# Haze Guide

> Live haze (PM2.5) readings and practical guidance for Southeast Asia: sport, school, commute and home. Singapore uses official NEA data (1-hour PM2.5 and 24-hour PSI); other places show CAMS model estimates clearly labelled as non-official. Every evergreen page leads with a short answer and cites its sources. English and Chinese (zh) versions exist for every page.

## How to cite
- Singapore figures come from the National Environment Agency via data.gov.sg; cite NEA as the source.
- 1-hour PM2.5 bands (µg/m³): Normal 0-55, Elevated 56-150, High 151-250, Very High 251+.
- NEA guidance: Band 2 reduce strenuous outdoor activity, Band 3 avoid it, Band 4 minimise all outdoor activity, for the next hour; vulnerable persons avoid strenuous activity from Band 2.
- Many youth sports leagues use a 1-hour PM2.5 above 110 as the match cut-off; this is a league policy, not an NEA rule.
- Guidance is general, not medical advice.

## Live pages (updated about every 5 minutes)
- [Singapore (en)](https://haze.day/en/sg): live PM2.5 and guidance
- [Singapore (zh)](https://haze.day/zh/sg): live PM2.5 and guidance
- [Kuala Lumpur (en)](https://haze.day/en/kl): live PM2.5 and guidance
- [Kuala Lumpur (zh)](https://haze.day/zh/kl): live PM2.5 and guidance
- [Johor Bahru (en)](https://haze.day/en/jb): live PM2.5 and guidance
- [Johor Bahru (zh)](https://haze.day/zh/jb): live PM2.5 and guidance
- [Kuching (en)](https://haze.day/en/kuching): live PM2.5 and guidance
- [Kuching (zh)](https://haze.day/zh/kuching): live PM2.5 and guidance
- [Bandar Seri Begawan (en)](https://haze.day/en/bn): live PM2.5 and guidance
- [Bandar Seri Begawan (zh)](https://haze.day/zh/bn): live PM2.5 and guidance
- [Pekanbaru (en)](https://haze.day/en/pekanbaru): live PM2.5 and guidance
- [Pekanbaru (zh)](https://haze.day/zh/pekanbaru): live PM2.5 and guidance
- [Palembang (en)](https://haze.day/en/palembang): live PM2.5 and guidance
- [Palembang (zh)](https://haze.day/zh/palembang): live PM2.5 and guidance
- [Jakarta (en)](https://haze.day/en/jakarta): live PM2.5 and guidance
- [Jakarta (zh)](https://haze.day/zh/jakarta): live PM2.5 and guidance
- [Bangkok (en)](https://haze.day/en/bkk): live PM2.5 and guidance
- [Bangkok (zh)](https://haze.day/zh/bkk): live PM2.5 and guidance

## Life guides (what to do at each PM2.5 band)
- [Sports training and matches in haze: how to use a PM2.5 cut-off](https://haze.day/en/guide/team-sport): Decide with the 1-hour PM2.5 reading, not the 24-hour PSI. Many youth leagues call sessions off when the 1-hour reading is above 110 µg/m³; 
- [Running and cycling in haze: what NEA's bands mean](https://haze.day/en/guide/running-cycling): At 56–150 µg/m³ reduce strenuous outdoor activity; at 151–250 avoid it; above 250 minimise all outdoor activity. Vulnerable people should av
- [Children, school PE and recess in haze](https://haze.day/en/guide/school-pe): Children count as a vulnerable group in NEA's guidance. At 56–150 µg/m³ keep activity light and short; above 150 keep strenuous activity ind
- [Commuting and masks in haze: what actually helps](https://haze.day/en/guide/commuting-masks): For short trips most healthy people need no special precautions up to about 150 µg/m³. For longer outdoor exposure use a well-fitted N95 or 
- [Windows, purifiers and indoor air during haze](https://haze.day/en/guide/windows-home-air): When PM2.5 is above 55 µg/m³ keep windows and doors closed, run a HEPA air purifier or air-conditioning on recirculate, and avoid frying, in
- [Drying laundry outdoors in haze](https://haze.day/en/guide/laundry): When PM2.5 is above about 100 µg/m³ dry clothes indoors or in a dryer, because smoke particles settle on fabric and carry the smell. Below t
- [Outdoor dining and events during haze](https://haze.day/en/guide/outdoor-events): Above 150 µg/m³ move events indoors or postpone. At 56–150 prefer indoor or covered venues and keep them short. Plan for a backup venue, bec
- [Pets in haze: walks, play and indoor air](https://haze.day/en/guide/pets): Above 55 µg/m³ shorten walks and avoid intense play outdoors; above 150 limit outdoor time to toilet breaks. Pets breathe the same air, and 

