RESUMO
A frequent practical problem of research in developing countries is the lack of reliable records on occupational hazards. To improve this situation, this article suggests and evaluates a two-phase method for estimating particle exposure. The first phase uses the focal group, or homogeneous group, technique to reconstruct the production process and estimate the level of dust exposure. The second phase applies the technique of individual history of exposure to hazards at work, an index that accumulates current and previous exposure. This method was introduced in a Portland cement plant to assess the dust-exposure levels of workers and to evaluate its usefulness in the association between estimated exposure levels and the frequency of health effects--particularly respiratory effects--that occurred as a result of such exposures. The results obtained from the analysis of the production process and of the exposure levels determined by the cement workers showed that it is possible to reconstruct the history of exposure to cement dust during each worker's occupational history. The results also showed that estimated exposure is related to respiratory damage; higher exposure resulted in more serious diseases. This supports the usefulness of the suggested methodology.