Indoor Air Pollution Flashcards
What are factors affecting indoor air pollutants?
- Ventilation= how much fresh air are we getting to dilute
- Temperature/relative humidity= humidity and bio pollutants, allergies
- Sources
Why is indoor air quality important?
- 70-90% of people’s time spent indoors
- Homes can be sinks for pollutants– levels can be 2-5x higher indoors than outdoors
- Less circulation because of improvements in energy efficiency
What is Ventilation?
If too little outdoor air enters a home, indoor air does not get diluted; higher levels of pollutant can build up
What are 3 ways outdoor air enters?
- Infiltration Ex. Cracks in windows - Natural ventilation Ex. Opening a window - Mechanical ventilation Ex. Outdoor air forced inside the home, HVAC system
What is Air Exchange Rate?
Rate at which indoor air is replaced by outdoor air
- average for American home: 0.7 to 1.0 air changes/hr
- tightly sealed homes without provisions for and exchange: ~0.2 air changes/hr
- Minimum recommended by ASHRAE: 0.35
- > 1,000 ppm CO2 suggests inadequate ventilation (NIOSH)
What are some Indoor Sources?
- Fuel combustion (hot water, stove, fire place)
- Tobacco smoke
- Building materials (paints, carpets, treated woods)
- Personal care products (air freshners, perfumes)
- Biological agents (mold, dust mites)
- Outdoor pollutants:
Radon
Pesticides
Air pollutants (e.g., criteria pollutants)
What is Temperature/Relative Humidity?
It affects concentrations of pollutants
- Mold
- Allergens/endotoxins
- (dehumidifiers)
- Optimal range: 30 to 60% RH to control mold (higher % favorable conditions for mold to grow)
Optimal range: 30 to 50% RH to control dust mites
Temperature- more of a comfort issue; volatile organic compounds can off-gas at room temp
What are some sources of Particulate Matter?
Environmental tobacco smoke, cooking, burning candles, outdoor air
What are some sources of Volatile Organic Compound (VOCs) ?
Consumer products, dry cleaning, construction materials, furnishings & carpet, outdoor air
What are some sources of Biological Agents?
Molds, pet dander, cockroaches, dust mites, pollen
What are some sources of Nitrogen Dioxide (NO2) ?
Unvented non-electric appliances and heaters, fireplaces
What are some sources of Carbon Monoxide (CO) ?
Appliances, cooking, heating, car exhaust (attached garage)
What are some sources of Ozone?
Laser printers, outdoor air, electrostatic air cleaners
What are some sources of Radon?
Soil, rocks, groundwater
What are Volatile Organic Compounds (VOCs)?
- Compounds emitted as gases from solids or liquids at room temperature
- Commonly found in: pesticides, solvents, cleaning agents, scented products
- Concentrations consistently higher indoors than outdoors
- Health effects: Conjunctival irritation, Respiratory irritation, Headache, Allergic skin reaction,Dyspnea, Nausea, Fatigue, Dizziness and Epistaxis (formaldehyde)
What is Particulate Matter?
-Size: Main determinant of health
SIZE MATTERS
-Small particles can remain suspended in air, travel great distances, penetrate the lung
- Sources: smoking, cooking, burning candles
What is Side-Stream Smoke?
- 2 to 6 times more tumorigenic per gram than mainstream smoke
- 2 to 6 times more toxic per gram than mainstream smoke
What is Nitrogen Dioxide?
- odorless, reddish gas
- Effects: irritation, acute lung damage, acute or chronic bronchitis
- Sources: unvented non-electric appliances, such as gas stoves, dryers, kerosene heaters, fireplaces
What is Carbon Monoxide?
- odorless, colorless gas
- Blinds to hemoglobin and disrupts oxgen transport
- Health effects: headaches, dizziness, confusion, death
- Susceptible sub-populations: elderly, the fetus, and persons with cardiovascular and pulmonary diseases
What is Ozone?
Airway irritant-exacerbates asthma:
- When breathed into the airways, ozone interacts with proteins and lipids on the surface of cells
- Epithelial cells are main target; become injured, release inflammatory mediators
Indoor Sources:
- indirectly by ion generators and some other electronic air cleaners
- directly by ozone generator air cleaners
- laser printers
What is Radon?
- odorless, colorless, tasteless gas
- naturally occurring in radioactive gas resulting from the decay of radium, itself a decay product of uranium
- found in nearly all soils
- Radon’s decay products are also radioactive (short-lived radionuclides)
- These ran decay products, free or attached to airborne particles, are inhaled
- Decay products emit an alpha particle. If occurs in lungs, high dose of radiation -> initiate carcinogenesis
- Tobacco smoke and radon act syngergistically
More information about Radon
- naturally occurring radioactive gas resulting from the decay of radium, itself a decay product of uranium
- Radon’s decay products are also radioactive (short-lived radionuclides)
- these radon decay products, free or attached to airborne articles, are inhaled
- decay products emit an alpha particle. Of occurs in lungs, high dose of radiation-> initiative carcinogenesis
- Tobacco smoke and radon act synergistically
- “Safe level”: 2 to 4 pCi/L
What are Biological Pollutants?
Biological Pollutants are, or are produced by, living things.
Name 5 Biological Pollutants
- Bacteria
- Staphylococcus aureus
- Legionella
- Escherichia coli
- Salmonella spp. - Viruses
- Fungi
- Aspergillus niger
- Penicillum funicolosum - Arthropods
- Dust Mites, cockroaches - Dander
- Dog, cat, hamster
