Best Nitrogen Dioxide Gas Detector NO2 (Expert Pick)

Nitrogen Dioxide Detector, NO2 Detector -

Best Nitrogen Dioxide Gas Detector NO2 (Expert Pick)

A nitrogen dioxide (NO2) detector senses the concentration of nitrogen dioxide gas in the air. These devices are used for personal protection in hazardous gas environments and to track NO2 levels produced by emissions. NO2 gas is a by-product of combustion and produced by diesel engines, coal-fired power stations, wastewater plants, and manufacturing processes. 

Pros

Cons

  • Small and low cost NO2 detectors help with worker safety and emission control.
  • NO2 gas detectors available for less than $399.
  • Portable NO2 detectors ensure that employees and personnel are not exceeding recommended exposure limits.
  • Bump testing and calibration can be forgotten by users.
  • Sensors typically last from 24 to 36 months.
  • NO2 gets confused with NO and NOx.

Which is The Best Nitrogen Dioxide Gas Detector?

 

What Is a Nitrogen Dioxide Gas Detector?

A nitrogen dioxide gas detector is an instrument used to detect the concentration of nitrogen dioxide in the air. These devices (specifically the Forensics Detectors FD-90A-NO2) have a long battery life, large screen that displays the NO2 concentration, and a belt clip to connect to clothing. In order to protect users, NO2 gas detectors also have LED, vibration, and buzzer alarms.

Nitrogen dioxide gas detectors are also known as NO2 monitors, nitrogen dioxide sniffers, nitrogen dioxide analyzers, or NO2 gas testers. These names all refer to the same device, a nitrogen dioxide gas detector.

What Does a Nitrogen Dioxide Meter Detect?

A nitrogen dioxide detector senses nitrogen dioxide gas and displays the levels in parts per million (ppm).

What Is Nitrogen Dioxide Gas?

Nitrogen dioxide has the chemical symbol NO2. It is known as a dirty gas with a brownish color. It is an unpleasant gas with an irritating taste and smell. Although NO2 is a pollutant found in emissions, it is also used in industry to make nitric oxide. NO2 gas is very dangerous to human health, hence the need to monitor and check air concentrations.

Is Nitrogen Dioxide Gas Toxic?

Yes it is.

Nitrogen dioxide (NO2) is an air pollutant that is commonly associated with respiratory diseases. According to the American Lung Association, NO2 gas lung effects include: 

 

  • Inflammation of the airways
  • Cough and wheezing
  • Poor lung function
  • Asthma attacks

    Can I Smell Nitrogen Dioxide Gas?

    Yes, humans can smell nitrogen dioxide gas.

    It is a dirty, polluting gas with a brownish color. It is an unpleasant gas with an irritating taste and smell.

    There are various studies that have investigated the minimum NO2 odor threshold for humans. NO2 can be detected at concentrations as low as few ppm. For example, 0.5  ppm (see here) and 1.5 ppm (see here) have been shown to be the minimum odor threshold for humans.

    However, it is a bad idea to rely on your sense of smell to determine the "concentration" of an aromatic gas like NO2.

    With time, the nose becomes desensitized to the odor - this phenomena is called olfactory fatigue.

    What Are the Different Types of Nitrogen Dioxide Gas Detectors?

    Type

    Description

     

    Nitrogen Dioxide Detector for Personal Protection

    The majority of nitrogen dioxide gas detectors are portable units. These are small, battery-powered detectors with a nitrogen dioxide sensor that can be clipped onto your clothes for personal protection. 

    nitrogen dioxide gas detector
    Nitrogen Dioxide Gas Monitor for Stationary Fixed Wall 

    Wall-mounted units provide continuous protection and warning of nitrogen dioxide gas leaks. These devices are perfect for indoor uses such as power stations, industries, or factories. If the levels of NO2 exceed the preset threshold (i.e., 5ppm OSHA PEL), the unit will provide an LED and buzzer warning.

    fixed wall mount H2S monitor

    How Does a Nitrogen Dioxide Gas Sensor Work?

    A nitrogen dioxide gas detector is composed of electronics and an NO2 sensor. The gas sensor converts the detected nitrogen dioxide level to an electronic signal for microprocessor analysis. After receiving the sensor signal, the unit displays the NO2 concentration. If the measurement exceeds the pre-set NO2 alarm value, the alarms are triggered.

    Gas

    Sensor Technology

    Pros

    Cons

    Nitrogen Dioxide (NO2)

    NO2 Electrochemical Gas Sensors

    The gas reacts with a working electrode, triggering an electrochemical redox reaction. The generated current is proportional to the detected gas level.

