Singapore haze: 1-hour PM2.5 readings elevated across all regions

Singapore haze: 1-hour PM2.5 readings in elevated range across all regions As of 6am, 24-hour PSI readings were in the unhealthy range in all five regions as well. SINGAPORE: Hazy conditions persisted across Singapore on Friday (Oct 9), with 1-hour PM2.5 readings in the elevated range in all five regions in the early morning. At 6am, the readings ranged from 92 in the north to 143 in the west. The central region recorded a reading of 140, while the south and east registered 134 and 117 respectively. The readings, however, were considerably higher in the wee hours of Friday before easing by 6am. The 24-hour Pollutant Standard Index (PSI) readings were also in the unhealthy range, ranging from 109 to 159. For those planning immediate outdoor activities, NEA advises checking the hourly PM2.5 levels. The 24-hour PSI forecast and corresponding health advisories should be used in planning next day outdoor activities. 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". In its Thursday evening advisory, the National Environment Agency (NEA) said that moderate to dense smoke plumes from southern and central Sumatra and West Kalimantan were observed to drift towards Singapore. Dry conditions are expected to persist over the southern parts of Sumatra and parts of Kalimantan. Under prevailing southeasterly or southerly winds, smoke haze may continue to drift towards Singapore, NEA said, adding that the 24-hour PSI for Singapore is forecast to be in the high moderate to mid unhealthy range.