GeoAnalitikSarawak had a station over API 100 on 41 of 45 recorded days, Selangor on 37, Johor and Negeri Sembilan on 35; counting fixed stations only, Sarawak falls to 38 and Selangor to 29.
The Department of Environment’s readings, station by station. 3 of 68 stations are mobile units, so every count is given both ways. Day counts are floors: DOE’s archive is missing all of 4 Sep and 67 other hours.
Figure 1. Each DOE station’s days over API 100: the darker the circle, the more days, counted on its worst hour of each day. Mobile units dashed and counted both ways; switch to the fixed stations to drop them. Pick a station, on the map, in the search or in a name below, for its count and the residents nearest it. Rings show the 50 km cutoff used to link residents to a station. Basemap: Protomaps, from OpenStreetMap. Readings: DOE APIMS. Residents: WorldPop.
On 32 days, 20 or more stations passed API 100 (28 on fixed stations); on 16 days a station passed 200 (11 on fixed stations)
Every row is one station, grouped by state from the Peninsula’s west coast, north to south, to its east coast, then Sabah, Sarawak and Labuan. Each cell is the station’s worst hour that day, in DOE’s band. The over-200 days rest partly on one unit: on 11–13 and 23–24 Sep only the IPD Serian mobile unit passed 200. Bands are DOE’s categories drawn in ink, not DOE’s colours. API is never mixed with PSI, ISPU or US AQI.
Good 0–50Moderate 51–100Unhealthy 101–200Very unhealthy 201–300Hazardous over 300No reading that day
Table 1. Each DOE station’s worst band per MYT day, 1 Sep – 16 Oct 2026, with its days over 100 beside its name. 4 Sep, missing at every station, is hatched, as is any other day a station sent no reading; a day with some hours missing is shaded from the hours it has. Tap or hover a cell for its band. Source: DOE APIMS. “Data dan maklumat tertakluk di bawah Terma Penggunaan Data Terbuka Kerajaan Malaysia 1.0” (https://www.doe.gov.my/wp-content/uploads/2021/07/TermaPenggunaan.pdf).
The highest hourly API in the archive is 454, at the IPD Serian mobile unit; the highest at a fixed station is 398 at Kuching, in the archive’s first hour
398 is not necessarily Kuching’s peak: the archive starts that hour. 521 was reported for 4 Sep, the day missing from our archive; it is the highest reported, not a measured maximum, and not our data.
| API | Station | When (MYT) | |
|---|---|---|---|
| 454 | IPD Serian (mobile unit) | 00:00, 5 Sep | Highest hourly API in the archive |
| 398 | Kuching | 10:00, 1 Sep | Highest at a fixed station; the archive’s first hour, so not necessarily the station’s peak |
Reported, not in our archive
| API | Station | When (MYT) | Reported by |
|---|---|---|---|
| 518 | IPD Serian (mobile unit) | 10 am, 4 Sep | Bernama, 4 Sep |
| 521 | IPD Serian (mobile unit) | 2 pm, 4 Sep | The Star, 4 Sep |
Table 2. The highest hourly reading in DOE’s archive, overall and at a fixed station, and the press readings for the missing day, with their outlets.
The Peninsula’s highest reading was 211 at Batu Pahat; Pasir Gudang stayed over 200 for 12 hours on 16 October, the Peninsula’s longest spell
| Peak API | Station | When (MYT) |
|---|---|---|
| 211 | Batu Pahat | 22:00, 6 Oct to 00:00, 7 Oct 3 hours at 211; longest spell over 200: 8 hours, 20:00, 6 Oct to 03:00, 7 Oct |
| 209 | Pasir Gudang | 10:00, 16 Oct 1 hour at 209; longest spell over 200: 12 hours, 05:00, 16 Oct to 16:00, 16 Oct |
| 202 | Larkin | 16:00, 16 Oct 1 hour at 202; over 200 for 1 hour, 16:00, 16 Oct |
| 198 | Johan Setia (mobile unit) | 07:00–08:00, 18 Sep 2 hours at 198; never over 200 |
| 195 | Klang | 17:00–18:00, 15 Oct 2 hours at 195; never over 200 |
Table 3. The five Peninsular stations with the highest peak readings in DOE’s archive, each with its peak and its longest unbroken run of hours over 200. Hourly readings, MYT.
