Development of an occupational airborne chemical exposure matrix

Background: Population-based studies of the occupational contribution to chronicobstructive pulmonary disease generally rely on self-reported exposures to vapours, gases,dusts and fumes (VGDF), which are susceptible to misclassification.Aims: To develop an airborne chemical job exposure matrix (ACE-JEM) for use with the UKStandard Occupational Classification (SOC 2000) system.
Methods: We developed the ACE-JEM in stages: (i) agreement of definitions, (ii) a binaryassignation of exposed/not exposed to VGDF, fibres or mists (VGDFFiM), for each of theindividual 353 SOC codes and (iii) assignation of levels of exposure (L; low, medium andhigh) and (iv) the proportion of workers (P) likely to be exposed in each code. We thenexpanded the estimated exposures to include biological dusts, mineral dusts, metals, dieselfumes and asthmagens.
Results: We assigned 186 (53%) of all SOC codes as exposed to at least one category ofVGDFFiM, with 23% assigned as having medium or high exposure. We assigned over 68%of all codes as not being exposed to fibres, gases or mists. The most common exposure was todusts (22% of codes with >50% exposed); 12% of codes were assigned exposure to fibres.We assigned higher percentages of the codes as exposed to diesel fumes (14%) comparedwith metals (8%).
Conclusions: We developed an expert-derived JEM, using a strict set of a priori definedrules. The ACE-JEM could also be applied to studies to assess risks of diseases where themain route of occupational exposure is via inhalation.