The influence of humidity on the performance of a low-cost air particle mass sensor and the effect of atmospheric fog

Jayaratne, Rohan; Liu, Xiaoting; Thai, Phong K.; Dunbabin, Matthew; Morawska, Lidia

doi:10.5194/amt-11-4883-2018

Cited by 257 publications

(218 citation statements)

References 22 publications

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“…These models have been selected due to their frequency of use in air quality monitoring studies and for their compact size and price which makes them suitable for large scale deployments. The Plantower PMS5003 has been widely studied [32,35,40,43,45,50,51]. The Alphasense OPC-R1 is a lower cost and lower size version of the OPC-N2 which is widely used and studied [33,35,40,52,53].…”

Section: Low-cost Pm Sensorsmentioning

confidence: 99%

“…Humidity and temperature fluctuations are known to alter the recorded particle mass as they can change the amount of water adsorbed by particles and therefore their recorded size but also modifies the refractive index of the particles. Low-cost PM sensors tend to over report above a given Relative Humidity (RH) (generally, around 80%) and if the particular conditions for condensation of water are reached this can further impact measurement [32,33]. Jayaratne et al [32] notes that this behaviour may also affect reference instruments such as Tapered Element Oscillating Microbalances (TEOMs) to a certain extent.…”

Section: Introductionmentioning

confidence: 99%

“…Low-cost PM sensors tend to over report above a given Relative Humidity (RH) (generally, around 80%) and if the particular conditions for condensation of water are reached this can further impact measurement [32,33]. Jayaratne et al [32] notes that this behaviour may also affect reference instruments such as Tapered Element Oscillating Microbalances (TEOMs) to a certain extent. In Nyarku et al [34] a mobile phone equipped with PM and Volatile Organic Compounds (VOC) sensors was tested against reference instruments with a range of pollutants, the PM sensor was found to have a linear response at elevated PM concentrations but not at the lower concentrations pertinent to ambient monitoring.…”

Section: Introductionmentioning

confidence: 99%

“…The great majority of the recent studies investigating the performance of low-cost PM sensors in a laboratory environment, average concentrations over extended periods of time, for example 1 h, are measured, or pollution events which concentration then decreases slowly over several minutes or hours [41]. Other laboratory studies often tested a small number of sensors or sensors from a same manufacturer [32,34,37,[43][44][45][46], and often employed high concentrations of PM, above 100 µg/m 3 that are left to decrease through gravity or particle loss [34,36,44,[46][47][48].…”

Section: Introductionmentioning

confidence: 99%

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Laboratory Comparison of Low-Cost Particulate Matter Sensors to Measure Transient Events of Pollution

Bulot

Russell

Rezaei

et al. 2020

Sensors

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Airborne particulate matter (PM) exposure has been identified as a key environmental risk factor, associated especially with diseases of the respiratory and cardiovascular system and with almost 9 million premature deaths per year. Low-cost optical sensors for PM measurement are desirable for monitoring exposure closer to the personal level and particularly suited for developing spatiotemporally dense city sensor networks. However, questions remain over the accuracy and reliability of the data they produce, particularly regarding the influence of environmental parameters such as humidity and temperature, and with varying PM sources and concentration profiles. In this study, eight units each of five different models of commercially available low-cost optical PM sensors (40 individual sensors in total) were tested under controlled laboratory conditions, against higher-grade instruments for: lower limit of detection, response time, responses to sharp pollution spikes lasting <1 min, and the impact of differing humidity and PM source. All sensors detected the spikes generated with a varied range of performances depending on the model and presenting different sensitivity mainly to sources of pollution and to size distributions with a lesser impact of humidity. The sensitivity to particle size distribution indicates that the sensors may provide additional information to PM mass concentrations. It is concluded that improved performance in field monitoring campaigns, including tracking sources of pollution, could be achieved by using a combination of some of the different models to take advantage of the additional information made available by their differential response.

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Section: Low-cost Pm Sensorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Laboratory Comparison of Low-Cost Particulate Matter Sensors to Measure Transient Events of Pollution

Bulot

Russell

Rezaei

et al. 2020

Sensors

View full text Add to dashboard Cite

show abstract

“…9(B) and (C), while more pronounced scatter is observed at an elevated temperature and humidity. In general, humidity of the air can affect the performance of optical PM sensors in several ways: failure of the electronic circuits/sensors, overestimated outputs in sensor signals due to hygroscopic growth of some particles, detection of water droplets in fog or mist as particles [24], [25], [26], [27], and deterioration of sensor performance due to absorption of infrared radiation by water [28]. Histogram of PMD PM 2.5 in Fig.…”

