Indoor Air Quality (IAQ)

Indoor Air Quality (IAQ)
Introduction
 Poor indoor air quality (IAQ) can be a significant health,
environmental & economic problem, and has become a public
health & liability issue for employers & building managers.
 The totality of attributes of indoor air that affect a person’s
health & wellbeing.
 IAQ Evaluation determine how well indoor air satisfies thermal
& respiratory requirements of occupants, prevents unhealthy
accumulation of pollutants, & allows for a sense of wellbeing.
 It also affects the personnel costs of any business, since research
findings show an association with occupant productivity.

 Building Related Illness-Diagnosable illness whose
symptoms can be identified and whose cause can be
directly attributed to airborne building pollutants
(e.g., hypersensitivity pneumonitis or Legionnaire’s
disease)
Sick Building Syndrome(SBS)
• Symptoms include eye, nose and throat irritation, headache, allergies,
fatigue
• 20% or more of occupants experience same symptoms
• No medically diagnosable symptoms
• Complaints persist for more than two weeks
• Symptoms often lessen after person leaves building

 Sector of population differ markedly in their
sensitivities to pollutants.
 Asthmatic are sensitive to variety of pollutants.
 Major indoor air pollutants(those of indoor origin)
typically completely different from outdoor air
pollutants.

 It is important to be clear on what you or others may
mean when discussing IAQ.
1. Engineer ( building ventilation rate)
2. Architect ( the occupants perception of the
building)
3. Microbiologist (level of spores from plants, moulds
etcetera)
4. Hygienist or toxicologist (the exposures to specific
pollutants)

Indoor air
“ Any enclosed space where people spend 1 hour/day or
more”
“ The air in Non-industrial buildings such as dwellings,
offices, schools & hospitals.”
 Exclude industrial buildings
 Exposure limits 40 hours/week

 IAQ is the totality of attributes of indoor air that affect
a person’s health & wellbeing. Attributes can mean
Pollutant level
Air temperature
Humidity
Air velocity
Odors etc.
Health (WHO)
“State of complete physical, mental & social wellbeing & not
merely the absence of disease or infirmity”

Regulation
 To indoor air is limited as compared to outdoor air quality
& industrial workplace air.
 National Health & Medical Research Council (NHMRC) &
National Occupational Health & Safety Commission (
NOHSC)
To improve air quality
 Improved ventilation codes
 Voluntary reduction of pollutant emissions
 Improved public education

Responsibility For IAQ
 Responsibility for IAQ falls to environmental or health
agencies in many developed countries.
 For example, in US Environmental Protection Agency
carries out extensive research & industry/community
activities.

Building Related illness & SBS
 Building Related Illness-Diagnosable illness whose
symptoms can be identified and whose cause can be be
directly attributed to airborne building pollutants
(e.g., hypersensitivity pneumonitis or Legionnaire’s disease)
 Sick Building Syndrome(Tight Building Syndrome) Used to
describe situations in which building occupants experience acute
health and /or comfort effects that appear to be linked to the
time spent in a particular building.
 No specific illness can be identified.
 Complaints may be localized in a particular room zone or
widespread throughout the building.

Common Health Effects of Indoor Contaminants
• Eye, nose and throat irritation
• Coughing and sneezing
• Headaches
• Fatigue
• Irritability
• Allergies, sinus congestion
• Dizziness
• Difficulty in concentrating

Sick Building Syndrome
• Symptoms include eye, nose and throat irritation,
headache, allergies, fatigue
• 20% or more of occupants experience same symptoms
• No medically diagnosable symptoms
• Complaints persist for more than two weeks
• Symptoms often lessen after person leaves building
• Clinically defined illness or disease
o E.g. Asthma, Legionnaires’ Disease, Hypersensitivity Pneumonitis

Why is There an Increase in IAQ problems?
• More time indoors
• More chemical pollutants in buildings
• Tighter buildings and reduced ventilation
• Deferred maintenance
Potential Causes
Ventilation rate, ventilation system, airborne chemical
pollution, micro-organisms & particulates,
temperature, humidity, lighting, personal &
organizational factors.

