Indoor Environmental Quality

Question 1

Factors affecting indoor environmental quality

Answer 1

Outdoor Sources – biological pollutants such as airborne molds and pollens; chemical pollutants such as smog and pesticides; fine particulate pollutants; and radon.

Indoor Sources – biological pollutants such as animal and insect allergens, molds and bacteria; chemical pollutants from ETS, off-gassing from building materials and furnishings, combustion gases from stoves, heaters, or fireplaces, solvent use, cleaning, hygiene and cosmetic products; and dusts.

Ventilation –
If too little air enters a home, pollutants can accumulate to levels that can pose health and comfort problems. This has been a particular problem with energy-efficient homes.
Buildings are mechanically ventilated, and unless designed, operated, and maintained properly, HVAC systems can be a source of dusts, odors, and other chemical pollutants indoors.

Question 2

Air exchange rate

Answer 2

The rate at which outdoor air replaces indoor air is described as the air exchange rate (AER). When the AER is low, pollutant levels can increase.

Question 3

Bed bug pollution

Answer 3

Bed bug infestations are commonly treated by insecticide spraying and discarding contaminated bedding/furniture.

Question 4

Mold pollution

Answer 4

indoor mold is currently the most important IEQ issue in industrialized nations.

Health effects are associated with chronic mold exposures, and research continues.

Question 5

Mold sources

Answer 5

Sources are substrates with uncontrolled moisture (water damage) that initiates the mold cycle.
This results in a shift in ecology, amplification and dissemination of spores and growth fragments.

Question 6

Mold cycle

Answer 6

Spore germination
Vegetative growth
Amplification
Dissemination

Question 7

Mold amplification

Answer 7

Results from increased water activity (>24 hours) due to catastrophe, chronic conditions, or neglect
Follows water migration
Deteriorates building materials
Affects indoor air quality

Question 8

Types of water damage

Answer 8

Catastrophic

• storm flooding
• sewage backflow
• Water pipe flooding

Insidious
-water intrusion, moisture buildup

Neglect

Question 9

Mold health effects

Answer 9

• Allergy – Water damage molds are recognized as potent allergens (e.g. Aspergillus, Penicillium, Aureobasidium, Cladosporium).
• Toxicity – Many molds can produce mycotoxins which may lead to neurological and hemorrhagic symptoms (e.g. Stachybotrys associated with bleeding lungs in infants).
• Infection – Immunocompromised persons are at risk for opportunistic mold infections.

Question 10

Mold prevention and control

Answer 10

• Design
• Construction
• Operation
• Maintenance (+ cleaning)

Question 11

Radon pollution

Answer 11

Radon-222 is a colorless, odorless, radioactive gas that is a decay product of radium-226 which is a decay product of thorium-232 and uranium-238, and occurs naturally in soil and rock.

Remediation focuses on venting radon away from the house interior by venting directly from beneath the slab through the roof of the house, or by horizontal crawlspace ventilation.

Question 12

Sources of respirable particles

Answer 12

fireplaces, stoves, kerosene heaters, and smoking, as well as from accumulated organic dusts due to poor cleaning practices.

Question 13

Health effects of respirable particles

Answer 13

eye, nose, and throat irritation, and increased risk for respiratory infections, bronchitis, asthma, and lung cancer.

Question 14

Steps to reduce respirable particles indoors

Answer 14

• Frequent cleaning is the best way to keep airborne dust levels from increasing indoors.
• This includes damp dusting, vacuuming of carpet at least 3 times/week, and upholstery once per week with a high-efficiency vacuum cleaner (disposable double-wall bag + exhaust filtration).
• Have carpet professionally cleaned once or twice per year depending on pets, children, and activities.