IPD Serian and Johan Setia, both mobile units, were their states’ worst-reading stations, at 38 and 37 days over 100
The third mobile unit, Politeknik Kota Kinabalu (mobile unit), had 12 days, behind Tawau’s 13. Our sources do not say why DOE sited the units there. Readings at Johan Setia (mobile unit) may include local smoke: 3 of its 8 sole-station days had detections within 25 km that day or the day before.
| IPD Serian (mobile unit) | 38 | |
|---|---|---|
| Johan Setia (mobile unit) | 37 | |
| Nilai | 35 | |
| Samarahan | 33 | |
| Larkin | 33 | |
| Cheras | 32 | |
| Seremban | 31 | |
| Sri Aman | 31 | |
| Putrajaya | 31 | |
| Batu Pahat | 31 |
Figure 2. The ten stations with the most days over API 100, 1 Sep – 16 Oct 2026; mobile units dashed.
On 30 days, 10 million or more residents lived nearest a station over API 100, 654 million resident-days in all (29 days and 643 million on fixed stations only)
WorldPop 2020 residents within 50 km of their nearest station; 93.9% of residents are linked. People whose nearest station read over 100 that day, which says where the readings were, not what anyone breathed. Not a health outcome.
All stationsFixed stations only10 millionNo readings
- 1 Sep
- 26.5 m16 Sep
- 1 Oct
- 16 Oct
Figure 3. Residents nearest a station over API 100, per MYT day, 1 Sep – 16 Oct 2026: all stations (ink columns) and fixed stations only (grey ticks); m is million. The only per-day chart in this study. Residents: Bondarenko M., Kerr D., Sorichetta A., and Tatem, A.J. 2020, WorldPop, University of Southampton, UK. doi:10.5258/SOTON/WP00684 (CC BY 4.0), summed to 1 km by the study. WorldPop’s data are “not intended, and should not be used, for purposes that discriminate against, exploit, surveil, or otherwise harm individuals or vulnerable populations”.
Schools and clinics: what officials reported, state by state
Schools close under the Education Ministry’s (KPM) rule, which changed during the season: API over 200 until 8 Oct; over 180 from 9 Oct, and over 150 for three days from 12 Oct; back to 200 on 14–15 Oct. States also closed schools on their own orders. No official national count of closed schools or pupils was found. Health figures come from sentinel facilities, not a census.
| Figure | What it counts | Reported by | Date |
|---|---|---|---|
| Perak | |||
| 362 | schools closed in Kinta Utara, Kinta Selatan and Kuala Kangsar after Tasek Ipoh read API 180 at 11 am; 154,404 pupils | Bernama | 9 Oct |
| Several states | |||
| – | Education Minister’s order: every school in Johor, Melaka, Negeri Sembilan, Selangor, Kuala Lumpur and Putrajaya, plus Rompin district (Pahang), closed on 9 Oct; no national school or pupil count given | The Star | 8 Oct |
| – | every school in Johor, Melaka, Negeri Sembilan and Putrajaya closed on 13 Oct, plus four Selangor districts and Kuantan and Rompin (Pahang) | SAYS | 12 Oct |
| – | every school in Johor, Melaka and Negeri Sembilan closed on Wednesday, 14 Oct (the report gives the weekday only), plus districts in Selangor, Pahang, Sabah (Tawau) and Sarawak | Berita RTM | 13 Oct |
| Johor | |||
| 1,198 | schools closed statewide on 8–9 Oct by the Regent’s decree; 617,258 pupils (the state government’s count) | Malay Mail | 7 Oct |
| 2 days | all Johor schools shut on 8 and 9 Oct, the same decree as reported by a second outlet | The Star | 7 Oct |
| 5 days | statewide closure extended to 12–16 Oct by the Regent’s decree | Bernama | 10 Oct |
| Sabah | |||
| API 150 | Tawau district schools closed from 14 Oct after the API exceeded 150; the state secretary said that evening they closed from 13 Oct | Bernama | 13 Oct |
