carbon monoxide
Enable an AI agent to recognise carbon monoxide, assess its condition and presence in a specific context, and determine which handling, monitoring or transformation actions are supported by evidence.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise carbon monoxide, assess its condition and presence in a specific context, and determine which handling, monitoring or transformation actions are supported by evidence.
Carbon monoxide is a colourless, odourless diatomic gas (CO) produced by incomplete combustion of carbonaceous fuels and by industrial reduction chemistry; it binds ferrous haem to form carboxyhaemoglobin, impairing oxygen delivery at parts-per-million air levels, and is also an extremely flammable compressed gas.
It can be Request or interpret a CO-specific measurement while checking selectivity, calibration and sampling coverage.; Compare CO observations across time and location using compatible units and averaging intervals.; Trace observed CO to candidate formation, release and removal processes without treating correlation as confirmed attribution.; Assess proposed storage, transfer or use against documented CO-specific containment and mixture constraints.; Evaluate a proposed CO-consuming transformation through its reaction conditions, material balance and linked products.; Flag conditions requiring an applicable exposure or emergency procedure while preserving uncertainty and the authority for the decision..
Distinguishing features
Establish molecular identity as CO, with one carbon atom and one oxygen atom; carbon dioxide is CO2 and requires a separate identification.
Require analytical discrimination from nitrogen: a nominal molecular-mass signal near 28 alone does not uniquely identify CO.
Distinguish free CO from carbonyl groups and metal-bound carbonyl ligands; the presence of a C-O unit alone does not establish free carbon monoxide.
Distinguish CO concentration in a mixture from the identity of the mixture itself; synthesis gas and combustion exhaust are not synonyms for CO.
Do not use smell, visible smoke or their absence to confirm or exclude CO; recognition requires suitable measurement or other substantiated chemical evidence.
Scope
+ Chemical identity and evidence that an observed substance or mixture component is carbon monoxide
+ Physical state, amount, purity and composition of CO-bearing material
+ CO concentration and its variation across location and time
+ Formation, release, transport and consumption of CO
+ CO-specific exposure, combustion and handling constraints
- Complete composition and behaviour of flue gas, synthesis gas or other mixtures containing CO
- Design, maintenance and certification of detectors, cylinders and ventilation equipment
- Diagnosis and treatment of carbon monoxide poisoning
- Operation of engines, furnaces and industrial reactors that produce or consume CO
- Whole-building air quality and emergency-response management
Characteristics
- Chemical identity
- CO; confirmed, provisional or unresolved identification Prevents confusion with CO2, nitrogen, carbon-containing aerosols and chemically bound carbonyl groups.
- Occurrence form
- Nominally pure substance, gas-mixture component, dissolved CO or other evidenced occurrence Determines which sampling methods, quantity expressions and physical assumptions apply.
- Physical condition
- Phase with temperature in K or °C and absolute pressure in Pa or bar Supports interpretation of storage condition, density and gas-volume measurements.
- CO amount
- mol, kg or gas volume with stated reference temperature and pressure Supports inventory accounting and estimates of material available for release or reaction.
- CO concentration
- mol/mol, ppm by volume or mg/m³, with wet/dry basis and relevant reference conditions Makes observations comparable and prevents unsupported conversions between concentration expressions.
- Observation support
- Measurement method, calibration evidence, sampling location, observation time, averaging interval and uncertainty Determines whether a reported value supports identification, trend assessment or a decision.
- Associated mixture constituents
- Links to measured or suspected co-constituents, including oxygen where relevant Mixture composition affects measurement interference, reactions and combustion assessment.
- Formation or release source
- Linked source or process with suspected, supported or confirmed attribution Separates detecting CO from establishing why it is present and whether it may continue to accumulate.
- Production or removal rate
- mol/s or mass/time, with process boundary and time interval Distinguishes an isolated inventory from ongoing formation, leakage or consumption.
- Exposure context
- Linked occupied environment or exposed organism, with concentration history and duration where known A concentration without exposure context is insufficient for evaluating consequences or applicable actions.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
CO identity and occurrence Establishes whether CO is present and what material occurrence the model describes.
An agent must distinguish the molecule from similar analytical signals, related compounds and mixtures that contain it.
Molecular identification
Connects a CO identification to evidence capable of discriminating relevant alternatives.
Selective evidence for CO
Records the identification method, its limitations and competing explanations for the observed signal.
- What evidence identifies CO rather than CO2, nitrogen or an interfering constituent? definition
- Which analytical method and reference or calibration evidence support that identification? provenance
Free CO and host material
Separates CO itself from its carrier mixture and from chemically bound carbonyl species.
Occurrence boundary
Identifies whether the subject is pure CO, a CO component or dissolved CO, and links the surrounding material.
