Zero Air Calibration Gas Mixtures

Zero air is a ultra-pure, hydrocarbon-free air mixture containing approximately 20.9% oxygen in nitrogen, with total hydrocarbon content below 0.1 ppm. It is used as a baseline reference gas to zero-set gas analyzers, CEMS, FID instruments, and ambient air monitors before introducing span calibration gases, ensuring accurate instrument response readings.

Zero air is the reference baseline used to establish the zero point on gas analyzers including FIDs, NDIR analyzers, chemiluminescence NOx monitors, UV fluorescence SO₂ analyzers, and CEMS instruments. Regulatory programs such as EPA 40 CFR Part 75 and Performance Specifications 2, 3, and 4 require periodic zero calibration checks using certified zero air.

Nitrogen is an inert balance gas that contains no oxygen, making it suitable for reactive and toxic gas calibration mixtures where oxygen interference must be avoided. Zero air contains approximately 20.9% oxygen and mimics ambient air composition without hydrocarbons. Analyzers designed to measure gases in an air matrix — such as ambient air monitors and FID-based instruments — require zero air rather than nitrogen as the balance gas.

Yes. All SpecGas Inc. calibration gas mixtures, including zero air blends, are produced as NIST-traceable standards using gravimetric blending methods and state-of-the-art analytical equipment. Each cylinder is accompanied by a certificate of analysis confirming traceability to NIST reference standards, meeting requirements for EPA, OSHA, and industrial quality programs.

SpecGas offers zero air calibration gas in a broad range of cylinder options including disposable aluminum and steel cylinders from 17 to 103 liters gas capacity, as well as refillable high-pressure aluminum and steel cylinders up to 250 ft³. Disposable cylinders are ideal for field applications and overseas shipping, while refillable cylinders suit high-volume laboratory and CEMS applications.

Yes. SpecGas Inc. provides custom gas blending services for zero air mixtures, including specific hydrocarbon removal thresholds, moisture content levels, and custom O₂ concentrations. Custom tolerances and concentrations are available upon request. Contact our technical team at (215) 443-2600 or via the online inquiry form for a consultation and quote.