Air quality on Thursday (Oct 29) morning was again suitable for normal activities, with hourly PM2.5 in the normal band (0 - 55 µg/m3) and 24-hour Pollutant Standards Index (PSI) in the moderate band (0 to 100) across Singapore.At 9am, the hourly concentration reading ranged from 31 in western Singapore to 44 in the northern region.Meanwhile, PSI is within the.