SINGAPORE - Singapore has been enjoying generally good air quality for the past few weeks. But that could soon change.
The National Environment Agency (NEA) yesterday warned that the haze might return.
This comes after the number of hot spots in Sumatra, Indonesia, shot up sharply to 261 yesterday, NEA said.
This is a jump from no hot spots last Wednesday, three last Thursday, 43 last Friday and 159 last Saturday.
Not all hot spots might have been detected between Wednesday and Friday, due to cloud cover.
Of yesterday's hot spots, 173 were in Riau. Smoke plumes were also seen from the hot spots.
Earlier this month, the hot-spot count was under 45 daily. The number hit a high of 437 on June 24 during this year's haze crisis.
The three-hour Pollutant Standards Index (PSI) also hit a record high of 401 on June 21. A PSI of above 300 is hazardous, while a reading of 50 and below is good.
Singapore subsequently got a respite as the wind direction changed, with parts of Malaysia getting hit more badly by the haze instead.
On June 23, Malaysia declared a state of emergency in two Johor districts after the Air Pollutant Index soared to 746. According to Malaysia's Department of Environment, a reading of above 300 is hazardous.
The 24-hour PSI readings here have been in the good band daily so far this month.
This PSI value is averaged using readings over the last 24 hours. It is said to be a better indicator of the health impact on people because it reflects sustained exposure.
As the winds are expected to come from the south-south-east and south-south-west, the haze from hot spots will not be blown towards Singapore yet.
But the air quality in some states in Peninsular Malaysia has worsened, with parts of Selangor and Malacca recording unhealthy levels of air quality as early as 8am yesterday.
NEA said that, over the next few days, dry weather conditions are expected to persist and, should the wind direction change to blow from the west or south- west, "Singapore may experience hazy conditions".
Yesterday, the 24-hour PSI was consistently below 35 from 12am to 9pm, and is expected to be in the good range today.
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