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Glossary of Terms

Air Advice IAQ Guidelines: Sensor Alert Criteria

Rev: February 2007

PARTICLE ALLERGENS
(Airborne Particulate Matter – PM)

Sensor Reporting Range: 0 – 50 ug/m3

Rationale: Acceptable particulate matter (PM) values are based on the lack of two major indoor PM sources: environmental tobacco smoke and cooking. Extensive evidence shows that even limited exposure to low PM levels can trigger or worsen asthma, allergies, or other symptoms in sensitive populations. Chronic exposures are highly correlated to chronic lung disease and reduced lung capacity in both adults and children. Short- and long-term PM exposure at any level can result in respiratory, eye, and mucous membrane irritation for any population, but sensitive groups are shown to be definitively at risk for marked adverse affects.

*Standard trigger criteria is based on scientific literature produced by ASHRAE, Health Canada, Indoor Air Quality Association, World Health Organization, California Air Resources Board, LEED and EPA.

CHEMICAL POLLUTANTS
(Total Volatile Organic Compounds – TVOCs)

Sensor Reporting Range: 0 – 4000 ug/m3

Rationale: Acceptable total volatile organic compound (TVOC) values are based on threshold response levels to mixtures of compounds. At low levels, VOCs are known to trigger or worsen asthma, allergy, and other adverse systems in sensitive populations. Respiratory, eye, skin, and mucous membrane irritation can occur. Some VOCs are known carcinogens. Both short- and long-term exposure to VOCs create risk for both sensitive and healthy populations, with total responses and percent of affected population increasing in conjunction with VOC level increases.

*Standard trigger criteria is based on scientific literature produced by ASHRAE, Health Canada, Lars Molhave, Washington State, Indoor Air Quality Association, European Union, LEED, and EPA.

CARBON DIOXIDE (CO2)

Sensor Reporting Range: 0 – 2000 ppm

Rationale: Acceptable carbon dioxide (CO2) levels are based on ambient backgrounds levels measured outdoors. Concentrations above ambient (300-450 ppm) generally occur from human occupancy and activity combined with lack of adequate ventilation. This can lead to health and comfort issues such as fatigue and/or a perception of “stale air.”  Above 1000 ppm daily average, CO2 can cause dizziness, fatigue, and headache for much of the population.

*Standard trigger criteria are based on scientific literature produced by ASHRAE, Health Canada, Indoor Air Quality Association, and LEED.

TEMPERATURE SUMMER
Sensor Reporting Range: 32 – 100 °F

TEMPERATURE WINTER

Rationale: Temperatures that are too high, too low, or inconsistent can stress the body as well as cause discomfort. Sensitive groups may be immediately affected by temperature fluctuations as little as a single degree. Potential impact on human comfort of limited (1 day or more) or extended (duration of test) temperature values outside the acceptable range support recommended and/or necessary action, as well as indicate poorly functioning, absent, or improperly installed equipment.

*Standard trigger criteria are based on scientific literature produced by ASHRAE, Health Canada, Indoor Air Quality Association, and Washington State Dept. of Health.

HUMIDITY (RH)

Sensor Reporting Range: 10 – 90%

Rationale: Acceptable relative humidity (RH) values are based on both comfort and health reasons. Sensitive groups may be exposed to conditions where respiratory, skin, or other conditions are exacerbated via dryness, moistness, and/or microbial growth. Prolonged exposure for all populations to low level RH (<25%) and high levels (>60%) can increase the risk of microbial growth.

*Standard trigger criteria are based on scientific literature produced by the American Lung Association, ASHRAE, Health Canada, Indoor Air Quality Association, and Washington State Dept. of Health.
**Lower ranges calculated when temperatures drop below 40 °F.

CARBON MONOXIDE (CO)

Sensor Reporting Range: 0 – 100 ppm

Rationale: Acceptable carbon monoxide (CO) levels are based on adverse affects on human health from prolonged exposure to high levels of CO. Carbon monoxide is made naturally in the body, with COHb blood levels found at up to 2.5% without sign of adverse effects. Above 5 ppm, COHb levels increase above 2.5%, which can adversely affect cardiovascular disease sufferers as well as pregnant women and their unborn child. Healthy individuals will be impacted at levels of 12-20 ppm, including reducing breathing capacity among other effects. CO occurring at above 20 ppm for a 1-hr average has a severe impact on sensitive groups and significantly impacts healthy individuals as well. At high levels, carbon monoxide can cause death.

*Standard trigger criteria are based on scientific literature produced by ASHRAE, UK Dept of Health, World Health Organization, Indoor Air Quality Association, California Air Resources Board, EPA and LEED.

RADON (Rn)

Sensor Reporting Range: 0 – 100 pCi/L

Rationale: Acceptable radon values are based on what is technologically feasible. Radon is a naturally occurring radioactive gas known to cause lung cancer. Outdoor radon levels are 0.4 pCi/L; average home concentrations are 1.3 pCi/L. Evidence shows that the risk of lung cancer is low at these levels. Long-term breathing of air with radon levels of 3 – 4 pCi/L can begin to pose a significant health risk. Evidence shows that radon at levels of 4 pCi/L or more will significantly elevate the risk of lung cancer as will smoking in conjunction with elevated Radon levels.