Ozone Measures and Conversions
Ozone Physical Properties
Density of ozone: 2.14 kg/m³
Molecular weight of ozone: 48
Density of oxygen: 1.43 kg/m³
Molecular weight of oxygen: 32
Density of air: 1.29 kg/m³
Density of water: 1,000 kg/m³
Atmospheric Pressure: 1 atm = 14.7psia
Understanding Units of Measurement
The different units of measurement can be confusing. Examples of typical units of measurement are given below.
Million = 1,000,000
Billion = 1,000,000,000
Trillion = 1,000,000,000,000
One millionth = 0.000001
One billionth = 0.000000001
One trillionth = 0.000000000001
One liter (L) = 1.06 quarts
One cubic meter (m³) = 35.31 cubic feet (ft³)
One cubic meter (m³) = 1,000 liters (L)
One liter (L) = 1,000 milliliter (ml) = 1,000 cubic centimeters
One gallon = 4.546 liters (L)
One feet (ft³) = 0.0283 cubic meter (m³)
One foot = 0.305 meters
28 grams = about 1 ounce
1 kilogram (kg) = 1,000 grams
1 milligram (mg) = 1÷1,000 gram = 0.001 gram
1 microgram (µg) = 1÷1,000,000 gram = 0.000001 gram
1 nanogram (ng) = 1÷1,000,000,000 gram = 0.000000001 gram
1 picogram (pg) = 1÷1,000,000,000,000 gram = 0.000000000001 gram
1,000 liters = 1 m³ = 264 US gallons
1 gal = 3.785 liters = 3,785 ml
1 m3= 35.3 ft³ = 264 US Gallons
Concentrations in Soil
Concentrations of chemicals in soil are typically measured in units of the mass of chemical (milligrams, mg or micrograms, µg) per mass of soil (kilogram, kg). Sometimes concentrations in soil are reported as parts per million (ppm) or parts per billion (ppb).
Concentrations in Water
Concentrations of chemicals in water are typically measured in units of the mass of chemical (milligrams, mg or micrograms, µg) per volume of water (liter, L, l). Concentrations in water can also be expressed as parts per million (ppm) or parts per billion (ppb). Occasionally, concentrations of chemicals in water may be written as grams per cubic meter (g/m³). This is the same as grams per 1,000 liters, which may be converted to milligrams per liter (mg/L). Therefore, 1 g/m³ = 1 mg/L = 1 ppm. Likewise, one milligram per cubic meter (mg/m³) is the same concentration in water as one microgram per liter (µg/L), which is about 1 ppb.
Concentrations in Air
Concentrations of chemicals in air are typically measured in units of the mass of chemical (milligrams, micrograms, nanograms, or picograms) per volume of air (cubic meter or cubic feet). However, concentrations may also be expressed as parts per million (ppm) or parts per billion (ppb) by using a conversion factor. The conversion factor is based on the molecular weight of the chemical and is different for each chemical. Also, atmospheric temperature and pressure affect the calculation. Typically, conversions for chemicals in air are made assuming a pressure of 1 atmosphere and a temperature of 25 degrees Celsius.
Units of Measure
ppm (Parts per Million)
This is a way of expressing very dilute concentrations of substances. Just as per cent means out of a hundred, so parts per million or ppm means out of a million. Usually describes the concentration of something in water or soil. One ppm is equivalent to 1 milligram of something per liter of water (mg/l) or 1 milligram of something per kilogram soil (mg/kg). So ppm is a measurement of concentration that indicate how many parts of ozone are in every 1 million parts of total gas.
ppb (Parts per Billion)
A weight to weight ratio used to describe concentrations. Parts per billion (ppb) is the number of units of mass of a contaminant per 1000 million units of total mass. As ppm, this describes the concentration of something in water or soil, but, instead of one part per million, ppb means one part per billion, that is, the unit moves to three decimal places.
