1001 Smart Cities
🇲🇽 Mexico City

SIMAT Air Monitoring and the Valley of Mexico Contingency Programme

🤖 AI-generated summary · ◆ 1 sourced claim · 🔎 Last verified

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.

1 sourced claim on this page, none individually verified yet — turn on “Sources in the text” to see each one.

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A reading of 155 ppb of ozone doubles the driving ban, halts building on sites over 5,000 square metres and caps a refinery at 75%. Peer-reviewed work finds that driving ban does not clean the air.

Outcome🔄 Ongoing
Evidence🔬 Peer-reviewed
what does this mean?The strongest source behind this entry is an independent peer-reviewed or academic study. It grades who did the looking — not how well the project went. All four grades →
Run bySIMAT / SEDEMA Mexico City (monitoring); CAMe, Comision Ambiental de la Megalopolis (declares contingencies)
Scale🗺️ Regional

Part of 1001 Smart Cities — 1,167 documented projects · 🏙️ 7 more in Mexico City · 🌫️ Air quality guide · 🌱 Environment projects

Mexico City has sampled its air since 1966 and has run the automatic RAMA network since 1986, when 25 stations began reporting ozone, carbon monoxide, sulphur dioxide and nitrogen oxides hourly. Since 2016 a reading of 155 ppb of ozone triggers a Phase I contingency, declared not by the city but by CAMe, the federal-state commission for the metropolitan area. The declaration binds: the Hoy No Circula ban doubles from 05:00 to 22:00, factories must cut ozone-precursor emissions by 40%, sites over 5,000 square metres stop building, and the Tula refinery is capped at 75% of process capacity. Whether the emergency lever itself works is contested.

Live 📅 since 1986

📊 Impact

Particulate pollution across Mexico City has fallen 60.4% since the 1990 ProAire programme began, which AQLI (University of Chicago) puts at 3.3 years of life expectancy — but that is the long-run policy mix (unleaded fuel, catalytic converters, fuel switching, transit), not the contingency mechanism. The Phase I ozone trigger has only ever been tightened, from 180 to 150 IMECA points in April 2016 and holding at 155 ppb since. On the emergency lever itself, peer-reviewed work finds no measurable air-quality benefit: the Saturday extension of Hoy No Circula had no discernible effect across eight pollutants, and drivers responded by buying second, older cars.

🎓 Lesson

A measured value with legal force is only as good as the lever it pulls. Mexico City has the oldest such trigger in the atlas and has never loosened it — yet the peer-reviewed evidence says the driving ban it reaches for does not clean the air.

