PSI in Singapore close to unhealthy levels on Wednesday but will improve with thunderstorms: NEA

24-hr PSI readings ranged from 85 to 102 at 11am on Wednesday (November 13) morning.
The Straits Times

Smell something burning again?

Keep your N95 mask close as the Pollutant Standards Index (PSI) reading inched up to the “unhealthy” range in the eastern part of Singapore on Wednesday (Nov 13) morning.

The National Environment Agency’s (NEA) hourly PSI table showed that the overall PSI reading for Singapore had steadily risen overnight.

At 12am on Wednesday, the 24-hr PSI reading ranged from 71 to 83, rising to hit a range of 85 to 102 by 11am on Wednesday morning.

24-hr PSI readings of 50 and below signify “good” air quality, while readings between 51 to 100 are classified “moderate”, and those between 101 to 200 are “unhealthy”.


Haze situation will improve as thunderstorms are expected: NEA

In a Twitter post on Wednesday, NEA said that the hazy condition is due to accumulation of particulate matter, and is “taking time to clear as winds have remained light since yesterday evening”.

However, thunderstorms are expected in the afternoon, which should help to improve the situation, NEA added.

In an earlier update issued on Tuesday (Nov 12) evening, NEA said that hotspots with smoke haze continued to be detected in southern Sumatra, despite showers over many areas of the southern ASEAN region.

Additionally, the prevailing winds are forecast to blow from the northeast or east in the areas north of the equator, and from the east or southeast at the south of the equator.

The map shows how the winds are blowing smoke haze from southern Sumatra into Singapore.
ASEAN Specialised Meteorological Centre (ASMC)

On Wednesday morning, the 1-hr PM2.5 readings ranged from 39 to 58 – considered “Band I (Normal)” and “Band II (Elevated)”.

PM2.5 readings measure the concentration of tiny particles less than 2.5 micrometres in diameter in the air. According the NEA, the 1-hour reading is best used as a guide of air quality for immediate activities.

1-hr PM2.5 and 24-hr PSI readings as of 11am in Singapore on November 13.

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