Gas Sensor Cross Sensitivity (Tables)

Gas Sensor Cross Sensitivity (Tables)

There is no such thing as a perfect gas sensor. All gas sensors have a sensitivity to other gases. The question is to what degree? Defining this degree of sensitivity is a term called cross sensitivity.

Pros

Cons

✅ Low Cost: Electrochemical sensors, catalytic sensors and semiconducting metal oxide sensors are low cost.

✅ Applications: The majority of applications used in our modern day life can operate with standard low cost sensors.
✅ Easy : Gas sensors are easy to design within electronics.
 Safety: Gas sensors offer many industries extra safety that save many lives every year.

⛔ Expensive: Infra Red sensors and PID sensors can get expensive.

⛔  Knowledge: People assume gas sensors are perfect, and are 100% specific. This is never the case.

⛔ Effort: It takes time and effort to understand a gas sensors characteristics and cross sensitivity behavior.

⛔ Information: Gas sensor cross sensitivity information is limited, and this article aims to present the most comprehensive list.

What is Gas Sensor Cross Sensitivity

While a sensor may be primarily designed to detect a specific gas, it will exhibit a response to other gases. This cross sensitivity can potentially lead to inaccurate measurements or false alarms if not properly accounted for or calibrated. 

What Factors Determine Cross Sensitivity?

The fundamentals of electrochemical gas sensors involve the oxidation or reduction of the target gas at the electrode surface, which generates a current proportional to the gas concentration. Cross sensitivity occurs when other gases also react with the electrode surface and produce a current, which interferes with the target gas signal. The degree of cross sensitivity depends on various factors, such as the electrode material, the gas diffusion rate, test flow rates, sensor age, calibration exposure time, soak time, recovery time since prior exposure and the operating temperature and humidity. 

How Can I Minimize Cross Sensitivity?

To minimize cross sensitivity, several strategies can be employed, such as using gas filters, optimizing the sensor design, and applying calibration and compensation techniques.

What type of Cross Sensitivities Are There?

  • Positive Response: The sensor responds to the target gas and another gas. This response gives the user the impression that there is target gas present when there isn’t or more target gas present than is the case. 
  • Negative Response: The sensor produces a reduced response to the target gas and may neutralize the positive response from the target gas. This often occurs when both reducing and oxidizing gases are present that can cancel the sensor output signal. From the safety standpoint, a negative cross-sensitivity presents a higher risk than a positive one, as it will diminish the response to the target gas and may prevent an alarm.
  • Inhibition: A gas or gas matrix inhibits the detection the target gas analyte from creating a positive sensor response.

Cross Sensitivity and Surrogate Gas

In some cases, the cross sensitivity behavior of a sensor is used for calibration purposes. This is only done when the target gas in unavailable in calibration gas form. Some examples include Hydrogen Peroxide and Chlorine Dioxide gas. In these cases, surrogate calibration must only be performed in a controlled laboratory environment, since cross sensitivity magnitudes can vary due to temperature, exposure time, soak time, sensor age, humidity, and gas flow rates. 

Cross Sensitivity Tables

Below we have composed the most comprehensive Cross Sensitivity Tables. This data has been collected over the many years of experience and testing, and in depth literature analysis from a plethora of trusted gas sensor suppliers. 

Treat the tables as estimates since cross sensitivity magnitudes may vary up to +/-100% based on sensor design and test conditions. Quoted metrics are based on test temperature at 20C and humidity at 50%RH.

In addition, gas mixtures (gas matrix) are rarely tested and results with mixed gases are unpredictable. The table is organized in alphabetic gas order.

Acrylonitrile (C3H3N)

Sensor Type: Electrochemical Gas Sensor
Product: NA

Gas

Concentration (ppm) Output Signal
(in ppm C3H3N)
Acetylene 10 10
Hydrogen Sulfide 50 < 1.0
Sulfur Dioxide 10 < 1.0
Nitric Oxide 50 < 1.0
Formaldehyde 10 < 1.0
Ammonia 50 0.0
Carbon Monoxide 100 < 1.0
Ethylene 100 < 1.0
Vinyl Chlorine 100 < 1.0
Ethanol 200 < 1.0

Acetylene (C2H2)

