Haze watch: PSI reading goes up to 70

SINGAPORE - Air quality readings in Singapore saw a minor spike on Thursday afternoon to around 70. The Pollutant Standards Index (PSI) has been hovering in the 50-62 range in recent months.

The 3-hour PSI reading hit 71 from noon to 1pm on Thursday, and was 70 at 4pm, according to the National Environment Agency's (NEA) website and Twitter feed. The 24-hour PSI readings were 58-63 at 4pm.

Buildings in the Central Business District were seen shrouded by haze.

A spokesman for the Meteorological Services said the current haze was due to the "weakening of winds overnight, which led to an accumulation of particulate matter in the atmosphere".

"The low level winds are expected to continue to blow predominantly from the northeast for the next two months," the weather agency said.

NEA recommends that normal activities be carried out when the 24-hour PSI is in the moderate range of 50-100.

If the 24-hour index hits the unhealthy band (101-200), healthy people should reduce prolonged or strenuous outdoor physical exertion, while the elderly, pregnant women and children should minimise such exertion.

The current index includes PM2.5, which are small, toxic particles, in its assessment of air quality.