Right.AlphasenseLow-cost particulate matter (PM) The third-party evaluation of the air quality sensor shows that it has a good correlation with the reference equipment, and the cost only accounts for a small part of this type of reference equipment.AlphasenseSales Manager, EuropeWill ParrettWelcoming the test results, he said: "As more and more low-cost sensors appear on the market, it is becoming more and more difficult for customers to choose a technology they can trust. Therefore, third-party evaluations such as these are very useful."

The release of these results comes at an opportune time, as there has been an increased focus on fine particulate matter in recent months as the health effects have become more widely understood. 2021 Year 9 Month of the World Health OrganizationWTOThe annual averagePMGuideline value reduced5 µg/m3，2022 Year 3 In April, the British government announced a consultation on new targets to be included in the Environmental Act, including 2040 years willPM2.5Reduced10 µg/m3of the target.

PMSensor evaluation involves3OnlyAlphasenseofOPC-R2sensors, they are deployed in CaliforniaRubidouxofSouth CoastAQMDof fixed environmental monitoring sites, running time from2021Year10Month12month, for a period of three months. Together with these sensors are federal equivalent method instruments (FEM), the monitored parameters include: particulate matterPM1、PM2.5、PM10and relative humidity and temperature.

OPCTest Background

The South Coast Air Quality Management Area is (South CoastAQMD）It is the agency responsible for achieving state and federal clean air standards in the South Shore Air Region of Southern California. The South Coast Air Area covers an area6745square mile, which contains Los Angeles, with a population of about1460Ten thousand.

In order to inform the public about the actual performance of commercial "low-cost" air quality sensors,South CoastAQMDAn air quality sensor performance evaluation center (AQ-SPEC) project to characterize sensors in field and laboratory environments.AQ-SPECThe project was established in2014years, in the past8During the year, the project team and more100Home Sensor Manufacturers/Developer/suppliers work closely together to evaluateMore170OnlyMonitoringNational Ambient Air Quality Standards(NAAQS)of the baseline contaminant sensor. To qualify for the assessment, the sensor must be less2000The cost of dollars and one of the target parameter lists must be monitored in real time or near real time.AlphasenseThe sensor is in line with this study, but the cost is well below the target cost quota.

Recognize the growing popularity of low-cost air quality sensors, because of concerns that sensor data should not be accepted without evaluating the accuracy and overall quality of the equipment.AQ-SPECThe project came into being. As new devices enter the market, there are concerns that low-quality data from unreliable sensors will not only lead to confusion, but will also jeopardize the successful development of low-cost sensor technology. In addition to the need to characterize the performance of air monitoring sensors,South CoastAQMDAttempts are also being made to inform the public about the advantages and potential disadvantages of such devices.

Gaseous and particulate pollutants are currently beingAQ-SPECAssessment. with a diameter equal to or less 10 and 2.5 Micron(Μm)of particulate matter (respectivelyPM10andPM2.5)-related health risks are particularly relevant to public health.PM2.5andPM10can go deep into the lungs,PM2.5It can even enter the bloodstream, mainly causing cardiovascular and respiratory effects, but also affecting other organs.

Alphasense OPC-R2Particulate Matter Sensor

Less than weight 30 grams, the longest dimension is 72 mm,OPC-R2(Optical particle counter) provides impressive performance for such a small sensor. The laser part of the sensor is used to detect particle size from 0.30 To12.4 µmof particles, 16 software."bin”。 Use an embedded algorithm to convert count measurementsPM1.0、PM2.5andPM10mass concentration. The sensor also measures temperature and relative humidity.

AllAlphasenseSensors are factory calibrated prior to shipment, and data acquisition software is available from www.alphasense.com Download for free.South CoastAQMDNo further calibration was performed prior to the start of the test.

OPCTest Evaluation Results

For allPMmeasurement,AlphasenseThe data recovery rate of the sensor is close 100%。OPC-R2The performance of the sensor is determined by twoFEMreference instruments were evaluated,South Coast AQMDThe cost of each instrument is estimated in 21,000 dollars 25,000 between dollars. InPMWithin the scope, twoFEMThere is a strong correlation between the instruments.

Alphasense OPC-R2Sensor1Hourly average results show:

PM1: andFEMThe instrument has a strong correlation (0.77 ）。

PM2.5: andFEMThe instrument has a moderate to strong correlation (0.67 ）。

PM10: andFEMinstruments with strong to very strong correlations (0.70 ）。

with the correspondingSouth Coast AQMDThe temperature and humidity of the weather station data have a strong correlation (respectivelyR2 ~0.95andR2 ~0.97）

R2is the linear correlation coefficient, which measures the linear relationship between the average measurement value of the three sensors under test and the corresponding reference instrument value. Approaching value 1 ofR2reflect near perfect agreement between sensor and reference readings, while the values 0 Indicates a complete lack of relevance.

Right.OPC-R2The successful evaluation of the sensor builds onAlphasenseof otherPMSensorOPC-N3In 2018 YearSouth Coast AQMDbased on the high level of performance demonstrated during the evaluation.OPC-N3thanOPC-R2Slightly larger, detectable particle size is 0.35 To40 µmparticles, and classify them 24 software."bin"In.OPC-N3Dimensions are 65 mm (width)x 75mm (long), weight less 105 g. withOPC-R2the same,OPC-N3RecordPM1.0、PM2.5andPM10(OPTIONALPM4.25) And measure temperature and relative humidity.Alphasense OPC-N3sensor (average 1 hours) the test results of the evaluation show that:

PM1: andGRIMMInstrument correlation is good (R2 ~ 0.80）。

PM2.5: separatelyFEM GRIMM、FEM BAM.andFEM T640instruments with moderate to good correlation (R2 ~ 0.64、0.44 and 0.57）。

PM10: andGRIMM、FEM BAM.andT640Instrument (R2 ~ 0.51、0.28 and 0.47) has a low to moderate correlation.

with the corresponding south coastAQMDThe temperature and humidity of the weather station data have a strong correlation (respectivelyR2 ~0.97andR2 ~0.98）

OPCTest Evaluation Summary

Alphasense OPC-R2sensors in all threePMAll performed well in the range. "We are rightSouth Coast AQMDHappy with the assessment; The evaluation results provide our customers with the assurance that high-quality data can be obtained from these low-cost sensors,"Will Parrettas it is said.

"We appreciateSouth Coast AQMDefforts, because third-party evaluations such as these can help customers choose reliable technologies. This builds confidence and trust in low-cost monitors, which in turn can significantly improve air quality monitoring and encourage wider adoption of air quality monitoring programs and initiatives."

The improved temporal and spatial resolution provided by the low-cost monitor provides the necessary data granularity to help governments, local authorities and educational institutions better understand the impact of air quality, while also being able to implement and evaluate effective air quality mitigation Measures.

By reducing the cost of each monitoring point without affecting data accuracy and quality, these sensors facilitate the development of monitoring networks, thereby providing a deeper understanding of the factors that affect air quality.

To understand aboutAlphasense OPCFor more information on products and gas sensors, please visit www.alphasense.com。

The full assessment report is available on the South CoastAQMDWebsitehttp://www.aqmd.gov/aq-spec/evaluations/field obtained on.