Figure 2. Association Between Exposure to Particulate Matter With Diameter of 2.5-μm or Less (PM2.5) and Total Bystander-Witnessed Out-of-Hospital Cardiac Arrest (OHCAs) of Cardiac Origin .
The OHCAs were adjusted for nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2), which were adjusted for ambient temperature at lag0-1, relative humidity at lag0-1, and incidence of influenza epidemic. Lag0-1 indicates difference in mean PM2.5 concentrations measured on the case day and 1 day before.
aOdds ratio for percent increase for every 10-μg/m3 increase in PM2.5 at lag0-1.
bTotal number of regions was 46, with Okinawa excluded from the West Japan region because of geographic differences (eTable 1 and eFigure 1 in the Supplement).