Air quality in Singapore reaches unhealthy range in central region due to transboundary haze from Indonesia fires

Summary

• Singapore’s central region recorded a 24-hour PSI of 103 at 7 pm on Sep 5, placing air quality in the unhealthy range.

• The west and east regions also entered the unhealthy range early Saturday, recording PSI readings of 103 and 102, respectively.

• The 24-hour PSI crossed 100 on Sept 4 for the first time since Oct 8, 2023, prompting daily haze advisories.

SINGAPORE: Singapore woke to hazy skies on Saturday, with air quality reaching the unhealthy range in three regions.

The central region recorded a 24-hour Pollutant Standards Index (PSI) of 103 at 7 pm, according to the National Environment Agency (NEA).

The west and east also started the day above the unhealthy threshold. Their readings were 103 and 102 at 6 am, then fell to 91 and 83 by 7 pm, Channel NewsAsia (CNA) reported the figures on Sept 5, citing NEA data.

Haze levels improved across two regions

The unhealthy PSI range starts at 101 and runs to 200. The other regions stayed within the moderate range throughout Saturday.

The north recorded a PSI of 78, while the south recorded 79 at 7 pm.

The improvement in the west and east came as haze conditions shifted during the day. The central region, however, remained just inside the unhealthy band by evening.

Singapore last saw the 24-hour PSI cross into the unhealthy range on Oct 8, 2023.

That prompted NEA to begin issuing daily haze advisories from Friday. The advisories include a 24-hour PSI forecast to help people plan outdoor activities and events.

Smoke continues drifting towards Singapore

Smoke plumes from fires in southern and central Sumatra, along with parts of Kalimantan, continued moving towards Singapore.

Most of the surrounding region remained dry on Saturday. Dry conditions are also expected to continue in the coming days.

Winds from the southeast or south could bring more smoke towards Singapore if fires in Indonesia stay active.

NEA forecasts the 24-hour PSI to range from the higher end of moderate to the lower end of unhealthy.

PSI measures several pollutants, while PM2.5 measures fine particles

The 24-hour PSI gives Singapore’s daily air quality reading and supports NEA’s health advisories.

It combines readings from six pollutants, including PM2.5, PM10, ozone, sulphur dioxide, nitrogen dioxide and carbon monoxide.

PM2.5 is especially important during haze because these tiny particles can harm health. The one-hour PM2.5 reading shows the average level at a particular point in time.

The 24-hour PSI, meanwhile, averages air quality over the previous 24 hours. The scale reaches the “very unhealthy” range at 201 and becomes “hazardous” above 300.

The Haze Task Force has also activated its respective action plans and advisories to protect public health and well-being.

With haze conditions still tied to fires across the region, it would be prudent to check the daily PSI forecast before planning outdoor activities.

A little planning can save people from spending unnecessary time breathing smoky air.