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Particulate matter sensor
PM1, PM2.5, PM4, PM10, TSP & TPC

Accurate measurement of different types of particles

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Where is it found?

Particles are emitted from a wide range of man-made sources. The most significant are road transport, non-combustion processes, industrial combustion plants and processes, commercial and residential combustion and power plants.

Natural sources are less important and include volcanoes and dust storms.

Why is it harmful?

Particles may be seen as one of the most critical of all pollutants. Particulate matter is the generic term to classify air pollutants comprising suspended particles in the air. The size, surface, number and composition of particles play an important role in human health effects. The upper respiratory tract is affected by PM10 while lung alveoli is affected by ultrafine particles (<0.1 μm diameter).

Particles can cause premature mortality in patients suffering from lung or heart disease, provocate heart attacks, aggravate asthma, reduce lung functionality, irritation in airways, coughing, difficulty breathing, etc.

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PM sensor

The particle sensor consists of sensors based on laser scattering technology. To cover different applications, two particle sensors are available:

  • Type A (specific for Kunak AIR Pro stations): an OPC (Optical Particle Counter) capable of measuring particles from 0.3 μm up to 40 μm thanks to 24 bin channels. The PM1, PM2.5, PM4, PM10, Total Suspended Particles (TSP) and Total Particle Counter (TPC) are calculated assuming a particle density profile. Field co-location studies have shown similar field performance as equivalence instruments based on the same technology, even in monitoring coarse particles (Certified Product for Indicative Ambient Particulate Monitors).
  • Type B (specific for Kunak AIR Lite stations): sensor with a range of measurement from 0.3 μm up to 10 μm. The sensor monitors accurately PM1 and PM2.5 concentration, while the expected error for PM10 is higher in the presence of coarse particles.

The effect of humidity is perfectly corrected in both sensors with the embedded algorithm achieving high accuracy at any environmental conditions except under foggy days or condensation, where the data is automatically invalidated by the software Kunak Cloud to prevent data noise.

Besides, the remote Kunak calibration tool allows you to adjust the correction factor to the specific location where the device is installed. Additionally, particle size distributions are available in Kunak AIR Cloud.

Type A (only for Kunak AIR Pro)

Type
Optical particle counter
Unit of measurement
μg/m3
Measurement range(1)
0 - 1,000 μg/m3 (PM1)
0 - 2,000 μg/m3 (PM2.5)
0 - 2,000 μg/m3 (PM4)
0 - 10,000 μg/m3(PM10)
0 - 15,000 μg/m3 (TSP)
0 - 8,000 counts/cm3 (TPC)
Resolution(2)
1 μg/m3
1 count/cm3(TPC)
Operating temperature range(3)
-10 to 50 ºC
Operating RH range(4)
0 to 99 %RH
Recommended RH range(4)
0 to 95 %RH
Operating life(5)
> 24 months
Repeatability(8)
2 μg/m3 (PM1)
3 μg/m3 (PM2.5)
3 μg/m3 (PM4)
5 μg/m3(PM10)
6 μg/m3(TSP)
Response time(9)
< 10 sec
Limit of Detection (LOD)(9)
0.5 μg/m3 (PM1)
0 - 2,000 μg/m3 (PM2.5)
0 - 2,000 μg/m3 (PM4)
0 - 10,000 μg/m3 (PM10)
0 - 15,000 μg/m3 (TSP)
0 - 8,000 counts/cm3 TSP
Typical accuracy (MAE)(10)
± 2 μg/m3 (PM1)
± 3 μg/m3 (PM2.5)
± 3 μg/m3 (PM4)
± 4 μg/m3 (PM10)
± 6 μg/m3 (TSP)
Typical precision R2 (10)
> 0.9 (PM1)
> 0.8 (PM2.5)
> 0.8 (PM4)
> 0.7 (PM10)
> 0.7 (TSP)
> 0.8 (TPC)
Typical slope(10)
0.85 - 1.18
Typical intercept (a)(10)
-1.8 μg/m3 ≤ a ≤ +1.8 μg/m3 (PM1)
-2 μg/m3 ≤ a ≤ +2 μg/m3 (PM2.5)
-2 μg/m3 ≤ a ≤ +2 μg/m3 (PM4)
-3 μg/m3 ≤ a ≤ +3 μg/m3 (PM10)
-4 μg/m3 ≤ a ≤ +4 μg/m3 (TSP)
DQO - Typical U(exp)(11)
< 50%
Typical intra-model variability(12)
< 2 μg/m3

Type B (only for Kunak AIR Lite)

Type
Optical particle counter
Unit of measurement
μg/m3
Measurement range(1)
0 - 1,000 μg/m3
Resolution(2)
1 μg/m3
Operating temperature range(3)
-10 to 60 ºC
Operating RH range(4)
0 to 99 %RH
Operating life(5)
> 24 months
Repeatability(8)
3 μg/m3 (PM1)
3 μg/m3 (PM2.5)
6 μg/m3 (PM10)
Response time(9)
< 10 sec
Limit of Detection (LOD)(7)
0.5 μg/m3 (PM1)
0.5 μg/m3 (PM2.5)
0.5 μg/m3 (PM10)
Typical accuracy (MAE)(10)
± 3 μg/m3 (PM1)
± 3 μg/m3 (PM2.5)
± 6 μg/m3 (PM10) *
Typical precision R2 (10)
> 0.85 (PM1)
> 0.8 (PM2.5)
> 0.5 (PM10)*
Typical slope(10)
0.80-1.25 (PM1)
0.83-1.20 (PM2.5)
0.75-1.35 (PM10)*
Typical intercept (a)(10)
-2 μg/m3 ≤ a ≤ +2 μg/m3 (PM1)
-3 μg/m3 ≤ a ≤ +3 μg/m3 (PM2.5)
-9 μg/m3 ≤ a ≤ +9 μg/m3 (PM10)*
DQO - Typical U(exp)(11)
< 50% (PM1 - PM2.5)
< 75% (PM10)*
Typical intra-model variability(12)
< 2 μg/m3
  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