Low-cost Particle Counter Research Articles

Challenges in Detecting Clouds in Polar Regions Using a Drone with Onboard Low-Cost Particle Counter

It is expected that uncrewed aerial vehicles (UAVs) will be used increasingly for operational atmospheric soundings to cover a broader area of the lower troposphere, including that in the polar regions and over the oceans. During the Japanese Antarctic Research Expedition of 2022/2023, 172 vertical profiles up to a maximum height of 1000 m a.s.l. were conducted from mid-December 2022 to mid-March 2023 using a commercially available inexpensive drone launched from the icebreaker RV Shirase. Over a quarter of the flights encountered clouds and snow, of which half produced icing on the body and blades of the drone. The onboard aerosol counter detected an increase in the particle number concentration in the cloud layers, which was synchronized with an increase in the attenuated backscatter coefficient of a shipboard lidar ceilometer. In the presence of icing, the concentration of particles >1.0μm exceeded 5000 particles L−1 as a median value, while the concentration was <1000 particles L−1 for cases without icing. Using an onboard aerosol counter and/or land-based ceilometer would be useful for detecting the icing environments.

Assessment of the exposure to PM2.5 in different Lebanese microenvironments at different temporal scales.

The weak potential of using the sole outdoor concentrations to represent personal exposure to PM2.5 is confirmed by the literature; therefore, it is important to account for a person’s movements over time when estimating the short-term personal air pollution exposure within different microenvironments (MEs). This study is an example of applying an assessment method of the exposure to PM2.5 in different microenvironments at different temporal scales. A low-cost particle counter (the Dylos 1700) was used; its performance was validated in comparison with equivalent instruments such the SidePak AM520 Personal Aerosol Monitor (R2 = 0.89). This validation also provided a function to convert measured particle number concentrations (PNCs) into calculated particle mass concentrations. The 150 profiles that was collected on a minute-by-minute basis regarding PM2.5 concentration from December 2018 to May 2021 highlight the influence of individual activities and contextual factors on the air quality, so that Lebanon’s annual PM2.5 mean (24.2 µg⁄m3) is 142% higher than the World Health Organization (WHO) annual mean guideline (10 µg⁄m3). Winter is the most polluted period due to the increased application of space heating devices. Additionally, the occurrence of dusty winds during the spring period leads to the elevated levels of dispersed PM2.5. Simultaneously, the rural zones are more polluted than urban ones due to the usage of more traditional heating equipment, in addition to the usage of chemical products like pesticides and fertilizers in agricultural activities in such areas. Furthermore, the (outdoor–indoor–transport) MEs indicate that the transport and indoor MEs have similar levels of suspended fine particulates, while outdoor MEs are less polluted. Studies based on the personal exposure to PM2.5 were generally applied on specific and limited places such as schools, workplaces, or residences. The study aims to shed light on the modern method in an attempt to estimate the personal exposure to PM2.5 and to inspire similar studies to achieve the maximum efficiency.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10661-022-10607-6.

Use of Low-Cost Particle Counters for Cotton Dust Exposure Assessment in Textile Mills in Low- and Middle-Income Countries.

ObjectiveThere is a lack of consensus on methods for cotton dust measurement in the textile industry, and techniques vary between countries—relying mostly on cumbersome, traditional approaches. We undertook comparisons of standard, gravimetric methods with low-cost optical particle counters for personal and area dust measurements in textile mills in Pakistan.MethodsWe included male textile workers from the weaving sections of seven cotton mills in Karachi. We used the Institute of Occupational Medicine (IOM) sampler with a Casella Apex 2 standard pump and the Purple Air (PA-II-SD) for measuring personal exposures to inhalable airborne particles (n = 31). We used the Dylos DC1700 particle counter, in addition to the two above, for area-level measurements (n = 29).ResultsThere were no significant correlations between the IOM and PA for personal dust measurements using the original (r = −0.15, P = 0.4) or log-transformed data (r = −0.32, P = 0.07). Similarly, there were no significant correlations when comparing the IOM with either of the particle counters (PA and Dylos) for area dust measurements, using the original (r = −0.07, P = 0.7; r = 0.10, P = 0.6) or log-transformed data (r = −0.09, P = 0.6; r = 0.07, P = 0.7).ConclusionOur findings show a lack of correlation between the gravimetric method and the use of particle counters in both personal and area measurements of cotton dust, precluding their use for measuring occupational exposures to airborne dust in textile mills. There continues to be a need to develop low-cost instruments to help textile industries in low- and middle-income countries to perform cotton dust exposure assessment.

Development of a low-cost air sensor package and indoor air quality monitoring in a California middle school: Detection of a distant wildfire

ABSTRACTA low-cost air sensor package was used to monitor indoor air quality (IAQ) in a classroom at the Albany Middle School in the San Francisco Bay Area of California. A rapid increase in carbon dioxide (CO2) was observed in the classroom as soon as it is occupied. When the classroom is unoccupied, the CO2 levels decay slowly toward the outdoor background level. All high CO2 concentrations observed inside the classroom, above the outdoor background, was due to exhaling of the occupants. The CO2 concentrations generally exceed the recommended level of 1000 ppb towards the end of the school day. The exceedances and slow decay may suggest that the ventilation rate in this school is not sufficient. The particulate level in the classroom was low until a distant wildfire advected large amount of particulate matter to the San Francisco Bay Area. Very high (10–15 times compared to the background) particle numbers (per m3 of particles with diameter >0.3 µm) were observed in the classroom during the wildfire. These particles were relatively small (0.3–1.0 µm) and the filters (MERV 8) of the ventilation system were unable to filter them out. Therefore, the measurements made by low-cost particle counters can inform the school administrators of adverse IAQ during future wildfire (or other combustion) events. The particle number was independent of the occupation before and during the wildfire suggesting that all observed particles were infiltrated into the classroom from outside. Consistent with previous studies, no appreciable increase in the local ambient CO2 background was observed during this distant wildfire event.Implications: Low-cost air sensors are effective in monitoring indoor air quality in classrooms. The CO2 levels in classrooms are mainly generated indoors due to exhalation of occupants. Concentration of CO2 generally exceed the recommended level of 1000 ppb towards the end of the school day. In contrast, the particulate matter mostly comes from outdoors and small particles penetrate though the filters normally used at schools. Distant wildfires do not increase the local CO2 background appreciably, but significantly increase the particulate matter concentrations both indoors and outdoors. Further investigations are needed to assure that ventilation rates in classrooms are sufficiently health protective.