Section: Methodsmentioning

confidence: 99%

Calibration of Portable Particulate Matter–Monitoring Device using Web Query and Machine Learning

Loh

Choi

2019

Safety and Health at Work

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BackgroundMonitoring and control of PM2.5 are being recognized as key to address health issues attributed to PM2.5. Availability of low-cost PM2.5 sensors made it possible to introduce a number of portable PM2.5 monitors based on light scattering to the consumer market at an affordable price. Accuracy of light scattering–based PM2.5 monitors significantly depends on the method of calibration. Static calibration curve is used as the most popular calibration method for low-cost PM2.5 sensors particularly because of ease of application. Drawback in this approach is, however, the lack of accuracy.MethodsThis study discussed the calibration of a low-cost PM2.5-monitoring device (PMD) to improve the accuracy and reliability for practical use. The proposed method is based on construction of the PM2.5 sensor network using Message Queuing Telemetry Transport (MQTT) protocol and web query of reference measurement data available at government-authorized PM monitoring station (GAMS) in the republic of Korea. Four machine learning (ML) algorithms such as support vector machine, k-nearest neighbors, random forest, and extreme gradient boosting were used as regression models to calibrate the PMD measurements of PM2.5. Performance of each ML algorithm was evaluated using stratified K-fold cross-validation, and a linear regression model was used as a reference.ResultsBased on the performance of ML algorithms used, regression of the output of the PMD to PM2.5 concentrations data available from the GAMS through web query was effective. The extreme gradient boosting algorithm showed the best performance with a mean coefficient of determination (R2) of 0.78 and standard error of 5.0 μg/m3, corresponding to 8% increase in R2 and 12% decrease in root mean square error in comparison with the linear regression model. Minimum 100 hours of calibration period was found required to calibrate the PMD to its full capacity. Calibration method proposed poses a limitation on the location of the PMD being in the vicinity of the GAMS. As the number of the PMD participating in the sensor network increases, however, calibrated PMDs can be used as reference devices to nearby PMDs that require calibration, forming a calibration chain through MQTT protocol.ConclusionsCalibration of a low-cost PMD, which is based on construction of PM2.5 sensor network using MQTT protocol and web query of reference measurement data available at a GAMS, significantly improves the accuracy and reliability of a PMD, thereby making practical use of the low-cost PMD possible.

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Diurnal and seasonal source‐proximal dust concentrations in complex terrain, West Greenland

Bullard

Prater

Baddock

et al. 2023

Earth Surf Processes Landf

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Diurnal and seasonal cycles of aeolian activity are well‐constrained for low latitude dust source regions and provide valuable insights into relationships between dust emissions and environmental drivers. Such cycles have received little systematic attention in high latitude dust source areas (≥50°N and ≥40°S), and understanding them will aid the modelling of atmospheric dust over different timescales. This paper examines the timing and drivers of atmospheric dust concentration close to source at ice‐free locations c. 6 km and c. 37 km from the Greenland Ice Sheet margin. Dust concentration, and associated environmental drivers including wind speed and velocity, air temperature and humidity, was measured from April–October 2018 and April–August 2019. Measured dust concentrations were a similar order of magnitude to source‐proximal values measured globally and varied from 0 to ≥1000 μg m−3. Diurnal cycles in the environmental drivers of dust emission were similar to those observed in low latitudes, but unlike in the low latitudes, there was no clear diurnal pattern of dust concentration. Only 3 out of 17 recorded dust events showed a significant positive relationship between wind speed and dust concentration, and factors such as wind direction, humidity and sediment availability are the over‐riding controls on dust activity at the event and seasonal scales. Whereas 7 dust events are attributed to down‐valley katabatic winds, 10 events were associated with a westerly sea breeze blowing up‐valley towards the ice sheet and high atmospheric moisture content. If deposited on the ice, this dust will alter ice albedo both directly and indirectly, (e.g. through the promotion of algal blooms) affecting cryospheric melt rates. Our results demonstrate an intricate relationship between first‐order controls and dust concentration that raises challenges for modelling the uplift and subsequent dust transport from high latitude sources, especially the appropriateness of assumptions based on emissions behaviour at low latitudes.

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The influence of humidity on the performance of a low-cost air particle mass sensor and the effect of atmospheric fog

Cited by 257 publications

References 22 publications

Laboratory Comparison of Low-Cost Particulate Matter Sensors to Measure Transient Events of Pollution

Laboratory Comparison of Low-Cost Particulate Matter Sensors to Measure Transient Events of Pollution

Calibration of Portable Particulate Matter–Monitoring Device using Web Query and Machine Learning

Diurnal and seasonal source‐proximal dust concentrations in complex terrain, West Greenland

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