What is the relationship between the gas detection concentration unit mg/m3 and ppm?

There are two ways to express the concentration of pollutants in the ambient atmosphere (air): 1. Representation of mass concentration: the mass number of pollutants per cubic meter of air, that is, mg/m3

2. Volume concentration representation: the volume of pollutants contained in one million volumes of air, that is, ppm. The gas concentration measured by most gas detection instruments is volume concentration (ppm). According to China's regulations, especially the environmental protection department, gas concentration is required to be expressed in units of mass concentration (such as mg/m3), and our national standard specifications are also expressed in units of mass concentration (such as mg/m3). What is the relationship between the two gas concentration units mg/m3 and ppm? How to convert between them? Using mass concentration unit (mg/m3) as the expression method of air pollutant concentration can easily calculate the true amount of pollutants. However, the mass concentration is related to the temperature and pressure environmental conditions of the detected gas, and its value will vary with changes in environmental conditions such as temperature and air pressure; the actual measurement needs to measure the gas temperature and atmospheric pressure at the same time. When using ppm as a description of the concentration of pollutants, this problem will not occur because the volume ratio is adopted.

Conversion of concentration unit ppm and mg/m3:

Calculate by the following formula: Mass concentration mg/m3=M gas molecular weight/22.4*ppm value*[273/(273+T gas temperature)]*(Ba pressure/101325) M is the gas molecular weight, ppm is the measured volume concentration value , T is temperature and Ba is pressure. If the humidity is very high, for example, under 100% relative humidity, another item is needed. Gas molecular weight? Where does it come from? Don’t worry! We have a gas molecular weight calculation software---as long as you enter the molecular formula of the gas, the gas molecular weight will be immediately obtained! God! Download the gas molecular weight calculation software:- --This software supports chemical formulas that may appear in the chemical field, supports chemical formulas containing middle and parentheses (can be nested), supports the input of single bond, double bond, and triple bond symbols in organic compounds, and supports non-integer coefficients Chemical formulas with subscripts, chemical formulas containing isotope symbols are supported, and so on. The calculation result will give the formula weight, simplified formula, and element content statistics. [Molecular weight of common gases: formaldehyde HCHO is 30.0260, benzene C6H6 is 78.1118, ammonia NH3 is 17.0306