1001 Smart Cities
🇻🇳 Hanoi

Air Quality Monitoring Network

🤖 AI-generated summary of the sources below · 🔎 Last verified · ◆ 9 sourced claims, none individually verified yet

This overview was generated with AI from the public sources listed below and checked against them before publication. It has not had a complete human fact-check — treat it as a starting point and follow the sources.

How this atlas is made · What “last verified” means · What “source-checked” means · The full record behind this page

✎ Updated 21 Aug 2026 Publication date recorded for 5 sources. · 2 revisions in all What changed →

Hanoi publishes real-time air quality on its moitruongthudo.vn portal, from a network the city began building in 2016 with two reference-grade stations and eight sensor units. The inventory is larger than the reality: a 2024 stocktake counted 61 monitoring stations across state and private operators — 35 of them the city's — but only six are reference-grade fixed stations, only 18 released historical data, and a station lost on average 50 days of data a year. During a 17-day pollution episode in October 2024 several stations went dark, and when winter smog returned at the end of November 2025 the portal itself was unreachable because its domain registration had expired. No reading triggers anything automatic: the health ministry's advice to keep young children home on hazardous-air days is a recommendation, not a rule.

Live 📅 since 2016
Outcome🔄 Ongoing
Evidence📰 Mediagrades the sourcing — this entry states no impact figure
what does this mean?The strongest source is press reporting; no primary evaluation was located. It grades who did the looking — not how well the project went. All four grades →
Run byHanoi People's Committee (city environment authority) for the city stations; national ministry, the U.S. Embassy and private networks run the rest
Scale🏙️ City-wide

🎓 Lesson

Count the stations that publish, not the ones installed: Hanoi's 61-station inventory shrinks to 18 that release their data — and the worst smog weeks are exactly when stations and the portal itself have gone dark.

🌱 EnvironmentAir qualitySensors & IoT

Sources

↗ VnExpress — Hanoi's air quality data gapPublished 4 December 2025The load-bearing analysis (December 2025): 61 stations counted in 2024 (35 city-run, 6 reference-grade), only 18 publishing historical data, average 50 days of data lost per station per year (range 12–128), the 17-day October 2024 episode, and the network's 2016 origins.
↗ VnExpress International — monitoring portal offline during smogPublished 30 November 2025moitruongthudo.vn went offline during the late-November 2025 pollution spike because its domain registration had expired; AQI readings 197–282 that morning.
↗ moitruongthudo.vn — Hanoi air quality portalThe city's own real-time publication channel — the operator side of the entry; station list and live AQI per station.
↗ Tien Phong — why many Hanoi stations stopped workingCoverage of station outages: sensors past replacement age, maintenance suspensions from late 2021 through 2022, named stations offline. Existence verified via search results; site not fetched directly in this pass.
↗ Việt Nam News — health ministry proposal on school closuresPublished 9 January 2025The health ministry recommends kindergarten and primary pupils stay home when AQI stays hazardous (301–500) for three consecutive days — advice, with no automatic trigger attached.

📅 How old is the evidence?

Two clocks, kept apart: when this entry’s sources were published, and what has happened to its record in the atlas. Documented span: since 2016. 3 of 5 sources carry a publication date, from 9 January 2025 to 4 December 2025.

When the sources were published

  1. Việt Nam News · pressViệt Nam News — health ministry proposal on school closures
  2. VnExpress International · pressVnExpress International — monitoring portal offline during smog
  3. VnExpress · pressVnExpress — Hanoi's air quality data gap

Every source, with links ↑

What happened to this record

  1. Entered the record
  2. Sources last read
  3. Publication date recorded for 5 sources
  4. Publication date recorded for 5 sources

Every revision, permanent →

Show your work What this page rests on and what it can’t tell you · all 9 claims with their sources · the forensic record

Evidence Passport · public beta 9 addressable claims, 5 source dossiers, one permanent baseline. The passport is unreviewed — an AI-assisted structural migration, not a human or expert endorsement. Every revision keeps a permanent copy under revision history.

Inspect the claims, one by one — verbatim text, sources and caveats for all 9

The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.

Claim 1 clm-e30ddd5437683911 quantitative
a network the city began building in 2016 with two reference-grade stations and eight sensor units
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The analysis dates the city's own investment to 2016: ten stations, of which two fixed reference-grade and eight sensor stations.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. VnExpress — Hanoi's air quality data gap
Claim 2 clm-860d8bb9ac5ef582 quantitative
a 2024 stocktake counted 61 monitoring stations across state and private operators — 35 of them the city's
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The stocktake counts 61 stations in 2024: 37 state-managed (35 under the Hanoi People's Committee, two under the national ministry and the U.S. Embassy) plus 22 private and international.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. VnExpress — Hanoi's air quality data gap
Claim 3 clm-db0853020eb11a8a descriptive
only six are reference-grade fixed stations
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Only six fixed stations meet reference-grade criteria; the rest are low-cost sensors with lower reliability.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. VnExpress — Hanoi's air quality data gap
Claim 4 clm-4b5b146cb61e78b5 quantitative
only 18 released historical data
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Of the 61 stations, only 18 publicly released historical data in 2024.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. VnExpress — Hanoi's air quality data gap
Claim 5 clm-ba728762ab2f25c4 quantitative
a station lost on average 50 days of data a year
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The analysis puts average data loss at 50 days per station per year, ranging from 12 to 128 days.
Caveat
An average across the stations that publish at all; the range runs from 12 to 128 days.