    • Small, fast response, & cheap
    • Easy to integrate with electronics
    • Immediate ON
    • Limited life from 24 to 36 months
    • Influenced by temperature and humidity
    Nitrogen Dioxide (NO2)

    NO2 Semiconducting Metal Oxide Gas Sensors

    Ozone molecules interact with a film of metal oxide material, where surface redox reactions take place. A power-law relationship transpires between the ozone concentration and conductivity of the sensor.

    • Long lifetime, lasting over five years
    • Very sensitive
    • Low cost and simple construction
    • Robust
    • Cross- sensitivity to oxidizing gases, such as Cl2 and O3
    • 10-minute warm-up time
    • Influenced by temperature and humidity

    What Do Nitrogen Dioxide Gas Sensors Look Like?

    Below is an image of an electrochemical nitrogen dioxide gas sensor.

    nitrogen dioxide sensor

    Below is an image of semiconducting nitrogen dioxide gas sensor from Spec Sensors and their development kit items.

    spec sensors nitrogen dioxide

     

    What Are Safe Nitrogen Dioxide Gas Levels?

    Various government agencies have recommended gas exposure limits, examples can be seen below:

    Agency

    Recommendation / Requirement

    National Institute for Occupational Safety and Health (NIOSH)

    NIOSH Recommended Exposure Limit (REL):

    1 ppm, 10-minute ceiling

    Occupational Safety and Health (OSHA)

    5 ppm average over 15 minutes (Permissble Exposure Limit)

    American Conference of Governmental Industrial Hygienists (ACGIH)

    3 ppm average over 8 hours & 5 ppm as a short term exposure limit

    What Is a Nitrogen Dioxide Gas Detector Used For?

    Nitrogen dioxide gas is used in a variety of manufacturing and industrial processes, hence the requirement for accurate detection and human exposure limits. NO2 gas applications include:

    • NO2 gas to make nitric acid: NO2 is used to make HNO3, often called nitric acid. This chemical is used to produce various nitrogen compounds to create chemical fertilizers, explosives, and other useful substances.
    • NO2 gas as a sterilization agent: NO2 is a sterilization gas used for medical and dental instruments. Used in a chamber-based system, advantages includes room temperature operation, low concentration, fast microbicidal activity, and low residue
    • NO2 gas as a bleaching agent: NO2 is used as a bleaching agent, similar to chlorine and bromates. These chemicals are strong oxidizers.  

      What Is the Best Nitrogen Dioxide Gas Detector?

      There are many nitrogen dioxide gas detectors on the market. The reputable brands include the following:

      Is Nitrogen Dioxide Gas Flammable?

      Not it is not.

      Is a Nitrogen Dioxide (NO2) Gas Detector the Same as a Nitric Oxide (NO) Detector? 

      No it is not.

      Most of us know nitric oxide gas (NO) as "laughing gas." Nitric oxide gas is very different from NO2. NO gas is used for pain relief by dentists and medical personnel to sedate patients undergoing medical procedures.

      There are specific NO sensors used for NO detection.

      What Is the Difference Between a Nitrogen Dioxide (NO2) Gas Detector and an NOx Gas Detector?

      The term NOx refers to nitrogen oxides, which include NO2 and NO. Although NO is very different from NO2, it does react with oxygen or ozone in the air to form NO2, hence the term NOx. The main pollutant is NO2. However, NO in the environment may transform into NO2.

      Other oxides of nitrogen include NO3 (nitrogen trioxide), N2O (nitrous oxide), N2O4, and N2O5, but are not as readily found as NO and NO2.

      How Do I Select a Nitrogen Dioxide Detector?

      To select the best personal protection nitrogen dioxide gas detector, follow this simple guide:

          • What is my budget and operating cost budget?
          • Do I need advanced functions such as data-logging or Bluetooth?
          • Do I need specific accreditations with the monitor such as a NIST traceability calibration?
          • Do I require a belt clip for attaching the device to my clothes?
          • Do I need after-sales support, USA headquarters, or fast calibration services?

        What About Atmospheric Nitrogen Dioxide Monitoring?

        Most of the nitrogen dioxide gas meters on the market are based on electrochemical detection sensors. These are used for personal protection and alarm in the ppm range for OSHA and NIOSH limits.

        For atmospheric and environmental NO2 measurements, sensitivity in the parts per billion (ppb) range is required. These systems are much more expensive and can exceed $10,000. These analyzers employ chemiluminescence detection methods. 

        Below is a picture of the Ecotech NO2 Analyzer that measures NO, NO2, and NOX in ambient air with a lower detection limit of 0.4 ppb and a range from 0 to 20 ppm.

