Indoor Air Quality
Occupational Safety& Health
Section
Labour Department
Factors Affecting IAQ
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Environmental Air Quality
Work activities
Building design
Ventilation system - mechanical vs. natural
Animals including insects
Temperature
Humidity
People
Factors Affecting IAQ
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Housekeeping standards in the work area
Personal habits e.g. perfumes, insecticides
Storage
Housekeeping in area of the air
conditioning system
 Temperature control
 Changes to the building design not
compatible with the ventilation system
Factors Affecting IAQ
 Carpeting and soft furnishings
 Use of split system units
 Pest control application/Painting etc without
venting the area after
 Duct conditions (mold growth/animal danger)
 Odours
 Office plants
Ventilation [S 52]
 Effective and suitable provision shall be
made for
 Circulation of fresh air
 Removal of all substance, fumes, dust
and other impurities that are likely to be
injurious to health
Temperature [ S 51 ]
Required to:
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Use methods to ensure reasonable temperature
Chief Labour Officer may order the
following:
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Raising the height of the roof of a building or
room
Insulating of the roof (use of insulating
materials; construction of a double roof)
Increase in the number of air changes per hour
Acceptable Indoor Air Quality
 Acceptable indoor air quality is air in which there
are no known contaminants at harmful levels; and
 With which the majority of persons (at least 80%)
do not express dissatisfaction based on several
criteria such as relative humidity, odours and air
movement.
(ASHRAE Standard 62-2001 – Ventilation for Acceptable Indoor Air
Quality)
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Forms of Heating, Ventilation and
Air Conditioning (HVAC) Systems
 Natural ventilation
 Mechanical ventilation
 Combination of Natural and Mechanical
Ventilation
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Natural Ventilation
 An example of natural ventilation is the use
of open windows to utilise the ‘fresh’ air
and the natural breeze.
Advantage: There are numerous air
exchanges.
Disadvantage: Limited control of the
temperature.
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Mechanical Ventilation
 An example of mechanical ventilation is the
use of fans.
Advantage: Utilises natural fresh air with
some control over air movement.
Disadvantage: Minimal control of the
temperature.
 90 degrees F
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Mechanical Ventilation (2)
 Another example of mechanical ventilation
is the use air conditioning systems.
Advantage: Greater control of the room
temperature to provide a
cooler atmosphere.
Disadvantage: Some degree of circulation of
the same air.
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Window AC Unit
Ductless Single Zone Mini-Split WallMounted Cool Only Air Conditioner
Central System
HVAC Considerations
 Choosing the correct system for the area
and activities undertaken
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The type of system (central system, split
system, window unit)
Filter type)
Materials used (galvanised vs. fiberboard
ducting)
 Are there provisions for the intake of make
up air or the exhaust of contaminated or
stale air?
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HVAC Considerations (2)
 Where are the intake and exhaust located?
 How often is the system serviced and what
is involved in the service?
 How often is the area serviced by the
system cleaned?
 What are the housekeeping practices,
particularly in the plant rooms?
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 The compartmentalisation of the building  How is the building divided ?
 Is one room at a different potential to
another?
 Are there closed doorways or ceiling
partitions which restrict the flow of air?
 Are there intake and exhaust vents in each
room?
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 The presence of indoor sources of contaminants
and their magnitude -
What goes on in the rooms being serviced
by the system?
Are there pollution sources near intake
areas?
Are there items which would cause the
accumulation of dust?
Are there conditions which would create
biological contaminants?
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Health Effects of IAQ
Two main categories
 Building Related Illness
 Sick Building Syndrome
Building Related Illness
Illnesses where the specific diagnosis can
be made, including the identification of the
causative agent
e.g. Breakdown of building materials
(Sinusitis)
Sick Building Syndrome
Sick building syndrome is defined as a
persistent set of symptoms occurring in
greater than 20 percent of a building’s
occupants, with no readily recognisable
cause.
Sick Building Syndrome
Signs and symptoms
include
 headache
 dermatitis
 nausea
 eye, nose, throat, and
respiratory irritation
 dizziness
 coughing
 muscle pain
 fatigue
 difficulty
concentrating
 sensitivity to odors
Some Common Substances
 Carbon dioxide - from human respiration
and processes involving combustion.
 Carbon monoxide - sources include
tobacco smoke and vehicular exhaust.
 Formaldehyde - from the off-gassing from
plywood; particle board; carpeting and
fabric; glues and adhesives.
More Common Substances
 Nitrogen oxides - vehicular exhaust;
tobacco smoke
 Ozone - copy machines
 Volatile Organic Compounds (VOC) paints; cleaning compounds; moth-balls;
 Ammonia
 Cleaning agents
‘Mould Invasion!! – Fungi in my air
 The cold hard fact is - MOULD IS
EVERYWHERE ALL THE TIME! Indoors,
outdoors and in the home.
 Mould should not be ‘growing’ indoors.
 If indoor levels are higher than outdoor
levels it is possible that indoor
conditions might be promoting
growth.
 Mould requires
moisture and nutrients
to grow.
 Relative humidity and
moisture sources (e.g.
leaks) must therefore
be strictly controlled
to prevent mould
growth.
 Mould produces toxins which can cause
allergic reactions in some ‘susceptible’
persons e.g. persons with compromised
immune systems; respiratory conditions
(asthma; sinusitis) .
 Many persons do not experience any
adverse effects from the presence of mould.
 Mould can be cleaned by using mild
detergent and water or commercially
available fungicide products.
 Care should be taken to wear respiratory
protection in addition to gloves and eye
protection. The Material Safety Data Sheet
must also be followed.
 Cleaning can only be done if the material is
non-porous. It is also essential that the item
be allowed to dry thoroughly.
Evaluating IAQ
The basic parameters considered when
evaluating IAQ are
• Relative humidity
• Temperature
• Carbon dioxide
Depending on the circumstances other
parameters could be considered.
 Recommended levels:
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Relative humidity: 30 – 60% (should be
maintained below 70%)
Temperature: 23 – 26 oC (air conditioned)
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Carbon dioxide: 1000 ppm (less than 700 ppm
above outdoor levels; complaints may
occur above 800 ppm)
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Outdoor air requirement vary with facility but for
offices 20 cfm/person is recommended (ACGIH)
Other Related Issues
 Psycho-social relationships (labour
relations)
 Psychological component (stress,
psychosomatic)
Occupational Safety & Health Section
Labour Department
Promoting the attainment and maintenance of
desirable standards of occupational safety and
health practice in Barbados.
AElcock