Gas Encyclopedia

Explore Gases by Hazard, Use and Detection Need

Browse 101 gas and refrigerant topics organized into six practical collections. Each gas page can explain properties, sources, hazards, applications, detection methods and the products or OEM capabilities that support real projects.

Browse all gases Gas detection guide
6main gas collections
101planned gas and refrigerant topics
3steps: learn, detect, source
1directory for the full site
TOX

Toxic Gases

18 gases

Gases that can cause poisoning, irritation, corrosive injury or serious health effects at relatively low concentrations.

Detection focusDetection priorities usually include occupational exposure, short-term peaks, confined spaces and emergency response.
CO Carbon MonoxideColorless combustion gas H₂S Hydrogen SulfideSewage, oil and confined-space hazard NH₃ AmmoniaRefrigeration and agricultural gas Cl₂ ChlorineWater treatment and chemical processing SO₂ Sulfur DioxideCombustion and industrial emissions NO₂ Nitrogen DioxideCombustion and air-quality pollutant NO Nitric OxideCombustion and process gas HCN Hydrogen CyanideHighly toxic combustion and process gas PH₃ PhosphineFumigation and semiconductor gas O₃ OzoneOxidizing air-treatment gas HCl Hydrogen ChlorideCorrosive acid gas HF Hydrogen FluorideHighly corrosive fluorine compound AsH₃ ArsineHighly toxic semiconductor gas Br₂ BromineCorrosive halogen vapor HBr Hydrogen BromideCorrosive acid gas CH₃SH Methyl MercaptanOdorous sulfur compound SO₂F₂ Sulfuryl FluorideStructural fumigation gas ClO₂ Chlorine DioxideDisinfection and bleaching gas
No matching gases were found in this collection.
LEL

Gases and vapors that may ignite, burn or form explosive mixtures with air when they reach a sufficient concentration.

Detection focusKey questions include LEL, UEL, ignition sources, gas density, ventilation and sensor placement.
CH₄ MethaneNatural gas, biogas and mining NG Natural GasFuel-gas mixture dominated by methane LPG Liquefied Petroleum GasPropane and butane fuel mixture C₃H₈ PropaneFuel gas and R290 refrigerant C₄H₁₀ ButanePortable fuel and process gas H₂ HydrogenLight, fast-diffusing fuel gas C₂H₂ AcetyleneWelding and cutting gas C₂H₄ EthylenePetrochemical and ripening gas C₂H₆ EthaneNatural-gas component CS₂ Carbon DisulfideHighly flammable solvent vapor VOC Gasoline VaporComplex flammable hydrocarbon vapor Mix Coal GasManufactured combustible gas mixture Mix BiogasMethane-rich renewable gas Mix SyngasHydrogen and carbon monoxide mixture
No matching gases were found in this collection.
O₂

Gases associated with oxygen deficiency, oxygen enrichment or displacement of breathable air in enclosed and poorly ventilated spaces.

Detection focusA gas does not need to be chemically toxic to create a fatal atmosphere. Oxygen measurement is often the first confined-space check.
O₂ OxygenDeficiency and enrichment hazards CO₂ Carbon DioxideIAQ, fermentation and asphyxiation N₂ NitrogenInerting and oxygen displacement Ar ArgonShielding gas and confined-space hazard He HeliumCryogenic and leak-testing gas SF₆ Sulfur HexafluorideElectrical insulation and greenhouse gas N₂O Nitrous OxideMedical, food and process gas Ne NeonInert specialty gas Xe XenonMedical and specialty gas
No matching gases were found in this collection.
VOC

Volatile organic compounds and solvent vapors found in coatings, printing, cleaning, manufacturing, laboratories and indoor environments.

