Typical Levels of Carbon Dioxide Gas CO2 Normal Levels in Air Indoors & Outside InspectAPedia® -
Toxicity of carbon dioxide gas, CO2 exposure limits
Symptoms of CO2 or carbon dioxide poisoning
Health effects of carbon dioxide gas exposure
Recommendations for gas measurement instruments, gas detector tubes, Draeger & Gastec tubes & pumps for detection of gases
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This document discusses the typical or normal levels of carbon dioxide gas (CO2) outdoors and inside buildings. We give references and explanation regarding Toxicity of Carbon Dioxide, based on literature search and search on Compuserve's Safety Forum by Dan Friedman. This is background information, obtained from expert sources. This text may assist readers in understanding these topics. However it should by no means be considered complete nor authoritative. Seek prompt advice from your doctor or health/safety experts if you have any reason to be concerned about exposure to toxic gases.
Links on this page also direct the reader to carbon monoxide gas information in a separate document.
IF YOU SUSPECT ANY BUILDING GAS-RELATED POISONING GO INTO FRESH AIR IMMEDIATELY
and get others out of the building, then call your fire department or emergency services for help.
How to use gas detection tubes for measuring the level of various gases
The colorimetric gas detection tubes, here showing a tube made by Drager, are a relatively inexpensive way to test for
the level of specific gases.
The tubes are quite accurate and can be selected and used down to very low concentrations of
various gases, provided that a properly chosen and calibrated gas testing pump is used. In some cases for very precise
measurements a correction factor needs to be applied for temperature at the time of measurement.
We use Drager tubes as
well as another system of tubes and pump made for and sold through GasTec for testing indoor levels of specific gases.
What are the component gases that make up normal air and in what proportions or percentages do they ocur?
At sea level on earth, what is the composition of the air we breathe? That is, what gases make up normal outdoor air?
How much CO2 is in air? How much oxygen is in air? and how much nitrogen is in the earth's atmosphere? Here is the
mix of gases in normal outdoor air.
The earth's atmosphere (measured close to ground level) is made up of 78.1% nitrogen, 20.9% oxygen, 0.9% argon,
0.03% carbon dioxide, and 0.04% other gases. Let's look at some typical CO2 levels in both percentage and expressed
in parts per million, which is how most instruments measure gas concentrations. [The mix of gases in air near some manufacturing
facilities or in some cities may be a bit different.]
What are typical Carbon Dioxide levels in air?
Carbon dioxide CO2 levels outdoors near ground level are typically 300 ppm to 400 ppm or 0.03% to 0.040% in concentration.
Carbon dioxide CO2 levels indoors in occupied buildings are typically around 600 ppm to 800 ppm or 0.06% to 0.08% in concentration. You'll
find this data in many indoor air quality articles and books and it's consistent with what we find typically in our own field measurements.
Carbon dioxide CO2 levels indoors in an inadequately vented space with heavy occupation is often measured around 1000 ppm or 0.10% in concentration.
I have measured levels around 1200 ppm in occupied basement offices in a hospital where the staff worked in an area which had
no decent fresh air intake into their ventilation system. In 1989 I also measured 1200 ppm at chest
height in the center of the sanctuary in a Jewish synagogue during the high holy days in a small
New York city. I also observed people nodding off. We were never
sure if it was a droning sermon, exhausted worshipers at the end of a long week, or the CO2 level.
But there was no doubt that we were not meeting recommended ventilation
standards for that space.
Carbon dioxide levels above 1500 to 2000 ppm are likely to be reached only in unusual circumstances (being enclosed in an
airtight closet for a long time) or in industrial workplace settings such as we cited above.
Carbon Dioxide CO2 Sources in the Atmosphere & Carbon Dioxide CO2 Level Changes as a Greenhouse Gas
Carbon dioxide (CO2) is emitted in a number of ways. It is emitted naturally through the carbon cycle and through human activities like the burning of fossil fuels.
Natural sources of CO2 occur within the carbon cycle where billions of tons of atmospheric CO2 are removed from the atmosphere by oceans and growing plants, also known as ‘sinks,’ and are emitted back into the atmosphere annually through natural processes also known as ‘sources.’ When in balance, the total carbon dioxide emissions and removals from the entire carbon cycle are roughly equal.
Since the Industrial Revolution in the 1700’s, human activities, such as the burning of oil, coal and gas, and deforestation, have increased CO2 concentrations in the atmosphere. In 2005, global atmospheric concentrations of CO2 were 35% higher than they were before the Industrial Revolution. For more information on CO2 trends in the atmosphere, visit the page on Atmosphere Changes.
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Dr. Roy Jensen, Department of Chemistry, Grant MacEwan College, Edmonton, AB for technical review and critique 8/23/07.
Dr. Jensen notes that if we increase the CO2 level in air in an enclosed space from
its normal level of about 0.03% (we counted it as starting at 0) to a level of 1.4%, we obtain a corresponding
decrease in the oxygen level from its normal level (at sea level) of about 20.9% down to 19.5%, for a 6.7%
reduction in the amount of oxygen available. The amount of oxygen lost is 6.7 % (1.4/20.9 * 100 %). Our earlier version of this document was incorrect in
this calculation.
