Results provided per 10 μg/m3 increase in ambient PM2.5. Average, rolling mean ambient PM2.5 concentrations averaged over all exposure days up through lag day(s) 1–7; Single day lag, individual lag day ambient PM2.5 concentrations. Linear mixed effect model adjusted for same-day ambient temperature, sex and study block. Significant associations highlighted in red. CEC, cholesterol efflux capacity (% change); PM2.5, Fine particulate matter.