Indoor Air Pollution

Question 0

What are factors affecting indoor air pollutants?

Answer 0

• Ventilation= how much fresh air are we getting to dilute
• Temperature/relative humidity= humidity and bio pollutants, allergies
• Sources

Question 1

Why is indoor air quality important?

Answer 1

• 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

Question 2

What is Ventilation?

Answer 2

If too little outdoor air enters a home, indoor air does not get diluted; higher levels of pollutant can build up

Question 3

What are 3 ways outdoor air enters?

Answer 3

- Infiltration
Ex. Cracks in windows
- Natural ventilation
Ex. Opening a window
- Mechanical ventilation
Ex. Outdoor air forced inside the home, HVAC system

Question 4

What is Air Exchange Rate?

Answer 4

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)

Question 5

What are some Indoor Sources?

Answer 5

• 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)

Question 6

What is Temperature/Relative Humidity?

Answer 6

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

Question 7

What are some sources of Particulate Matter?

Answer 7

Environmental tobacco smoke, cooking, burning candles, outdoor air

Question 8

What are some sources of Volatile Organic Compound (VOCs) ?

Answer 8

Consumer products, dry cleaning, construction materials, furnishings & carpet, outdoor air

Question 9

What are some sources of Biological Agents?

Answer 9

Molds, pet dander, cockroaches, dust mites, pollen

Question 10

What are some sources of Nitrogen Dioxide (NO2) ?

Answer 10

Unvented non-electric appliances and heaters, fireplaces

Question 11

What are some sources of Carbon Monoxide (CO) ?

Answer 11

Appliances, cooking, heating, car exhaust (attached garage)

Question 12

What are some sources of Ozone?

Answer 12

Laser printers, outdoor air, electrostatic air cleaners

Question 13

What are some sources of Radon?

Answer 13

Soil, rocks, groundwater

Question 15

What are Volatile Organic Compounds (VOCs)?

Answer 15

• 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)

Question 16

What is Particulate Matter?

Answer 16

-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

Question 17

What is Side-Stream Smoke?

Answer 17

• 2 to 6 times more tumorigenic per gram than mainstream smoke
• 2 to 6 times more toxic per gram than mainstream smoke

Question 18

What is Nitrogen Dioxide?

Answer 18

• 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

Question 19

What is Carbon Monoxide?

Answer 19

• 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

Question 20

What is Ozone?

Answer 20

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

Question 21

What is Radon?

Answer 21

• 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

Question 22

More information about Radon

Answer 22

• 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

Question 23

What are Biological Pollutants?

Answer 23

Biological Pollutants are, or are produced by, living things.

Question 24

Name 5 Biological Pollutants

Answer 24

1. Bacteria
   - Staphylococcus aureus
   - Legionella
   - Escherichia coli
   - Salmonella spp.
2. Viruses
3. Fungi
   - Aspergillus niger
   - Penicillum funicolosum
4. Arthropods
   - Dust Mites, cockroaches
5. Dander
   - Dog, cat, hamster

Question 25

What is Regulation of Indoor Air?

Answer 25

Indoor Air (apart from occupational air)
• no specific federal laws
• state and local jurisdictions regulate air quality in public buildings
- standards in ventilation and air exchange rates
- controlling activities (e.g., smoking)
- limit use of products that affect air quality

Private residence
• must rely on education

Question 26

What are some Health Effects of Indoor Air Pollutants?

Answer 26

Irritation- eyes, nose, throat, upper airways, skin

Respiratory symptoms- wheezing, coughing, chest tightness, shortness of breath, asthma aggravation

Neurological symptoms- nausea, dizziness, headache, loss of coordination, tiredness, loss of concentration

Immunological reactions- inflammation, allergic reactions, delayed hypersensitivity

Cancer

Question 27

What is Sick Building Syndrome (SBS)?

Answer 27

Set of non-specific symptoms associated with time spent in building
- respiratory tract irritation, skin irritation, headache, dizziness, nausea, fatigue, concentration problems

Symptoms diminish or cease when occupants leave the building

> 20% of building occupants report SBS

Cannot be traced to specific pollutants or sources within the building

Question 28

What is Building Related Illness?

Answer 28

• discrete, identifiable disease or illness
• can be traced to a specific pollutant or sources within a building
• coughing, chest tightness, fever, chills, muscle aches or more serious outcomes
• legionnaires disease= disease from water, moist in water
• hypersensitivity pneumonitis, humidifier fever

Question 29

What is Indoor Air Regulation?

Answer 29

Occupational Air: OSHA

Indoor Air: No specific federal laws

• State and local jurisdictions regulate air quality in public buildings
• standards in air exchange rates
• smoking policies

Private residence- must rely on education