1. INTRODUCTION to Indoor Air Quality
(IAQ)

2. History of Indoor Air Quality
Greek philosophers, 500 BC, concerned with air quality in mines
Roman, Pliny the Elder, advised masks for stonecutters and asbestos miners
Early 1800s, first recommendations for ventilation standards to control odor
Florence Nightangle(1858) recommended air exchange rate of 25 cfm/person to avoid re-infection in hospitals

3. Questions Regarding Indoor Air Quality
What is Indoor Air Quality?
What is the relationship between indoor and outdoor air quality?
Why should you be concerned about the quality of air that you breath?
What causes indoor air problems?
What are the factors affecting indoor air quality?
How does outdoor air enter a house?
What are the health effects from indoor air pollutants?
Can you give examples of indoor air contaminants?
Do you know the origin of air quality problems?
What are the guidelines for IAQ?
What is an IAQ prediction model?
What are the strategies to improve indoor air quality?

4. What is Indoor Air Quality ?
Refers to good and bad effects of the contents of air inside a structure on its occupants
Good indoor air quality(IAQ) has no unwanted gases or particles in it at concentrations which will adversely affect someone
Poor indoor air quality has gases or particles in excessive concentration so as to affect the satisfaction or health of occupants

5. Relationship between Indoor and Outdoor Air Quality
Indoor pollutant concentrations may be higher or lower than outdoor air concentrations
Outdoor contaminants may be present indoors at a sufficient concentration to affect the occupants
Example : Pollen and mold spores from outdoors causes
hay fever and allergies indoors

6. Why should you be concerned about the quality of air that you breath?
The contaminant indoor air could damage people’s health
Indoor air pollutants are among the top five environmental risk
People spend about 90% of their time indoors and so the health problems that result from exposure to indoor pollution increases
According to World Health Organization (WHO) approximately 30% of all commercial buildings have significant IAQ problems

7. Statistics on Indoor Air Pollution
Indoor radon exposure is estimated to be the second leading cause of lung cancer (American Lung Association )
Environmental tobacco smoke (ETS) causes an estimated 3,000 lung cancer deaths and 35,000 to 50,000 heart disease deaths in non-smokers, as well as 150,000 to 300,000 cases of lower respiratory tract infections in children under 18 months of age each year (ALA)
1.4 million buildings in the United States have indoor problems (OSHA)
Legionnaires Disease strikes 25,000 people and kills over 4000 people every year (Center for Disease Control)

8. Sources of Pollutants
Normal Biological Processes - people and pets generate carbon dioxide, moisture, odors and microbes
Combustion appliances such as wood stoves, gas stoves, furnaces, fireplaces and gas heaters
Use of consumer products such as spray cans, air fresheners, spray cleaners and construction materials
Cigarette smoking
Soil under and around buildings
Appliances such as humidifiers, air conditioners and nebulizers

9. Sources involved in IAQ problems
Evaluations by National Institute for Occupational Safety and Health (NIOSH) for studies on more than 500 Indoor Air quality health hazard cases
Problem Origin
 Percent
Typical Sources
Inadequate Building Ventilation Systems
53%
Lack of outside air, poor air distribution, uncomfortable temperature and humidity, contaminant sources inside the system
Contaminants Originating Inside Building
15%
Solvent vapors, dusts, formaldehyde, building materials, furnishings
Building Products 4%
Concrete, wood, furnishings.
Unknown Causes
13%
Unidentified sources
Outdoor Contaminants Entering Building
10%
Motor vehicle exhaust, pollen, fungi, smoke, construction
Microbiological Agents 5%
Bioaerosols, Legionella

10. Reasons of IAQ Problems based on NIOSH study

11. Factors affecting IAQ Meteorological conditions Ventilation condition
Pollutant decay
Pollutant removal
Pollutant release
Permeability of structures
Outdoor air quality

12. How does Outdoor Air enter Indoors
Infiltration - outdoor air flows into the house through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors
Natural Ventilation - air moves through opened windows and doors
Mechanical Ventilation - from outdoor-vented fans that intermittently remove air from a single room, such as bathrooms and kitchen, to air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house

13. Health effects due to Indoor Air Pollutants
Headaches
Nausea
Respiratory infections
Asthma
Hypersensitivity pneumonitis
Humidifier fever
Legionnaire’s disease
Lung cancer

14. What is Sick Building Syndrome (SBS)?
Condition of a building in which more than 20% of the occupants are suffering from adverse health effects but with no clinically diagnosable disease present
It is a condition of a building ; not of the occupants
It takes place due to long term exposure to low levels of contaminants