Sensor Type: Electrochemical Gas Sensor
Product: FD-90A-C2H2

Gas Concentration (ppm) Output Signal
(in ppm C2H2)
Acetylene 10 10
Hydrogen Sulfide 50 < 1.0
Sulfur Dioxide 10 < 1.0
Nitric Oxide 50 < 1.0
Formaldehyde 10 < 1.0
Ammonia 50 0.0
Carbon Monoxide 100 < 1.0
Ethylene 100 < 1.0
Vinyl Chlorine 100 < 1.0
Ethanol 200 < 1.0


Alcohol

Sensor Type: Electrochemical Gas Sensor
Product: FD-90A-ALCOHOL

Gas Concentration (ppm) Output Signal
(in ppm C4H8)
Methanol 50 50
Isobutylene* 50 60
Ethanol 50 20
Isopropanol 50* 30


Acid 

Sensor Type: Electrochemical Gas Sensor
Product: FD-90A-ACID

Gas Concentration (ppm) Output Signal
(in ppm SO2)
Sulfur Dioxide* 10 20
Formic Acid 10 20
Acetic Acid 10 2
HCl 10 1

Ammonia (NH3)

Sensor Type: Electrochemical Gas Sensor
Product: FD-90A-NH3

Gas Concentration (ppm) Output Signal
(in ppm NH3)
Ammonia 10 10
Hydrogen Sulfide* 25 50
Carbon Dioxide 5,000 0.0
Carbon Monoxide 100 0.0
Hydrogen 1,000 0.0
Isobutylene 100 0.0
Ethanol 200 < 1.0


Arsine (AsH3)

Sensor Type: Electrochemical Gas Sensor
Product: NA

Gas Concentration (ppm) Output Signal
(in ppm AsH3)
Arsine 10 10
Sulfur Dioxide 10 1.5
Nitric Oxide 35 -0.5
Ammonia 30 0.0
Hydrogen 1000 0.7
Nitrogen Dioxide 10 -2.0
Hydrogen Sulfide 2 1.8
Carbon Dioxide 5000 0.0
Chlorine 10 -1.3
Ethylene 50 0.0
Carbon Monoxide 100 0.9

 

Benzene (C6H6)

Sensor Type: Photoionization Detector (PID Sensor) 
Product: FD-90A-C6H6

Gas Concentration (ppm) Output Signal
(in ppm C6H6)
Benzene 10 10
Acetone 10 12
Isobutylene* 10 7
Xylene 10 5
Toluene 10 6

Reference: Blackline and Ion

Bromine (Br2)

Sensor Type: Electrochemical Gas Sensor
Product: FD-90A-Br2

Gas Concentration (ppm) Output Signal
(in ppm Br2)
Bromine 10 10
Ethylene 100 0
Formaldehyde 7 0
Carbon Monoxide 300 0
Ethanol 60 0
Hydrogen 100 0
Hydrogen Sulfide 20 < -10
Hydrogen Chloride 20 0
Nitrogen Dioxide 10 12
Ozone* 1 2


Carbon Disulfide (CS₂)

Sensor Type: Electrochemical Gas Sensor
Product: FD-90A-CS2

Gas Concentration (ppm) Output Signal
(in ppm CS₂)
Carbon Disulfide 100 100
Ethylene 100 < 2
Carbon Monoxide* 200 100
Hydrogen 100 0
Hydrogen Sulfide 20 0
Nitric Oxide 100 0
Nitrogen Dioxide 20 0
Phosphine 20 0
Sulfur Dioxide 100 0


Carbon Monoxide (CO)

Sensor Type: Electrochemical Gas Sensor
Product: FD-90A-CO

Gas Concentration (ppm) Output Signal
(in ppm CO)
Carbon Monoxide 10 10
Hydrogen Sulfide 15 -0.1
Sulfur Dioxide 10 -0.2
Nitric Oxide 50 -16.0
Nitrogen Dioxide 10 -2.6
Ammonia 50 0.0
Hydrogen 100 24.0
Ethylene 100 10.0
Chlorine 15 -0.5
Ethanol 200 1.5

Chlorine (Cl2)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-Cl2

Gas Concentration (ppm) Output Signal
(in ppm Cl2)
Chlorine 10 10
Hydrogen Sulfide 10 -12.0
Sulfur Dioxide 20 0.0
Nitric Oxide 10 0.1
Nitrogen Dioxide 10 20
Ozone* 10 20
Carbon Monoxide 100 0.0
Ammonia 100 0.1
Hydrogen 1,000 -0.1
Carbon Dioxide 30,000 0.0

Chlorine Dioxide (ClO₂)