- Is the subject free CO, dissolved CO or a chemically bound species requiring a neighbouring model? boundary
- Which sample, stream or material contains the CO, and what establishes that association? provenance
CO condition and quantity Describes the physical condition and amount of CO within an explicit material boundary.
Inventory, concentration and physical condition answer different questions and cannot safely substitute for one another.
Phase and inventory
Records the conditions needed to interpret the amount of CO held or moving through a system.
Conditioned CO amount
Associates CO amount and phase with the pressure, temperature and boundary to which they apply.
- What amount of CO is present within the stated container, sample or process boundary? measurement
- What phase, temperature and absolute pressure apply, and are reported gas volumes actual or referenced? measurement
Mixture composition
Describes the fraction of CO and relevant co-constituents without taking ownership of the entire mixture.
Comparable CO concentration
Preserves concentration basis and the mixture information needed for interpretation.
- What is the CO concentration, including units, wet or dry basis and conditions required for conversion? measurement
- Which co-constituents or impurities materially affect the proposed measurement, handling or use? boundary
CO detection and exposure Connects CO observations to their spatial and temporal coverage and any relevant exposure context.
A single detector reading does not establish all concentrations in an environment or the exposure history of an organism.
Measurement coverage
Records what a CO observation can resolve and where its evidence ends.
Bounded detector observation
Captures sampling location, response characteristics and limitations affecting a CO reading or nondetection.
- Where and when was CO sampled, over what averaging interval, and with what detection limit and uncertainty? measurement
- Could sensor interference, saturation, response delay or sampling placement limit this observation? boundary
Exposure interpretation
Links ambient CO evidence to exposure assessment while leaving diagnosis to the appropriate model.
Exposure evidence and action basis
Separates measured environmental CO, inferred exposure and biological evidence, and identifies the applicable decision rule.
- What concentration history, duration and occupancy evidence support the exposure assessment, and what remains unknown? measurement
- Which authoritative procedure or exposure criterion applies to this setting and averaging interval? action
CO formation and fate Explains the evidenced pathways by which CO enters, moves through and leaves the relevant system.
An agent must distinguish ongoing production from residual presence and chemical consumption from simple relocation.
Formation and release
Links CO presence to candidate generating processes or releases from existing inventories.
Attributed CO input
Records evidence for combustion-related formation, other chemical generation or leakage without assuming a source from detection alone.
- Which process or inventory could supply this CO, and what evidence supports the attribution? provenance
- Is CO input continuing, intermittent or ended, and what rate or temporal evidence establishes that state? measurement
Transport and consumption
Distinguishes movement and dilution of CO from reactions that consume it.
Accounted CO fate
Tracks whether CO leaves a boundary, changes concentration through mixing or is converted into other substances.
- Does the observed decrease reflect transport, dilution, sampling effects or evidenced chemical consumption? boundary
- For a proposed CO-consuming reaction, what conditions, products and material balance establish the expected outcome? action
CO handling and reactivity Records CO-specific constraints on containment, transfer and intentional chemical use.
Actions involving CO depend on toxicity, combustible-mixture conditions and the verified capabilities of the surrounding system.
Containment and transfer
Relates the actual CO-bearing material to documented equipment and handling constraints.
Supported CO handling
Identifies the evidence required to support storage or transfer under the actual composition, pressure and temperature.
- What documented compatibility and operating limits apply to the equipment contacting this CO-bearing material? provenance
- Which containment, leak-monitoring and release-control requirements must be satisfied before the proposed transfer or use? action
Combustible mixture conditions
Evaluates CO combustion potential in relation to oxidant availability and the actual operating conditions.
Contextual CO combustion assessment
Keeps combustion assessment separate from exposure assessment and ties it to an evidenced mixture and operating envelope.
- What CO and oxidant concentrations, temperature, pressure and ignition conditions characterize the proposed operation? measurement
- Which validated combustion data and operating procedure support allowing, restricting or stopping that operation? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Ambient outdoor carbon monoxide (air-quality pollutant)
- Indoor / household carbon monoxide (heaters, cooking, tobacco smoke)
- Occupational / workplace carbon monoxide
- Motor-vehicle exhaust carbon monoxide
- Fire-smoke / smoke-inhalation carbon monoxide
- Commodity compressed carbon monoxide (cylinders, UN 1016)
- Industrial fuel-gas carbon monoxide (syngas, blast-furnace gas, coke-oven gas, producer gas)
- Endogenous carbon monoxide (haem-oxygenase pathway, baseline carboxyhaemoglobin)
- Which of these kinds and varieties hold for the sense of carbon monoxide this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- CAS Registry Number - 630-08-0 - Primary chemical identity (NIST, ICSC, OSHA).
- IUPAC InChI - InChI=1S/CO/c1-2 - NIST Chemistry WebBook.
- IUPAC InChIKey - UGFAIRIUMAVXCW-UHFFFAOYSA-N - NIST Chemistry WebBook.
