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NH3 sensor

Ammonia

Reliable real-time
information on NH3

GasPlug TECHNOLOGY | PATENTED DESIGN

Ammonia
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Where is it found?

Ammonia (NH3) is a colourless gas with a pungent odour that can be detected by humans at 0.4-1 ppm, being the exposure limit 50 ppm.

NH3 is originated from both natural and anthropogenic sources, the main ones being agriculture (fertiliser application and fabrication)and livestock (manure management), followed by waste and water management (slurries, composting and landfills). Other sources are household and industrial cleaners, which can directly affect humans exposed to them.

Why is it harmful?

NH3 is a volatile gas poisonous if inhaled at high concentrations, causing respiratory tract and eye irritation, while causing throat and skin irritation in lesser amounts. It is highly soluble in water, so it is associated with acid deposition and eutrophication, affecting to land and water ecosystems by reducing biodiversity.

Besides, it is explosive when mixed with air or oxygen at very high concentrations. NH3 also contributes to the formation of particulate aerosols in the atmosphere as a secondary particulate precursor.​

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NH3 cartridge

The NH3 cartridges contain electrochemical sensors capable of accurately measuring NH3 in different ranges. There are 3 types of NH3 cartridges for different applications:

  • Type A is used to detect from low concentrations up to 50 ppm with a typical noise of less than 0.3 ppm when the ambient temperature is less than 25 ºC. This sensor is responsive to H2S when present at high concentrations (ppm level), which is relevant since the two substances can coexist in the same environment. Therefore, to accurately measure NH3, it is necessary to have the H2S cartridge installed in the same device. Thus, thanks to Kunak’s algorithm which considers both concentrations, it is possible to correct the interference of H2S and obtain precise measurements of NH3.
  • Type B is a higher-range version used to carry out continuous measurements of concentrations up to 1,500 ppm, with decreased precision at low concentrations. Both Type A and Type B sensors are recommended only for industrial leak detection.
  • Type C cartridge can measure continuous (background) concentrations of NH3, with a range up to 100 ppm. It is responsive to H2S, which is why it is recommended to install an H2S cartridge in the same device to correct this interference when H2S is present at high concentrations (ppm level). This cartridge is recommended for continuous NH3 monitoring applications such as farms and livestock.

Technical specifications

Type
Electrochemical
Unit of measurement
mg/m3, ppm
Measurement range(1)
0 - 50 ppm(A)
0 - 1,500 ppm(B)
0 - 100 ppm(C)
Resolution(2)
0.01 ppm
Operating temperature range(3)
-10 to 50ºC(A)
-20 to 43ºC(B)
-20 to 40ºC(C)
Operating RH range(4)
0 to 99 %RH
Recommended RH range(4)
15 to 90 %RH
Operating life(5)
> 24 months
Guarantee range(6)
100 ppm(A)
5,000 ppm(B)
200 ppm(C)
Limit of Detection (LOD)(7)
0.02 ppm(A-C)
0.15 ppm(B)
Repeatability(8)
0.03 ppm(A)
0.5 ppm(B)
0.1 ppm(C)
Response time(9)
< 45 sec(A)
< 45 sec(B-C)
Typical accuracy (MAE)(10)
± 0.3 ppm(A)
± 1.5 ppm(B)
± 0.5 ppm(C)
Typical Intra-model variability (12)
< 0.1 ppm(A-C)
< 0.2 ppm(B)
  1. Measurement range: concentration range measured by the sensor.
  2. Resolution: the smallest unit of measurement that can be indicated by the sensor.
  3. Operating temperature range: temperature interval at which the sensor is rated to operate safely and provide measurements.
  4. Operating RH range (Recommended RH range): humidity interval at which the sensor is rated to operate safely and provide measurements.
  5. Operating life: lifetime of the sensor at normal conditions.
  6. Guarantee range: limit covered by the guarantee.
  7. LOD (Limit Of Detection): measured at laboratory conditions at 20ºC and 50% RH. The limit of detection is the minimum concentration that can be detected as significantly different at zero gas concentration, based on the metric from the Technical Specification CEN/TS 17660-1:2022.
  8. Repeatability (measured at laboratory conditions at 20ºC and 50% RH): closeness of the agreement between the results of successive measurements of the same measure carried out under the same conditions of measurement, based on the metric from the Technical Specification CEN/TS 17660-1:2022.
  9. Response time: time needed by the sensor to reach 90% of the final stable value.
  10. Statistical metric: statistics obtained between the device hourly measurements and reference instruments for 1 to 8 months field test between -10 to +30ºC in different countries. (*) The expected error for PM10 is higher in the presence of coarse particles.
  11. Mean Absolute Error: it is the average mean absolute error (MAE) obtained between the device hourly measurements and reference instruments for 1 to 8 months of field test between -10 to +30ºC in different countries.
  12. Error: it is the error of the sensor at reading measurement or full scale.
  13. DQO-Typical U(exp): Data Quality Objective expressed as the Expanded Uncertainty in the Limit Value obtained between hourly measurements of the device and the reference instruments for 1 to 8 months field test between -10 to +30ºC in different countries, based on the metric from the European Air Quality Directive 2008/50/EC and from the Technical Specification CEN/TS 17660-1:2022. (*) The expected error for PM10 is higher in the presence of coarse particles.
  14. Typical intra-model variability: calculated as the standard deviation of the three sensor means in 1 to 8 months field test between -10 to +30ºC in different countries.

It is essential to have an instrument that is capable of accurately measuring pollution levels and providing reliable results to make informed decisions on air quality and public health.

Javier Fernández

CEO & Co-founder - Kunak