        NO2 analyzer

        How Long Does a Nitrogen Dioxide Detector Last For?

        Nitrogen dioxide gas detectors incorporate small electrochemical sensors that usually last between 24 and 36 months.

        There are NO2 gas sensor that employ semiconducting metal oxide technology and last over 5 years. Unfortunately, they are not as specific as electrochemical sensors. Some sensor and detectors are here:

        How Do I Test My Nitrogen Dioxide Detector?

        The best way to test your nitrogen dioxide gas detector is to expose it to a known gas source. Generally referred to as bump testing, this is a good practice to perform daily. Frequent testing is especially important in personal protection NO2 applications where safety is paramount.

        What Is a Nitrogen Dioxide Bump Test?

        • Bump testing NO2 gas is a procedure where the user exposes the detector to a small amount of “blast” target gas to ensure the device operates and alarms as programmed.
        • The function of this NO2 gas test is to verify proper operation and build user confidence, particularly in hazardous applications.
        • It is recommended to NO2 bump test when first purchased, with subsequent testing every week. If using in LIFE-THREATENING and / or DANGEROUS applications, bump test daily.
        • Nitrogen dioxide bump test gas can be found here.

        What Is Nitrogen Dioxide Detector Gas Calibration?

        Nitrogen dioxide gas detector calibration is the technical task of adjusting the monitor to a more accurate gas reading. Over time, the sensors on the device will degrade or produce drifting readings. We suggest calibrating your NO2 detector every 6 to 12 months, the typical time period for gas detectors.

        Gas calibration is a technical task that requires certain key pieces of equipment. These include a calibration gas bottle, gas regulator, tubing, and calibration cap fitting. You need to communicate with the manufacturer to determine the recommended calibration gas concentrations and mixtures. For the Forensics Detectors NO2 gas monitors, we recommend the calibration gas here.
        Be attentive and calibrate daily if:
        • The user employs the device as an analytical tool where accuracy is paramount.
        • The device is used in an extreme environment (temp and humidity extremes create sensor drift).
        • The user is performing an imminently dangerous application. Bump testing fails. In this case, you must calibrate to make sure the sensors and monitor operate properly.
        • The NO2 gas detector alarms in the fresh air. This could mean that the sensor has drifted past an alarm set-point.
        • Calibration and bump testing are mandatory because injury or death can occur if the device fails. Take it very seriously.
        Also, it is prudent to have a calibration schedule that the owner or employees strictly follow. See gas calibration here.

        How Do I Take Care of My Nitrogen Dioxide Gas Detector?

        • Store your NO2 gas detector at a normal room temperature.

        • Store it away from electromagnetic or magnetic sources, such as phones.

        • Store it in a clean environment with no dust or particles.

        • Store away from any exhaust gas, concentrated vapors, and harsh chemicals.

        • Clean the casing of your detector with a damp cloth.

        • Store it in a stable place where there are no vibrations or continuous shaking.

        How Do I Properly Use a Nitrogen Dioxide Gas Detector?

        When operating an NO2 gas detector, there are some important tips to consider. After reading your product manual, be sure to keep these tips in mind:

        • Turn ON the NO2 gas monitor in the fresh air. 

        • Ensure the NO2 gas monitor is within its calibration period.

        • Ensure the NO2 gas monitor has been bump tested and validated as operational. 

        • Check the alarm set-points. Set your alarms as desired (some units may not have adjustable alarms).

        • If performing analytical measurements, keep the unit stationary. Ensure humidity and temperature are also tracked and are as constant as possible.

        Final Words

        • Nitrogen dioxide is a poisonous and toxic gas. It is emitted during combustion, especially from diesel engines. NO2 is also used for sterilization, industrial processes, and manufacturing applications.

        • NO2 gas meters can be used for personal protection in hazardous environments when using nitrogen dioxide in industry, working with emissions, or sterilization and bleaching purposes.

        • NO2 gas detectors are affordable, costing less than $400 per unit. 

        About The Author

        Dr. Koz is the President of FORENSICS DETECTORS, where the company operates from the scenic Palos Verdes Peninsula in Los Angeles, California. He is a subject matter expert on gas sensor technology, gas detectors, gas meters, and gas analyzers. He has been designing, building, manufacturing, and testing toxic gas detection systems for over 20 years.

        gas detector expert

        Every day is a blessing for Dr. Koz. He loves to help customers solve their unique problems. Dr. Koz also loves spending time with his wife and his three children going to the beach, grilling burgers, and having a cold beer. 

        Read more about Forensics Detectors here.

        Email:  drkoz@forensicsdetectors.com
        Phone: +1 424-341-3886

         

         


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