Haze FAQ
One page per question: a short answer first, then the detail and the official sources.
Singapore now
Check your area →45 µg/m³ · Normal (1-hour PM2.5, model estimate, not official)
Is it safe to exercise outdoors in haze?It depends on the 1-hour PM2.5. Up to 55 µg/m³ normal activities are fine; at 56–150 reduce strenuous exercise; at 151–250 avoid it; above 250 minimise all outdoor activity (NEA). Vulnerable people should avoid strenuous activity from 56.Will youth training or matches be cancelled because of haze?That is the organiser's call. Many leagues use a 1-hour PM2.5 above 110 µg/m³ as the cut-off, and some check the 1-hour reading rather than the 24-hour PSI. Always wait for the organiser's final message.Should I check the 1-hour PM2.5 or the 24-hour PSI?Use the 1-hour PM2.5 to decide what to do in the next hour, and the 24-hour PSI to plan tomorrow. The PSI is a 24-hour rolling average, so it moves slowly.What should I do at home during haze?Keep windows and doors closed when PM2.5 is above 55 µg/m³, run a HEPA purifier or air-conditioning on recirculate, and avoid frying, incense and candles.What is PM2.5 and why does it matter?PM2.5 is airborne particles smaller than 2.5 micrometres, measured in micrograms per cubic metre (µg/m³). They are small enough to be breathed deep into the lungs, and wildfire smoke is rich in them.What do NEA's PM2.5 bands and PSI bands mean?1-hour PM2.5: Normal 0–55, Elevated 56–150, High 151–250, Very High 251+ µg/m³. 24-hour PSI: Good 0–50, Moderate 51–100, Unhealthy 101–200, Very unhealthy 201–300, Hazardous above 300.Who counts as vulnerable in haze?NEA's guidance singles out the elderly, pregnant women, children, and people with chronic lung disease or heart disease. They should avoid strenuous activity from Band 2 (above 55 µg/m³).Which mask works in haze, and do I need one?A well-fitted N95, KN95 or FFP2 respirator filters fine smoke particles; ordinary surgical masks do not filter them well. Most healthy people on short trips do not need one at moderate levels, but it helps for longer outdoor exposure.When are schools closed because of haze?Each government and school decides. Singapore's Haze Task Force said school closures would be considered when the next-day air-quality forecast exceeds a 24-hour PSI of 300 (CNA, 9 October 2026); in Malaysia, schools have closed in areas where the API passed 200.How long will the haze last?Nobody can promise a date. It lasts while fires keep burning and the wind carries smoke your way, and it eases with steady rain. Check the next-24-hours chart for the likely trend and the official outlook for the multi-day picture.Does rain clear haze?Yes, rain helps by washing particles out of the air and damping fires, but a short shower rarely ends a haze episode while fires keep burning.Why do apps show different numbers: US AQI, Singapore PSI and Malaysia API?They are different indices with different formulas and breakpoints, and some apps use low-cost sensors or models. A US AQI of 250 can sit alongside a Malaysian API of about 175, so compare like with like and trust the local official index.Do air purifiers help during haze?A HEPA purifier sized for the room removes fine particles and can noticeably lower indoor PM2.5, especially with windows closed. It does not replace staying indoors during very high readings.