Relationship of IAQ to Productivity
 Costs for care health
 Sick leave
 Diminished performance at work caused by adverse
health
 Costs of investigation occupant complaints
Thermal comfort & lighting quality

 Fisk & Rosenfeld noticed improved productivity by
changing indoor environment. Potential annual
benefits were
10-30% reduction in acute respiratory infections &
reduced allergy & asthma Symptoms
20-50% reduction in acute non-specific health
symptoms
0.5-5% increase in the performance of office work
Annual cost savings & productivity gains US$30-170
billion.

Building Ventilation
• Purpose - Remove or dilute airborne contaminants
• Supply air - mixture of outside air and re-circulated air.
Components
o Air intakes, dampers, filters
o Heating & cooling units, coils, drain pans
o Ductwork
o Supply vents
o Exhaust vents
o Plenum

Regulations
ASHRAE Outdoor Airflow Requirements, 62.1-
2004
• Vbz = RpPz+RaAz
o Vbz = Breathing zone outdoor airflow
o Rp = Outdoor airflow rate required per person.
o Pz = zone population
o Ra = Outdoor airflow rate required per unit area.
o Az = zone floor area

 A space within a building used by occupants must be
provided with means of ventilation with outdoor air
which will maintain adequate air quality.
Mechanical air-handling system in a building must
control.
 Circulation of objectionable odors &
 Accumulation of harmful contamination by micro-
organisms, pathogens & toxins.
 Contaminated must be disposed of in a manner which
doesn’t unduly create a nuisance or hazard in the
building or other property.

Poorly Located Air Intakes
• Entrainment of vehicle exhaust from parking areas
• Entrainment of bio-aerosols from debris on the ground
• Entrainment of exhaust from adjacent roof vents, e.g.
HVAC system, sewer
Poor Filters or Poor Filter Maintenance
• Excessive dust and dirt in the supplied air
• Insects
• Mold spores

Ductwork
• Leaks
o Energy loss
o Can draw contaminants into ducts
• Duct liners
o Can degrade; particles enter supplied air

Ventilation to Meet Occupant Needs
• ASHRAE Standards
• Temperature
• Relative Humidity
• Minimum outdoor air requirements
• CO2 levels below 1000 ppm.
• Outdoor air supplied at 15 cfm/person

Ventilation – Engineering Controls
• Modify ventilation system
• Modify pressure relationships
• Filters
• Ion generators
• Humidification systems

 Performance and maintenance of ventilation system
 Changing of filters
 Checking correct installation of filters
 Cleaning of condensate trays & cooling coils
 Checking fan operation & operation of dampers that
influence airflow rates.
Ventilation measurement may be necessary
 After significant change in the building, HVAC system, or
occupancy or activity in the building.
 When control settings have been re-adjusted
 When accurate records of the system’s performance are not
available.

“Dilution is the solution”
“When all else fails, ventilate”
 Relation between indoor & outdoor air.
 Urban population spend 96% of each day, on average, in a
rang of enclosed environment such as home, the workplace,
schools, shops etc.
 Outdoor air is used to ventilate the office introduces outdoor
pollutants( carbon monoxide, VOCs such as benzene)
 Behavior of occupants ( smoking, use of appliances)
 Indoor pollutants are limited in their dispersion

 Major indoor air pollutants & sources
“Indoor pollution sources that release gases or particles into the air
are the primary cause of indoor air quality problems.”
 Formaldehyde and VOCs from new building materials
<6months old
 Transportable building
 House dust
 Environmental tobacco
 Combustion products
 Auto-exhausts
 Asbestos

 office/schools
 Shopping centers
 Hospitality buildings
 Transit vehicles
Time spent in each environment is important,
according to ABS statistics for 1997
Home-57%
employment+education-14%
Shopping-2%
Hospitality-18%
Transit Vehicles-5%
Outdoors-4%

