ABSTRACT
Occupational qualitative or semi-quantitative exposure assessment is based on several factors, often descriptive, and the potential exposure level may be valued on an ordinal scale (low, medium, high). The qualitative assessment usually employs a walkthrough survey at the work site and gives a description of exposure that is very much dependent of the knowledge and experience of the assessor. In contrast, quantitative assessment depends on measurements results and, consequently, is usually more precise and detailed. However, due to the high costs associated, environment monitoring is carried out only occasionally and the results are dependent on the conditions predominant at the time of sampling (Viegas et al., 2012). Considering this and other difficulties some researchers have developed exposure assessments based on work tasks. Identifying all the tasks developed in each
concern, because they can produce an elevated dose rate at target tissues and organs, potentially altering metabolism, overloading protective and repair mechanisms and amplifying tissue responses (Preller et al., 2004). Moreover, in the last years it has been assumed that short-term high exposure levels can play an important role in the etiology of chronic occupational diseases conventionally associated with exposures accumulated over a long time period (Checkoway & Rice 1992). Such hypotheses have been proposed also for allergens/irritants and asthma (Preller et al., 2004). Task-based exposure assessment have been also used in several ergonomic studies since permit to modelling exposure across days within individuals and to define sampling strategy of a measurement day (Mathiassen et al., 2003, Svendsen et al., 2005).
