoms with spontaneous recovery within 2 to 5
days. Where AS 1668 governs the use of mechanical ventilation and
air conditioning in buildings, AS 3666 addresses the maintenance of
air conditioning systems in an effort to control the incidence of
Legionella. The building manager must comply with these standards
when operating HVAC systems. Pollens and allergens such as house dust
mite, pet dander and insect allergens (cockroach) are unlikely to
be an issue in a mechanically ventilated office providing pollen producing
indoor plants are avoided (Environment Australia 2001).
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to top
Indoor air quality is a complex issue involving a multitude of factors.
Despite the fact that poor IAQ may lead to adverse health effects
in office workers, it has largely been ignored by government and OHS
authorities. Since the 1970s, IAQ has become a liability for employers
and building managers who fail to provide a ‘safe’ working
environment (Brown 2004). Despite the obligations under the OHS Act
2004 on employers and management to ensure a workplace that is without
risks to health, little guidance is provided by the OHS legislation
on IAQ. Part of the problem appears to be the shifting of responsibility
to others, generally the building manager responsible for the ventilation
system, and yet it is clear their knowledge on IAQ is likely to be
limited. Furthermore, the inability in OHS to take into consideration
the synergistic effects of multiple air contaminants found within
acceptable exposure levels, also limits their capacity to acknowledge
and address the problem even when complaints about IAQ abound. Lastly,
poor IAQ does not lend itself to a cause and effect outcome as the
factors associated with it are extensive and complex. As such IAQ
is inherently multidisciplinary and should involve a variety of people
from building designers (architects and engineers), building manager
(operates and maintains the building and its ventilation system),
OHS consultant, specialists (industrial hygienists and IAQ consultants),
the building owner/occupier, management as well as its occupants.
The OHS consultant is in an ideal position to assess IAQ complaints
as part of their risk management procedure. This audit tool will provide
the OHS consultant with a quick and simple tool to assess and investigate
complaints about IAQ from workers, engage the appropriate professional
and provide control strategies by which to address these.
Want to know more about indoor air quality? A
comprehensive course on Air
Pollution is available at the Australian
College of Environmental Studies. The course highlights the contaminants
likely to be present in your home and workplace and their adverse
health effects. More importantly, using the principles of building
biology, it will provide you with the ability to . For more information,
click here.back
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