Carbon Dioxide Concentration - Comfort Levels

CO2 acceptance and comfort level

Indoor comfort and air quality includes parameters like

  • temperature
  • odor
  • high or low levels of gases

Since CO2 is exhaled by people at predictable levels the content of Carbon Dioxide in the indoor air can be used as a significant indication of air quality.

Fresh supply air correlates to the indoor level of CO2 as:

  • 15 cfm ventilation rate per occupant - aprox. 1000 ppm CO2
  • 20 cfm ventilation rate per occupant - aprox. 800 ppm CO2

Normal CO2 Levels

The effects of CO2 on adults at good health can be summarized to:

  • normal outdoor level: 350 - 450 ppm
  • acceptable levels: < 600 ppm
  • complaints of stiffness and odors: 600 - 1000 ppm
  • ASHRAE and OSHA standards: 1000 ppm
  • general drowsiness: 1000 - 2500 ppm
  • adverse health effects may be expected: 2500 - 5000 ppm
  • maximum allowed concentration within a 8 hour working period: 5000 - 10000 ppm  
  • maximum allowed concentration within a 15 minute working period: 30000 ppm

The levels above are quite normal and maximum levels may occasionally happen from time to time. In general - ventilation rates should keep carbon dioxide concentrations below 1000 ppm to create indoor air quality conditions acceptable to most individuals.

Extreme and Dangerous CO2 Levels

  • slightly intoxicating, breathing and pulse rate increase, nausea: 30000 - 40000 ppm
  • above plus headaches and sight impairment: 50000 ppm
  • unconscious, further exposure death: 100000 ppm

Carbon Dioxide Standard Levels

The recommendations in ASHRAE standard 62-1989 are

  • classrooms and conference rooms 15 cfm per occupant (person)
  • office space and restaurants 20 cfm per occupant
  • hospitals 25 cfm per occupant
  • 1 cfm (ft3/min) = 1.7 m3/h = 0.47 l/s

Related Topics

  • Physiology - Human physiology, air quality and comfort temperatures, activity and metabolic rates, health effects of carbon monoxide and more

Related Documents

Tag Search

  • en: CO2 comfort levels parts per million ppm
  • es: Niveles de confort CO2 partes por mill√≥n ppm
  • de: CO2 Komfortstufen ppm ppm

Search the Engineering ToolBox

- "Search is the most efficient way to navigate the Engineering ToolBox!"

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your SketchUp model with the Engineering ToolBox - SketchUp Extension/Plugin - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Translate the Engineering ToolBox!
About the Engineering ToolBox!