Fig. 3
Morris water maze for examining spatial learning (acquisition phase, days 1 ~ 4) and memory ability (probe trial, day 5) in SH rats after 3 months of exposure to particulate matter with an aerodynamic diameter of < 2.5 μm (PM2.5; exposure group). There were no significant differences in the mean escape latency, mean distance moved, mean area crossing, mean time spent, or mean swimming velocity between the control (high-efficiency particulate air; HEPA) and exposure groups (PM2.5)