Sensor Type: Electrochemical Gas Sensor 
Product: 
FD-90A-ClO2

Gas Concentration (ppm) Output Signal
(in ppm ClO2)
Chlorine Dioxide 10 10
Hydrogen Sulfide 20 -5.0
Nitrogen Dioxide 10 16.0
Carbon Monoxide 100 0.0
Hydrogen 3,000 0.0
Chlorine* 10 13
Carbon Dioxide 5,000 0.0
Ozone* 10 30


Cyclohexanol (C6H12O)

Sensor Type: Electrochemical Gas Sensor
Product:
NA
Gas Concentration (ppm) Output Signal
(in ppm C6H12O)
Cyclohexanol 10 10
Carbon Dioxide 3000 0
Carbon Monoxide 25 100
Methane 1000 0


Diborane (B2H6)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-B2H6

Gas Concentration (ppm) Output Signal
(in ppm B2H6)
Diborane 10 10
Carbon Monoxide 5 30
Methanol 10 40
Cyclohexane 2000 0
Ammonia 100 0
Methane 5000 0
Carbon Dioxide 5000 0

Ethylene (C2H4)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-C2H4

Gas Concentration (ppm) Output Signal
(in ppm C2H4)
Ethylene 10 10
Hydrogen Sulfide 50 < 1.0
Sulfur Dioxide 100 < 1.0
Nitric Oxide* 100 60.0
Formaldehyde 10 < 1.0
Ammonia 50 0.0
Carbon Monoxide 100 < 1.0
Acetylene* 10 15.0
Vinyl Chloride 100 < 1.0
Ethanol 500 < 1.0

Ethylene Oxide (C2H4O)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-C2H4O

Gas Concentration (ppm) Output Signal
(in ppm ETO)
Ethylene Oxide 50 50
Carbon Monoxide 25 10.0
Isobutylene* 50 45.0
Ethylene 50 35.0
Acetylene 50 35.0
Ethanol 100 45.0
Methyl Alcohol 30 25.0
Formic Acid 100 30.0


Formaldehyde (CH2O)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-CH2O

Gas Concentration (ppm) Output Signal
(in ppm CH2O)
Formaldehyde 10 10
Carbon Monoxide 50 1.6
Ethanol 2,000 1.2
Acetic Acid 2,000 -0.3
Ethylene 100 0.3
Methyl Alcohol 100 0.1
Isopropanol 100 0.1

Fluorine (F2)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-F2

Gas Concentration (ppm) Output Signal
(in ppm F2)
Fluorine 10 10
Alcohols 1000 0
Arsine 0.2 -0,03
Bromine yes;n/d
Carbon Dioxide 5000 0
Carbon Monoxide 100 0
Chlorine 1 1.4
Diborane 0.25 -0.01
Hydrocarbons % range 0
Hydrochloric Acid 5 -7
Hydrogen 10000 0
Hydrogen Cyanide 1 -0.05
Hydrogen Sulfide 1 -2
Nitrogen 100% 0
Nitrogen Dioxide 10 8
Ozone 0.25 0.3
Phosphine 0.3 approx. -0.1 ppm; n/d
Sulfur Dioxide 20 -0.2

Hydrazine (N2H4)

Sensor Type: Electrochemical Gas Sensor
Product: 
NA

Gas Concentration (ppm) Output Signal
(in ppm F2)
Hydrazine 10 10
Ammonia 1.2 1
Carbon Dioxide 1000 0
Carbon Monoxide 1 1.8
Methane 1000 0
Methylhydrazine 1 0.8



Hydrogen (H2)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-H2

Gas Concentration (ppm) Output Signal
(in ppm H2)
Hydrogen 100 100
Hydrogen Sulfide 25 0.0
Sulfur Dioxide 5 0.0
Carbon Monoxide 50 200.0
Nitric Oxide 35 < 10.0
Nitrogen Dioxide 5 0.0
Ethylene 100 80.0
Chlorine 10 0.0


Hydrogen Bromide (HBr)

Sensor Type: Electrochemical Gas Sensor
Product: 
NA

Gas Concentration (ppm) Output Signal
(in ppm HBr)
Hydrogen Bromide 10 10
Chlorine 20 -8
Carbon Monoxide 100 1
Hydrogen 1,000 <1
Nitrogen Dioxide 10 2
Sulfur Dioxide 20 52
Ethylene 100 1
Hydrogen Sulfide 5 60


Hydrogen Chloride (HCl)

