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New Personal Guide Based On 1-hr PM2.5 Concentration Readings To Guide The Public During Haze Season

1. The National Environment Agency (NEA) and the Ministry of Health (MOH) have introduced a personal guide to the 1-hour average concentration of fine particulate matter (PM2.5) to help individuals decide on their immediate outdoor activities during the haze season. The personal guide is now available on the haze microsite ( and the myENV app.

Using the 1-hr PM2.5 Concentration for Immediate/Current Activities

2. The 1-hr PM2.5 concentration is the average concentration of PM2.5, in micrograms per cubic metre (µg/m3), measured in the air over the past hour. Since 2014, NEA has been publishing the 1-hr PM2.5 concentration readings on an hourly basis across the five regions in Singapore. The 1-hr PM2.5 concentration is a useful indication of the current air quality. In 2016, NEA introduced bandings and descriptors to help the public interpret the 1-hr PM2.5 concentration readings.

3. MOH and NEA are now making available a personal guide to the 1-hr PM2.5 concentration level that the public can refer to when deciding on their immediate activities, such as going for a walk or run (see Annex A). The 1-hr PM2.5 concentration levels can be volatile and can fluctuate over the day due to weather conditions, especially during periods of transboundary haze. When planning activities within the same day, members of the public are advised to closely monitor the 1-hr PM2.5 readings and check the latest readings before proceeding.

4. The public are advised to consider their own individual health and physical conditions when using the personal guide. This is because each individual’s reaction to pollutants may vary, and the amount of physical exertion that can be performed differs. For the general population, symptoms that may arise from short-term exposure to PM2.5, such as throat or eye irritations, are expected to resolve after withdrawing from the exposure.

Using the 24-hr PSI Forecast for Future Activities

5. To plan for the next day’s activities or events, individuals and organisations should continue to refer to the 24-hr PSI forecast and accompanying health advisory. The 24-hr PSI is a rolling average of the PSI readings over the past 24 hours. Since 2013, during the Southwest Monsoon months when there is likelihood of transboundary haze affecting Singapore, NEA has been publishing a forecast of the 24-hr PSI for the next 24 hours accompanied with a corresponding health advisory. The forecast is based on NEA’s assessment of the air quality, weather conditions, hotspot and haze situation in the region.

6. The Government’s Haze Task Force comprising 28 government agencies and led by NEA will continue to use the 24-hr PSI forecast to implement action plans to minimise and manage the impact of haze on Singapore, guide risk assessment of immediate activities and advise major decisions such as school closure and suspension of training or outdoor work.

7. Singapore’s air quality readings are taken from a network of air quality monitoring stations across the island. Current air quality readings, including the forecast range for the 24-hr PSI, as well as NEA’s daily haze advisory1 are available on NEA’s website (, the haze microsite (, NEA’s Facebook ( and Twitter (@NEAsg), and the myENV app.

[1] Forecast air quality readings and NEA’s daily haze advisory are only available during periods of transboundary haze.

13 JULY 2020

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