Sources carrying this claim

  1. VnExpress — Hanoi's air quality data gap
Claim 6 clm-1dba31767c2886ae quantitative
During a 17-day pollution episode in October 2024 several stations went dark
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The analysis records a severe 17-day episode in October 2024 during which multiple stations went offline or withheld data.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. VnExpress — Hanoi's air quality data gap
Claim 7 clm-21b883404447dbcb descriptive
the portal itself was unreachable because its domain registration had expired
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Both reports document that moitruongthudo.vn went offline during the late-November 2025 smog because the domain registration had expired; it was later restored.
Caveat
The portal was restored; the outage lasted through the morning of the pollution spike.

Sources carrying this claim

  1. VnExpress International — monitoring portal offline during smog
  2. VnExpress — Hanoi's air quality data gap
Claim 8 clm-a4203340865c4e12 descriptive
the health ministry's advice to keep young children home on hazardous-air days is a recommendation, not a rule
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The ministry recommends that kindergarten and primary pupils stay home when AQI stays hazardous (301–500) for three consecutive days — guidance to schools and parents, with no automatic mechanism attached.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Việt Nam News — health ministry proposal on school closures
Claim 9 clm-baedd99c6b7635b5 quantitative
61-station inventory shrinks to 18 that release their data
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Restates the stocktake's central finding: 61 stations counted, 18 publishing historical data.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. VnExpress — Hanoi's air quality data gap
Forensic record — source dossiers, gaps, hashes and the exact revision this page renders

This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.

unreviewed Revision 2026-08-20-source-dates-r2 effective 2026-08-15 · created 2026-08-21

Awaiting operator and domain-expert review; publication of this revision implies neither.

sha256:1875b87d3b04c6b05bbe3fc10543f0da31d4d12ae77daadc8b401d5c20644fa9
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
9
of 9 claims mapped
5
source dossiers
3
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
Hanoi People's Committee (city environment authority) for the city stations; national ministry, the U.S. Embassy and private networks run the rest
Actor types
city-government, national-government
Funding model
public
Funding description
Not recorded
Cost
Not recorded
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

5 source dossiers

VnExpress — Hanoi's air quality data gap vnexpress.net · 8 linked claims

Open original source ↗

Stable source ID
src-c99189602536fe7b
Publisher
Name not classified · vnexpress.net
Type / language
web-page · language not classified
Published
2025-12-04
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-15
Dossier created
2026-08-21
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The load-bearing analysis (December 2025): 61 stations counted in 2024 (35 city-run, 6 reference-grade), only 18 publishing historical data, average 50 days of data lost per station per year (range 12–128), the 17-day October 2024 episode, and the network's 2016 origins.

Descriptive only — not page/paragraph exact
Claims linked
VnExpress International — monitoring portal offline during smog e.vnexpress.net · 1 linked claim

Open original source ↗

Stable source ID
src-84ed42c16642798c
Publisher
Name not classified · e.vnexpress.net
Type / language
web-page · language not classified
Published
2025-11-30
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-15
Dossier created
2026-08-21
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

moitruongthudo.vn went offline during the late-November 2025 pollution spike because its domain registration had expired; AQI readings 197–282 that morning.

Descriptive only — not page/paragraph exact
Claims linked
moitruongthudo.vn — Hanoi air quality portal moitruongthudo.vn · background

Open original source ↗

Stable source ID
src-5a73e4ea55b8c902
Publisher
Name not classified · moitruongthudo.vn
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-15
Dossier created
2026-08-21
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The city's own real-time publication channel — the operator side of the entry; station list and live AQI per station.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Tien Phong — why many Hanoi stations stopped working tienphong.vn · background

Open original source ↗

Stable source ID
src-f30703261422a660
Publisher
Name not classified · tienphong.vn
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-15
Dossier created
2026-08-21
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Coverage of station outages: sensors past replacement age, maintenance suspensions from late 2021 through 2022, named stations offline. Existence verified via search results; site not fetched directly in this pass.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Việt Nam News — health ministry proposal on school closures vietnamnews.vn · 1 linked claim

Open original source ↗

Stable source ID
src-c517c7d1d012dd27
Publisher
Name not classified · vietnamnews.vn
Type / language
web-page · language not classified
Published
2025-01-09
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-15
Dossier created
2026-08-21
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The health ministry recommends kindergarten and primary pupils stay home when AQI stays hazardous (301–500) for three consecutive days — advice, with no automatic trigger attached.

Descriptive only — not page/paragraph exact
Claims linked
Known limits of this passport
  • Publisher names and source languages have not yet been classified; domains are recorded without guessing.
  • Existing source notes are descriptive locators, not page- or paragraph-exact citations.
  • A missing archive, publication date or content hash is shown as null rather than inferred.
  • The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim.

Continue exploring

Compare this project

🇮🇩 Court-Ordered Air Quality Monitoring · Jakarta Jakarta's court-won network also triggers nothing automatically — the same rung Hanoi's advisory readings sit on. 🇮🇳 GRAP: Air Quality Readings as a Legal Trigger · New Delhi The contrast: in Delhi a measured AQI has legal force and triggers restrictions automatically — in Hanoi the number carries advice. 🇻🇳 iHanoi Citizen App · Hanoi Two Hanoi portals going opposite ways: the air site lapsed with its own domain, the complaint map now names wards that miss deadlines.

Explore the wider context

📟 A Reading Is Not a Decision🌫️ Air quality guide🏙️ Hanoi city profile🌱 Environment projects📖 Air quality index (AQI)📖 Low-emission zone📖 Urban sensor network
📎 Cite this project

1001 Smart Cities (2026). “Air Quality Monitoring Network” — Hanoi, Vietnam. The Smart City Atlas. https://1001smartcities.org/projects/hanoi-air-quality-monitoring/ (last verified 2026-08-15). Data: CC BY 4.0.

The underlying data is free to reuse with attribution — see the open data page.

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