[Air sampling. Why and how?]

The determination of airborne contaminants concentration levels at the workplace is presented as an answer to industrial hygiene problems. A step by step logical method is presented, based upon a preliminary survey as wide as achievable, then the sampling step occurs in order to complete the first assessment. Contaminant exposure, identification of pollution sources and effectiveness of engineering controls can be evaluated by air sampling and analysis. Two field experiences are given as examples (lead and styrene exposures).