In recent years, my countrys ozone industry has developed rapidly, with a wide variety of products. Some products express the concentration of the unit in confusion, which is easy to be misunderstood.

    Method of expressing ozone concentration in gas

    One is expressed by the mass of ozone contained in a unit volume. Commonly used units are mg/L, mg/m3, μg/m3, referred to as mass concentration, and their relationship is: 1mg/L=103mg/m3=106μg/m3

    Various standards in my country adopt mass concentration.

    The other uses ppm or ppb as the concentration unit, called volume concentration. The ppm (partspermillion) unit refers to the volume of ozone contained in one million gas volume, and the volume concentration is customarily used in the United States, Japan and other countries. 1ppm=103ppb

    But the meaning of ppb (partspermillion) is not clear. In the United States and France, "billion" means one billion (109), and ppb means one-billionth (10-9); in the United Kingdom and Germany, "billion" means one trillion (1012), and ppb means One part per trillion (10-12). Therefore, this is a confusing expression. The International Association of Pure and Applied Chemistry made a "not suitable" decision in July 1971.

    In my country, ppb generally refers to 10-9.

    The volume percentage (vol) and pphm are also used to express the volume concentration. Their relationship is

    1%(vol)=104ppm=106pphm=107ppb

    The two units can be converted by the following formula:

    X(ppm)=40x/3x?A(mg/m3) or A=3x/40x?X

    In the formula: A-ozone concentration expressed in mg/m3

    X-ozone concentration expressed in ppm

    M-the molar mass of gas (ozone is 48)

    22.4——NPT (standard state, 273K, 101.3KPa, that is, 0℃, 760mmHg) gas molar volume

    For example, if the ozone content in the atmosphere is 1 ppm, it is expressed in mg/m3.

    A=40x/3x?X=40x/3x=2.14 (mg/m3).

    The standard status in the United States, Japan and the international global inspection system means that the gas volume at 298K (25°C) and 101.3kPa (760mmHg) is 24.45L/mol, so

    1ppm=1.963mg/m3.

    There is also a weight percentage to express the concentration of ozone. Generally expressed in% (wt), the meaning of% (wt) is: the mass of ozone/the mass of gas containing ozone × 100%.

    In this way, in the standard state

    1ppm=2.14mg/m3=1.66×10-4% (wt)

    1% (wt) (in air)=12.93g/m3=6042ppm

    1% (wt) (in oxygen)=14.3g/m3=6682ppm

    The density of air is 1293g/m3 and the density of oxygen is 1430g/m3.

    5.2 Expression method of ozone concentration in gas

    The units of ozone dissolved in water are mg/l, g/m3 and ppm (wt)

    mg/L——It means the mass of ozone (mg)/volume of ozone water (m3)

    g/m3——is the mass of ozone (mg)/volume of water containing ozone (m3)

    ppm-is the mass of ozone/the mass of ozone-containing water×106

    1mf/l=1g/m3=1ppm