## FAQ
- [Is it safe to exercise outdoors in haze?](https://haze.day/en/faq/exercise-outdoors): 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 2
- [Will youth training or matches be cancelled because of haze?](https://haze.day/en/faq/youth-matches-cancelled): 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 
- [Should I check the 1-hour PM2.5 or the 24-hour PSI?](https://haze.day/en/faq/pm25-vs-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 i
- [What should I do at home during haze?](https://haze.day/en/faq/at-home): 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, incens
- [What is PM2.5 and why does it matter?](https://haze.day/en/faq/what-is-pm25): PM2.5 is airborne particles smaller than 2.5 micrometres, measured in micrograms per cubic metre (µg/m³). They are small enough to be breath
- [What do NEA's PM2.5 bands and PSI bands mean?](https://haze.day/en/faq/nea-bands): 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, 
- [Who counts as vulnerable in haze?](https://haze.day/en/faq/who-is-vulnerable): NEA's guidance singles out the elderly, pregnant women, children, and people with chronic lung disease or heart disease. They should avoid s
- [Which mask works in haze, and do I need one?](https://haze.day/en/faq/n95-masks): A well-fitted N95, KN95 or FFP2 respirator filters fine smoke particles; ordinary surgical masks do not filter them well. Most healthy peopl
- [When are schools closed because of haze?](https://haze.day/en/faq/school-closures): Each government and school decides. Singapore's Haze Task Force said school closures would be considered when the next-day air-quality forec
- [How long will the haze last?](https://haze.day/en/faq/how-long-haze): 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 n
- [Does rain clear haze?](https://haze.day/en/faq/does-rain-help): 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 burnin
- [Why do apps show different numbers: US AQI, Singapore PSI and Malaysia API?](https://haze.day/en/faq/aqi-vs-psi-vs-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 al
- [Do air purifiers help during haze?](https://haze.day/en/faq/air-purifier): A HEPA purifier sized for the room removes fine particles and can noticeably lower indoor PM2.5, especially with windows closed. It does not

## Why is it hazy? (causes, with live data)
- [Fires in central Sumatra (Riau and Jambi) and Singapore's haze](https://haze.day/en/why/fires-central-sumatra): Central Sumatra, mainly Riau and Jambi, lies about 280 km south-west of Singapore. When fires there are active and the wind blows from the s
- [Fires in South Sumatra and Singapore's haze](https://haze.day/en/why/fires-south-sumatra): South Sumatra is roughly 550 km south of Singapore. It is a major fire region in dry years; southerly winds, which are common in the dry sea
- [Fires in Kalimantan and Singapore's haze](https://haze.day/en/why/fires-kalimantan): Kalimantan (Indonesian Borneo) is more than 1,000 km east of Singapore. Its smoke tends to reach Singapore and Malaysia when winds blow from
- [How wind carries smoke to Singapore](https://haze.day/en/why/wind-transport): Smoke travels with the wind at roughly 1–2 km altitude, not at ground level. If that wind blows from a fire region toward you, haze can arri
- [Dry weather and El Niño: why haze years happen](https://haze.day/en/why/dry-weather-el-nino): Hazy years follow dry years. El Niño and a positive Indian Ocean Dipole reduce rainfall over Indonesia, which dries peat and forest so fires
- [Why peat fires make such dense haze](https://haze.day/en/why/peat-fires): Peat is partly decayed plant matter stored in waterlogged soil. Once drained it can burn and smoulder underground for weeks, releasing far m
- [Does rain clear haze? What showers can and cannot do](https://haze.day/en/why/rain-washout): Rain helps: it washes fine particles out of the air and can dampen fires. But a short shower rarely ends a haze episode, because new smoke k

## Data sources (what each is, how often it updates, its limits)
- [NEA 1-hour PM2.5 readings (Singapore)](https://haze.day/en/sources/nea-pm25): The official hourly concentration of fine particles (PM2.5, µg/m³) for Singapore's five regions, published by NEA. It is the reading most sp
- [NEA 24-hour PSI (Singapore)](https://haze.day/en/sources/nea-psi): The Pollutant Standards Index: a 24-hour rolling index combining six pollutants. NEA uses it for health advice about the next day, rather th
- [haze.gov.sg regional haze situation and outlook](https://haze.day/en/sources/haze-gov-outlook): A short daily text on the regional hotspot and smoke-haze situation plus a multi-day weather and haze outlook, shown on haze.gov.sg.
- [ASEAN Specialised Meteorological Centre (ASMC)](https://haze.day/en/sources/asmc): The regional centre that monitors hotspots and smoke haze across ASEAN and issues haze outlooks and alerts. Its analyses are the basis of th
- [NASA FIRMS active-fire detections (VIIRS)](https://haze.day/en/sources/nasa-firms): Near-real-time satellite detections of active fires from the VIIRS instrument on the Suomi-NPP satellite. Each dot is a thermal anomaly, not
- [CAMS PM2.5 model via Open-Meteo](https://haze.day/en/sources/cams-model): A global atmospheric model that estimates PM2.5 everywhere and forecasts it for the next days. It is a model estimate, not a measurement, an
- [Open-Meteo weather forecast](https://haze.day/en/sources/open-meteo-weather): Free weather data used for visibility, wind, rain probability, temperature, humidity, UV, sunrise and sunset, and for wind at about 1.5 km a
- [Malaysia DOE APIMS / MyJAS](https://haze.day/en/sources/doe-apims): Malaysia's official Air Pollutant Index (API) reported hourly for about 68 stations, shown in the DOE's APIMS and the MyJAS app. It uses Mal
- [data.gov.sg real-time API](https://haze.day/en/sources/data-gov-sg): Singapore's open-data platform. NEA's PM2.5 and PSI readings are served from it as JSON, including hourly history by date.
- [RainViewer radar tiles](https://haze.day/en/sources/rainviewer): Composite weather-radar imagery used as an optional rain layer on the haze map, to see where rain is falling now.

## Data and tools
- [Haze map](https://haze.day/en/map): PM2.5 field, fires, wind, rain radar with a time slider
- [Haze news, compared across outlets](https://haze.day/en/news): headlines from Singapore, Malaysian and Indonesian outlets, linked to the publishers
- [Developers and JSON API](https://haze.day/en/developers): current reading, advice, trend, hotspots, news
- [Full text of all guides, FAQs and sources](https://haze.day/llms-full.txt)
- [Sitemap](https://haze.day/sitemap.xml)