Nitric Oxide
NONitric oxide (NO) is a colorless, reactive combustion gas produced during high temperature fuel burning in boilers, furnaces, engines, and generators. In air, NO rapidly oxidizes to nitrogen dioxide (NO₂), a more toxic gas, which is why accurate monitoring is critical in combustion environments. Because NO and NO₂ behave differently but are closely linked, paired NO/NO₂ monitoring is recommended for complete coverage. A nitric oxide gas detector is commonly installed in boiler rooms, generator exhaust areas, and mechanical rooms to verify combustion efficiency, detect unsafe concentrations, and protect personnel. Occupational safety guidelines set an OSHA permissible exposure limit (PEL) for nitric oxide at 25 ppm (8 hour TWA), making continuous monitoring an important part of compliance and risk reduction.
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Key Information
Essential safety and exposure information for Nitric Oxide
Health Effects
- Mainly affects the respiratory system and blood when inhaled
- Short term exposure causes irritation of the eyes and airways triggering coughing and chest tightness with shortness of breath and dizziness
- At higher concentrations it can impair oxygen delivery because it combines with hemoglobin in the blood and can lead to loss of consciousness
- It rapidly oxidizes in air forming NO2 NO₂ and exposure and can result in delayed lung injury and pulmonary edema
Common Sources
- Boiler rooms
- Mechanical rooms
- Power plants
- Industrial processes
- Semiconductor manufacturer
- Laboratories
- Medical facilities
- Welding operations
Exposure Limits
- OSHA PEL
- 25 ppm
- NIOSH REL
- 25 ppm
- NIOSH IDHL
- 100 ppm
- ACGIH TLV
- 25 ppm
Regulatory Status
- Nitric oxide (NO) is regulated primarily as a toxic gas that can also form nitrogen dioxide (NO₂) in air. OSHA sets an 8‑hour TWA of 25 ppm, with NIOSH and ACGIH adopting the same 25 ppm limit and NIOSH establishing an IDLH of 100 ppm for emergency response. Environmentally, the EPA regulates NO indirectly as part of NOₓ emissions under the Clean Air Act due to its role in ozone and smog formation. For transport, the DOT classifies nitric oxide as UN 1660, Hazard Class 2.3 (toxic gas) under hazardous materials regulations. ASHRAE does not publish NO‑specific limits, but addresses nitric oxide through ventilation and indoor air quality standards (62.1/62.2) to control combustion by‑products in occupied and mechanical spaces.
Detection Requirements
- Sensor Technology
- Electrochemical
- Detection Range
- 0-100 ppm
- Alarm Setpoints
- Low 25 ppm, Mid 35 ppm, High 50 ppm
- Mounting Height
- Breathing Zone 4-6 ft / 1.2-1.8 m from the floor
Related Applications
Industries and environments where Nitric Oxide detection is critical
Hospitals
Continuous monitoring for oxygen deficiency levels in hospitals and labs with a fixed gas detection system ensures the safety of patients and staff.
Welding Shops
Combustible gas, oxygen, and fume detection for fabrication facilities and metal working environments
Boiler Rooms
Continuous monitoring of natural gas, CO, and CO2 in schools & boiler rooms ensures the safety of students and faculty.
Detection Solutions
Sensors and detectors for Nitric Oxide monitoring
cGas Detector Analog Transmitter
Single channel, analog gas detector with Plug & Play Smart Sensor Technology.
cGas Detector Digital Transmitter
One or two channel Modbus® or BACnet® gas detector with flexible customization options and Plug & Play Smart Sensor Technology.
cGas-SC Self-Contained Controller
A self contained controller with up to 3 gas channels, Plug & Play Smart Sensor Technology and configurable logic control and priority settings. Offers superior user customization and reliable gas detection performance for monitoring many gases.
cGas-SD Sample Draw System
A Self-contained, single sensor sample draw gas detection system that draws sample air from locations where it is difficult to install a gas detector.
CXT2 Explosion Proof Transmitter
Reliable, accurate monitoring of toxic or combustible gases in potentially explosive and harsh environments, including hazardous-rated areas.
Related Gases
Other Toxic Gases we detect