Singapore wakes up to unhealthy air quality, central region PSI hits 154

Air quality across all five regions in Singapore are in the unhealthy range.The Pollutant Standard Index (PSI) reading for southern Singapore slipped into the unhealthy range at 10pm, while air quality in northern Singapore entered the unhealthy range at 1am.It hit a high of 154 in central Singapore at 6am.At 7am on Tuesday (Sept 15) morning, the PSI reading was between 104 and 153 — within the unhealthy range — with central Singapore recording the highest PSI of 153.But one-hour PM2.5 — an indicator of fine micro-pollutants in the air — has been improving across Singapore..Data from the National Environment Agency (NEA) shows that at 7am, only central Singapore (57) has a marginally elevated PM2.5 reading. Meanwhile, one-hour PM2.5 reading for the four remaining regions is between 24 and 38, within the normal band. Readings of between 56 and 150 denote the elevated band.