15. Health Symptoms and Possible Contaminants
Health Symptoms and Possible Contaminants
SYMPTOM
POSSIBLE
CONTAMINANTS
PRIMARY
SOURCES
ENVIRONMENTAL
CONDITION
· Headache
· Fatigue
· Poor Concentration
· Dizziness
· Tiredness
· Bio-aerosols
· VOCs
· Ventilation systems
· Humidifiers
· Drip pans
· Cooling coils in AHVs
· Plants
· Outside air
· Ergonomic
Conditions
· Noise and
Vibration
· Headache with nausea
· Ringing in ears
· Pounding heart
· CO
· Formaldehyde
· Incomplete
Combustion (vehicle
Exhaust, stoves,
fireplaces)
· Building products
· Furnishings
· Dry Throat
· Shortness of breath
or Bronchial Asthma
· Irritation and
Infection of
Respiratory Tract
· NO2
· Particulates
Combustion
· Building Products
· Smoking
· Relative
humidity

16. Health Symptoms and Possible Contaminants
PRIMARY
SOURCES
ENVIRONMENTAL
CONDITION
· Nasal Problems
(Stuffiness,Irritation)
· NO2
· Formaldehyde
· Bio-aerosols
· Incomplete Combustion
· Building Products
· Furnishings
· Ventilation Systems
· Humidifiers
· Drip Pans
· Cooling Coils in AHVs
· Outside Air
· Relative Humidity
· High Temperatures
· Skin Problems
(Dryness, Irritation,
Rashes)
· Warm Air
· Low Relative
Humidity
· Excessive Air
Movement
· Eye Problems
(Burning, Dry Gritty
Eye)
· VOC's
· Particulates
· Building Product
Deterioration
· Artificial Light

17. List of Pollutants affecting IAQ
Volatile organic compounds (VOCs)
Dust and dirt
Radon
Bio-aerosols
Environmental tobacco smoke (ETS)
Respirable Particulate Matter (RPM)
Carbon and Nitrous Oxides

18. Origin of Indoor Air Quality Problems
Inadequate ventilation
Pollutants from material processed inside the building
Pollutants drawn in from outside air
Biological contamination
Pollutants from building materials and furnishings
Saving energy

19. Guidelines for IAQ pollutants
CONCENTRATION
REMARKS
Asbestos
40 CFR
0.2-2 fibers/cucm 
EPA
OSHA Standard (8hr TWA)
Carbon Dioxide
1000 ppm 
5000 ppm 
ASHRAE Standard
Ministry of Labor Standard(TWAEV)
Carbon Monoxide
9 ppm
50 ppm  
9 ppm 
35 ppm 
OSHA Standard for 1hr
ASHRAE-Average over 8 hr
NIOSH standard for 1hr

20. Guidelines (contd.) POLLUTANT CONCENTRATION REMARKS Formaldehyde
0.4 ppm
0.75 ppm 
ASHRAE Standard
OSHA (8 hr TWA)
Nitrogen Dioxide
5 ppm
3 ppm 
0.053 ppm
OSHA
Ministry of Labor Standard (TWAEV)
Annual National Ambient Air Quality Standard (USA)
Ozone
0.05 ppm
0.1ppm
0.08 ppm 
WHO
OSHA (8hr TWA)
WHO-Criteria Document
Particulates
260 µg/cum 
150 µg/cum 
National Ambient Air quality Standard-24 hr geometric mean
EPA, 24 hr annual geometric mean 

21. Guidelines (contd.) POLLUTANT CONCENTRATION REMARKS Radon
4 picoCuries/L
4 WML radon progeny calendar year 
ASHRAE Standard
Mine Safety and Health Administration
Volatile Organic Compounds (VOC)
1-5 mg/cum
3 mg/cum
US Environmental Protection Agency Guidelines
Molhave, 1990
Microbial fungi
<50 CFU/cum
<150 CFU/cum
<500 CFU/cum
2 Species
3 Species
Agriculture Canada Standard

22. What is an IAQ Prediction Model?
It is basically a Mass Balance Equation
The equation is
(Pollutant flowing) – (Pollutant flow out)
+ (Source emissions) – (Sink removal)
= Indoor air pollution accumulation
Units are mass/time

23. Strategies to improve Indoor Air Quality
Pollutant Source Control
Increased Ventilation
Dehumidification
Use of Air Cleaners
Dust collectors
Filters