Dual-wavelength light-scattering technique for selective detection of volcanic ash particles in the presence of water droplets

Jurányi, Z.; Burtscher, H.; Loepfe, M.; Nenkov, M.; Weingärtner, E.

doi:10.5194/amt-8-5213-2015

Cited by 15 publications

(7 citation statements)

References 29 publications

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“…Scattering matrices for a number of typical atmospheric particulates including anthropogenic cement dust, natural dust (loess, desert sand, and volcanic ash), smolder smoke, soot, and water droplets are selected to discuss their application in identification methods for different kinds of particles (Bond & Bergstrom, ; Jurányi et al, ; Keller et al, ; Muñoz et al, ; Volten et al, ; Zhang et al, ). Soot particles were generated by burning of n‐heptane, while smolder smoke was emitted by nonflaming combustion of cotton (Zhang et al, ).…”

Section: Resultsmentioning

confidence: 99%

“…Journal of Geophysical Research: Atmospheres discuss their application in identification methods for different kinds of particles (Bond & Bergstrom, 2006;Jurányi et al, 2015;Keller et al, 2006;Muñoz et al, 2007;Volten et al, 2001;Zhang et al, 2011). Soot particles were generated by burning of n-heptane, while smolder smoke was emitted by nonflaming combustion of cotton (Zhang et al, 2011).…”

Section: Discrimination Of Representative Atmospheric Particulatesmentioning

confidence: 99%

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Scattering Matrix for Typical Urban Anthropogenic Origin Cement Dust and Discrimination of Representative Atmospheric Particulates

Liu

Zhang

et al. 2018

JGR Atmospheres

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The complete scattering matrix for cement dust was measured as a function of scattering angle from 5° to 160° at a wavelength of 532 nm, as a representative of mineral dust of anthropogenic origin in urban areas. Other related characteristics of cement dust, such as particle size distribution, chemical composition, refractive index, and micromorphology, were also analyzed. For this objective, a newly improved apparatus was built and calibrated using water droplets. Measurements of water droplets were in good agreement with Lorenz‐Mie calculations. To facilitate the direct applicability of measurements for cement dust in radiative transfer calculation, the synthetic scattering matrix was computed and defined over the full scattering angle range from 0° to 180°. The scattering matrices for cement dust and typical natural mineral dusts were found to be similar in trends and angular behaviors. Angular distributions of all matrix elements were confined to rather limited domains. To promote the application of light‐scattering matrix in atmospheric observation and remote sensing, discrimination methods for various atmospheric particulates (cement dust, soot, smolder smoke, and water droplets) based on the angular distributions of their scattering matrix elements are discussed. The ratio −F12/F11 proved to be the most effective discrimination method when a single matrix element is employed; aerosol identification can be achieved based on −F12/F11 values at 90° and 160°. Meanwhile, the combinations of −F12/F11 with F22/F11 (or (F11 − F22)/(F11 + F22)) or −F12/F11 with F44/F11 at 160° can be used when multiple matrix elements at the same scattering angle are selected.

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Section: Resultsmentioning

confidence: 99%

Section: Discrimination Of Representative Atmospheric Particulatesmentioning

confidence: 99%

Scattering Matrix for Typical Urban Anthropogenic Origin Cement Dust and Discrimination of Representative Atmospheric Particulates

Liu

Zhang

et al. 2018

JGR Atmospheres

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“…Sensor bekerja pada tegangan 5 V dan arus maksimum 120 mA serta telah dilengkapi dengan internal microcontroller unit (MCU), sehingga sensor ini dapat langsung melakukan komunikasi secara serial dengan MCU lainnya. Deteksi PM2.5 menggunakan prinsip hamburan cahaya untuk mengukur konsentrasi partikulat di udara, dimana hamburan tersebut bergantung dari ukuran, bentuk, indeks bias, dan sudut hamburan partikel, serta panjang gelombang dari laser (11) . Selain itu, pada lingkungan yang lembap, butiran-butiran uap air menempel pada partikulat di udara mengakibatkan akurasi sensor menjadi berkurang (12) .…”

Section: Alat Ukur Pm25 Dan Co2 Berbasis Low-cost Sensorunclassified

Pemantauan Konsentrasi PM2.5 dan CO2 Berbasis Low-Cost Sensor secara Real-Time di Cekungan Udara Bandung Raya

