Air: Source of Atmospheric Gases
Composition of air, which is the source of the industrial gas products nitrogen, oxygen, argon, neon, krypton and xenon. Effects of temperature, humidity, elevation and trace components on properties of air and on air compression and separation processes.  Links to physical properties tables, to psychrometric charts that  depict inter-relationships among the various physical properties of air, to an online psychrometric properties calculator for easy calculation of properties, and to individual gas information pages.  Includes discussion of the carbon dioxide concentration in air, seasonal variation, year-to-year variation, longer term variation over recent and geological time scales.
     Moist Air Properties and Relationships
     Psychrometric chart (I-P Units) (pdf)
     Psychrometric chart (SI Units)  (pdf)
     Psychrometric Calculator (determine physical and thermodynamic properties on-line)
     Carbon Dioxide in Air

Air Separation Technologies - An Overview
The Overview page provides an Introduction to air separation processes and supply system optimization. The following pages provide more information on various topics:
     Cryogenic Air Separation Processes and Liquefiers
     Non-Cryogenic Separations
     Product Supply and Delivery Modes
     Plant Selection and System Optimization

Industrial Gas Applications & Characteristics
Introduction to industrial gas sources, properties, uses and applications.
     Oxygen - O2
     Nitrogen - N2
     Argon - Ar
     Neon, Krypton, Xenon - Ne, Kr, Xe
     Carbon Dioxide - CO2 
     Hydrogen - H2

Physical Properties of Industrial Gases & Other Materials
Properties of industrial gases and other common chemicals - in tabular form.
     Physical Properties (English Units)
     Physical Properties (Metric)

Conversion Factor Tables
Quantity conversion tables for easy reference
     Oxygen Unit Conversion (gas, liquid, weight, volume)
      Nitrogen Unit Conversion (gas, liquid, weight, volume)
      Argon Unit Conversion (gas, liquid, weight, volume)
     Hydrogen Unit Conversion (gas, liquid, weight, volume)
     CO2 Unit Conversion (gas, liquid, solid, weight, volume)

Atmospheric Pressure versus Elevation
Average pressure versus elevation - useful for air compressor sizing and power calculations.