🌱 EnvironmentAir qualitySensors & IoTOpen dataHealth & careTraffic management

Sources

↗ SIMAT — Direccion de Monitoreo Atmosferico, SEDEMA CDMX (operator)Operator site for the network and the hourly index. Returned 503 to automated fetching throughout this review; content verified indirectly. Do not cite a data licence from it — none was readable.
↗ La situacion actual del sistema de monitoreo ambiental en la ZMVM — Investigaciones Geograficas, UNAM (peer-reviewed)Published December 2009Network history: 'En 1966 ... se instalo la primera red de monitoreo con 4 estaciones con equipos manuales'; 'En 1986 se inicio la operacion de la Red Automatica de Monitoreo Atmosferico (RAMA) con 25 estaciones y equipos automaticos para medir monoxido de carbono, dioxido de azufre, oxidos de nitrogeno y ozono' (In 1966 the first monitoring network was installed with 4 manual stations; in 1986 RAMA began operating with 25 automatic stations measuring CO, SO2, NOx and ozone).
↗ Acuerdo — Programa para Prevenir y Responder a Contingencias Ambientales Atmosfericas en la ZMVM, Periodico Oficial del Estado de Mexico, 28 May 2019 (instrument)The governing instrument, published the same day in the Gaceta Oficial de la CDMX and the Periodico Oficial del Estado de Mexico. File exists at this URL; direct fetch returned 503 during review, so the thresholds and measures below are sourced from the CAMe communiques that apply it.
↗ Contingencias ambientales en el valle de Mexico: guia basica — Grupo Animal (independent explainer)Published 22 March 2026Threshold, verbatim: Phase I activates at 'concentraciones de ozono superiores a 155 ppb (partes por billon)' (ozone concentrations above 155 ppb), against an air-quality standard of 'no rebasar 90 partes por billon, durante una hora'. Also documents that the trigger has been progressively lowered since 1990, never raised.
↗ Se mantiene la Fase I de contingencia ambiental en ZMVM — News Report MX, reproducing the CAMe communique (press)Published 13 February 2026The mandatory measures, verbatim from the CAMe communique: industry 'reduciran el 40% de sus emisiones de precursores de ozono' (will cut ozone-precursor emissions by 40%); the Miguel Hidalgo refinery at Tula 'no operara a mas del 75% de capacidad del total de proceso'; the Francisco Perez Rios thermoelectric plant 'Reduccion del 30% del consumo de combustoleo'; private vehicles off the road 'de las 5:00 a las 22:00 horas'.
Show 5 more sourcesShow fewer
↗ Activan contingencia ambiental por ozono en la ZMVM: restricciones y doble Hoy No Circula — TV Azteca (press)Published 8 January 2026Declaring body and a worked example: the 'Comision Ambiental de la Megalopolis (CAMe)' activated Phase 1 on a 'concentracion maxima de ozono' of 160 ppb at the Cuajimalpa (CUA) station, banning hologram 2 vehicles outright plus hologram 1 and 0/00 by plate digit, 05:00 to 22:00.
↗ Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City — Davis, Scientific Reports (2017) (peer-reviewed)Published 2 February 2017Finds the Saturday expansion of Hoy No Circula had virtually no discernible effect on pollution across eight major pollutants, against ex-ante predictions of a 15%+ emissions cut. nature.com blocked automated fetching (auth redirect); finding confirmed at title and abstract level.
↗ Driving Restriction and Air Quality in Mexico City — Resources for the Future, on Davis, Journal of Political Economy (2008) (independent)Published 18 August 2008Verbatim: 'When hourly air pollution records from monitoring stations were examined, they showed no evidence that the program has improved air quality'; mechanism: 'no one got out of their cars. Instead, the evidence indicates that HNC has led to an increase in the total number of vehicles in circulation', many of them high-emission used imports.
↗ Mexico City: ProAire (1990) — Air Quality Life Index, EPIC, University of Chicago (independent)Published 23 August 2023 archived copyVerbatim: 'particulate pollution has declined by 60.4% since the introduction of the 1990 ProAire policies'; 'In terms of life expectancy, that implies a difference of 3.3 years'. AQLI credits the ProAire policy sequence (catalytic converters, unleaded petrol, fuel switching, transit), not the contingency programme.
↗ Spatio-Temporal Representativeness of Air Quality Monitoring Stations in Mexico City — Frontiers in Public Health (2020) (peer-reviewed)Published 9 November 2020Independent test of network coverage over 49 SIMAT stations and nine pollutants, 2009-2018. Verbatim: 'the distribution and the number of the monitoring stations is sufficient to evaluate the majority of pollutants, with the exception of sulfur dioxide (SO2)', where the shortfall is 'constrained to the southern part' of the city.

📅 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 1986. 8 of 10 sources carry a publication date, from 18 August 2008 to 22 March 2026.

When the sources were published

  1. Resources for the Future (RFF) · researchDriving Restriction and Air Quality in Mexico City — Resources for the Future, on Davis, Journal of Political Economy (2008) (independent)
  2. SciELO México · researchLa situacion actual del sistema de monitoreo ambiental en la ZMVM — Investigaciones Geograficas, UNAM (peer-reviewed)
  3. Springer Nature · researchSaturday Driving Restrictions Fail to Improve Air Quality in Mexico City — Davis, Scientific Reports (2017) (peer-reviewed)
  4. Frontiers · researchSpatio-Temporal Representativeness of Air Quality Monitoring Stations in Mexico City — Frontiers in Public Health (2020) (peer-reviewed)
  5. Energy Policy Institute at the University of Chicago (EPIC) · researchMexico City: ProAire (1990) — Air Quality Life Index, EPIC, University of Chicago (independent)
  6. TV Azteca · pressActivan contingencia ambiental por ozono en la ZMVM: restricciones y doble Hoy No Circula — TV Azteca (press)
  7. News Report MX · pressSe mantiene la Fase I de contingencia ambiental en ZMVM — News Report MX, reproducing the CAMe communique (press)
  8. Grupo Animal · pressContingencias ambientales en el valle de Mexico: guia basica — Grupo Animal (independent explainer)

Every source, with links ↑

What happened to this record

  1. Sources last read
  2. Entered the record

Every revision, permanent →

Show your work What this page rests on and what it can’t tell you · all 1 claims with their sources · the forensic record

Evidence Passport · public beta 1 addressable claim, 10 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 1

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-5887d055c8893288 quantitative
Particulate pollution across Mexico City has fallen 60.4% since the 1990 ProAire programme began, which AQLI (University of Chicago) puts at 3.3 years of life expectancy
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
No support note recorded
Caveat
The impact itself notes this is the long-run policy mix (unleaded fuel, catalytic converters, fuel switching, transit), not the contingency mechanism, whose emergency lever shows no measurable air-quality benefit in peer-reviewed work.

