Fig. 4: Cyclic PM2.5 exposures precede aSAH peaks.

Plot of 90-day moving average of daily particulate matter 2.5 (PM2.5) levels (green line) and 90-day moving sum of aneurysmal subarachnoid hemorrhage (aSAH) incidence (blue). Peaks in PM2.5 often appear to precede peaks in aSAH incidence.