(IAQ). History of Indoor Air Quality Greek philosophers, 500 BC, concerned with air quality in mines...
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Transcript of (IAQ). History of Indoor Air Quality Greek philosophers, 500 BC, concerned with air quality in mines...
(IAQ)
History of Indoor Air QualityGreek 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 QualityWhat 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 PollutantsNormal Biological Processes - people and pets generate
carbon dioxide, moisture, odors and microbesCombustion appliances such as wood stoves, gas stoves,
furnaces, fireplaces and gas heatersUse of consumer products such as spray cans, air
fresheners, spray cleaners and construction materialsCigarette smokingSoil under and around buildingsAppliances such as humidifiers, air conditioners and
nebulizers
Sources involved in IAQ problems
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
Evaluations by National Institute for Occupational Safety and Health (NIOSH) for studies on more than 500 Indoor Air quality health hazard cases
Reasons of IAQ Problems based on NIOSH study
Inadequate Ventilation
53%
Bioaerosols5%
Outside Contamination
10%
Building products
4%
Unknown causes
13%
Inside contamination
15%
Factors affecting IAQMeteorological 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
HeadachesNauseaRespiratory infectionsAsthmaHypersensitivity pneumonitisHumidifier feverLegionnaire’s diseaseLung 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
SYMPTOM POSSIBLECONTAMINANTS
PRIMARYSOURCES
ENVIRONMENTALCONDITION
· 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
· Ergonomic Conditions · Noise and Vibration
· Dry Throat · Shortness of breath or Bronchial Asthma · Irritation and Infection of Respiratory Tract
· NO2
· Formaldehyde · VOCs · Particulates
· Incomplete Combustion · Building Products · Furnishings · Smoking
· Relative humidity
Health Symptoms and Possible Contaminants
Health Symptoms and Possible Contaminants
SYMPTOM POSSIBLECONTAMINANTS
PRIMARYSOURCES
ENVIRONMENTALCONDITION
· 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)
· Formaldehyde · Ventilation Systems · Humidifiers · Outside Air
· Warm Air · Low Relative Humidity · Excessive Air Movement
· Eye Problems (Burning, Dry Gritty Eye)
· NO2
· Formaldehyde · VOC's · Particulates · Bio-aerosols
· Incomplete Combustion · Building Products · Furnishings · Ventilation Systems · Humidifiers · Cooling Coils in AHVs · Outside Air · Building Product Deterioration
· Artificial Light
List of Pollutants affecting IAQVolatile 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
POLLUTANTCONCENTRATIO
NREMARKS
• 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
• EPA• OSHA Standard for 1hr• ASHRAE-Average over 8
hr• NIOSH standard for 1hr
Guidelines for IAQ pollutants
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
Guidelines (contd.)
What is an IAQ Prediction Model?
It is basically a Mass Balance EquationThe 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 collectorsFilters