Relationship and conversion of gas concentration mg / m3 and ppm
There are two ways to express the concentration of pollutants in the ambient atmosphere (air):
1. Mass concentration method: mass number of pollutants contained in air per cubic meter, ie mg / m 3
2.Volume concentration representation: the volume of pollutants contained in one million volumes of air, that is, ppm
The concentration expressed by the mass of pollutants in the atmosphere per cubic meter is called mass-volume concentration, and the unit is milligram / cubic meter or grams / cubic meter. Most of the gas concentrations measured by the online smoke monitoring system are volume concentration (ppm). According to China's regulations, especially the environmental protection department, the gas concentration is required to be expressed in units of mass concentration (such as: mg / m3). Our country The standard specifications are also expressed in mass concentration units (such as: mg / m3).
What is the relationship between these two gas concentration units, mg / m3 and ppm? How are the two converted?
Using the mass concentration unit (mg / m3) as the expression method of air pollutant concentration, it is convenient to calculate the true amount of pollutants. But the mass concentration is related to the temperature and pressure environmental conditions of the test gas, and its value will vary with the temperature and pressure And other environmental conditions vary; in actual measurement, the temperature and atmospheric pressure of the gas need to be measured at the same time. When using ppm as a description of the concentration of pollutants, this problem does not occur because of the volume ratio.
Conversion of concentration unit ppm to mg / m3: Calculated as follows:
如果湿度很大时,例如在100%相对湿度下,还需另外一项.气体分子量。 Mass concentration mg / m3 = M gas molecular weight / 22.4 * ppm value * [273 / (273 + T gas temperature)] * (Ba pressure / 101325) If the humidity is very high, such as at 100% relative humidity, you need to One. Gas molecular weight.
Where: M — molecular weight of the gas,
T — temperature
Ba — pressure
Gas concentration refers to the pollutants in the atmosphere. Common volume concentration and mass-volume concentration are used to indicate its content in the atmosphere.
Volume concentration is expressed as the volume of pollutants in the atmosphere per cubic meter (cubic centimeters) or (ml / m3). The commonly used method is ppm, that is, 1 ppm = 1 cubic centimeter / cubic meter = 10-6. In addition to ppm, there are ppb and ppt. The relationship between them is:
1ppm = 10-6 = one millionth,
1ppb = 10-9 = one billionth,
1ppt = 10-12 = one trillionth,
1ppm = 103ppb = 106ppt
The concentration expressed by the mass of pollutants in the atmosphere per cubic meter is called mass-volume concentration.
Its conversion relationship with ppm is:
X = M · C / 22.4
C = 22.4X / M
In the formula: X—the concentration value of pollutants expressed in milligrams per standard cubic meter;
C—concentration value of pollutant expressed in ppm;
M—the fractional amount of the pollutant.
Note: This formula is a commonly used quick calculation formula. For gas detection, the calculation results of the quick calculation formula basically meet the requirements for use. Relationship between mg / m3 and ppm and conversion formula
专注 一体化解决方案 和 气体检测分析仪 , 粉尘检测仪 , 气体检测报警仪 ,氧含量分析仪,可燃气体检测仪 等.生产,销售,研发，售后一条龙科技服务商. 咨询热线: 400-025-9821 Nanjing Aiyi Technology focuses on integrated solutions and gas detection analyzers , dust detectors , gas detection alarms , oxygen content analyzers , combustible gas detectors, etc. Production, sales, research and development, after-sale one-stop technology service providers. Consulting hotline : 400-025-9821
- Relationship and conversion of gas concentration mg / m3 and ppm
- How to install a fixed combustible gas detector
- How to choose an online oxygen content analyzer suitable for process requirements
- How to choose a fixed detector
- In-tank inspection safety equipment: confined space gas detector
- Detailed 4-20mA current loop of combustible gas concentration detector
- Key points for purchasing a limited space gas detector
- How to choose the bus and branch line of the gas detector?
- Ai teaches you the routine maintenance of flammable gas alarm
- Aiyi Technology teaches you how to troubleshoot the combustible gas detector