Unhealthy air quality persists in Singapore on Wednesday; 24-hour PSI at 11pm: 92 -116

Traffic along the CTE at 7.10am on Sept 16.
Traffic along the CTE at 7.10am on Sept 16. ST PHOTO: STEPHANIE YEOW
A much improved haze situation along Rivervale Drive in Punggol East at 7.20am on Sept 16.
A much improved haze situation along Rivervale Drive in Punggol East at 7.20am on Sept 16. ST PHOTO: STEPHANIE YEOW

SINGAPORE - There has been improvement in the haze situation in Singapore on Wednesday (Sept 16), but air quality continued to remain at the lower end of the unhealthy zone.

Prevailing winds from the south-east and heavy showers over most parts of Singapore provided some relief from the hazy conditions in the early afternoon, with the Pollutant Standards Index (PSI) readings dropping to between the high end of the moderate to the low end of the unhealthy range.

As of 11pm, the 24-hour PSI was between 92 and 116. The unhealthy range is 101-200.

The three-hour PSI, an indicative reading not tied to health advisory, was 80 at 11pm. It crossed the very unhealthy 200-mark on Monday night but stayed within the unhealthy range throughout Tuesday. If the air quality stays above 200 for 24 hours, it would be considered very unhealthy (201-300).


A haze update by the National Environment Agency (NEA) at 5pm on Wednesday indicated that the 24-hour PSI for the next 24 hours is expected to be in the low section of the unhealthy range. 

The improvement in the situation was due to a shift in the prevailing winds, which started to blow from the south-east. Showers in the afternoon also brought a temporary respite to the haze conditions. Prevailing winds for today and tomorrow are forecast to continue blowing from the south-east or south. Thundery showers are also forecast over some areas of Singapore in the late morning and early afternoon.

However, moderate to dense haze is still persisting in central and southern Sumatra. As such, the haze in Singapore may enter the mid section of the very unhealthy range should denser haze from Sumatra be blown towards the Republic due to unfavourable winds.


The Government will roll out the Haze Subsidy Scheme on Wednesday, which caps medical fees for haze-related conditions for elderly and lower-income groups.

There has been a 7-8 per cent increase in polyclinic visits for respiratory conditions on Monday compared to the past three Mondays before the September school holidays which began on Sept 7, said NEA officials at a briefing on Tuesday.