- Wikidata - Q2025 - Item for the chemical substance carbon monoxide.
- UN number - UN 1016 - Compressed carbon monoxide; Class 2.3 with subsidiary 2.1.
- NA / DOT id (cryogenic liquid) - NA 9202 / DOT 9202 - Refrigerated liquid carbon monoxide (NIST; NIOSH Pocket Guide).
- EC / EINECS - 211-128-3 - European Community inventory number (ICSC 0023).
- ICSC - 0023 - ILO/WHO International Chemical Safety Card.
- RTECS - FG3500000 - NIOSH Pocket Guide.
- Which of these identifiers and schemes hold for the sense of carbon monoxide this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- WHO Global Air Quality Guidelines (2021), World Health Organization: 24-hour AQG 4 mg/m³ (99th percentile); interim target 1 is 7 mg/m³.
- US National Ambient Air Quality Standards, 40 CFR 50.8, US EPA: 9 ppm (8-hour) and 35 ppm (1-hour), not to be exceeded more than once per year (as compiled in ATSDR 2012).
- OSHA PEL, 29 CFR 1910.1000 Table Z-1: 50 ppm (55 mg/m³) 8-hour TWA.
- NIOSH REL: 35 ppm (40 mg/m³) up to 10-hour TWA; ceiling 200 ppm (229 mg/m³); IDLH 1200 ppm.
- ACGIH TLV (as cited by ATSDR 2012 from ACGIH 2008): 25 ppm 8-hour TWA, basis carboxyhaemoglobinaemia; BEI 3.5% COHb and 20 ppm CO in end-exhaled air.
- Cal/OSHA PEL: 25 ppm (29 mg/m³) 8-hour TWA and 200 ppm STEL.
- UN Recommendations on the Transport of Dangerous Goods (as on ICSC 0023): UN 1016, hazard class 2.3, subsidiary risk 2.1.
- ANSI/PGMA G300-2018, Safety and Performance of Portable Generators (Portable Generator Manufacturers' Association).
- ANSI/UL 2201-2018, Carbon Monoxide (CO) Emission Rate of Portable Generators (UL).
- Which of these standards and regulation hold for the sense of carbon monoxide this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Unwanted product of incomplete combustion in traffic, stoves, boilers, charcoal, kerosene, tobacco smoke and structure fires - the dominant public-health exposure.
- Workplace contaminant from portable generators, small gasoline engines, marine generators, pressure washers, forklifts and coal-fired plant.
- Industrial C1 feedstock and reducing gas in syngas, methanol, acetic-acid and hydroformylation chemistry, and as the combustible fraction of blast-furnace, coke-oven and producer gas.
- Compressed or cryogenic commodity gas shipped as UN 1016 or NA 9202.
- Calibration and span gas for ambient-air and emissions monitors.
- Clinical biomarker: blood carboxyhaemoglobin and exhaled CO used to assess smoking status and CO poisoning.
- Which of these real-world use hold for the sense of carbon monoxide this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Air concentration (ambient, indoor or workplace) - WHO 24-hour AQG 4 mg/m³; US NAAQS 9 ppm (8-hour) and 35 ppm (1-hour); OSHA PEL 50 ppm; NIOSH REL 35 ppm, ceiling 200 ppm, IDLH 1200 ppm; undiluted exhaust or fire gas can be thousands of ppm - ppm or mg/m³ (NIOSH: 1 ppm = 1.15 mg/m³)
- Blood carboxyhaemoglobin (COHb) - ACGIH biological exposure index 3.5% of haemoglobin; clinical poisoning is judged from rising COHb together with symptoms, not from air ppm alone - % of total haemoglobin
- End-exhaled carbon monoxide - ACGIH BEI 20 ppm (23 mg/m³) - ppm
- Explosive (flammable) limits in air - 12.5-74.2 - volume %
- Boiling and melting points - boiling point −191 °C; melting point −205 °C - °C
- Relative vapour density (air = 1) - 0.97 (mixes with air; does not reliably layer) - dimensionless
- Auto-ignition temperature - 605 - °C
- Which of these typical measurements hold for the sense of carbon monoxide this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Acute inhalation poisoning via carboxyhaemoglobin formation; no odour warning even at toxic concentrations (ICSC).
- Delayed neurological injury after apparent recovery from a high exposure.
- Rapid build-up to IDLH or fatal levels in rooms, garages, boat-deck voids and other semi-enclosed spaces, including from generators that appear to be outdoors.
- Fire and explosion: extremely flammable gas; air mixtures explosive between about 12.5% and 74%; heating of cylinders risks bursting (ICSC, GHS).
- The gas mixes with air and can pass through walls and ceilings, so a leak is not confined to the room of origin (ICSC).
