INTRODUCTION to Indoor Air Quality

1. INTRODUCTIONto 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

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 exposureto low levels of contaminants

15. Health Symptoms and Possible Contaminants

16. Health Symptoms and Possible Contaminants

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

20. Guidelines (contd.)

21. Guidelines (contd.)

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