Sensor Type: Electrochemical Gas Sensor
Product:
FD-90A-HCl

Gas Concentration (ppm) Output Signal
(in ppm HCl)
Hydrogen Chloride 10 10
Carbon Monoxide 100 0.0
Sulfur Dioxide* 10 25.0
Nitric Oxide 20 50.0
Nitrogen Dioxide 10 1.0
Hydrogen 2,000 0.0
Hydrogen Sulfide 25 100.0
Nitrogen 100% 0.0
Chlorine 20 -5.0


Hydrogen Cyanide (HCN)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-HCN

Gas Concentration (ppm) Output Signal
(in ppm HCN)
Hydrogen Cyanide 10 10
Carbon Monoxide 300 0.0
Sulfur Dioxide 5 18.1
Nitric Oxide 35 0.0
Nitrogen Dioxide 5 -9.5
Hydrogen Sulfide 5 14.9
Ethylene 100 0.0
Carbon Dioxide 5000 0.0
Ethanol 600 0.0


Hydrogen Fluoride (HF)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-HF

Gas Concentration (ppm) Output Signal
(in ppm HF)
Hydrogen Fluoride 10 10
Hydrogen Sulfide 25 -1.0
Sulfur Dioxide 20 -0.2
Nitric Oxide 50 0.0
Nitrogen Dioxide 5 4.3
Carbon Monoxide 100 0.0
Hydrogen 1,000 0.0


Hydrogen Peroxide (H2O2)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-H2O2

Gas Concentration (ppm) Output Signal
(in ppm H2O2)
Hydrogen Peroxide 10 10
Sulfur dioxide 20 20

Hydrogen Sulfide (H₂S)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-H2S

Gas Concentration (ppm) Output Signal
(in ppm H2S)
Hydrogen Sulfide 10 10
Carbon Monoxide 100 0.0
Nitric Oxide 50 -0.7
Nitrogen Dioxide 10 -2.1
Ammonia 50 3.8
Hydrogen 1,000 0.0
Chlorine 15 -7.8
Sulfur Dioxide 20 16.1
Ethylene 100 0.0
Ethanol 2,000 0.0


Mercaptan (CH4S)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-CH4S

Gas Concentration (ppm) Output Signal
(in ppm CH4S)
Methanethiol 10 10
Carbon Monoxide 50 < 5.5
Sulfur Dioxide 5 < 2.1
Nitrogen Dioxide 5 < -3.5
Nitric Oxide 25 0.0
Ammonia 50 0.0
Hydrogen 1,000 < 10.0
Hydrogen Sulfide 25 40.0


Nitric Oxide (NO)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-NO

Gas Concentration (ppm) Output Signal
(in ppm NO)
Nitric Oxide 10 10
Hydrogen Sulfide 25 11.0
Carbon Monoxide 100 0.0
Nitrogen Dioxide 5 < 0.2
Sulfur Dioxide 5 < 0.3
Ethylene 100 0.0
Hydrogen 1,000 < 0.3


Nitrogen Dioxide (NO₂)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-NO2

Gas Concentration (ppm) Output Signal
(in ppm NO2)
Nitrogen Dioxide 10 10
Hydrogen Sulfide 15 < -5.0
Carbon Monoxide 300 0.0
Nitric Oxide 35 0.0
Chlorine 10 1
Sulfur Dioxide 5 -5.0
Ozone 10 5


Ozone (O₃)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-O3

Gas Concentration (ppm) Output Signal
(in ppm O3)
Ozone 10 10
Hydrogen Sulfide 20 -4.0
Sulfur Dioxide 20 < 1.0
Nitric Oxide 50 < 1.0
Nitrogen Dioxide 10 10
Carbon Monoxide 100 0.0
Ammonia 100 0.0
Hydrogen 1,000 0.0
Chlorine 10 9.0
Carbon Dioxide 10,000 0.0


Oxygen (O₂)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-O2, FD-103-O2, FD-600-O2

Gas Concentration Output Signal
(in %O2 equivalent)
Oxygen 10% 10%
Carbon Dioxide 5% 0.1%
Hydrogen 0.2% -0.2%


Phosgene (COCl2)

Sensor Type: Electrochemical Gas Sensor
Product:
NA

Gas Concentration (ppm) Output Signal
(in ppm COCl2)
Phosgene 10 10
Chlorine 5 26.4
Carbon Dioxide 3,000 0.0
Carbon Monoxide 50 0.0
Hydrogen 1,000 0.0
Hydrogen Sulfide 5 -3.3
Ammonia 10 -2.5
Nitric Oxide 10 0.0


