What’s the latest haze situation in Singapore?
Sign up now: Get ST's newsletters delivered to your inbox
SINGAPORE – The haze has made a comeback after the 24-hour PSI in Singapore first dipped into unhealthy levels on the morning of Sept 4.
Since then, air quality has hit several peaks, such as when the one-hour PM2.5 breached “very high” levels in the west on the afternoon of Oct 14, and when the 24-hour PSI reached the “very unhealthy” range in the west that night.
For those who want a quick check on the latest haze situation, The Straits Times has created a widget for easy reference.
The left tab shows real-time 24-hour PSI readings – a 24-hour rolling average of six key air pollutants, including PM2.5 – in five regions across Singapore: north, south, east, west and central. The tab on the right provides the PM2.5 figures for the same five regions.
During hazy periods, the one-hour PM2.5 – an indicator of fine micro-pollutants in the air – is what people should be watching because it points to current air quality.
PM2.5 levels should be checked immediately before outdoor activities, such as going for a jog.
PM2.5 is the dominant pollutant during periods of transboundary haze and has the most influence over the 24-hour PSI readings.
Hazy conditions seen from Holland Village on Oct 15.
ST PHOTO: JASON QUAH
The 24-hour PSI is computed based on the daily average concentration of six pollutants, including PM2.5, sulphur dioxide, carbon monoxide and ozone. It is an index to provide easily understandable information about daily levels of air quality.
Fuller details on the differences between PSI and PM2.5 can be found in this ST explainer.
When the 24-hour PSI is “very unhealthy”, the elderly, pregnant women and children should minimise outdoor activity, the National Environment Agency said on its website.
If the one-hour PM2.5 is in the high band, they should avoid all outdoor activity for the next hour.
Follow the ST live blog for the latest news and updates.