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Gases - Dangerous Concentration Levels

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Gases - Dangerous Concentration Levels
GasGas Concentration (0/00)
Tolerable > 1 hourTolerable < 1 hourImmediately Dangerous
Ammonia 0.1 0.3 3.5
Bromine Vapor 0.001 0.004 0.05
Carbon Dioxide 10 30 40
Carbon Monoxide 0.2 0.5 2.0
Chlorine Vapor 0.001 0.004 0.05
Hydrochloric Acid 0.01 0.05 1.5
Hydrogen Sulphide 0.2 0.6
Iodine Vapor 0.0005 0.003 0.05
Sulphuric Acid 0.05 0.5
  • 1 ppm = 10-6 = 0.0001 o/o = 0.001 o/oo
  • o/oo  = 1000 ppm 
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