What Gases Make Up Air?
Concentrations of various gases in air
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Gases that make up outdoor air: this article provides a table of the components in outdoor air - a list of the various gases found in air by percentage.
The table gives the percent of each gas found in typical outdoor air, includes citations of authoritative sources, and discusses variations in the data. These gas percentages are a useful reference for comparison when making both outdoor and indoor site measurements and studies of air quality and air contaminants.
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What are Typical Concentrations of all of the Gases in Air
Outdoor air is commonly used as a baseline for comparison with indoor air quality. Provided that the outdoor air location sampled is not close to a particular source of contamination such as particulates or chemicals from a nearby trash burning or industrial facility, or such as gases from an adjacent garage or highway this is a reasonable approach. The table below provides the components of indoor air in typical percentages of make-up.
| Component Gases of Outdoor Air | ||
|---|---|---|
| Gas In order of percentage of outdoor air |
Outdoor Air Percent | Symbol, Comments |
| Nitrogen | 78.084% | N2, one of four chief components of air |
| Oxygen | 20.947% | O2, second of four chief components |
| Argon | 0.934% | Ar, third of four chief components, an inert gas |
| Carbon dioxide | 0.033% to - 0.04% | CO2, fourth of chief components of outdoor air, together these four 99.998% of air A healthy human breathing outdoor air exhales a mixture with about 6% less oxygen and much higher CO2 , in a breath mixture of about 14% O2 and 4.4% CO2 but as exhaled breath is mixing with a much greater volume of indoor air, the normal indoor CO2 will not normally approach that 4% level. See CARBON DIOXIDE - CO2 for details. |
| Trace Gases detectable in outdoor air | ||
| Neon | 18.2 ppm (parts per million) | Ne |
| Helium | 5.2 ppm | He |
| Methane | 2.0 ppm | CH4, |
| Krypton | 1.1 ppm | Kr |
| Sulfur dioxide | 1.0 ppm | SO2,, |
| Hydrogen | 0.5 ppm | H2 |
| Nitrous Oxide | 0.5 ppm | N2O NITROGEN OXIDES [PDF document] |
| Xenon | 0.09 ppm | Xe |
| Ozone | 0.07 ppm | O3, |
| Nitrogen dioxide | 0.02 ppm | NO2 |
| Iodine gas | 0.01 ppm | I2 |
| Ammonia | very low trace levels | NH3 |
| Carbon monoxide | very low trace levels | CO, Typical IAQ screening should not detect in indoor air. See CARBON MONOXIDE - CO for details. |
...
Notes to the table above
Notes:
1. Moeckel, W.E.; Weston, K.C., "Composition and Thermodynamic Properties of Air in Chemical Equilibrium", Technical Report NACA-TN-4265, Lewis Flight Propulsion Lab., Cleveland, 1 April 1958,
updated 25 February 2008, Website citation: www.osti.gov, U.S. DOE
2. Bender, M. L., T. Sowers, J.‐M. Barnola, and J. Chappellaz (1994),
Changes in the O2/N2 ratio of the atmosphere during recent decades reflected in the composition of air in the firn at Vostok Station, Antarctica, Geophys. Res. Lett., 21(3), 189–192, doi:10.1029/93GL03548.
3. A.P. Jones, "Indoor Air Quality and Health", School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK,
Atmospheric Environment
Volume 33, Issue 28, December 1999, Pages 4535–4564
...
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Citations & References
In addition to any citations in the article above, a full list is available on request.
- [1] CADAC, Commercial And Domestic Appliance Company, produces a range of gas and camping products. we are guessing that typically they'd be marketing LP - liquid propane. Web search 07/22/2010 - original source: http://www.cadac.co.za/index.php?page=company describes Cadac products. their tel: support line on 0860 22 3 22 0
- [2] Canadian Centre for Occupational Health and Safety, web search 07/22/2010, original source: http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/propane/health_pro.html
- [3] "Residential Electric Water Heater Installation Instructions and Use & Care Guide", American Water Heater Co., October 2001, American Water Heater Co., Johnson City, TN, [manufacturer of residential & commercial water heaters, also manufacturer of Polaris/Commercial water heaters], Tel: 800-999-9515, web search 1/12/2012, original source: americanwaterheater.com/support/manuals/res-elect.pdf [copy on file]
- [4] Portions of this data were extract5ed from CompuServe's SAFETYNET forum 1989 and from the following articles:
- [5] [73766,1245] GASES.TOX 08-May-87 17240 53 Title: Toxicity & hazards discussion of various gases
- [6] Keywords: Discussion of the toxicity and hazards of various gases, ammonia, arsine, bromine, carbon dioxide, carbon monoxide, ozone, nitric oxide, nitrogen dioxide, propylene, and sulfur dioxide.
- [7] [74756,40] CO 20-Dec-86 7050 40 Title: Carbon Monoxide discussion by Jack Peterson
- This is a discussion of carbon monoxide from lift trucks, by Jack Peterson, in response to a query on the message board. Excellent information from one of the leading experts on the topic. ASCII file - Uploaded by Len Wilcox, 74756,40 [an old Compuserve address].
- [8] [76701,115] COALAR.TXT 19-Aug-88 12814 17 Title: Message thread on Carbon Monoxide Alarms
- [9] Keywords: CO CARBON MONOXIDE ALARM ALARMS MONITOR MONITORING TESTING
- [10] [Portions of this file was excerpted and edited from contents of a 1986 Compuserve message board discussion on Carbon Monoxide alarms, featuring comments by one of the leading authorities on CO, Jack Peterson.-- DJF]
- [11] U.S. Army Field Manual FM-8-285-Noxious_Chemicals discusses Ammonia, Carbon Monoxide, Hydrogen Sulfide, Oxides of Nitrogen, Hazards caused by fire
- [12] Sulfur dioxide, Exposure Limits, U.S. Department of Labor, OSHA, web search 4/12/12, original source:
http://www.osha.gov/dts/chemicalsampling/data/CH_268500.html - [13] "Residential Electric Water Heater Installation Instructions and Use & Care Guide", American Water Heater Co., October 2001, American Water Heater Co., Johnson City, TN, [manufacturer of residential & commercial water heaters, also manufacturer of Polaris/Commercial water heaters], Tel: 800-999-9515, web search 1/12/2012, original source: americanwaterheater.com/support/manuals/res-elect.pdf [copy on file]
- [14] More information about gas hazards, gas toxicity, or other environmental hazards is available from public and professional agencies and associations such as the American Industrial Hygiene Association (AIHA) www.aiha.org, OSHA www.osha.gov, and the Mine Safety & Health Administration www.msha.gov. Also see Industrial Hygiene News.
- "When Wrinkle-Free Clothing Also Means Formaldehyde Fumes", Tara Siegel Bernard, The New York Times, 11 December 2010, pp. B1, B5.
- Formaldehyde MSDS, Mallinckrodt Baker, Inc., 222 Red School Lane, Phillipsburg, NJ 08865, Mallinckrodt Chemicals and J.T. Baker, Tel: 800-582-2537 (U.S.) or 908-859-2151 (outside the U.S.) retrieved 12/13/2010, original source: http://www.jtbaker.com/msds/englishhtml/f5522.htm Note that the company's website "about us" link brings readers to Avantor Performance Materials, formerly Mallinckrodt Baker. Quoting:
- Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The HOME REFERENCE BOOK - the Encyclopedia of Homes and to use illustrations from The ILLUSTRATED HOME .
Carson Dunlop Associates provides extensive home inspection education and report writing material. In gratitude we provide links to tsome Carson Dunlop Associates products and services.
- Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
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