Singapore air quality enters unhealthy range in three regions - CNA
PSI readings have dipped in and out of the unhealthy range over the past weeks.
File photo of haze situation from Tanjong Pagar Plaza overlooking Sentosa Cove on Sep 14, 2026. (Photo: CNA/Raydza Rahman)
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SINGAPORE: Air quality in parts of Singapore was in the unhealthy range on Sunday (Sep 27), with western Singapore crossing the threshold overnight and recording a 24-hour Pollutant Standards Index (PSI) of 105 as of 6am.
The air quality in the central region had entered the unhealthy band on Saturday evening, followed by the eastern region at midnight. The PSI readings for central and eastern regions hit 127 and 114 respectively as of 6am.
Air quality in other two regions of Singapore were in the moderate range, with the north at 89 and the south at 94.
PSI readings have dipped in and out of the unhealthy range over the past weeks.
CNA Games Guess Word Crack the word, one row at a time Buzzword Create words using the given letters Mini Sudoku Tiny puzzle, mighty brain teaser Mini Crossword Small grid, big challenge Word Search Spot as many words as you can Show More Show Less The central region last recorded unhealthy air quality on the evening of Sep 20.
On Saturday, the National Environment Agency (NEA) said in its daily haze advisory that the 24-hour PSI was forecast to be in the moderate to low unhealthy range.
If the air quality over the next 24 hours is in the moderate range, all groups - healthy people, the elderly, pregnant women, children and those with chronic lung or heart disease - can continue with normal activities, said NEA.
If the air quality is unhealthy, healthy individuals should reduce prolonged or strenuous outdoor physical exertion. In such instances, the elderly, pregnant women and children should minimise such activities, and those with chronic lung and heart disease should avoid them altogether.
NEA also said that that while some showers are forecast over Singapore and parts of the surrounding region overnight and on Sunday, dry conditions are expected to continue over southern Sumatra and the southern and eastern parts of Kalimantan.
As such, there could be a risk of smoke haze affecting Singapore as the prevailing winds are forecast to blow from the southeast or southwest.
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.
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.
While the 24-hour PSI is an average of the past 24 hours, the one-hour PM2.5 reading reflects the air quality at a single point in time.
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.
