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Optical particulate matter sensors in PM <sub/>2.5</sub> measurements in atmospheric air
摘要： Monitoring systems are needed to obtain information about particulate matter (PM) concentrations and to make such information accessible to the public. Small, low-cost, optical sensors could be used to improve the spatial and temporal resolution of PM data. The paper presents results of collocated comparison of four low-cost PM sensors and TEOM analyser, conducted from 20-08-2017 to 24-12-2017 in Wroc?aw, Poland. Plantower PMS7003 and Nova Fitness SDS011 sensors proved to be the best in terms of precision and were linearly correlated with TEOM data. Alphasense OPC-N2 sensors exhibited only moderate precision and linearity. Winsen ZH03A sensors had low repeatability between units and only one copy demonstrated good operation possibilities. All tested sensors had a bias in relation to PM2.5 concentrations obtained from TEOM.
关键词： air quality monitoring,PM2.5,particulate matter,TEOM,optical sensors
更新于2025-09-23 15:21:01
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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - Quantum cascade laser-based in situ measurement of atmospheric CO and CO <sub/>2</sub> in Gandhinagar using 1f and 2f wavelength modulation spectroscopy
摘要： We report the design, development and field deployment of a quantum cascade laser-based tunable diode laser spectroscopy (TDLS) system for high-sensitivity measurement of atmospheric CO and CO2. Two distributed-feedback quantum cascade lasers are used to interrogate the rotational-vibrational transitions of CO at 4594.99 nm and CO2 at 4319.30 nm. The mean mole fraction values for CO and CO2 for the measurements made at Gandhinagar from 19-25 July 2019 are 477 ppb and 486 ppm respectively. The detection limit of the system is 3 ppb CO and 45 ppb CO2 for integration time of 17 s and 69 s respectively.
关键词： air quality monitoring,greenhouse gas monitoring,quantum cascade laser,wavelength modulation spectroscopy
更新于2025-09-23 15:19:57
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Colorimetric Detection of Carcinogenic Alkylating Fumigants on Nylon-6 Nanofibrous Membrane. Part I: Investigation of 4-( <i>p</i> -Nitrobenzyl) Pyridine as A “New” Sensing Agent with Ultra-High Sensitivity
摘要： Alkylating fumigants are widely used in agricultural production for the control of soil-borne pests, but the acute toxicity and carcinogenicity of these chemicals pose a health threat to farm workers as well as residents. A nanofibrous membrane-based colorimetric sensor relying on the nucleophilic substitution reaction of 4-(p-nitrobenzyl) pyridine (NBP) is introduced for the convenient and portable detection of alkylating fumigants. Comparing with the traditional use of NBP in detecting alkylating agents, this sensor system achieves a ppb-level detection sensitivity toward alkylating fumigant gases without a high-temperature incubation or the addition of extra bases. The mechanisms of the detection reaction and the detection sensitivities of different fumigants were studied with computational methods, and the results comprehensively prove the proposed optimized detection mechanisms. The detection limit of methyl iodide, methyl bromide, and 1, 3-dichloropropene successfully reaches to the limiting exposure concentrations (PEL or REL) with a naked-eye detectable color difference within 5 min with a dynamic detection procedure. The designed sensing system is promising for a real-time monitoring of the air quality related to alkylating fumigants in the environment, especially in agricultural and industrial areas.
关键词： Alkylating agent,NBP,Air quality monitoring,Colorimetric sensor,Nanomaterial
更新于2025-09-10 09:29:36