INDOOR AIR QUALITY

Grey Isley, CIE, CMR

What is Indoor Air Quality? When did it start? Why do we care? How do we impact it?

History

• 800-600 BCE Derinkuyu, Turkey (Underground

City)

Extended to a depth of 60 m ( approx. 200 ft) and

sheltered 20,000 people along with livestock and food

stores.

Utilized a series of ventilation shafts and systems to

provide fresh air to inhabitants.

History

• 800-600 BCE Derinkuyu, Turkey (Underground

City)

• 400 BCE Yakhchal construction

An ancient evaporative cooler used to store ice and food

in Persia (modern day Iran).

Important because it demonstrates early steps to control

the indoor environment in a manner to achieve a required

or desired state of comfort or operation.

History

• 800-600 BCE Derinkuyu, Turkey (Underground City)

• 400 BCE Yakhchal construction

• 80 – 15 BCE Marcus Vitruvius Pollio

Wrote The Ten Books on Architecture. Emphasized the structure must be solid, useful and beautiful.

Stressed that buildings must be placed to take advantage of nature and avoid sickness from swamp winds.

Developed a type of central heat, hypocaust, where hot air from a fire was channeled into the floors and walls of public baths and villas.

History

• 800-600 BCE Derinkuyu, Turkey (Underground

City)

• 400 BCE Yakhchal construction

• 80 – 15 BCE Marcus Vitruvius Pollio

• 200 AD Mosaic Tiles used for cooling

Spaces in the tiles retain water. As air passes across the

tiles it is cooled.

History

• 800-600 BCE Derinkuyu, Turkey (Underground

City)

• 400 BCE Yakhchal construction

• 80 – 15 BCE Marcus Vitruvius Pollio

• 200 AD Mosaic Tiles used for cooling

• 500 AD Native Americans in Arizona use

ventilation and passive heating strategies in

structures

Modern Day • Energy Crisis of 1970’s resulted in buildings becoming

more efficient

• Introduction of HVAC during the same period resulted

in people keeping buildings closed up more.

• Introduction of new building materials, such as

plywood, have resulted in exposure to more chemicals.

• The green building push of the 2000’s has drawn

attention to the aspect of IAQ but an increase push in

efficiency has resulted in additional issues that were

not previously a problem.

What is Indoor Air Quality?

Indoor Air Quality Defined The absence or presence of concentrations of air pollutants or conditions that affect the health or comfort of a building’s occupants

Indoor Air Quality Defined Acceptable Indoor Air Quality: (ASHRAE 62-1999) Air in Which there are no known contaminants at harmful concentrations and with which a substantial majority (80%) of the people exposed do not express dissatisfaction.

Indoor Air Quality Defined Acceptable Indoor Air Quality: (ASHRAE 62-1999) Air in which there are no known contaminants at harmful concentrations and with which a substantial majority (80%) of the people exposed do not express dissatisfaction.

What Impacts IAQ?

2 types of stressor: • Energy Stressors- anything that can be related to a wavelength.

• Light, Heat, Noise

• Mass Stressors- anything related to particles • Dust, Chemicals, Mold, Asbestos

Energy Stressors • Primarily associated with comfort and often not considered part

of IAQ. • Can be overlooked easily but are some of the most commonly

known aspects of comfort or discomfort in a space. • Most often the major cause of IAQ problems or directly impact a

mass stressor that is causing discomfort.

Mass Stressors

Mass Stressors • Tobacco Smoke • Combustion Contaminants- Particles and vapors • Biological- Mold, insect/animal droppings and dander, body odor, dust

mites, bacteria • VOC’s- Cleaners, paint, air fresheners, perfumes • Formaldehyde- Particle board, carpet, furniture • Other Chemicals- Ozone generators, Environmental chemicals • Soil Gas- Sewer and radon • Pesticides • Particles and Fibers- Insulation, degrading material, paper • Moisture- A major component and influences many of the other stressors

Comfort (Energy Stressors)

• Thermal comfort depends on the heat transfer between human body and the environment

• Can be subjective and objective

• Body reacts with strain which can include increased blood pressure, changes in respiration and

oxygen consumption, fatigue, and change in body temperature.

Comfort (Energy Stressors) Indoor comfort is affected by: (ASHRAE 55-2004)

• Metabolic Rate • Clothing amount • Air temperature • Radiant temperature • Air speed • Humidity

Comfort (Energy Stressors)

Comfort (Energy Stressors)

Mass Stressor (Acceptable Levels) Each stressor has what is considered an acceptable level

• Some are defined while others are more subjective and based on normal conditions or environments

• OSHA defines levels for many of the most common or dangerous components found in industry • OSHA 1910 subpart Z (general industry) • OSHA 1915 subpart Z (Shipyard) • OSHA 1926 subpart Z (construction)

• Examples of defined.

• Formaldehyde (PEL) • TWA- o.75 ppm for 8 hrs. (daily exposure) • STEL – 2 ppm for 15 minutes (short term exposure)

Mass Stressor (Acceptable Levels) Bioaerosols

• Much less precise than chemicals or certain particulates

• Some such as allergens are related to exposure and allergen sensitivity

• Mold is very subjective and based upon comparison to a normal or everyday environment.

Moisture A driving force for many contaminants.

• Needed for fungal growth • Can impact comfort • Reduces effectiveness of envelope systems • Needed for dust mites

Can be in the form of bulk or vapor.

• Recommended that humidity be below 60% but prefer 50% for control of all contaminants

• Should not drop too low as low humidity can cause discomfort.

How Do We Control IAQ Ventilation

• Dilution and removal of contaminants

Elimination • Control and limitation of contaminants in the environment • Limit the introduction through the selection and storage of materials

Cleaning • Removal through cleaning, upkeep and maintenance of the structure

Control

• Proper operation of the building and the HVAC system

What is Indoor Air Quality? When did it start? Why do we care? How do we impact it?