Evaluation of Exposure to Chemical Agents

This chapter explains why workplace measurements of air contaminants are made, discusses the options available in terms of number, time, and location, and relates these options to the criteria that govern their selection and the consequences of various choices. The most common purpose of measurement of exposure of workers is to estimate the dose so as to prevent or predict adverse health effects. Sampling methods for gases and vapors must have some means of capturing the contaminant for subsequent analytical evaluation. Sampling methods based on filtration, impaction, and impingement were some of the earliest techniques developed to aid in evaluating exposures in the dusty trades. To understand their use, it is necessary to consider the properties of aerosols that affect sampling. When accompanied by close observation of the operation in question, wipe sampling can help identify sources of contamination and poor work practices.