INTRODUCTION to Indoor Air Quality (IAQ)

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

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?

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

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

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

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)

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

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

Reasons of IAQ Problems based on NIOSH study

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

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

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

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

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

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

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

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

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

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 

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

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

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