AIR SAMPLING

There are many different types of chemical pollutants in the air. Their various physical states and chemical natures require different approaches to sampling.

Dusts and aerosols

• Collection on a filter followed by:
  • weighing
  • chemical analysis
• Direct reading instrument

Examples

Cement dust, welding fume, flour, hardwood, dyes & pigments, Soldering fume, oil mist, rubber process dust and fume.

Gases and vapours

• Collection on a solid adsorbent (e.g. charcoal)
• Collection on a chemically treated adsorbent
• Absorption in a liquid.
• Direct reading instruments
• Colour indicator tubes

Examples

Acid gases, hydrocarbons, solvents, ammonia, formaldehyde, carbon monoxide, hydrogen sulphide, chlorine.

Sample Analysis

Techniques most commonly used include:

• Gas chromatography
• High pressure liquid chromatography
• Ion chromatography
• UV/Vis spectrophotometry
• Atomic absorption/emission spectrophotometry