Haze guides

Short guides to the API, what causes haze and when, N95 masks, air purifiers, and the API level that closes schools.

• What is the API, and what do the numbers mean?The Air Pollutant Index is published hourly by Malaysia's Department of Environment. Here is what each band means and what to do at each one.2 min read
• Haze in Malaysia: the causes, the season, and when it clearsWhy haze returns most years, which months are worst, and what decides whether an episode persists or breaks.2 min read
• PM2.5 and PM10: the difference, and which one to worry aboutThe two particles behind almost every Malaysian API reading, why size decides the harm, and how a concentration becomes an index number.2 min read
• What API closes schools in Malaysia? The number that decidesSince October 2026, schools close when the API goes above 180, or stays above 150 for three days in a row. When outdoor activity stops, who makes the call, and where the official word appears.2 min read
• API or AQI? Why other apps show a different numberMalaysia publishes the API; most international apps show the US AQI. The same concentration can produce two very different numbers. Here is why.2 min read
• N95 masks for haze: how to choose one and wear itWhy cloth and surgical masks do not help in haze, what makes an N95 different, and why fit matters more than the brand on the box.2 min read
• Air purifiers for haze: what matters, and what does notThe filter you actually need, how to match the machine to the room with CADR, and the features that only add to the price.2 min read
• Air quality near me: which DOE station covers your area?Bangsar, Sunway, Puchong, Skudai, Butterworth and many other areas have no station of their own. Here is the nearest Department of Environment station, and how far it is.2 min read
• Haze, children and babies: what parents need to knowWhy children are more exposed to haze, why N95 masks do not suit them, how to keep the air clean at home, and the signs that need a doctor.2 min read
• Is it safe to exercise outdoors in the haze? The API levels to followRunning, cycling and outdoor sport during haze: the API levels the Ministry of Health and the National Sports Institute advise, and the signs to stop.2 min read
• Haze and high-risk groups: asthma, older people, heart disease, pregnancyWho is hit hardest by haze, what the Ministry of Health advises at each API level, and the warning signs that need a doctor or 999.2 min read
• DIY air purifier: the Corsi–Rosenthal box for hazeFour MERV 13 filters and a 20-inch box fan clean haze smoke as well as a commercial purifier, for a fraction of the cost. How to build one, and how to use it safely.3 min read
• Malaysia's haze history: 1997, 2005, 2013, 2015, 2019 and 2026The peak readings, the emergencies declared and the schools closed in each of Malaysia's major haze episodes, from Kuching's 839 in 1997 to the 2026 episode.4 min read