No metadata available
Chemical Identity
CAS Number
Various
Formula
NOx
Molecular Weight
46.01 g/mol
Exposure Limits Comparison
Health Effects
Respiratory Irritation
Yes
Pulmonary Edema
Yes
Bronchitis
Yes
Delayed Effects
Yes
Yi-Chun LinPh.D.Taiwan
Laser Materials ProcessingPublished
Jan 6, 2026
Nitrogen Oxides Compound
Nitrogen Oxides Compound safety information for laser cleaning. Health hazards, exposure limits, and protective equipment requirements.
Chemical Properties
Detection Monitoring
- SensorTypes
- Electrochemical
- Chemiluminescence
- NDIR
- Metal oxide
- DetectionRange
- 0-50 ppm typical
- AlarmSetpoints
- Low
- 1 ppm (NIOSH STEL for NO2)
- High
- 5 ppm (OSHA ceiling for NO2)
- Evacuate
- 20 ppm (NIOSH IDLH for NO2)
- ColorimetricTubes
- Dräger NO2 0.5/a
- Gastec 9L
- Kitagawa 175
- AnalyticalMethods
Method Technique DetectionLimit NIOSH 6014 Spectrophotometry 0.01 ppm (NO2) OSHA ID-182 Ion chromatography 0.007 ppm - OdorThreshold
- NO2: 0.1-1 ppm (provides warning but overlaps toxic range). NO: odorless (NO WARNING).
Environmental Impact
- AquaticToxicity
- Toxic to aquatic life. LC50 (fish, 96h): varies by species and form. Forms acidic solutions.
- Biodegradability
- Reacts in atmosphere. Converts to nitric acid. Not biodegradable.
- Bioaccumulation
- Does not bioaccumulate.
- SoilMobility
- High mobility as gas. Deposits as nitrates. Contributes to soil acidification.
- AtmosphericFate
- Photochemical reactions produce ozone. Forms nitric acid with water vapor. Contributes to acid rain. Residence time: hours to days.
- OzoneDepletion
- true
- GlobalWarmingPotential
- N2O: 298 (CO2=1)
- ReportableReleases
- Water
- 10 lbs NO2 to navigable waters
- Air
- 10 lbs/day NO2 (CERCLA RQ)
Ppe Requirements
- Respiratory
- SCBA or positive-pressure supplied-air respirator for >1 ppm NO2 or unknown concentrations. Air-purifying with acid gas cartridge acceptable for ≤1 ppm NO2 only.
- Eye Protection
- Chemical safety goggles, face shield for high concentrations
- Skin Protection
- Nitrile or butyl rubber gloves for liquid contact. Chemical-resistant clothing if high concentrations.
Reactivity
- Stability
- NO2/N2O4 equilibrium temperature-dependent. May decompose under heat/pressure.
- Polymerization
- Will not polymerize
- IncompatibleMaterials
- Reducing agents
- Flammable materials
- Organic materials
- Ammonia
- Carbon disulfide
- Hydrogen sulfide
- Petroleum
- Alcohols
- HazardousDecomposition
- Nitrogen
- Oxygen
- Toxic nitrogen oxides
- ConditionsToAvoid
- Heat
- Pressure
- Incompatible materials
- Moisture (forms corrosive acids)
- ReactivityHazard
- Strong oxidizer. Reacts violently with reducing agents and combustibles. Forms nitric acid with water. May explode under heat/pressure.
Regulatory Classification
- UnNumber
- UN1067 (nitrogen dioxide/dinitrogen tetroxide), UN2201 (nitrous oxide)
- DotHazardClass
- 2.3 (Toxic gas), 5.1 (Oxidizer)
- DotLabel
- Poison Gas, Oxidizer
- NfpaCodes
- Health
- 3
- Flammability
- 0
- Reactivity
- 0
- Special
- OX (Oxidizer)
- EpaHazardCategories
- Acute toxicity (inhalation)
- Oxidizing gas
- Corrosive
- SaraTitleIii
- true
- CerclaRq
- 10 pounds (4.54 kg) for NO2
- RcraCode
- P078 (nitrogen dioxide)
Contaminants That Produce Nitrogen Oxides
Nitrogen Oxides forms when laser ablation of nitrogen-containing compounds occurs at high temperature. Paint with nitrogen-based pigments, adhesives containing amines, and contaminated stainless welds are primary sources. NOx requires exhaust capture and is regulated under OSHA PEL of 5 ppm (NO2) to prevent pulmonary irritation in closed work areas.
