The Commonly Used Standard Gases

Standard gas for environmental monitoring

1.Sulfur dioxide (SO₂) standard gas ‌

It is used for calibrating air quality monitoring stations in accordance with the requirements of “Technical Guidelines for the Preparation of Ecological Environment Planning” (HJ 1359-2024), and the concentration range is usually 0.1 to 1000 ppm‌.

2.Nitrogen oxides (NOx) standard gas ‌

It contains components such as NO and NO₂, and is used for vehicle exhaust detection (such as the National VI standard) and industrial emission monitoring ‌.

3.Non-methane total hydrocarbons (NMHC) standard gas ‌

Nitrogen is used as the balancing gas for the calibration of VOCs online monitoring systems, with common concentrations ranging from 1 to 1000 ppm‌.

Industrial safety standard gas

1.Methane (CH₄) standard gas ‌

Coal mine gas detection, natural gas leakage alarm, concentration coverage 0.1% to 100% LEL (lower explosive limit) ‌.

2.Carbon monoxide (CO) standard gas ‌

Safety monitoring in the metallurgical and chemical industries, typical concentration 50-5000 ppm‌.

3.Hydrogen sulfide (H₂S) standard gas ‌

The detection of toxic gases in petrochemical and sewage treatment plants shall comply with GB 17681-2024 “Technical Specifications for Safety Monitoring of Major Hazard Sources of Hazardous Chemicals” ‌.

Laboratory analytical standard gas

1.High-purity nitrogen (N₂) ‌

As carrier gas for gas chromatograph, the purity should be ≥99.999%‌.

2.Helium (He) standard gas ‌

Calibration of mass spectrometer, concentration accuracy reaches ppb level ‌.

3.Oxygen (O₂) standard gas ‌

Medical ventilators, combustion efficiency testing, common concentrations 21% to 100%‌.

Standard gas for special fields

1.Sulfur hexafluoride (SF6) standard gas ‌

Insulation testing of high-voltage equipment in the power industry shall comply with the environmental protection requirements of GB/T 41002-2022 “General Technical Specification for Children ‘s Luggage” ‌.

2.Argon (Ar) standard gas ‌

Semiconductor manufacturing protective gas, purity ≥99.9999%‌.