SINGAPORE: After a deterioration in air quality on Sunday (Sep 22) following clearer skies in recent days, the haze situation may improve this week with rain forecast over the next few days.

The National Environment Agency (NEA) said in a media advisory on Sunday evening that slightly hazy conditions can be expected in Singapore on Monday, with thundery showers forecast in the afternoon.

A total of 246 hotspots were detected in Sumatra on Sunday, with an additional 474 hotspots detected in Kalimantan. A forecast shift in winds on Monday are expected to bring showers over the region. 

“For the next few days, an increase in rain showers can be expected over the region, including Sumatra and Kalimantan, and the prevailing winds are forecast to blow from the northeast or southeast,” said NEA. 

“The showers may help to improve the hotspot and haze situation in Sumatra and Kalimantan, although hotspot activities in parts of Sumatra and Kalimantan can be expected to persist.”

NEA said it is monitoring the situation closely, and will provide further updates when necessary.

READ: Understand the haze – What do Singapore’s air quality readings mean?

READ: Cutting through the haze: When do you need an N95 mask?

Haze ECP

Haze seen from East Coast Park on Sep 22, 2019. (Photo: Jaime Hippie)

For the next 24 hours, the 1-hr PM2.5 concentration readings in Singapore are expected to be in Band II (Elevated), and may return to Band I (Normal) tomorrow. 

PM2.5 is a measure of tiny particles less than 2.5 micrometres in diameter in the air. When the PM2.5 reading is in the elevated range, haze particles can affect the heart and lungs, especially in people who have chronic heart or lung conditions.

According to NEA, one-hour PM2.5 readings are a “good indicator of current air quality”, and can be used for those deciding whether to go for immediate outdoor activities, such as a jog.

The 24-hr PSI is forecast to be between the high end of Moderate range and the low end of Unhealthy range, and may enter the mid-section of the Unhealthy range if denser haze from the surrounding region is blown in.

According to the National Environment Agency (NEA), PSI readings of 50 and below denote “good” air quality, “moderate” for 51-100 and “unhealthy” for 101-200.

The one-hour PM2.5 reading at 11pm ranged between 66-82 µg/m3, which is in the Elevated band. The reading was highest in the central region, registering at 82 µg/m3.

As of 11pm, the PSI readings were:

  • 115 in the north
  • 121 in the east
  • 126 in the south
  • 113 in the west
  • 114 in the central region