| Sarawak | |||
| 647 | schools under 12 district education offices to close 7–11 Sep, announced 4 Sep; 198,559 pupils (108,477 + 90,082) | The Borneo Post | 4 Sep |
| 710 | schools closed 7–11 Sep once the Bintulu and Tatau/Sebauh offices were added; 238,303 pupils (the study’s sums of the department’s figures) | Bernama | 5 Sep |
| – | Serian and Lubok Antu schools to stay closed until the API there falls below 200 | Bernama | 12 Sep |
| 3 districts | Serian, Sri Aman and Lubok Antu schools closed for one day, 14 Oct, after readings above 150 | The Star | 14 Oct |
| The closure rule (KPM) | |||
| API 180 | closes ministry schools from 9 Oct; over 150 for three days in a row closes them from 12 Oct | Berita RTM | 8 Oct |
| API 200 | schools close when the API exceeds 200, under the National Haze Action Plan (the Education Minister’s post) | Bernama | 14 Oct |
| API 200 | the same post in Bernama’s Malay report: “melebihi 200” (exceeds 200) | Bernama (BM) | 14 Oct |
| API 200 | KPM back on the National Haze Action Plan: schools close when the API “reaches” 200 | Malaysia Gazette | 15 Oct |
| API 200 | the same, in Bernama’s Malay report: “mencecah 200” (reaches 200) | Bernama (BM) | 15 Oct |
| API 200 | the Health Ministry: every educational institution closes if the API exceeds 200 | Bernama | 16 Oct |
| Health (MOH sentinel facilities, not a census) | |||
| 219 | asthma cases in epidemiological week 33 | Bernama | 23 Aug |
| 1,811 | asthma cases in week 34 (23–29 Aug) | New Straits Times (Bernama) | 29 Aug |
| 2,644 | URTI cases in week 35 (30 Aug – 5 Sep), at 78 sentinel facilities | Bernama (BM) | 15 Oct |
| 7,065 | URTI cases in week 36, the highest weekly count reported | New Straits Times | 22 Sep |
| 3,875 | URTI cases in week 40, in MOH’s statement of 10 Oct, issued on the week’s last day | Bernama | 10 Oct |
| 5,613 | URTI cases in week 40, the Health Minister’s later count in the Dewan Rakyat | Parliament of Malaysia (Dewan Rakyat Hansard, unrevised) | 15 Oct |
| 76 | sentinel facilities in MOH’s 27 Aug statement (58 health clinics and 18 hospital outpatient departments); later statements say 78 | Bernama | 27 Aug |
Table 4. Cited facts, each from one report; dates are the reports’ dates. Each outlet’s name links to its report.
Limits
- Day counts are floors: a day counts when any hour that day passed the line, and the archive lacks some hours.
- A station’s reading stands for the air at that station, not for its whole state or district.
- Residents are counted at their nearest DOE station within the cutoff; it is a link by distance, not a measured exposure.
- Press readings for the missing day are cited, not added to our counts.
- The study names no company or concession.
Data, method and credits
- Air quality: Department of Environment Malaysia (Jabatan Alam Sekitar), Air Pollutant Index Management System (APIMS), https://eqms.doe.gov.my/APIMS/main. “Data dan maklumat tertakluk di bawah Terma Penggunaan Data Terbuka Kerajaan Malaysia 1.0” (https://www.doe.gov.my/wp-content/uploads/2021/07/TermaPenggunaan.pdf).
- Residents: Bondarenko M., Kerr D., Sorichetta A., and Tatem, A.J. 2020, WorldPop, University of Southampton, UK. doi:10.5258/SOTON/WP00684 (CC BY 4.0). Summed to 1 km by the study.
- Basemap: Protomaps, © OpenStreetMap contributors, available under the Open Database License (ODbL).
- Schools and health: press and official statements, one row each in the study’s research file, with links.
- No credited source or agency endorses this study, and no figure here is official.
- Every licence, DOI and the method: Method and credits.