No metadata available
Algae and Lichen Growth
No metadata available
Biological Blood Residue
No metadata available
Electroplating Solution Residue
No metadata available
Fertilizer Salt Deposits
No metadata available
Insect Impact Residue
No metadata available
Pesticide Chemical Residue
No metadata available
Pharmaceutical Drug Residue
Chemical Properties
Molecular formula, CAS number, molecular weight, and chemical structure
- Type
- chemical_properties
- Id
- nitrogen-oxides-physical-data
Physical Properties
Chemical and physical characteristics
- BoilingPoint
- NO: -151.7°C, NO2: 21.2°C, N2O4: 21.2°C
- MeltingPoint
- NO: -163.6°C, NO2: -11.2°C
- VaporPressure
- NO: >760 mmHg @ 20°C (gas), NO2: 760 mmHg @ 21°C
- VaporDensity
- NO: 1.04 (Air=1), NO2: 1.58 (Air=1)
- SpecificGravity
- NO2: 1.45 (liquid @ 21°C)
- FlashPoint
- Not applicable (non-flammable)
- AutoignitionTemp
- Not applicable
- ExplosiveLimits
- Not applicable (supports combustion)
- Appearance
- NO: colorless gas, NO2: reddish-brown gas, N2O4: colorless liquid/gas
- Odor
- NO2: pungent, irritating odor @ 0.1-1 ppm. NO: odorless
Alternative Names
Synonyms and chemical identifiers
- Synonyms
- NOx
- Nitrogen dioxide (NO2)
- Nitric oxide (NO)
- Dinitrogen tetroxide (N2O4)
- Nitrogen peroxide
- CommonTradeNames
- OtherIdentifiers
- RtecsNumberQW9800000 (NO2)EcNumber233-272-6 (NO2)PubchemCid3032552 (NOx)
Health Effects
Adverse health impacts from exposure to this compound
- Route
- inhalation
- Effect
- Acute respiratory tract irritation, coughing, and potential pulmonary edema
- Severity
- severe
- Onset
- immediate
- Route
- inhalation
- Effect
- Chronic exposure leading to bronchitis and emphysema
- Severity
- high
- Onset
- long-term
- Route
- eye_contact
- Effect
- Severe irritation, conjunctivitis, and possible corneal damage
- Severity
- high
- Onset
- immediate
- Route
- skin_contact
- Effect
- Chemical burns and irritation upon contact with liquefied forms
- Severity
- moderate
- Onset
- immediate
Personal Protective Equipment
Required safety equipment for handling this compound
- Respiratory
- SCBA or positive-pressure supplied-air respirator for >1 ppm NO2 or unknown concentrations. Air-purifying with acid gas cartridge acceptable for ≤1 ppm NO2 only.
- Skin
- Nitrile or butyl rubber gloves for liquid contact. Chemical-resistant clothing if high concentrations.
- Eye
- Chemical safety goggles, face shield for high concentrations
- MinimumLevel
- Level C for known <1 ppm NO2, Level B for >1 ppm or NO/NO2 mixtures
- SpecialNotes
- NO2 is brown gas, NO is colorless. Both highly toxic. Delayed pulmonary edema possible 6-72 hours after exposure. STEL critical - short exposures very dangerous.
Exposure Limits
OSHA, NIOSH, and ACGIH exposure thresholds
- OshaPelPpm
- 25
- OshaPelMgM3
- 9
- NioshRelMgM3
- 1.8
- AcgihTlvPpm
- 3
- AcgihTlvMgM3
- 5.6
- WorkplaceExposure
- OshaPeltwa8Hr: 5 ppmstel15Min: nullceiling: nullNioshReltwa8Hr: 2 ppmstel15Min: 5 ppmceiling: nullidlh: 20 ppm (NO2), 100 ppm (NO)AcgihTlvtwa8Hr: 0.2 ppmstel15Min: 1 ppmceiling: nullBiologicalExposureIndices0: [object Object]1: [object Object]
Storage Requirements
Safe storage conditions and compatibility
- TemperatureRange
- Store cylinders <52°C. Keep away from heat.
- Ventilation
- Outdoor storage strongly preferred. Indoor: mechanical ventilation with emergency backup. NOx gas detection mandatory.
- Incompatibilities
- Flammable materials
- Combustible materials
- Reducing agents
- Ammonia
- Carbon disulfide
- Hydrogen sulfide
- Petroleum products
- ContainerMaterial
- Steel cylinders for compressed gas. Stainless steel or glass for liquid.
- Segregation
- Separate from flammables and combustibles by 20 feet or firewall. Oxidizer storage area.
- QuantityLimits
- Per fire code: limit cylinders in buildings. Many facilities store outdoors only.
- SpecialRequirements
- Cylinder restraints mandatory. Leak detection system required. Post "OXIDIZER" and "POISON GAS" signs. Emergency procedures posted. Monitor cylinder integrity regularly.
Emergency Response
Procedures for spills, exposure, and incidents
- FireHazard
- Non-flammable but supports combustion. Strong oxidizer. Increases fire intensity. May explode when heated.
