Before delving into topics such as ozone generator output, measuring dissolved ozone in water, and other important information related to ozone, it is crucial to understand the units of measurement commonly used in the ozone industry. The terminology and assumed knowledge in the “ozone world” can be complex, so take a moment to read the following and ensure we are all on the same page.

## Ozone Concentration Units

wt% = percent by Weight

This refers to the percentage of ozone gas by weight in a given volume, rather than by volume itself. This gives the concentration of ozone gas in the gas flow passing through the ozone generator.

ug/ml = micrograms per milliliter

This unit is utilized to quantify the ozone concentration in certain applications. It is equivalent to g/m3 and 1 ug/ml ozone is equal to 1 g/m3 ozone.

g/m3 = grams per cubic meter

This is the most accurate method to measure the concentration of ozone produced by an ozone generator. It provides the amount of ozone in grams that is present in a given volume of feed gas passing through the generator, typically measured in cubic meters.

ppm = parts per million

The unit of measurement commonly used to determine the concentration of ozone in ambient air is parts per million (ppm), which represents the number of parts of ozone gas in one million parts of another gas, usually air. It’s important to note that ppm can be measured by weight or volume, and in the ozone industry, it’s usually measured by volume. Ppm is also used to measure the concentration of ozone in water, where 1 ppm equals 1 mg/L of ozone in water.

ppb = parts per billion

1 ppb (parts per billion) is a unit of measurement for very low levels of ozone in ambient air. It is equal to 0.001 ppm (parts per million).

mg/l = milligrams per liter

This unit is commonly used to measure ozone concentration in water, where 1 mg/l is equal to 1 ppm ozone in water. However, it can also be used to measure ozone concentration in air as a concentration. 1 mg/l ozone in air is equivalent to 1 g/m3, 1 ug/ml, or 1 gamma, and these terms can be used interchangeably.

## Ozone Output Units

mg/hr = milligrams per hour

This unit is often used to measure the output of smaller ozone generators. One gram per hour of ozone is equivalent to 1,000 milligrams per hour of ozone.

g/hr = grams per hour

The most common way to measure overall ozone generator output is in grams per hour (g/hr). This measurement refers to the weight of ozone produced by the generator in one hour. To calculate this rating, the gas flow through the ozone generator and the quantity of ozone in that gas must be measured. This information can then be used to determine the g/hr rating of the generator.

kg/hr = kilograms per hour

This unit is typically used to measure the output of extremely large ozone generators. One kilogram per hour of ozone production is equivalent to 1,000 grams per hour or 1,000,000 milligrams per hour.

lb/day= pounds per day

This unit is typically used to measure the output of larger ozone generators in English units. One pound per day of ozone production is equal to 18.89 grams per hour of ozone production.

## Feed-gas Flow Measurements

LPM = liters per minute

The metric unit used to measure the flow of feed-gas through the ozone generator is liters per minute (LPM). It can be used to measure the flow of either oxygen or air. Another unit of measure is standard cubic feet per hour (SCFH), which is commonly used in the United States. 1 LPM is equivalent to 2.11 SCFH.

SCFH = standard cubic feet per hour

This unit of measurement is used to measure the flow of feed-gas through the ozone generator in the English system. It can refer to the flow of oxygen or air. One SCFH is equivalent to 0.47 LPM.

m3/hr = cubic meters per hour

This is a metric measurement used mainly for large-scale flow rates and ozone generators to determine the flow of feed-gas through the system. It can be oxygen or air flow. One cubic meter per hour (m3/hr) equals 16.66 liters per minute (LPM).