PSI hits 102: Haze pushes air quality in central Singapore into unhealthy range
Singapore's air quality is back in the unhealthy range at 1pm on Saturday (Sept 19), as the 24-hour Pollutant Standards Index (PSI) reading hits 102 in central Singapore.Elsewhere, western Singapore recorded the next highest reading of 90 — in the moderate range.Data from the National Environment Agency (NEA) shows one-hour PM2.5 concentration reading in central Singapore entering the elevated band at 10am, before climbing gradually to as high as 149 at 12pm. The one-hour PM2.5 concentration reading at 1pm ranges from 71 to 141, which is in the elevated band. Readings between 56 to 150 denote the elevated band, while readings between 151 to 250 are in the high-band.What PM2.5 readings meanThe National Environment Agency (NEA) groups PM2.5 readings into four bands: normal (0-55 µg/m3), elevated (56 to 150), high (151 to 250), and very high (251 and above).The public can check PM2.5 readings for guidelines on immediate outdoor activities.They should note that the health impact of haze depends on their health status, as well as the duration and intensity of outdoor activity.