Sources carrying this claim

  1. Mexico City: ProAire (1990) — Air Quality Life Index, EPIC, University of Chicago (independent)
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 effective 2026-07-26 · created 2026-08-20

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

sha256:df26edbf23c8f69eb2dba9f4e8fc5c1ca9a6877ddd566abafefd26eb1301eb15
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
1
of 1 claims mapped
10
source dossiers
8
publication dates recorded
1
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
SIMAT / SEDEMA Mexico City (monitoring); CAMe, Comision Ambiental de la Megalopolis (declares contingencies)
Actor types
city-government, regional-government
Funding model
public
Funding description
Not recorded
Cost
Not recorded
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

10 source dossiers

SIMAT — Direccion de Monitoreo Atmosferico, SEDEMA CDMX (operator) aire.cdmx.gob.mx · background

Open original source ↗

Stable source ID
src-47984d6448b0a1d5
Publisher
Name not classified · aire.cdmx.gob.mx
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Operator site for the network and the hourly index. Returned 503 to automated fetching throughout this review; content verified indirectly. Do not cite a data licence from it — none was readable.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
La situacion actual del sistema de monitoreo ambiental en la ZMVM — Investigaciones Geograficas, UNAM (peer-reviewed) scielo.org.mx · background

Open original source ↗

Stable source ID
src-201abc1db9283292
Publisher
Name not classified · scielo.org.mx
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Network history: 'En 1966 ... se instalo la primera red de monitoreo con 4 estaciones con equipos manuales'; 'En 1986 se inicio la operacion de la Red Automatica de Monitoreo Atmosferico (RAMA) con 25 estaciones y equipos automaticos para medir monoxido de carbono, dioxido de azufre, oxidos de nitrogeno y ozono' (In 1966 the first monitoring network was installed with 4 manual stations; in 1986 RAMA began operating with 25 automatic stations measuring CO, SO2, NOx and ozone).

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Acuerdo — Programa para Prevenir y Responder a Contingencias Ambientales Atmosfericas en la ZMVM, Periodico Oficial del Estado de Mexico, 28 May 2019 (instrument) legislacion.edomex.gob.mx · background

Open original source ↗

Stable source ID
src-0b5472fb6f78d2eb
Publisher
Name not classified · legislacion.edomex.gob.mx
Type / language
pdf · language not classified
Published
2019-05-28
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The governing instrument, published the same day in the Gaceta Oficial de la CDMX and the Periodico Oficial del Estado de Mexico. File exists at this URL; direct fetch returned 503 during review, so the thresholds and measures below are sourced from the CAMe communiques that apply it.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Contingencias ambientales en el valle de Mexico: guia basica — Grupo Animal (independent explainer) grupoanimal.mx · background

Open original source ↗

Stable source ID
src-bc3793a4e4b7745a
Publisher
Name not classified · grupoanimal.mx
Type / language
web-page · language not classified
Published
2026-03-22
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Threshold, verbatim: Phase I activates at 'concentraciones de ozono superiores a 155 ppb (partes por billon)' (ozone concentrations above 155 ppb), against an air-quality standard of 'no rebasar 90 partes por billon, durante una hora'. Also documents that the trigger has been progressively lowered since 1990, never raised.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Se mantiene la Fase I de contingencia ambiental en ZMVM — News Report MX, reproducing the CAMe communique (press) newsreportmx.com · background

Open original source ↗

Stable source ID
src-607e83083d5487b0
Publisher
Name not classified · newsreportmx.com
Type / language
web-page · language not classified
Published
2026-02-13
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The mandatory measures, verbatim from the CAMe communique: industry 'reduciran el 40% de sus emisiones de precursores de ozono' (will cut ozone-precursor emissions by 40%); the Miguel Hidalgo refinery at Tula 'no operara a mas del 75% de capacidad del total de proceso'; the Francisco Perez Rios thermoelectric plant 'Reduccion del 30% del consumo de combustoleo'; private vehicles off the road 'de las 5:00 a las 22:00 horas'.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Activan contingencia ambiental por ozono en la ZMVM: restricciones y doble Hoy No Circula — TV Azteca (press) tvazteca.com · background

