Haze pushes air quality in central Singapore back into unhealthy range as PSI hits 102

The Republic’s air quality returned to the unhealthy range at 9pm on Thursday (Sept 17) as 24-hour Pollutant Standards Index (PSI) hit 102 in central Singapore.Elsewhere, western Singapore recorded the next highest PSI reading of 93.Data from the National Environment Agency (NEA) shows one-hour PM2.5 concentration reading in central Singapore entering the elevated band at 11am, before climbing gradually to 93 by 9pm. Readings between 56 to 150 denote the elevated band.Meanwhile, one-hour PM2.5 reading was between 40 and 64 in the four remaining regions, with western Singapore recording the next highest reading of 64, also in the elevated band. High moderate to low-unhealthy forecastIn its daily haze situation update on Thursday evening, NEA had said the country’s 24-hour PSI forecast is expected to be in the high moderate to low unhealthy range.Explaining this, the agency noted that smoke haze was observed to have drifted from southern and central Sumatra towards Singapore, while smoke plumes were also detected over southwestern Kalimantan.