Post by : Rohit Dhiman

SINGAPORE: Air quality in central Singapore deteriorated into the unhealthy range on Saturday morning as haze continued to affect the city-state. The latest readings showed a rise in the 24-hour Singapore air quality index, while hourly PM2.5 levels also moved into the elevated category in more than one region. According to the latest readings, the 24-hour Pollutant Standards Index, or PSI, in Singapore's central region crossed the unhealthy threshold at around 11am on Oct 3. By noon, the central region recorded a PSI of 104. The development comes as Singapore continues to experience hazy conditions linked to smoke plumes moving from parts of Indonesia. The National Environment Agency has warned that prevailing southeasterly and southerly winds could transport smoke haze towards Singapore while dry weather persists across the surrounding region. 

Central Singapore Records Unhealthy PSI Reading

The central region was the only area to enter the unhealthy range in the latest midday readings. At 12pm, the 24-hour PSI stood at 104 in the central region. The other four regions remained within the moderate range at the same time. The eastern region recorded 95, followed by 92 in the west, 87 in the south and 77 in the north. Singapore classifies a 24-hour PSI reading between 101 and 200 as unhealthy. The moderate range extends from 51 to 100, meaning even a relatively small increase can push a region from moderate into the unhealthy category. NEA's health guidance advises healthy people to reduce prolonged or strenuous outdoor physical activity when the PSI reaches the unhealthy range.  The latest figures are particularly important for people spending extended periods outdoors, including workers, students, elderly residents and those involved in outdoor exercise.

PM2.5 Levels Rise in Central and Eastern Singapore

Alongside the increase in the 24-hour PSI, the one-hour PM2.5 readings also showed elevated pollution in two regions. At noon, the one-hour PM2.5 reading was in the elevated band in both central and eastern Singapore. Unlike the 24-hour PSI, which represents average air quality over the previous 24 hours, the one-hour PM2.5 figure provides a more immediate picture of particulate pollution at a particular time. PM2.5 refers to extremely fine particles measuring 2.5 micrometres or smaller. These particles are a major component of haze and can penetrate deep into the respiratory system. NEA places one-hour PM2.5 concentrations between 56 and 150 micrograms per cubic metre in the elevated band. The agency recommends using the one-hour PM2.5 reading when deciding whether to carry out immediate outdoor activities.

Indonesian Smoke Haze Continues to Affect Singapore

The worsening Singapore haze comes amid continuing smoke activity across parts of the region. NEA reported that moderate to dense smoke plumes from southern Sumatra had been observed drifting towards Singapore. Smoke haze was also detected from fires in Kalimantan. The regional situation has been influenced by prolonged dry conditions, with satellite observations showing hotspots and smoke activity in parts of southern Sumatra and Kalimantan. NEA has said that cloud cover can make it difficult to determine the full extent of the hotspot and smoke-haze situation. Prevailing winds are an important factor in determining how much smoke reaches Singapore. When winds blow from affected areas towards the island, pollutants can travel across national borders and contribute to transboundary haze. This phenomenon has previously caused significant fluctuations in Singapore's air quality, with different regions recording different PSI levels depending on weather conditions, wind direction and the concentration of pollutants.

Dry Weather Could Keep Air Pollution Elevated

Weather conditions are expected to remain an important factor in the coming days. NEA's Oct 2 advisory said dry conditions were expected to persist over Singapore and the surrounding region, while smoke haze could be transported towards the country under prevailing southeasterly or southerly winds. The agency forecast the 24-hour PSI to remain in the moderate to low-unhealthy range. The combination of dry weather, regional fires and favourable wind patterns can increase the possibility of haze reaching Singapore. However, the actual air quality can change during the day depending on wind direction, rainfall and the movement of smoke plumes. This means residents may see noticeable differences in air quality between regions and between different hours of the day.

What Should People Do When PSI Enters the Unhealthy Range?

NEA advises healthy people to reduce prolonged or strenuous outdoor physical activity when the 24-hour PSI reaches the unhealthy range. For elderly people, pregnant women and children, prolonged or strenuous outdoor activity should be minimised. People with chronic lung or heart conditions are advised to avoid such activity when the PSI is unhealthy. For immediate outdoor activities, NEA recommends checking the one-hour PM2.5 reading rather than relying only on the 24-hour PSI. The one-hour reading provides a more immediate indication of particulate pollution, while the 24-hour PSI and forecast are intended to help people plan activities for the following day.  Residents can continue monitoring official air-quality updates through NEA's platforms and the myENV application.

What Is the PSI Level Considered Unhealthy in Singapore?

A 24-hour PSI reading from 101 to 200 is classified as unhealthy in Singapore. A reading from 201 to 300 is considered very unhealthy, while a reading above 300 falls into the hazardous category. With the central region recording a PSI of 104 at noon on Saturday, the area had moved just beyond the unhealthy threshold.

What Is PM2.5 and Why Does It Matter During Haze?

PM2.5 consists of very small airborne particles measuring 2.5 micrometres or less. During haze events, PM2.5 becomes a major pollutant of concern because these fine particles can enter deep into the lungs. Singapore's one-hour PM2.5 system uses four bands: normal, elevated, high and very high. The elevated band covers readings from 56 to 150 micrograms per cubic metre.

Read Also: Indore Gets Advanced Blood Test for Early Alzheimer’s Detection

Which Areas of Singapore Are Seeing Poorer Air Quality?

The latest midday readings showed the central region with the highest 24-hour PSI at 104, placing it in the unhealthy category. The east recorded 95, the west 92, the south 87 and the north 77. While these four regions remained moderate, the readings show that haze conditions were affecting different parts of Singapore to varying degrees. The elevated one-hour PM2.5 readings in the central and eastern regions also indicate that particulate pollution was more pronounced in those areas at the time of the latest measurement.

Singapore Haze Situation Remains Weather Dependent

The latest deterioration is part of a broader haze episode that has affected Singapore at various points in recent weeks. Earlier this season, the country's air quality also entered the unhealthy range in multiple regions, with the central region recording particularly high PSI levels. The situation can improve if rainfall reduces fire activity or if wind conditions change and disperse the smoke. Conversely, prolonged dry weather and continued fires in parts of the region could keep haze conditions elevated. For now, authorities are urging residents to follow the latest air-quality readings and health advisories, particularly when planning outdoor activities. The most immediate indicator is the one-hour PM2.5 reading, while the 24-hour PSI forecast remains important for planning activities over the next day.

#world news #Global News #Asia News #Singapore News