This part of ISO 8573 provides a selection of suitable test methods from those available for the measurement of contamination gases in compressed air. It specifies sampling technique, measurement and evaluation, uncertainty considerations and reporting for the applicable gaseous contaminants carbon monoxide, carbon dioxide, sulphur dioxide, nitric oxide, nitrogen dioxide and hydrocarbons in the range C₁ to C₅ (see ISO 8573-5 for C₆ and above). The methods given are also suitable for other gases.