The Potential of a Low-Cost Particle Counter to Quantify Airborne Particulate Matter in a Laboratory Animal Facility

The Potential of a Low-Cost Particle Counter to Quantify Airborne Particulate Matter in a Laboratory Animal Facility

Personal exposure monitoring of PM2.5 in indoor and outdoor microenvironments

Adverse health effects from exposure to air pollution are a global challenge and of widespread concern. Recent high ambient concentration episodes of air pollutants in European cities highlighted the dynamic nature of human exposure and the gaps in data and knowledge about exposure patterns. In order to support health impact assessment it is essential to develop a better understanding of individual exposure pathways in people's everyday lives by taking account of all environments in which people spend time. Here we describe the development, validation and results of an exposure method applied in a study conducted in Scotland.A low-cost particle counter based on light-scattering technology — the Dylos 1700 was used. Its performance was validated in comparison with equivalent instruments (TEOM-FDMS) at two national monitoring network sites (R2=0.9 at a rural background site, R2=0.7 at an urban background site). This validation also provided two functions to convert measured PNCs into calculated particle mass concentrations for direct comparison of concentrations with equivalent monitoring instruments and air quality limit values.This study also used contextual and time-based activity data to define six microenvironments (MEs) to assess everyday exposure of individuals to short-term PM2.5 concentrations. The Dylos was combined with a GPS receiver to track movement and exposure of individuals across the MEs. Seventeen volunteers collected 35 profiles. Profiles may have a different overall duration and structure with respect to times spent in different MEs and activities undertaken. Results indicate that due to the substantial variability across and between MEs, it is essential to measure near-complete exposure pathways to allow for a comprehensive assessment of the exposure risk a person encounters on a daily basis. Taking into account the information gained through personal exposure measurements, this work demonstrates the added value of data generated by the application of low-cost monitors.

Using a new, low-cost air quality sensor to quantify second-hand smoke (SHS) levels in homes

To determine if a low-cost particle counter, the Dylos DC 1700, can be used in homes to quantify second-hand smoke (SHS) concentrations. Participants were recruited from a hospital-based study of attitudes on smoking. Two photometric devices (Dylos DC1700 and Sidepak AM510 Personal Aerosol Monitor) capable of measuring and logging concentrations of particulate matter were placed in smoking and non-smoking homes for approximately 24h. Acquired data were randomly allocated to one of two groups: one was used to generate a calibration equation using regression techniques; the second was used for validation of the generated model. The mean difference and limits of agreement between the two instruments were calculated using the validation dataset. Summary air-quality results were also compared across the entire dataset. Over 500 001 minute concentration measurements were collected from 34 homes. 25 301 randomly selected paired-measurements were used to generate a calibration equation (R(2) 0.86) converting the particle number concentration from the Dylos to a mass concentration of PM2.5 as measured by the Sidepak. The mean difference (limits of agreement) between the remaining 25 102 paired measurements was -0.09 (-49.7 to 49.5) with 3.2% of values outside the limits of agreement. Differences in the air quality information generated by the two instruments were generally small and unlikely to impact on user interpretation. The Dylos appears to be a valid instrument for measuring PM2.5 in household settings. The Dylos may be useful in air quality-based interventions designed to change smokers' behaviours with the possibility of encouraging cessation and/or smoke-free homes.

A low-cost particle counter as a realtime fine-particle mass monitor.

Exposure to particles with aerodynamic diameters less than 2.5 μm is estimated to cause significant morbidity and mortality worldwide leading many countries to develop ambient air pollution standards and guidelines. At local scales, community and environmental justice groups are also concerned about PM 2.5 concentrations that may be elevated above regional concentrations typically measured by centrally located monitors and standards as well. In an attempt to develop a low cost, easy to use monitor we evaluated a low-cost optical particle counter, the Dylos™, as a fine particulate mass sensor. Modified into a system called the Berkeley Aerosol Information Recording System (BAIRS), we compared performance against standard commercial instruments in chambers using polystyrene latex spheres, ammonium sulphate, and woodsmoke and in an urban ambient setting. Overall we find that the limit of detection of the BAIRS is less than 1 μg m (-3) and the resolution is better than 1 μg m(-3) for PM 2.5. The BAIRS sizes small (<0.5 μm) particles, and is able to accurately estimate the mass concentration of particles of varying composition including organic, inorganic, and ambient particles. It is able to measure concentrations up to 10.0 mg m (-3). In an ambient roof-top test of the BAIRS and a more expensive commercially available light scattering particle monitor the BAIRS response tracked well with the commercial monitor and daily means were within 80% of each other. We conclude that with appropriate modification the system could be developed into an accurate low cost realtime particle mass monitor for use in a wide range of applications.