Phosphine (PH₃)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-PH3

Gas Concentration (ppm) Output Signal
(in ppm PH3)
Phosphine 10 10
Hydrogen Sulfide 15 12.0
Sulfur Dioxide 20 6.2
Ammonia 50 0.0
Hydrogen 1,000 0.0
Carbon Monoxide 1,000 0.0
Ethylene 100 0.0


Silane (SiH4)

Sensor Type: Electrochemical Gas Sensor
Product:
NA

Gas Concentration (ppm) Output Signal
(in ppm SiH4)
Silane 10 10
Sulfur Dioxide 20 6.6
Nitric Oxide 50 0.0
Ammonia 50 0.0
Carbon monoxide 100 4.1
Nitrogen Dioxide 10 -3.1
Hydrogen Sulfide 2 1.7
Chlorine 15 -3.9


Sulfur Dioxide (SO2)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-SO2

Gas Concentration (ppm) Output Signal
(in ppm SO2)
Sulfur Dioxide 10 10
Hydrogen Sulfide 15 0.1
Carbon Monoxide 100 0.0
Nitric Oxide 50 0.1
Nitrogen Dioxide 5 -5.5
Hydrogen 1,000 0.2
Ammonia 20 0.0
Chlorine 5 -1.5
Acetylene 10 < 2.0
Ethylene 50 0.2


Styrene (C8H8)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-C8H8

Gas Concentration (ppm) Output Signal
(in ppm VOC)
Styrene 10 10
Isobutylene 5 5
Ethylene 5 3.16
Formaldenhyde 5 6
Methyl Mercaptan 5 7
Ethylene Oxide 5 3.83
Ethanol 5 1.83
Carbon Disulfide 5 1.23
Dimethyl Disulfide 2 6.8
Methanol 5 5.95
Methyl Sulfide 5 8.97
Styrene 0.5 7.5
Benzene 5 1.1
Toluene 5 0.81
O-xylene 5 0.58
Gasoline Volatilization 
(dimensionless)
/ Responded well
Acrylonitrile / Responded well
Acetylene / Responded well
Formic acid 5 5.36
Acetic acid 5 1.1
Carbon Monoxide 5 3.38
Hydrogen Chloride 5 0.27
Hydrogen Cyanide 5 0.36
Ammonia 5 1.5
Hydrogen 5 1.15
Trimethylamine 5 0.65
Nitrogen Dioxide 5 1.86

Tetrahydrothiophene (C4H8S) THT

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-THT

Gas Concentration ( mg/m3) Output Signal
(in mg/m3 C4H8S)
Tetrahydrothiophene  10 10
Hydrogen Sulfide 25 8.5
Carbon Monoxide 50 0.1
Nitric Oxide 35 < 130.0
Sulfur Dioxide 5 0.0
Nitrogen Dioxide 10 16.0

Vinyl Chloride (C2H3Cl)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-C2H3Cl

Gas Concentration (ppm) Output Signal
(in ppm C2H3Cl)
Vinyl Chloride 10 10
Carbon Monoxide 25 15.0
Isobutylene 50 35.0
Ethylene 50 65.0
Acetylene 50 85.0
Ethanol 100 55.0

Volatile Organic Compound  (VOC)

Sensor Type: Electrochemical Gas Sensor
Product: 
FD-90A-VOC

Gas Concentration (ppm) Output Signal
(in ppm VOC)
Volatile Organic Compound 10 10
Isobutene 5 5
Ethylene 5 3.16
Formaldenhyde 5 6
Methyl Mercaptan 5 7
Ethylene Oxide 5 3.83
Ethanol 5 1.83
Carbon Disulfide 5 1.23
Dimethyl Disulfide 2 6.8
Methanol 5 5.95
Methyl Sulfide 5 8.97
Styrene 0.5 7.5
Benzene 5 1.1
Toluene 5 0.81
O-xylene 5 0.58
Gasoline Volatilization 
(dimensionless)
/ Responded well
Acrylonitrile / Responded well
Acetylene / Responded well
Formic acid 5 5.36
Acetic acid 5 1.1
Carbon Monoxide 5 3.38
Hydrogen Chloride 5 0.27
Hydrogen Cyanide 5 0.36
Ammonia 5 1.5
Hydrogen 5 1.15
Trimethylamine 5 0.65
Nitrogen Dioxide 5 1.86

 


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