Haze and Outdoor Work in Singapore: MOM’s 1-Hour PM2.5 Bands for Employers

Short answer: On 20 October 2026, MOM issued haze outdoor work guidance for Singapore employers: plan next-day outdoor work from the PSI forecast and adjust during the day using 1-hour PM2.5 readings in four bands. At 251 µg/m³ and above, outdoor work must be prohibited for vulnerable employees and minimised for everyone else. Employers should also hold at least a one-week mask supply.

This article is general information only and is not legal, tax or immigration advice. For matters needing legal advice, we work with a panel of experienced Singapore law firms.

What did MOM change for haze and outdoor work?

MOM added guidance on adjusting outdoor work using the 1-hour PM2.5 readings, which complements the existing PSI-forecast guidance. The aim is to let employers respond within the day as air quality changes, rather than only planning from the next-day forecast (MOM press release, 20 October 2026).

MOM frames this as guidance and reminds employers to take precautions to protect workers from haze exposure. MOM’s wider haze guidance is at mom.gov.sg/haze, and live PSI and PM2.5 readings are at haze.gov.sg.

How should employers plan next-day outdoor work using the PSI forecast?

Use the PSI forecast to plan outdoor work for the following day, including which activities to reduce or reschedule. MOM’s Table 1 sets the response by forecast range.

PSI forecast	Healthy employees	Elderly, pregnant employees	Chronic lung or heart disease
100 or below (Good / Moderate)	Normal activities	Normal activities	Normal activities
101 to 200 (Unhealthy)	Reduce prolonged or strenuous outdoor work	Minimise prolonged or strenuous outdoor work	Avoid prolonged or strenuous outdoor work
201 to 300 (Very Unhealthy)	Avoid prolonged or strenuous outdoor work	Minimise outdoor work	Avoid outdoor work
Above 300 (Hazardous)	Minimise outdoor work	Avoid outdoor work	Avoid outdoor work

At forecasts above 200, MOM says masks should be provided if prolonged or strenuous work cannot be avoided. Above 300, employers should add measures such as redeployment, shorter and less intense work, regular indoor rest breaks or deferring non-essential jobs, and the risk assessment should account for poor visibility in lifting operations involving tower and mobile cranes.

What do the four 1-hour PM2.5 bands require?

Employers should progressively reduce outdoor work as the 1-hour PM2.5 reading rises. MOM’s Table 2 sets two columns, healthy and vulnerable employees.

1-hour PM2.5 band	Healthy employees	Vulnerable employees	General measures
Band 1, Normal (0 to 55 µg/m³)	Normal activities	Normal activities	Monitor the haze situation
Band 2, Elevated (56 to 150 µg/m³)	Reduce strenuous outdoor work	Avoid strenuous outdoor work	Mechanical aids, job rotation, indoor rest breaks, hydration
Band 3, High (151 to 250 µg/m³)	Avoid strenuous outdoor work	Avoid outdoor work	If strenuous work is unavoidable, provide masks (N95 or equivalent)
Band 4, Very High (251 µg/m³ and above)	Minimise outdoor work	Prohibit outdoor work	Defer non-essential jobs; masks or appropriate respirators if work is unavoidable; hourly rest breaks (for example 10 to 15 minutes), taken indoors where possible

MOM defines its terms: reduce means do less, minimise means do as little as possible, avoid means do not do, and prohibit means must not allow. Strenuous means involving a lot of energy or effort, and prolonged means continuous exposure for several hours.

Who counts as a vulnerable employee?

MOM’s guidance defines vulnerable employees as the elderly, pregnant women and those with chronic heart or lung diseases. Employers should identify these workers in advance, because a same-day reading leaves little time to work out who can be moved indoors.

Do not ask workers to disclose a medical condition at the moment the reading spikes. Collect the information when the haze plan is prepared, treat it as confidential personal data and limit access to those who assign work.

What should a haze management plan contain?

MOM reminds employers to review their haze management plans. The plan should cover the four items below, and then the practical details your sites need.

1. Identify workers who are more susceptible to the effects of haze.
2. Decide which outdoor work activities will be reduced or rescheduled.
3. Set criteria for restricting outdoor work as haze conditions worsen, tied to the PSI forecast and the PM2.5 bands above.
4. Maintain at least a one-week supply of masks as part of the haze-related business continuity plan, if any employees must work outdoors.

On top of MOM’s four items, name the person who checks haze.gov.sg and at what times, and who may stop work on site. Record each decision with the reading and time. A record showing that you moved a rigging team indoors at 160 µg/m³ is useful evidence if an incident is later investigated.

What does this mean for dormitories, lorries and Work Permit holders?

Many outdoor workers in construction, marine, landscaping, cleaning and logistics hold Work Permits. MOM’s guidance is framed around employees generally, not by nationality, so employers should not treat nationality as a reason to defer rest breaks or masks.

Think through the movement of workers. If workers ride in lorries to a site or wait outdoors for transport, that exposure counts. Plan indoor rest areas, including at the dormitory or site office, and stock masks where workers collect their equipment. Our guide to housing migrant workers under the dormitory framework covers the accommodation side, and our heat-stress checklist for 1 December 2026 covers the companion duty for hot weather, so the two plans can share rest areas and hydration arrangements.

What should employers do this week?

The reasoning is simple: a PSI forecast is issued for the day ahead, while particulate levels at a work site can change by the hour. A plan that relies only on the forecast leaves supervisors guessing when the afternoon reading jumps, and the new bands give them a defined trigger for each step down in outdoor activity.

Update the haze plan now, because readings can move between bands within a day. NEA has published haze situation updates through October 2026 (NEA update, 23 October 2026).

1. Add the four PM2.5 bands to the plan next to the existing PSI table.
2. Check mask stock for at least one week of outdoor headcount, including N95 or equivalent masks and respirators for Band 4.
3. Brief supervisors on who may stop work and where the indoor rest areas are.
4. Update the vulnerable-worker list and the reassignment options for each.
5. Check contracts and customer deadlines for a delay clause, so supervisors are not pushed to override the plan.

Frequently asked questions

Is the 1-hour PM2.5 guidance law?

It is guidance issued by MOM, which urges employers to take appropriate precautions. Check with your safety adviser or lawyer how it interacts with your workplace safety obligations before departing from it.

Which reading should I use, PSI or PM2.5?

Use the PSI forecast to plan the next day, and the 1-hour PM2.5 reading to adjust during the day as conditions change.

Are masks compulsory?

MOM says masks should be provided where strenuous outdoor work cannot be avoided at Band 3, and masks or appropriate respirators at Band 4 if outdoor work is unavoidable.

What counts as strenuous work?

MOM defines strenuous as involving a lot of energy or effort. Heavy lifting, digging and sustained manual handling are typical examples.

Do the rules differ for foreign workers?

The guidance does not distinguish by nationality. The vulnerable-employee test and the bands are framed for employees generally.

Need help with work pass and workforce planning for outdoor teams? Contact Little Big Employment Agency for pass, PR and citizenship applications. Email [email protected] or call, SMS or WhatsApp +65 8501 7133.

Last reviewed: 26 October 2026. The Editorial Team, Little Big Employment Agency.