Comparing: 0.1 ppm = 100 ppb
mg/l (Milligrams per Liter)
A unit of the concentration of a constituent in water or wastewater. It represents 0.001 gram of a constituent in 1 liter of water. It is approximately equal to one part per million (ppm). mg/l is a measurement of concentration and can be used to indicate the concentration of ozone in gas or liquid. This is a common term used to measure the amount of ozone dissolved into water. In this case, is how many milligrams of ozone there are in one liter of total volume.
Because of the difference between the density of air and water, we can say that:
1 mg/l of ozone = 1 ppm of ozone in water
1 ppm of ozone = 2140 mg/l in air
µg/ml (Microgram per Milliliter)
In the metric system, a microgram (μg -according to the International System of Units) is a unit of mass equal to one millionth (1×10-6) of a gram. μg is a measurement of concentration that, in this case, indicates how many micrograms of ozone there are in one milliliter of total volume. µg/ml can be used to indicate the concentration of ozone in gas or liquid.
Comparing: 1 µg/ml = 1 mg/l = 1g/m³ = 1 gamma
g/m³ (Grams per Cubic Meter)
It is a measurement of concentration which indicates how many grams of ozone there are in one cubic meter of total volume. This can indicate volume of a gas or liquid. g/m³ is most commonly used to measure the concentration of ozone in a gas stream.
1 g/m³ = 1 mg/l = 1 ppm of ozone in water
1 g/m³ = 467 ppm of ozone in air
1 ppm = 2.14 mg/m³ in air
% by weight (Percent by weight)
It is a measurement of concentration which indicates the percentage (%) of ozone within a given gas stream. % by weight is a very common method to illustrate the concentration of ozone from an Ozone Generator. Since the weight of the gas changes if it is air or oxygen gas with which the ozone gas is mixed, the % by the weight becomes more complicated than g/m³.
1% Ozone = 12.8 g/m³ Ozone in air
1% Ozone = 14.3 g/m³ Ozone in oxygen
Ozone Production Measurement
g/hr, or, gm/hr (Grams per Hour)
Is a measurement of ozone production. This is the most common method of measuring the output of an Ozone Generator. We can measure the concentration of ozone in g/m³, then when we calculate for flow rate with a measurement such as LPM (liters per minute), we can determine how many grams of ozone are produced in one hour of time.
mg/hr (Milligrams per Hour)
This indicates the same thing as g/hr, normally used to rate Smaller Ozone Generators.
1 g/hr of ozone = 1,000 mg/hr of ozone production
lb/day (Pounds per Day)
Is a measurement of ozone production. This is a common measurement of ozone production for large Ozone Generators, and is commonly used in some industries.
1 lb/day of ozone = 18.89 g/hr ozone production
In Water By Weight
1 g O3/m³(in water) = 1 mg/l = 1 ppm O3 (by weight)
In Air By Volume
1 g O3 / m³ = 467 ppm O3
1 ppm O3 = 2.14 mg O3/m³
1 ppm O3 = 214 µg/m³ (used more often in Europe)
1 ppm O3 = 0.00214 µg/ml – 1 µg/ml (used in medical ozone)
100 pphm (parts per hundred million) = 1 ppm (used in rubber testing)
In Air by Weight
1 g O3/m³ = ± 782 ppm O3
1% O3 = ± 12.8 g O3/m³
1% O3 = 7,824 ppm O3
In Oxygen by Weight
1 g O3/m³ (of O2) = ± 6.99 ppm
1% O3 = ±14.3 g O3/m³ in O2
100g O3 = 6,99% ppm O3 (in O2)
Adjust Flow Rate Conversion
How to determine Ozone Dosage in Water
required ozone production = water flowrate x ozone dosage
How to determine the output of an ozone generator
ozone production (mg/hr) = flowrate (lpm) x ozone concentration (g/m³)
How to determine the ozone solubility in Water
dissolved concentration in liquid (mg/l) = ozone concentration (g/m³) x solubility ratio (bunsen coefficient) x pressure (gas pressure in atmospheres)