Air quality across Singapore remains in unhealthy range

Air quality across Singapore remains in unhealthy range Under prevailing southeasterly to southerly winds, smoke haze from central and southern Sumatra and many parts of Kalimantan may continue to drift towards Singapore, NEA said. SINGAPORE: Air quality across all five regions of Singapore remained in the unhealthy range on Thursday (Oct 8), with the west recording a 24-hour Pollutant Standards Index (PSI) reading of 161 at 6am. The 24-hour PSI readings entered the unhealthy range across Singapore at noon on Wednesday and remained there overnight into Thursday morning. As of 6am, the 24-hour PSI was 147 in central Singapore, 128 in the east, 120 in the south and 113 in the north. The 1-hour PM2.5 readings were in the elevated band in central and western Singapore, while readings in the north, south and east were in the normal band. On Wednesday, the 1-hour PM2.5 reading in the west rose to 152 at 4pm, entering the "high" band for the first time this haze season, before falling back into the elevated band an hour later. In an advisory on Wednesday evening, the National Environment Agency (NEA) said moderate to dense smoke plumes from southern Sumatra were observed drifting towards Singapore. Moderate to dense smoke haze was also observed from hotspots in Kalimantan. Dry conditions are expected to continue over central and southern Sumatra and many parts of Kalimantan. Under the prevailing southeasterly to southerly winds, smoke haze from these areas may continue to drift towards Singapore, NEA said. The 24-hour PSI for Singapore is forecast to be in the unhealthy range. When planning outdoor activities for the next 24 hours, the public is advised to use the 24-hour PSI forecast and health advisories. When 1-hour PM2.5 levels are elevated, healthy people are advised to reduce strenuous outdoor activity for the next hour, while the elderly, pregnant women, children and people with chronic heart or lung conditions should avoid such activity. The 24-hour PSI is Singapore's indicator of daily air quality and forms the basis of NEA's daily health advisories. It is calculated using six air pollutants - PM2.5, PM10, ozone, sulphur dioxide, nitrogen dioxide and carbon monoxide - and reflects the average air quality of the past 24 hours. The 1-hour PM2.5 reading, on the other hand, is the hourly average of the PM2.5 pollutant levels. PM2.5 is fine particulate matter with a diameter of 2.5 micrometres or shorter, and is the dominant pollutant during haze that causes harm to health. A 24-hour PSI reading is considered "unhealthy" when it is in the 101 to 200 range, "very unhealthy" when it is within the 201-300 range and "hazardous" when it goes over 300. The hourly PM2.5 reading is classified in four bands: normal, elevated, high and very high. It is considered elevated when it ranges from 56 to 150. The "high" band ranges from 151 to 250, and readings above that are classified as "very high".