The Ministry of Manpower (MOM) issued guidance on 20 October for employers to adjust outdoor work during the day using 1-hour PM2.5 readings. It adds to the existing guidance, which uses the PSI forecast to plan the next day's work.
4Haze bands1-hour PM2.5 readings
251Very High band startsµg/m³, 1-hour PM2.5
1 weekMask stockEmployers with outdoor workers
Source: MOM, guidance on 1-hour PM2.5 readings, 20 October 2026.
In short
- Four bands set out what to do as hourly haze readings rise.
- Vulnerable workers should not work outdoors in the Very High band.
- Employers should keep at least a week's supply of masks.
What this means for you
If you work outdoors
- Working outdoors? Check the hourly PM2.5 on haze.gov.sg: from 151 (High), strenuous outdoor work should be avoided.
- If you are pregnant, older, or have a heart or lung condition, tell your supervisor: you should not work outdoors in the Very High band.
- Ask for an N95 or equivalent mask when strenuous outdoor work cannot be avoided at High or above.
If you are an employer
- List vulnerable workers now, so they can be moved indoors quickly.
- Keep at least a one-week supply of masks in your haze plan.
- Plan with the PSI forecast the day before, and adjust with the hourly readings on the day.
Download
What each hourly PM2.5 band means for outdoor work
The four hourly bands
| 1-hour PM2.5 (µg/m³) | Healthy workers | Vulnerable workers |
|---|---|---|
| Normal, 0 to 55 | Normal activities | Normal activities |
| Elevated, 56 to 150 | Reduce strenuous outdoor work | Avoid strenuous outdoor work |
| High, 151 to 250 | Avoid strenuous outdoor work | Avoid outdoor work |
| Very High, 251 and above | Minimise outdoor work | No outdoor work |
Vulnerable workers are the elderly, pregnant women, and people with chronic heart or lung disease.
Planning a day ahead: the PSI forecast
| PSI forecast | Healthy workers | Workers with chronic lung or heart disease |
|---|---|---|
| 100 or less | Normal activities | Normal activities |
| 101 to 200 | Reduce prolonged or strenuous outdoor work | Avoid prolonged or strenuous outdoor work |
| 201 to 300 | Avoid prolonged or strenuous outdoor work | Avoid outdoor work |
| Above 300 | Minimise outdoor work | Avoid outdoor work |
Above a PSI of 400, MOM recommends full-face respirators for prolonged outdoor work. Both readings are on haze.gov.sg.
Your numbers
| On a Very High day | Figure |
|---|---|
| Rest breaks | About 10 to 15 minutes every hour |
| Over an 8-hour outdoor shift | 80 to 120 minutes of breaks |
| Mask stock to keep | At least one week's supply |
Foundific calculation for an 8-hour shift with one break an hour.
What to do next
- Check readings: haze.gov.sg shows the PSI forecast and the hourly PM2.5.
- Unwell? Sick leave needs a medical certificate; the leave application email gives the wording.
- Overtime: if lost hours are made up later, the overtime pay calculator shows what is owed.
- Pay: outdoor and site jobs are in the Singapore salary guide.
