The multiplicative impacts of working hours and fine particulate matter concentration on life expectancy: A longitudinal analysis of US States

This study contributes to interdisciplinary research on the social and environmental determinants of population health, with a focus on the interaction between working hours and fine particulate matter (PM_2.5) concentration. The authors estimate longitudinal models of the relationship between US state-level average life expectancy and both average working hours and PM_2.5 concentration for the 2005–2014 period. Results obtained from two-way fixed effects models indicate that average life expectancy is negatively associated with both average working hours and fine particulate matter concentration. Findings also indicate clear moderating relationships: the negative association between life expectancy and working hours is amplified as PM_2.5 concentration increases, and the negative relationship between life expectancy and fine particulate matter concentration is amplified when average working hours increase. The results of this study underscore the need for additional research on the multiplicative impacts of socioeconomic factors and environmental factors in the modeling of population health.