Carbon Monoxide is a poisonous gas that is 250 times better at binding with hemoglobin in blood cells than is oxygen. If inhaled carbon monoxide will cause adverse health effects starting with dizziness, light headiness, shortness of breath, and nausea, exposure may also lead to sleepiness coma and death all depending on dosage and exposure time. Carbon dioxide is a very serious indoor air quality concern that causes more accidental poisoning death each year in America than any other poison.

Carbon Dioxide On the other hand carbon dioxide does not typically build up to levels in the ambient indoor air that can result in serious negative health effects. Carbon dioxide itself is not a serious concern in most indoor environments but is tested as part of an indoor air quality investigation because elevated levels of carbon dioxide indicates poor building ventilation, and this same poor ventilation not only results in the build up of typically harmless carbon dioxide, but also causes the build up of various air born irritants such as body odor, volatile organic compounds, particulate matter, and bio-allergens.

Indoor levels of carbon dioxide should be under 1000 ppm or no more than 700 ppm higher than outdoor levels.

High levels of carbon dioxide can cause similar effects to carbon monoxide if it can build up to dangerous levels indoors but this does not typically happen indoors. Hypercapnia is typically caused by extreme concentrations of carbon dioxide such as are encountered from re breathing exhaled carbon dioxide such may occur with scuba diving complications, not breathing properly ( hyperventilation suffocation like conditions, ) or from volcanoes belching out massive amounts of carbon dioxide.

Carbon dioxide itself is not a direct indoor air quality concern in most indoor environments however considering all the various industrial processes going on in indoor environments every day their always may be some strange exceptions where neglect and carelessness can result in indoor levels of carbon dioxide becoming high enough to limit the amount of available oxygen.

Volatile Organic Compound levels in indoor environments (VOC's)

what are normal levels of Volatile Organic Compound (VOC) levels Global consensus has resulted in the emergence of preliminary guidelines or tVOC standards for IAQ (Australian NHMRC, 1993; Finnish society of IAQ, 1995: Seifert, 1999: Hong Kong EPA, 1999; Japan MoH, 2000).

Depending on Location (home, school, etc. ), recommended levels range from 200 to 1300 ug/m3 or about 50 to 325 ppb .05 to .325 ppm (Toluene units) or approximately 100 to 650 ppb .1 to .650 isobutylene unis.

By all acounts the IAQ tVOC threshold for normal environments should not exceed 500 ppb (0.5 ppm) Toluene units, which is equivalent to 1000 ppb (1ppm) isobutylene units.

Field experience suggests the following guide for the use of PIDs to assess indoor environments:

< 100 ppb or (.1ppm) isobutylene units: normal outdoor air

100-400 ppb or (.1-.4ppm) isobutylene units normal indoor air

500 + ppb or (.5ppm) + isobutylene units: indicates potential of IAQ contaminants

Reference RAE Systems Application Note AP-212