By Mothership
Air quality in Singapore almost hit the unhealthy range on Monday morning, Sep. 14.
The 24-hour Pollutant Standards Index (PSI) reading at 11am was between 78 and 99, just within the moderate range, according to the National Environment Agency (NEA) website.
The unhealthy range reading is between 101 and 200.
The public is advised to reduce prolonged or strenuous outdoor physical exertion if the 24-hr PSI reading crosses into the unhealthy range.
Central Singapore was haziest just before noon.
From NEA
1-hour PM2.5: 113
Just before at 10am, the one-hour PM2.5 reading hit 113 in central Singapore.
One-hour PM2.5 measures the concentration of tiny airborne particles over a single hour.
The one-hour PM2.5 concentration readings act as a real-time gauge of the air during hazy conditions.
It provides the most current indication of air quality.
The reading is expressed in micrograms per cubic metre, where particles are less than 2.5 micrometres in diameter.
Readings of between 56 and 150 indicate the elevated range, while readings of between 151 and 250 indicate the high range.
For those considering engaging in outdoor activities immediately, they should refer to the one-hour PM2.5 concentration reading.
Vulnerable persons are advised to follow the guide on outdoor activities during haze episodes.