Open original source ↗

Stable source ID
src-6202143141e6282f
Publisher
Name not classified · tvazteca.com
Type / language
web-page · language not classified
Published
2026-01-08
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Declaring body and a worked example: the 'Comision Ambiental de la Megalopolis (CAMe)' activated Phase 1 on a 'concentracion maxima de ozono' of 160 ppb at the Cuajimalpa (CUA) station, banning hologram 2 vehicles outright plus hologram 1 and 0/00 by plate digit, 05:00 to 22:00.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City — Davis, Scientific Reports (2017) (peer-reviewed) nature.com · background

Open original source ↗

Stable source ID
src-142cf226d14bd860
Publisher
Name not classified · nature.com
Type / language
web-page · language not classified
Published
2017-02-02
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Finds the Saturday expansion of Hoy No Circula had virtually no discernible effect on pollution across eight major pollutants, against ex-ante predictions of a 15%+ emissions cut. nature.com blocked automated fetching (auth redirect); finding confirmed at title and abstract level.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Driving Restriction and Air Quality in Mexico City — Resources for the Future, on Davis, Journal of Political Economy (2008) (independent) resources.org · background

Open original source ↗

Stable source ID
src-d95c6fcb1d70fd51
Publisher
Name not classified · resources.org
Type / language
web-page · language not classified
Published
2008-08-18
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Verbatim: 'When hourly air pollution records from monitoring stations were examined, they showed no evidence that the program has improved air quality'; mechanism: 'no one got out of their cars. Instead, the evidence indicates that HNC has led to an increase in the total number of vehicles in circulation', many of them high-emission used imports.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
Mexico City: ProAire (1990) — Air Quality Life Index, EPIC, University of Chicago (independent) aqli.epic.uchicago.edu · 1 linked claim

Open original source ↗

Stable source ID
src-4bb2673671ea07ec
Publisher
Name not classified · aqli.epic.uchicago.edu
Type / language
web-page · language not classified
Published
2023-08-23
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
Open archived copy ↗ · 2026-07-08
Content hash
No captured content hash
Locator
Open the recorded source note

Verbatim: 'particulate pollution has declined by 60.4% since the introduction of the 1990 ProAire policies'; 'In terms of life expectancy, that implies a difference of 3.3 years'. AQLI credits the ProAire policy sequence (catalytic converters, unleaded petrol, fuel switching, transit), not the contingency programme.

Descriptive only — not page/paragraph exact
Claims linked
Spatio-Temporal Representativeness of Air Quality Monitoring Stations in Mexico City — Frontiers in Public Health (2020) (peer-reviewed) frontiersin.org · background

Open original source ↗

Stable source ID
src-51adc4848f86f3cf
Publisher
Name not classified · frontiersin.org
Type / language
web-page · language not classified
Published
2020-11-09
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-07-26
Dossier created
2026-08-20
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Independent test of network coverage over 49 SIMAT stations and nine pollutants, 2009-2018. Verbatim: 'the distribution and the number of the monitoring stations is sufficient to evaluate the majority of pollutants, with the exception of sulfur dioxide (SO2)', where the shortfall is 'constrained to the southern part' of the city.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
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

🇲🇽 Hoy No Circula: Mexico City's Plate-Based Driving Restriction · Mexico City The lever this trigger pulls: a Phase I doubles the 1989 plate ban — and the peer-reviewed record says the ban never cleaned the air. 🇮🇳 GRAP: Air Quality Readings as a Legal Trigger · New Delhi Delhi gave an AQI reading legal force in 2017; Mexico City has measured hourly since 1986 and its ozone trigger has only tightened. 🇮🇩 Court-Ordered Air Quality Monitoring · Jakarta Jakarta's court-built network triggers nothing; Mexico City's 155 ppb halts large building sites and caps a refinery at 75%.

Explore the wider context

📟 A Reading Is Not a Decision📖 Air quality index (AQI)📖 Adaptive traffic signals📖 Automated speed enforcement (speed cameras)
📎 Cite this project

1001 Smart Cities (2026). “SIMAT Air Monitoring and the Valley of Mexico Contingency Programme” — Mexico City, Mexico. The Smart City Atlas. https://1001smartcities.org/projects/mexico-city-air-quality-contingency/ (last verified 2026-07-26). Data: CC BY 4.0.

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

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