8287085 Updating a diesel engine exhaust job-exposure matrix with published measurement data

<h3>Objective</h3> Job-exposure matrices (JEMs) based on expert judgement or measurement data are limited by the exposure information available at their development. Over time, more information about hazardous exposures is understood through additional measurements and peer-reviewed publications. This study presents a systematic approach to updating an existing diesel engine exhaust (DEE) JEM using published data. <h3>Methods</h3> The literature was searched for occupational exposure studies that measured DEE as elemental carbon (EC) between January 2010-May 2022. Four-digit North American Industry Classification System (NAICS) 2002 and National Occupational Classification-Statistics (NOC-S) 2006 codes were assigned to each identified subgroup within the studies. EC exposures were categorized as low (0-10µg/m3), moderate (10-20µg/m3), or high (&gt;20µg/m3). Weighted arithmetic means were calculated for each industry-occupation intersection (IOI) identified in the literature. These means were used to adjust, or retain, the exposure level within JEM cells using a decision-tree based on the number of studies, workplace locations, and pooled sample size of the weighted mean. Concordance was measured between the updated JEM (Diesel Exhaust in Canada JEM (DEC-JEM)), the previous JEM, and the Canadian Job-Exposure Matrix (CANJEM). <h3>Results</h3> Thirty-seven studies were identified from the published literature reporting on 53 unique IOIs (20 NAICS, 34 NOC-S), including occupations in mining, construction, and transportation industries. Exposure levels for 66% of identified IOIs increased, most in construction. After the decision-tree’s results were expanded to the full DEC-JEM, the exposure level of 486 IOIs (12.5% of DEC-JEM) and 286,710 workers (15.8% of DEE-exposed workers) increased. There was significant correlation between qualitative exposure levels in DEC-JEM and CANJEM (Kendall’s tau=0.364, p&lt;0.001). <h3>Conclusion</h3> This study describes a systematic approach for updating an existing JEM to incorporate new scientific knowledge. DEC-JEM better reflects existing exposure knowledge in several industries, particularly construction. Future analyses include investigating its use as an exposure assessment tool in disease surveillance.