Ozone Data

Occupational exposure limits

The following occupational exposure limits for ozone apply in the UK, other parts of Europe, the USA and Canada:

0,1 ppm:

0,3 ppm:

the limit for regular exposure for up to 8 hours per day, 5 days per week (Netherlands: 0,06 ppm)

exposure should be limited to 15 minutes at a time

Ozone data

  • Molecular formula

O3

  • ·Principal characteristic

oxidising gas

  • Molecular weight

48,0

  • Concentration

up to 18% by weight in oxygen

  • Boiling point

-111,9 °C

  • Melting point

-192,7 °C

  • Critical temperature

-12,1°C

  • Critical pressure

54,6 atm.

  • Density

2,14 kg O3/m3 @ 0°C 1013mbar

  • Relative density (to air))

1,7

  • Solubility in water

3 ppm at 20 °C

  • Heat of formation

144.7 kJ/mole

  • Bond angle

116°

  • Electrochemical potential
-2,07 V
  • Flash point
not applicable
  • Auto ignition temperature
not applicable
  • Flammability
non-flammable, but vigorously supports combustion
  • Hazardous decomposition products
none

Ozone is a colourless gas at all concentrations experienced in industry. It has a pungent characteristic odour usually associated with electrical sparks and thunder storms. The odour is generally detectable by the human nose at concentrations between 0,02 and 0,05 ppm or approx. 1/100th of the recommended 15 minute exposure level.

Ozone is an unstable gas which decomposes to biatomic oxygen at normal temperatures. Decomposition is accelerated by contact with solid surfaces, by contact with chemical substances and by the effect of heat. Ozone is produced by ozone generators which aren normally fed by oxygen generators. Ozone injection is done by diffusors or venturi's.

Because ozone is an unstable gas, there may be danger of explosion at high temperatures in the presence of materials such as hydrogen, iron, copper and chromium. In practice, occasional fires have occurred inside ozone generators, but with the exception of experiments under extreme conditions, we know of no reports of explosions.

For information on ozone monitors and sensors for room control.