SINGAPORE: Singapore's air quality improved on Thursday evening (Sep 19), with the Pollutant Standards Index (PSI) falling to the moderate range in certain areas.
The 24-hour PSI had increased to 154 in the south early on Thursday before falling throughout the day.
As of 6pm, the PSI readings were:
- 98 in the north
- 105 in the east
- 110 in the south
- 103 in the west
- 97 in the central region
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 6pm ranged between 21-36µg/m3, which is in the normal band.
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 better air quality comes after a day of unhealthy readings on Wednesday, when PSI levels ranged from 90 to 149 across the day.
NEA said the improved situation was due to "a strengthening of winds blowing from the southeast", which helped disperse the smoke haze from Singapore.
For the rest of the day, slightly hazy conditions are expected, it added.
The 24-hr PSI is forecast to be between the high end of the moderate range and low end of the unhealthy range.
As for the one-hour PM2.5 readings over the next 24 hours, they are expected to remain in the normal range, and may enter the elevated range if haze from the surrounding region is blown in.
"Given the air quality forecast for the next 24 hours, healthy persons should reduce prolonged or strenuous outdoor physical exertion," said NEA.
"The elderly, pregnant women and children should minimise prolonged or strenuous outdoor physical exertion, while those with chronic lung or heart disease should avoid prolonged or strenuous outdoor physical exertion."
A total of 196 hotspots were detected mostly in Riau, Jambi, South Sumatra and Lampung provinces of Indonesia, said NEA, down from 238 on Wednesday.
The haze has also affected neighbouring Malaysia, with air quality remaining at "unhealthy" or "very unhealthy" levels in most of the country on Thursday. Nearly 2,500 schools were closed, affecting 1.7 million students.
The haze originated from peat and forest fires in Indonesia, where many still practise the slash-and-burn agricultural methods.
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