Air quality returns to moderate range in central Singapore

SINGAPORE: Air quality in central Singapore returned to the moderate range on Thursday (Sep 10), according to the National Environment Agency (NEA), with the 24-hour Pollutant Standards Index (PSI) in the region standing at 100 at 10pm.The 24-hour PSI in the central region had crossed into the unhealthy range late on Wednesday, reaching 102 at 11pm, according to NEA.It rose to 104 at 6am on Thursday, and fluctuated slightly through the day before sitting at 102 at 9pm and dropping to 100 an hour later.Air quality in the other regions remained in the moderate range. In its daily haze advisory earlier on Thursday, NEA said that moderate to dense smoke plumes continued to be detected from fires in southern Sumatra and Kalimantan, with smoke from southern Sumatra observed drifting towards Singapore.While showers occurred over Singapore on Thursday, with showers also forecast over central and northern Sumatra in the coming days, dry conditions are expected to persist over Kalimantan and southern Sumatra. This could result in a risk of haze in Singapore should fires persist, under prevailing southeasterly or southerly winds, NEA said.NEA forecast the 24-hour PSI for Singapore to be in the high moderate to low unhealthy range for the 24 hours from 6pm.Air quality dipped into the unhealthy range for the first time since 2023 on Sep 4, with the PSI reaching as high as 123 in the central region. This persisted into Sep 5 before air quality returned to the moderate range at 9pm that day. The unhealthy PSI reading prompted NEA to start providing daily haze advisories from the evening of Sep 4.The unhealthy PSI band runs from 101 to 200, while a reading is considered "very unhealthy" if it is between 201 and 300, and "hazardous" if it is above 300.