ABCDEFGHIJKLMNOPQRSTUVWXYZ
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Rebreathed Fraction of Air
Source:
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https://tinyurl.com/rebreathed-air-fraction
maintained by: Twitter:@DavidElfstrom
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420
Co = Outdoor Air CO₂ ppm (note Aranet4 meter calibrates to 420 ppm)
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38000
Ca = Volume fraction of CO₂ added to exhaled breath (ppm)
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Indoor ppmFraction 1 in X breaths
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5000.2%475
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6000.5%211
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7000.7%136
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8001.0%100
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9001.3%79
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10001.5%66
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11001.8%56
https://doi.org/10.1034/j.1600-0668.2003.00189.x
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12002.1%49
Risk of indoor airborne infection transmission estimated from carbon dioxide concentration
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13002.3%43
S. N. Rudnick, D. K. Milton, Indoor Air, Volume 13, Issue 3, September 2003, p237-245
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14002.6%39
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15002.8%35
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16003.1%32
Reasonable approximation
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17003.4%30
Based on 40,000 ppm in breath and 400 ppm outdoor air:
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18003.6%28
For every additional 400 ppm over outdoor, rebreathed fraction increases 1%
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19003.9%26Indoor CO₂ ppmRebreathed1 in X breaths
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20004.2%244000%None
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22004.7%218001%100
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24005.2%1912002%50
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26005.7%1716003%33
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28006.3%1620004%25
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30006.8%1524005%20
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32007.3%1428006%17
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34007.8%1332007%14
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36008.4%1236008%13
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38008.9%1140009%11
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40009.4%11440010%10
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42009.9%10480011%9
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440010.5%10520012%8
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460011.0%9
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480011.5%9
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500012.1%8
⬅ occupational health limit for CO2 exposure (such as for an industrial process using CO2 gas): 5000 ppm
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