Scientists and Health Professionals took a close look at
Indoor Air and found a lot of things that can make us sick.”
• Molds
• Dust Mites
• Pests
• Even Our Pets

 Micro-organisms in indoor air
• Examples
o Bacteria
o Fungi
o Pollen
o Viruses
o Dust mites

 Dust Mites
• Microscopic relatives of spiders
• Feed on dead skin scales and other organic debris
• 2,000,000 in an average bed
• Dust mite feces - a common allergen
• Prefer relative humidity level above 55%
 Viruses
• Smallest and simplest of all life forms
• Depend completely on their hosts for reproduction
• Continually undergo evolutionary change
• Examples
o Influenza
o HIV
o Rhinovirus

 Hanta Virus
• Carried in wild rodents, especially deer mice
• Can cause respiratory failure and death
• Approximately 43 % of diagnosed cases have been fatal
• Infection is caused by inhalation of airborne particles of infected urine, droppings
or saliva from infected animals
Bacteria
• Single-celled prokaryotic organisms
• Most are very small spheres, rods or filaments
• Reproduce by simple cell division
• Some produce end spores, which are extremely resistant to harsh
conditions
• A few require living hosts
• Higher concentrations indoors than outdoors
• Majority of bacteria in air are shed from human skin and respiratory tracts

 Measurement of IAQ
Sampling protocols
 Building sampling selection
 Building operation
 Sampling period
 Number of buildings

 Measurement methods
Formaldehyde
 Is measured using AS 2365.6 determination of
formaldehyde-impinger sampling in chromo tropic
acid method ( standard Australia 1995b)
VOCs (volatile organic compound)
 Measured in accordance with AS2986.1 workplace air
quality-sampling and analysis of volatile organic
compound by solvent desorption/gas chromatography
(standards Australia 2003a)

Pesticides
 sorbent sampling with a detection limit of 40μg/m³
Carbon monoxide
 AS 2365.2 methods for sampling and analysis of indoor
air-determination of carbon monoxide-direct reading
portable instrument method describes a method for
measuring concentration of 0-500ppm

Carbon dioxide
 Is measured by instrument with gas infrared detectors
at concentrations from ambient (350ppm to
5000ppm)
Nitrogen Oxide
 AS 2365.1.2 methods for sampling and analysis of
indoor air-determination of nitrogen dioxide-
spectrophotometric method-treated filter/passive
badge sampling procedures (Standards Australia
1990a)

Ozone
 Is measured by using a direct-reading UV absorption
instrument according to AS 3580.6.1-1990 Methods
For Sampling & Analysis of Ambient Air-
Determination of Ozone-Direct Reading Instrumental
method with a measurement range to 0.5ppm and
detection limit below 0.01ppm.
Radon
 AS 2365.4 Methods For Sampling & Analysis of indoor
air-determination of radon specifies three methods for
radon measurement with detection limits 3-40 Bq/m³

 Respirable particulate Matter
 Environmental tobacco smoke
 House dust mite allergen
Control of IAQ
IAQ control is applied at the design stage of building by:
 Selecting low emission building material
 Ensuring ventilation
 Ensuring persist condensation & water pooling in
prevented
 Having a plane for operation & maintenance
 Documenting all above actions for future review &
assessment

 State of Environment Report on Indoor Air Quality
(Brown 1997).
1) Inspect the building to ensure that it functions as originally designed
and to accepted general practice (use a checklist of building faults,
building contents, cleaning practices)
2) Inspect operational component of the building for proper function
(ventilation, heating, cooling appliances)
3) Apply a standard indoor air environment questionnaire to occupants
to determine personal wellbeing & environmental comfort.
4) Take air samples for assessment relative to NHMRC or other indoor
air quality goals where potential sources of pollutants are identifiable
from building inspection.

5) Record result of sampling & analysis for comparison with IAQ goals
with baseline results of similar buildings, & with future assessment of
IAQ in the building.
At all steps: identify factors where action is necessary.

Indoor Air Quality (IAQ)

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