23rd Apr 2020

# Ozone Units of Measure

ppm, ppb, g/m3, mg/l, and many others

What do these all mean? What do they have to do with ozone? Why do scientific papers have to be so confusing? Let us try to help, keep reading.

## ppm = Parts per Million

As a measurement of concentration, ppm (Parts per Million) would indicate how many parts of the gas in question (ozone in our case) are in every 1 million parts of total gas. For example; if we state there is 1 ppm ozone, that means for every 1 million parts of gas, 1 of these is ozone. The tricky thing with ppm is that we can be measuring the "parts" by volume or weight. Sometimes you may see this as ppmv, indicating parts per million by volume. The most common ozone measurement is ppm, and is used to measure ozone in air and ozone dissolved into water.

## ppb = Parts per Billion

This indicates the same thing as ppm, only change the million to a billion. This moves a decimal point 3 places. For example 0.1 ppm = 100 ppb.

## mg/l = Milligrams of Ozone per Liter

Is a measurement of concentration. This indicates how many milligrams of ozone there are in one liter of total volume. Mg/l can be used to indicate the concentration of ozone in gas or liquid.

1 mg/l of ozone = 1 ppm of ozone in water. Due to the density of air this is no longer true and 1 ppm of ozone = 2140 mg/l. This is a common term used to measure the amount of ozone dissolved into water.

## ug/ml = Microgram per Milliliter

Is a measurement of concentration. This indicates how many micrograms of ozone there are in one milliliter of total volume. Ug/ml can be used to indicate the concentration of ozone in gas or liquid.

1 ug/ml = 1 mg/l = 1g/m3 = 1 gamma - these terms are equal, no conversion is necessary

## g/m3 = Grams of Ozone per Cubic Meter

Is a measurement of concentration. This 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 (by mass)

1 g/m3 = 467 ppm of ozone in air

1 ppm = 2.14 mg/m3 in air (by volume)

## g/hr (gm/hr) = Grams of Ozone 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 of ozone per hour

This indicates the same thing as g/hr only on a smaller scale. Smaller ozone generators may be rated in mg/hr.

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 within the ozone world.

1 lb/day of ozone = 18.89 g/hr ozone production