- FireSuppression
- Do not fight fire if gas cylinder involved - extreme explosion risk. Evacuate. Cool cylinders with water spray from safe distance. Let fire burn out.
- SpillProcedures
- EVACUATE. Liquid NO2/N2O4: extreme hazard. Ventilate area. SCBA mandatory. Contain with soda ash or lime neutralization. Never use water directly on liquid NOx.
- ExposureImmediateActions
- Remove to fresh air immediately. Administer 100% oxygen. Severe respiratory irritation likely. Monitor for delayed pulmonary edema (6-72 hours). Seek immediate medical attention - hospitalize for observation even if asymptomatic.
- EnvironmentalHazards
- Contributes to acid rain, smog, ozone formation. Toxic to vegetation. Report significant releases.
- SpecialHazards
- DELAYED PULMONARY EDEMA - asymptomatic period 6-72 hours then sudden respiratory failure. NO converts to NO2 in air (more toxic). Strong oxidizer. Corrosive to respiratory tract. May explode under pressure.
Regulatory Classification
DOT, UN, and NFPA hazard classifications
- UnNumber
- UN1067 (nitrogen dioxide/dinitrogen tetroxide), UN2201 (nitrous oxide)
- DotHazardClass
- 2.3 (Toxic gas), 5.1 (Oxidizer)
- DotLabel
- Poison Gas, Oxidizer
- NfpaCodes
- Health3Flammability0Reactivity0SpecialOX (Oxidizer)
- EpaHazardCategories
- Acute toxicity (inhalation)
- Oxidizing gas
- Corrosive
- SaraTitleIii
- true
- CerclaRq
- 10 pounds (4.54 kg) for NO2
- RcraCode
- P078 (nitrogen dioxide)
Environmental Impact
Toxicity, biodegradability, and environmental fate
- AquaticToxicity
- Toxic to aquatic life. LC50 (fish, 96h): varies by species and form. Forms acidic solutions.
- Biodegradability
- Reacts in atmosphere. Converts to nitric acid. Not biodegradable.
- Bioaccumulation
- Does not bioaccumulate.
- SoilMobility
- High mobility as gas. Deposits as nitrates. Contributes to soil acidification.
- AtmosphericFate
- Photochemical reactions produce ozone. Forms nitric acid with water vapor. Contributes to acid rain. Residence time: hours to days.
- OzoneDepletion
- true
- GlobalWarmingPotential
- N2O: 298 (CO2=1)
- ReportableReleases
- Water10 lbs NO2 to navigable watersAir10 lbs/day NO2 (CERCLA RQ)
FAQ
Common Questions and Answers
As a laser cleaning operator, how can I protect myself from NOx exposure while working on metal surfaces?
- Prioritize engineering controls like local exhaust ventilation or fume extractors positioned near the laser head to capture NOx gases at the source, ensuring airflow rates of at least 100-200 linear feet per minute to dilute concentrations below safe levels. Wear a full-facepiece respirator with cartridges rated for acid gases (e.g., NIOSH-approved for NOx) if ventilation is insufficient, and always monitor air quality using a portable NOx detector calibrated for NO and NO2. Adhere to OSHA exposure limits of 25 ppm for NO and 5 ppm for NO2 over an 8-hour shift to prevent respiratory irritation or long-term lung damage.
Detection & Monitoring
Methods for detecting and measuring this compound
- SensorTypes
- Electrochemical
- Chemiluminescence
- NDIR
- Metal oxide
- DetectionRange
- 0-50 ppm typical
- AlarmSetpoints
- Low1 ppm (NIOSH STEL for NO2)High5 ppm (OSHA ceiling for NO2)Evacuate20 ppm (NIOSH IDLH for NO2)
- ColorimetricTubes
- Dräger NO2 0.5/a
- Gastec 9L
- Kitagawa 175
- AnalyticalMethods
- [object Object]
- [object Object]
- OdorThreshold
- NO2: 0.1-1 ppm (provides warning but overlaps toxic range). NO: odorless (NO WARNING).
Reactivity
Chemical reactivity and incompatibilities
- Stability
- NO2/N2O4 equilibrium temperature-dependent. May decompose under heat/pressure.
- Polymerization
- Will not polymerize
- IncompatibleMaterials
- Reducing agents
- Flammable materials
- Organic materials
- Ammonia
- Carbon disulfide
- Hydrogen sulfide
- Petroleum
- Alcohols
- HazardousDecomposition
- Nitrogen
- Oxygen
- Toxic nitrogen oxides
- ConditionsToAvoid
- Heat
- Pressure
- Incompatible materials
- Moisture (forms corrosive acids)
- ReactivityHazard
- Strong oxidizer. Reacts violently with reducing agents and combustibles. Forms nitric acid with water. May explode under heat/pressure.
Incredibly fast, clean - and easy to do yourself.
It's finally here in the Bay area. We'll arrive with everything you need. Try it out free:
