20/10/2026
Going out now — PM2.5 or PSI?
Here’s the simple way to remember it:
NOW = 1-hour PM2.5
LATER = 24-hour PSI
For activities in the next few hours, refer to the latest 1-hour PM2.5 information. For planning ahead, use the 24-hour PSI forecast and health advisory.
Quick check: if you’re heading outside now, which one would you look at first?