SINGAPORE, Oct 4 — Air quality in the Republic improved this morning as 24-hour Pollutant Standards Index (PSI) in central Singapore returned to the moderate range.

It entered the unhealthy range at 11am yesterday.

At 10am today, PSI readings across Singapore ranged from 76 to 99 — in the moderate range. The highest reading of 99 was recorded in the central region.

Meanwhile one-hour PM2.5, an indicator of fine particulate matter in the air, ranged between 15 and 44. Concentration readings from 0 to 55 denote the normal band.

In its daily haze situation update yesterday evening, the National Environment Agency (NEA) said the country’s 24-hour PSI is forecast to be in the high-moderate to low-unhealthy range.

It noted that moderate to dense smoke plumes from southern Sumatra were observed drifting towards Singapore and surrounding region, while smoke haze was also observed from fires in Kalimantan.

Data from the Asean Meteorological Centre shows that the number of hotspots in Kalimantan decreased from 232 to 178 yesterday, while hotspots in Sumatra fell from 232 to 175.

Given that dry weather conditions are expected to persist over Singapore and the surrounding region today, and with prevailing south-easterly or south-westerly winds, there remains a risk of smoke haze affecting Singapore, NEA said.

Members of the public should check the latest one-hour PM2.5 concentration readings before engaging in outdoor activities. — AsiaOne