GASES, EXPOSURE, TESTING Toxic Gas Exposure Hazards and Test Protocols including links
to our toxic gas exposure screening and gas testing protocols.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
A Toxic Gas Testing Plan: A Gas Sampling Plan for Residential and Commercial buildings lists some of the toxic indoor gases for which we test, depending on the building complaint and building conditions
CCSP, 2008: Analyses of the effects of global change on human health and welfare and human systems. A Report by the U.S.
Climate Change Science Program and the Subcommittee on Global Change Research. [Gamble, J.L. (ed.), K.L. Ebi, F.G. Sussman,
T.J. Wilbanks, (Authors)]. U.S. Environmental Protection Agency, Washington, DC, USA. Web search 08/28/2010, original source: http://nepis.epa.gov/
Gas Exposure Hazard Levels: for Toxic Gas Exposure to Ammonia, Arsine, Arsenic, Bromine, Carbon Dioxide, Carbon Monoxide, Hydride, Ozone - allowable exposure levels and hazard levels
Health Effects of Carbon Dioxide - see "National Advisory Committee for Acute Exposure Guideline Levels (AEGLs) for Hazardous Substances; Proposed AEGL Values, Federal Register Document", http://www.epa.gov/EPA-TOX/2002/February/Day-15/t3774.htm note that these are proposed guidelines
GTSP, 2006: Carbon Dioxide Capture and Geologic Storage: A Core Element of a A Global
Energy Technology Strategy to Address Climate Change (PDF, 37 pp., 6.05 MB, About PDF).
April 2006, JJ Dooley et al. Global Energy Technology Strategy Program (GSTP)
IPCC, 2005: Special Report on Carbon Dioxide Capture and Storage, Special Report of the
Intergovernmental Panel on Climate Change [Metz, Bert, Davidson, Ogunlade,
de Coninck, Heleen, Loos, Manuela, and Meyer, Leo (Eds.)]. Cambridge University Press, The
Edinburgh Building Shaftesbury Road, Cambridge CB2 2RU England
Fluorine, Its Compounds, and Air Pollution,: a Bibliography with Abstracts, US Environmental Protection Agency, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina 27711, December 1976. Web search 08/28/2010, original source: http://nepis.epa.gov. NOTE: because the EPA's original source of this document in PDF format is damaged we have created a text image file, converted to a new PDF for readability.
Formaldehyde: US EPA. UFFI (Urea Formaldehyde Foam Insulation) was previously considered a hazard (formaldehyde outgassing). Subsequent research virtually closed concern regarding this material; however formaldehyde appears to remain a health concern for sensitive individuals.
Nitrogen Oxides: Air Quality Criteria for Oxides of Nitrogen, Vol III of III, US EPA, EPA600/8-91/049cF, August 1993, web search 08/28/2010, original source: http://nepis.epa.gov [Large PDF 25MB] Key chapters in this document evaluate the latest scientific data on (a) health effects of
NOx measured ill laboratory animals and exposed human populatIOns and (b) effects of NOx
on agricultural crops, forests, and ecosystems, as well as (c) NOx effects on visibility and
nonbiological materials. Other chapters describe the nature, sources, distribution,
measurement, and concentratiOns of NOx m the environment These chapters were prepared
and peer reviwed by experts from various state and Federal government offices, academia,
and private industry for use by EPA to support decision makIng regarding potentIal risks to
public health and the enVIronment Although the document IS not intended to be an
exhaustIve literature reVIew, It IS intended to cover all the pertinent literature through early
1993
Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
Sampling for gases in air such as VOC's, MVOC's, toxic chemicals, and combustion products.
Unfortunately no single test or tool can detect all possible building contaminants. We use methods and equipment which can test for common contaminants. If the identity of a specific contaminant is known in advance we can also test for a very large number of specific contaminant gases in buildings.
We use gas sampling equipment provided by the two most reliable companies in the world, Draeger-Safety's detector-tubes and Drager accuro� bellows pump, the Gastec� cylinder pump and detector-tube system produced by Gastec or Sensidyne, and
we also use Sensidyne's Gilian air pump. For broad screening for combustibles and a number of other
toxic gases and for leak tracing we also use Amprobe's Tif8850. All of these instruments, their applications, and sensitivities (minimum detectable limits) for specific gases are described in our Gas Sampling Plan online document.
Radon Gas U.S. EPA Radon level maps, web search 2005, original source: http://www.epa.gov/iaq/radon/zonemap/zmapp33.htm
"Table Z-1 Limits for Air Contaminants, 1910.1000 Table Z-1" OSHA standard for air contaminant limits (http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9992) - includes for CO2, Carbon dioxide.........| CAS No. 124-38-9 | 5000 ppm | 9000 mg/m3 limits for carbon dioxide as an air contaminant.
GASES, EXPOSURE, TESTING Toxic Gas Exposure Hazards and Test Protocols including links
to our toxic gas exposure screening and gas testing protocols.
Use of Ozone as a "mold" remedy is ineffective and may be dangerous.