Air quality in Singapore mostly unhealthy; PM2.5 elevated in four regions

SINGAPORE: Air quality in Singapore was mostly unhealthy on Monday (Oct 19), with the 24-hour Pollutant Standard Index (PSI) ranging from 92 at a moderate level in the north to 139 at an unhealthy level in the west.

Hourly PM2.5 readings were elevated in the western, central, southern and eastern regions.

Singapore's air quality remained in the unhealthy band across most regions throughout Sunday. The country's west, the only outlier, was in the very unhealthy range from 8pm on Saturday and only joined the other regions at 5pm on Sunday. 

At 10am, its 24-hour PSI hit 230 - marking a new high for this year's haze season.

The National Environment Agency (NEA) said in its Sunday evening advisory that the 24-hour PSI was expected to be in the unhealthy band on Monday - ranging from 101 to 190.

Showers are forecast over Singapore and the surrounding region for Monday, with winds expected to blow from the south-southeast or south, which may limit smoke haze from Kalimantan to Singapore, said the agency.

However, some smoke haze from Sumatra may drift towards Singapore, it added.

Smoke haze moving from Kalimantan to Singapore could also decrease on Tuesday due to forecast southeasterly or southerly winds, as well as expected showers surrounding Singapore.

"However, the winds are likely to turn east-southeasterly from Tuesday night, which may bring smoke haze from fires in Kalimantan towards Singapore overnight," said NEA.

ADVICE FOR VULNERABLE GROUPS 

NEA advises the elderly, pregnant women and children to minimise prolonged or strenuous outdoor physical exertion when the 24-hour PSI is in the unhealthy range. 

Those with chronic diseases, as well as lung or heart diseases, should avoid such activities during unhealthy air quality. 

For deciding whether to wear a mask during immediate outdoor activities, the public is advised to refer to the hourly PM2.5 readings instead. 

When the 1-hour PM2.5 readings are in the high band, vulnerable individuals, including the elderly, pregnant women and those with chronic heart or lung conditions, should avoid outdoor activities, according to the Ministry of Health (MOH).

Those who need to go outdoors for immediate activities may wear a well-fitting N95 mask or equivalent to reduce their exposure to haze particles.

When PM2.5 readings reach the very high band of 251 and above, healthy individuals should also minimise all outdoor activities. Those who need to venture outdoors may similarly use an N95 mask for protection.

However, MOH said N95 masks are generally not needed for commuting between home and school or work, or in indoor environments.

The ministry has also advised the elderly, pregnant women and those with severe heart or lung conditions who experience breathing difficulties to consult their doctor before using an N95 mask.

Those who experience discomfort while wearing one should take a break from using it.

Besides N95 masks, KN95, FFP2 and KF94 masks are also effective in reducing exposure to haze particles, according to MOH.

Members of the public can visit the HazeMaskGoWhere website for more information on collection locations and live updates on mask availability at the vending machines.