ABSTRACT
Occupational and work-related asthma can be caused or aggravated by exposure to a wide range of chemical and biological agents. Exposure is defined as direct physical contact with an agent and since inhalation is obviously the most important route of exposure, this chapter mainly focuses on airborne agents. Dermal exposure is also discussed briefly, since systemic allergic sensitization to some asthmagens can also occur after skin contact. Relevant questions to address in exposure assessment at the workplace include: Which sensitizing proinflammatory or irritant agents are present at the workplace: in handled materials, used equipment, the surrounding air, etc.? What are the exposure levels: how much of each agent is inhaled by the worker? When does exposure occur: which job tasks are associated with (high) airborne exposure? How does exposure vary between and within workers with different tasks and over time? Exposure assessment at the workplace can be defined as the systematic, both qualitative and quantitative, characterization of exposure. The objectives of the assessment should first be defined. A measurement procedure usually consists of three steps: (a) sampling at the workplace; (b) storage and transport to a laboratory, where samples are further processed; and (c) analysis of the contents of extracts with chemical, immunochemical, enzymatic, microbiological or molecular biological methods. In this chapter, two main topics are thoroughly covered: sampling and analysis methods. Exposure assessment strategies including compliance and exposure modeling as well as job-exposure matrices are also examined.
