Reduced metabolic insulin sensitivity following sub-acute exposures to low levels of ambient fine particulate matter air pollution

► Sub-acute exposure to ambient PM2.5 was associated with a worsening of metabolic insulin sensitivity. ► The findings suggest that autonomic imbalance may be a mechanism responsible for PM-induced insulin resistance. ► Sub-acute PM2.5 exposure did not promote systemic inflammation, an increase in blood pressure or alter vascular function. ► These findings support the plausibility that PM2.5 could potentiate the development of diabetes mellitus.