- Reacts with chlorine, fluorine and sulfur (toxic fumes) and with metal powders and oxidants (fire/explosion) (ICSC).
- Ordinary smoke alarms and pulse oximeters do not detect CO; expired or poorly placed CO alarms fail silently.
- GHS (ICSC 2024): toxic if inhaled; may damage fertility or the unborn child; causes damage to blood and, with repeated exposure, to blood and central nervous system.
- Which of these failure modes and hazards hold for the sense of carbon monoxide this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Ambient limit: WHO 2021 24-hour 4 mg/m³ versus US NAAQS 9 ppm 8-hour (~10 mg/m³) and 35 ppm 1-hour.
- Workplace 8-hour limit: OSHA 50 ppm (US federal, unchanged in Table Z-1) versus NIOSH REL 35 ppm, ACGIH TLV 25 ppm and Cal/OSHA PEL 25 ppm.
- Older WHO short-term indoor figures (15 min / 1 h / 8 h) are still cited in some national rules; the 2021 update that is tabulated as an AQG level is the 24-hour value.
- Industrial mixtures are named locally as blast-furnace gas, water gas, producer gas or syngas rather than as carbon monoxide.
- Language names in common use include carbonic oxide (older English), Kohlenmonoxid/Kohlenoxyd (German), oxyde de carbone (French), ossido di carbonio (Italian), koolmonoxyde (Dutch) and tlenek węgla (Polish) (NIST synonym list).
- Which of these regional variation hold for the sense of carbon monoxide this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Carbon dioxide (CO₂) - CO₂ is the complete-oxidation product and is not a haem poison at ordinary ambient levels. Measure with a CO-specific electrochemical or IR cell, not a CO₂ NDIR 'air quality' sensor; in blood, raised PaCO₂ is not the same as raised COHb.
- Hydrogen cyanide - Both are fire gases that cause cellular hypoxia. Cyanide inhibits cytochrome oxidase and does not raise COHb; separate laboratory assays (COHb versus blood cyanide) and different antidotes.
- Simple asphyxiants (N₂, Ar, CH₄) - Simple asphyxiants act by displacing oxygen; CO poisons at oxygen levels that would otherwise be survivable. Pulse oximeters read COHb as oxyhaemoglobin; use co-oximetry.
- Methane and other fuel gases - Shared explosion risk, but methane's LEL is much lower (~5%) and it is not toxic at low ppm. A combustible-gas LEL head is not a CO detector; use an electrochemical CO cell.
- Phosgene and other carbonyls - Phosgene (COCl₂) is a delayed pulmonary irritant, not a COHb former. Identity is by GC or FTIR, not by a CO alarm.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of carbon monoxide this model covers, and on what evidence? provenance
Sources
- WHO global air quality guidelines: particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide - 2021 health-based 24-hour AQG for CO (4 mg/m³, interim target 7 mg/m³) and CO as a classical ambient pollutant.
- Ambient (outdoor) air pollution - WHO description of CO as a colourless, odourless, tasteless toxic gas from incomplete combustion of wood, petrol, charcoal, natural gas and kerosene.
- Carbon monoxide (NIST Chemistry WebBook, SRD 69) - Chemical identity: formula CO, molecular weight 28.0101, CAS 630-08-0, InChI/InChIKey, UN 1016, NA 9202, and synonym list.
- ICSC 0023 - Carbon monoxide - Physical constants, explosive limits, GHS and UN transport class, odourless toxic compressed gas, and workplace hazards (ILO/WHO, April 2024).
- Toxicological profile for Carbon Monoxide - Exposure routes, health effects, and the compiled table of occupational and ambient regulations and biological exposure indices.
- CARBON MONOXIDE (OSHA Occupational Chemical Database) - OSHA PEL, NIOSH REL/ceiling, Cal/OSHA PEL/STEL, physical properties, and COHb as the occupational health metric.
- NIOSH Pocket Guide to Chemical Hazards - Carbon monoxide - IDLH 1200 ppm, unit conversion 1 ppm = 1.15 mg/m³, LEL/UEL, DOT IDs 1016 and 9202, and sampling methods.
- Carbon Monoxide Hazards at Work - Workplace sources (generators, small engines, marine exhaust, forklifts), enclosed-space accumulation, and portable-generator CO standards.
What the second pass must settle
- Does an existing Vercy world model already own carbon monoxide, requiring this registry entry to link to it rather than create a second model?
- Which authoritative sources should establish CO property data, equipment compatibility and combustion limits across the intended operating conditions?
- Which detector technologies and analytical methods must be supported, and what CO-specific interference and calibration limitations apply to each?
- Which jurisdictions and use settings are intended, and which exposure criteria, alarm requirements and response procedures apply in each?
- Should dissolved and adsorbed CO be fully represented here or handled through links to solution and surface models, and where is the boundary with coordinated carbonyl species?