Sya’bani¹,

Chandra

Majid³

et al. 2020

Jurtekling

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Field observation of PM2.5 and CO2 concentrations and meteorological conditions using low-cost sensors in real-time was carried out in the Greater Bandung air basin on Mar. 12 – Apr. 25, 2019. PM2.5 and CO2 sensors, as well as detectors of meteorological parameters, have been calibrated in the Laboratory. The instruments were placed in two locations (±300 m apart horizontally and ±20 m vertically), namely Tokong Nanas Building (Location 1 / L1) and Deli Building (L2), Telkom University, Bandung. Data was stored in the data logger and sent to the cloud database every 2-min through the GSM module. The results show that the same air mass in both locations has identified, except for some events that are affected by anthropogenic activities (those concentrations in L2 L1) and wind speed/direction (time delay). The daily-average PM2.5 and CO2 concentrations at L1 and L2 are 52 µg m-3 and 580 ppm, and 70 µg m-3 and 809 ppm. PM2.5 and CO2 mass concentrations relatively higher (±172 µg m-3 and 916 ppm) at night due to a stable atmosphere (potential temperature, dθ/dz 0, typical data from 20:00 to 3:00 local time), lower planetary boundary layer, and mixed local emissions and transboundary air pollutants. Meanwhile, lower CO2 concentrations in daytime mostly occur due to the activity of vegetation, which actively absorbs CO2 in the photosynthesis process. The fluctuation of those concentrations due to polluted air suggests that the performances of low-cost sensors can be adequately used properly for ambient air quality monitoring. Keywords: CO2, low-cost sensors, PM2.5, potential temperatureABSTRAKPemantauan konsentrasi PM2.5 dan CO2 serta kondisi meteorologi berbasis low-cost sensors secara real-time di cekungan udara Bandung Raya telah dilakukan pada 12 Maret-25 April 2019. Sensor PM2.5 dan CO2, serta detektor parameter meteorologi telah dikalibrasi di Laboratorium. Alat ukur ditempatkan di dua lokasi dengan perbedaan jarak ±300 m dan ketinggian ±20 m, yaitu Gedung Tokong Nanas (Lokasi 1 / L1) dan Gedung Deli (L2), Universitas Telkom, Bandung. Komunikasi data menggunakan modul GSM (SIM900A) dan data disimpan di data logger dan dikirimkan ke cloud database per 2 menit. Hasil pengukuran menunjukkan bahwa massa udara di kedua lokasi memiliki tren data konsentrasi PM2.5 dan CO2 yang relatif homogen, kecuali pada beberapa kejadian yang dipengaruhi oleh aktivitas antropogenik (konsentrasi PM2.5 dan CO2 di L2 L1) serta arah dan kecepatan angin (adanya perbedaan konsentrasi massa PM2.5 akibat penundaan waktu). Rerata harian konsentrasi PM2.5 dan CO2 di L1 dan L2 berturut-turut adalah 52 µg m-3 dan 580 ppm serta 70 µg m-3 dan 809 ppm. Konsentrasi massa PM2.5 dan CO2 yang relatif lebih tinggi (±172 µg m-3 dan 916 ppm) di malam hari akibat atmosfer yang lebih stabil (temperatur potensial, dθ/dz 0, tipikal dari pukul 20:00-03:00), penurunan planetary boundary layer, dan terjadinya pencampuran partikulat lokal dengan polutan udara lintas batas. Sedangkan, konsentrasi CO2 yang relatif lebih rendah di siang hari sebagian besar terjadi akibat aktivitas vegetasi yang aktif menyerap CO2 pada proses fotosintesis. Fluktuasi konsentrasi karena udara tercemar menunjukkan bahwa kinerja low-cost sensors dapat digunakan dengan baik untuk memantau kualitas udara di atmosfer.Kata kunci: CO2, low-cost sensor, PM2.5, temperatur potensial

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“…The CIP was not used for this study because it is unable to resolve the morphology of sub-75 μm particles, while a depolarization module in the CAS-POL allows for classification of particle morphologies and composition. [30–33] NIOSH calibration experiments of the CAS-POL using size-selected coal dust demonstrated that the CAS-POL was capable of sizing coal dust particles by analyzing forward light-scattering measurements with T-matrix (sub-1.5 μm) and ray tracing with diffraction on facets (RTDF) (1.5–75 μm) theories for irregular particles. [34] While the coal dust calibration tests focused only on the use of forward scattered light to estimate particle size, the current study also analyzes the backscattered and polarized light to classify particles according to shape and composition, as both coal dust and water droplets are present during each knockdown test.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the CAS-POL and IOM samplers for determining the knockdown efficiencies of water sprays on float coal dust

Seaman

Bugarski

Beck

et al. 2018

Journal of Occupational and Environmental Hygiene

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Float coal dust, generated by mining operations, is distributed throughout mine airways by ventilating air designed to purge gases and respirable dust. Float coal dust poses an explosion hazard in the event of a methane ignition. Current regulation requires the application of inert rock dust in areas subjected to float coal dust in order to mitigate the hazard. An alternate method using water sprays, which have been effective in controlling respirable dust hazards, has been proposed as a way to control float coal dust generated on longwall faces. However, the knockdown efficiency of the proposed water sprays on float coal dust needs to be verified. This study used gravimetric isokinetic Institute of Occupational Medicine (IOM) samplers alongside a real-time aerosol monitor (Cloud Aerosol Spectrometer with polarization; CAS-POL) to study the effects of spray type, operating pressure, and spray orientation on knockdown efficiencies for seven different water sprays. Because the CAS-POL has not been used to study mining dust, the CAS-POL measurements were validated with respect to the IOM samplers. This study found that the CAS-POL was able to resolve the same trends measured by the IOM samplers, while providing additional knockdown information for specific particle size ranges and locations in the test area. In addition, the CAS-POL data was not prone to the same process errors, which may occur due to the handling of the IOM filter media, and was able to provide a faster analysis of the data after testing. This study also determined that pressure was the leading design criteria influencing spray knockdown efficiency, with spray type also having some effect and orientation having little to no effect. The results of this study will be used to design future full-scale float coal dust capture tests involving multiple sprays, which will be evaluated using the CAS-POL.

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Dual-wavelength light-scattering technique for selective detection of volcanic ash particles in the presence of water droplets

Cited by 15 publications

References 29 publications

Scattering Matrix for Typical Urban Anthropogenic Origin Cement Dust and Discrimination of Representative Atmospheric Particulates

Scattering Matrix for Typical Urban Anthropogenic Origin Cement Dust and Discrimination of Representative Atmospheric Particulates

Pemantauan Konsentrasi PM2.5 dan CO2 Berbasis Low-Cost Sensor secara Real-Time di Cekungan Udara Bandung Raya

Comparison of the CAS-POL and IOM samplers for determining the knockdown efficiencies of water sprays on float coal dust

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