Detection focusBroadband VOC instruments may indicate total loading, while compound-specific risk assessment may require selective measurement or laboratory analysis.
TVOC Total Volatile Organic CompoundsCombined VOC indicator CH₂O FormaldehydeBuilding-material and process emission C₆H₆ BenzeneToxic aromatic hydrocarbon C₇H₈ ToluenePaint, adhesive and printing solvent C₈H₁₀ XyleneCoatings and industrial solvent CH₃OH Methanol VaporAlcohol solvent and fuel vapor C₂H₅OH Ethanol VaporAlcohol vapor and disinfectant C₃H₆O Acetone VaporFast-evaporating solvent IPA Isopropyl Alcohol VaporCleaning and electronics solvent C₈H₈ StyreneResins, plastics and composites C₂H₄O Ethylene OxideSterilization and chemical process gas MEK Methyl Ethyl KetoneCoating and adhesive solvent C₆H₁₄ n-HexaneExtraction and industrial solvent TCE TrichloroethyleneDegreasing solvent vapor PCE PerchloroethyleneDry-cleaning solvent vapor CHCl₃ ChloroformLaboratory and process solvent CH₃COOH Acetic Acid VaporCorrosive organic vapor DMF DimethylformamideIndustrial polar solvent C₃H₃N AcrylonitrilePolymer-production vapor C₂H₃Cl Vinyl ChloridePVC manufacturing gas
No matching gases were found in this collection.
A2L

Refrigerant Gases

23 refrigerants

Refrigerants used in air conditioning, heat pumps, cold storage, appliances, vehicles and industrial refrigeration systems.

Detection focusSelection and detection depend on refrigerant chemistry, safety class, expected leak level, equipment standard and installation environment.

A2L & lower-GWP refrigerants

6 topics
R32 R32 RefrigerantDifluoromethane, A2L R454B R454B RefrigerantLower-GWP A2L blend R1234yf R1234yf RefrigerantAutomotive A2L refrigerant R1234ze R1234ze RefrigerantLow-GWP HFO refrigerant R452B R452B RefrigerantA2L replacement blend R455A R455A RefrigerantLow-GWP A2L blend

Common HFCs and blends

8 topics
R134a R134a RefrigerantAutomotive and commercial cooling R410A R410A RefrigerantAir-conditioning blend R404A R404A RefrigerantCommercial refrigeration blend R407C R407C RefrigerantAir-conditioning blend R448A R448A RefrigerantLower-GWP refrigeration blend R449A R449A RefrigerantCommercial refrigeration blend R452A R452A RefrigerantTransport refrigeration blend R513A R513A RefrigerantLower-GWP R134a alternative

Natural refrigerants

4 topics
R290 R290 RefrigerantPropane, A3 R600a R600a RefrigerantIsobutane, A3 R717 R717 Ammonia RefrigerantAmmonia, B2L R744 R744 Carbon Dioxide RefrigerantCarbon dioxide refrigerant

Legacy refrigerants

5 topics
R22 R22 RefrigerantHCFC refrigerant R12 R12 RefrigerantLegacy CFC refrigerant R502 R502 RefrigerantLegacy refrigerant blend R507A R507A RefrigerantLegacy refrigeration blend R245fa R245fa RefrigerantChiller and foam-blowing fluid
No matching gases were found in this collection.
SiH₄

High-purity process gases used in semiconductor fabrication, photovoltaics, electronics, laboratories and advanced manufacturing.

Detection focusThese applications often require highly selective detection, low alarm thresholds, gas-cabinet monitoring and carefully managed cross-sensitivity.

Dedicated specialty-gas pages

10 topics
SiH₄ SilanePyrophoric deposition gas B₂H₆ DiboraneHighly toxic dopant gas GeH₄ GermaneSemiconductor deposition gas NF₃ Nitrogen TrifluorideChamber-cleaning gas WF₆ Tungsten HexafluorideTungsten deposition gas BCl₃ Boron TrichlorideEtching and doping gas CF₄ Carbon TetrafluoridePlasma etching gas C₂F₆ HexafluoroethaneEtching and chamber-cleaning gas ClF₃ Chlorine TrifluorideHighly reactive cleaning gas SF₄ Sulfur TetrafluorideReactive fluorinating gas

Common process gases linked to their primary pages

7 topics
H₂ HydrogenCarrier and process gas NH₃ AmmoniaNitridation and process gas Cl₂ ChlorineEtching and cleaning gas HCl Hydrogen ChlorideEtching and cleaning gas HF Hydrogen FluorideEtching and cleaning gas PH₃ PhosphineDopant gas AsH₃ ArsineDopant gas
No matching gases were found in this collection.
How this directory is organized: a gas may be relevant to more than one industry or hazard. Gas Nose keeps one primary educational page for each core gas whenever possible, then connects refrigerant, application and specialty-gas pages through internal links to avoid duplicate content.
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