As at 8pm on October 23rd,
24-hr PSI:131 – 153
3-hr PSI: 244
1-hr PM2.5(µg/m3):162 – 228
There has been a sharp deterioration in haze conditions in several regions of Singapore from about 9pm tonight. This was due to denser haze from the sea areas south of Singapore being blown in by the prevailing south-south easterly winds. As at 11pm today, the 24-hr PSI was 104-152, in the Unhealthy range, and the1-hr PM2.5 was 35-471 µg/m3. The1-hr PM2.5 concentration of 471 µg/m3 in the west region is the highest recorded so far for this year.
PM or particulate matter refers to particles found in the air, including dust, dirt, soot, smoke, and liquid droplets. While some particles can be suspended in the air for long periods of time, some are large or dark enough to be seen as soot or smoke.
Particles less than 10 micrometers in diameter (PM10) pose a health concern because they can be inhaled into and accumulate in the respiratory system while particles less than 2.5 micrometers in diameter (PM2.5) are referred to as “fine” particles and are believed to pose the greatest health risks.
The total number of hotspots detected in Sumatra today was 233. Moderate to dense smoke haze is still persisting in parts of central and southern Sumatra. Some haze from Kalimantan is also observed to have spread to the sea areas southeast of Singapore.
The current haze conditions are expected to gradually improve over the next few hours. For tomorrow, the prevailing winds are forecast to blow from the southeast or south, and hazy conditions can still be expected. Reduced visibility is also expected if PM2.5 concentration levels are elevated. The 24-hr PSI for the next 24 hours is expected to be in the low to mid sections of the Unhealthy range.
The health impact of haze is dependent on one’s health status, the PSI level, and the length and intensity of outdoor activity. Reducing outdoor activities and physical exertion can help limit the ill effects from haze exposure.