Haze in Singapore: 1-hr PM2.5 reading hits 284 in West, 206 in Central region as at 2pm on 14 Oct

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This places both regions in the "Very High" band, while conditions continue to be "Elevated" or "High" in the rest of the regions.

The 1-hr PM2.5 reading has reached 284 in western Singapore, and 206 in the central region, as of 2pm on Tuesday (14 October). That stands in Band 4, i.e., the 'Very High' range, according to the National Environment Agency's air quality indicators.

At the time of writing, the 1-hr PM2.5 reading across all regions of the country are as follows:

UPDATE: As of 3pm on 14 October, the East region has also entered the "Very High" range with a 1-hr PM2.5 reading of 208. The latest numbers are as follows:

The 1-hour PM2.5 reading and the 24-hour Pollutant Standards Index (PSI) measure different things. As explained by NEA, PM2.5 refers to fine particles no larger than 2.5 micrometres in diameter. The 1-hour reading, reported in micrograms per cubic metre, reflects more recent conditions and can rise before the PSI changes.

Meanwhile, the PSI is Singapore’s official air-quality index. It is calculated using pollutant sub-indices – including PM2.5, PM10, sulphur dioxide, ozone, carbon monoxide and nitrogen dioxide, and reported in bands. On haze days, PM2.5 is usually the pollutant driving the PSI. A 1-hour PM2.5 reading in the "Very High" band does not, by itself, mean the 24-hour PSI has reached the "Very Unhealthy" band.

The PSI bands are:

0–50: Good,
51–100: Moderate,
101–200: Unhealthy,
201–300: Very Unhealthy, and
above 300: Hazardous.

The PSI uses a 24-hour measure, so it may take time to reflect a sudden deterioration in air quality. To that effect, the 1-hour PM2.5 reading can offer a more immediate picture of local conditions.

AQI (Air Quality Index) is a term often used for other countries' air-quality scales, including the US scale. It is not interchangeable with Singapore’s PSI: the same number on an AQI and the PSI does not necessarily represent the same air quality, NEA explained. People using third-party apps should check which scale is displayed.

What happens if the 24-hour PSI reaches "Very Unhealthy"?

In a media release on 9 October (Friday), the Haze Task Force said agencies would be ready to implement further measures if the 24-hour PSI exceeded 200. The advice depends on the forecast, the length and intensity of outdoor exposure, and a person’s health.

At that level, people are advised to avoid prolonged outdoor activity. Children, older adults, and pregnant women should minimise outdoor activity, while people with chronic heart or lung conditions should avoid it. Schools and preschools would move activities indoors; preschools are required to stop outdoor activities and strenuous indoor activities.

Employers are also advised to minimise outdoor work for vulnerable workers and avoid it for workers with chronic heart or lung conditions. At the same time, the Ministry of Manpower has advised platform workers who are exposed to the haze while performing outdoor deliveries to similarly follow the measures outlined in its advisory as much as possible.

In the event of such readings, air-conditioned rooms at community clubs and selected Residents’ Committee or Residents’ Network centres would be opened as haze shelters. The following groups of eligible Singaporeans will also be able to collect N95 masks through designated distribution points:

Vending machines at selected public transport hubs, social service offices, and PA venues: