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Diurnal variation of aethalometer correction factors and optical absorption assessment of nucleation events using multi-wavelength photoacoustic spectroscopy

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Journal of Environmental Sciences 2019年第9期31卷 96-109页

作者： Tibor Ajtai Gergely Kiss-Albert Noemi Utry Adam Toth Andras Hoffer Gabor Szabo Zoltan Bozoki Department of Optics and Quantum Electronics University of Szeged H-6720 Szeged Hungary Hilase Development Production Service and Trading Limited Szekesfehervar H-8000 Hungary MTA-SZTE Research Group on Photoacoustic Spectroscopy H-6720 Szeged Hungary ELI-HU Non-Profit Ltd H-6720 Szeged Hungary Department of Earth and Environmental Sciences University of Pannonia P.O. Box 158 Veszprem H-8201 Hungary MTA-PE Air Chemistry Research Group P.O. Box 158 Veszprem H-8201 Hungary

A field measurement campaign was carried out during the late winter and early spring of2015 in Budapest, the capital of Hungary. The size distribution(SD) and optical absorption of carbonaceous particulate matter(CPM) was measured online using a Scanning Mobility Particle Sizer(SMPS), a 7λ-aethalometer and an inhouse developed 4λ-Photoacoustic Spectrometer. Based on the SD data, the measurement period could be classified into days with and without new particle formation events(normal days and nucleation days),although particular nucleation-like events were observed on normal days as well. Three characteristic size modes were observed with CMDs of circa 15, 25 and 110 nm that corresponded to the nucleation, traffic and heating modes. Based on the temporal behavior of these modes both types of days were divided into distinctive daily periods(heating hours,traffic hours and nucleation hours). The optical absorption spectra(OAC and AAE) also displayed the same part of day behavior to that of SD. That way this paper is among the first to assess the optical response of urban nucleation events. Due to the simultaneous measurement of OAC by the 7λ-aethalometer and a 4λ-Photoacoustic Spectrometer, OAC was measured overall at 11 wavelengths. That way aethalometer correction factors(f and C)were determined at all aethalometer wavelengths using in situ reference photoacoustic measurements. Correction factors were found to have both wavelength and time of the day variation. In the case of f, no clear trend could be observed, however, Cref values increased both as a function of wavelength.

关键词： Photoacoustic spectroscopy Aerosol Angstr?m exponent aethalometer Nucleation Size distribution

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Aerosol Properties over Ranchi Measured from aethalometer

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Atmospheric and Climate Sciences 2011年第3期1卷 91-94页

作者： Manoj Kumar Kumari Lipi S Sureshbabu N C Mahanti 不详

Continuous and near-real-time measurements of the mass concentration of Aerosol Black Carbon (BC) were carried out 1st to 31st July 2010 of rainy season and compare with data of July-2010 to March-2011 using an aethalometer (model AE-31 of Magee Scientific, USA). The principle of the aethalometer is to measure the attenuation of a beam of light transmitted through a filter, while the filter is continuously collecting an aero-sol sample. This measurement is made at successive regular intervals of a time base period has been. the BC mass concentration is estimated by measuring the change in the transmittance of a quartz filter tape, on to which the particles impinge. The instrument was operated at a time base of 5 min, round the clock with a flow rate of 4-liter min–1, to study the impact of rainy season on black carbon concentrations over a typical urban environment namely Ranchi, India. BC concentrations were high during morning (0600 to 0900 h) and evening hours (1900 to 2300 h) compared to afternoon hours. During early morning hours, high values of BC are attributed to the turbulence set-in by the solar heating which breaks the night-time stable layer and aero-sols in the nocturnal residual layer are mixed up with those near the surface.

关键词： Black Carbon (BC) aethalometer Aerosol

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A short climatology of black and brown carbon and their sources at a suburban site impacted by smoke in Brazil

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Journal of Environmental Sciences 2024年第2期136卷 498-511页

作者： Admir Creso Targino Patricia Krecl Gabriel Yoshikazu Oukawa Eva Maria Mollinedo Graduate Program in Environmental Engineering Federal University of TechnologyAv.Pioneiros 3131LondrinaPR 86036-370Brazil Department of Environmental Engineering Federal University of TechnologyAv.Pioneiros 3131LondrinaPR 86036-370Brazil

Emissions from biomass burning challenge efforts to curb air pollution in cities downwind of fire-prone regions,as they contribute large amounts of brown carbon(Br C)and black carbon(BC)*** investigated the patterns of Br C and BC concentrations using aethalometer data(atλ=370 and 880 nm,respectively)spanning four years at a site impacted by the outflow of *** data required to be post processed for the shadowing effect since,without correction,concentrations would be between 29%and 35%*** Br C concentrations were consistently higher than the BC concentrations,indicating the prevalence of aerosols from biomass *** results were supported by the Angstrom coefficient(A_(370/880)),with values predominantly larger than 1(mean±standard deviation:1.25±0.31).A_(370/880)values below 1 were more prevalent during the wet season,which suggests a contribution from fossil fuel *** observed sharp Br C and BC seasonal signals,with mean minimum concentrations of 0.40μg/m^(3)and 0.36μg/m^(3),respectively,in the wet season,and mean maximum concentrations of 2.05μg/m^(3)and 1.53μg/m^(3)in the dry *** largest concentrations were observed when northerly air masses moved over regions with a high density of fire *** burning of residential solid waste and industrial combustion caused extreme Br C and BC concentrations under favourable wind *** neither pollutant is included in any ambient air quality standards,our results suggest that transboundary smoke may hamper efforts to meet the World Health Organization guidelines for fine particles.

关键词： Light-absorbing carbonaceous matter Black carbon Wildfires Biomass burning aethalometer

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Evaluating the performance and influencing factors of three portable black carbon monitors for field measurement

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Journal of Environmental Sciences 2024年第5期139卷 320-333页

作者： Liqing Wu Yicheng Shen Fei Che Yuzhe Zhang Jian Gao Chong Wang State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China Jinan Ecological Environmental Protection Grid-Based Supervision Center Jinan 250013China

Black carbon(BC)is associated with adverse human health and climate *** BC spatial distribution imperatively requires low-cost and portable *** portable BC monitors are commercially available,but their accuracy and reliability are not always satisfactory during continuous field *** study evaluated three models of portable black carbon monitors,C12,MA350 and DST,and investigates the factors that affect their *** monitors were tested in urban Beijing,where portable devices running for one month alongside a regular-size reference aethalometer *** study considers several factors that could influence the monitors'performance,including ambient weather,aerosol composition,loading artifacts,and built-in *** results show that MA350and DST present considerable discrepancies to the reference instrument,mainly occurring at lower concentrations(0-500 ng/m^(3))and higher concentrations(2500-8000 ng/m^(3)),*** discrepancies were likely caused by the anomalous noise of MA350 and the loading artifacts of *** study also suggests that the ambient environment has limited influence on the monitors'performance,but loading artifacts and accompanying compensation algorithms can result in unrealistic *** on the evaluation,the study suggests that C12 is the best choice for unsupervised field measurement,DST should be used in scenarios where frequent maintenance is available,and MA350 is suitable for research purposes with post-processing *** study highlights the importance of assigning portable BC monitors to appropriate applications and the need for optimized real-time compensation algorithms.

关键词： Black carbon aethalometer Loading artifact Performance evaluation Portable device

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Observation of black carbon aerosol in Beijing, 2003

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Frontiers of Environmental Science & Engineering 2007年第3期1卷 345-349页

作者： LOU Shujuan MAO Jietai WANG Meihua Beijing Weather Modification Office Beijing 100089China Department of Atmospheric Sciences Peking UniversityBeijing 100871China

The objective of this study was to determine the black carbon concentration in Beijing in *** aerosol properties were measured using an aethalometer and a tapered element oscillating microbalance(TEOM)on the roof of the Physics Building of Peking University(39.99°N,116.31°E)from July to August 2003 and from November 2003 to January *** average black carbon(BC)concentrations in the summer and winter were 8.80 and 11.4μg/m3,*** winter,two different cyclone cut offs were installed at the inlet of an *** BC mass concentration in TSP,PM_(10),and PM_(2.5)were *** results indicated that in winter aerosol,90%of BC exited in PM_(10)and 82.6%of BC exited in PM_(2.5).The BC in PM_(10)accounted for 5.11%of the PM_(10)mass.

关键词： black carbon aerosol PM_(10) aethalometer

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Comparative Studies of Instruments That Measure Black Carbon Properties in Mexico City

Comparative Studies of Instruments That Measure Black Carbon...

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第七届亚洲气溶胶会议

作者： Darrel Baumgardner Armando Retama Universidad Nacional Autonoma de Mexico Ciudad Universitaria Mexico City DF 04510 LMD - Ecole Polytechnique Palaiseau France

A new instrument, the Photoacoustic Extinctiometer （PAX）, was operated in Mexico City during a four week period to measure the light absorption and scattering coefficients of black carbon （BC） and to estimate the relative mass concentration of BC. The PAX was installed in the mobile laboratory of Mexico City’s air quality network, Red Automático de Monitorea Atmosférica （RAMA）, along with a suite of gas analyzers, a TEOM, an aethalometer and a Sunset Laboratory semi-continuous analyzer for elemental and organic carbon （EC/OC）. The measurements were made at four locations with the city area, each representing distinctly different sources of BC: 1) a primarily residential area with limited traffic, 2) an industrial region with emissions from diesel trucks, 3) a central market area with heavy automotive traffic and 4) a transportation hub with concentrated emissions from buses and mini-buses. The results indicate that the differences between the aethalometer and PAX are sensitive to the emission sources as are the differences in the BC mass concentrations derived from the absorption measurements made by the aethalometer and the PAX and those measured by the Sunset EC/OC analyzer.

关键词： black carbon properties aethalometer photoacoustic light absorption.

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基于能见度、相对湿度和PM2.5浓度的雾-霾划分方案及其时空变化和理化特征

基于能见度、相对湿度和PM2.5浓度的雾-霾划分方案及其时空变化和...

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作者：郭斌中国气象科学研究院

学位级别：硕士

近年来,中国东部和中部地区雾-霾事件频繁发生,造成大气能见度严重下降,对人体健康造成巨大影响。但当前的研究中雾-霾划分方案有多种,多采用相对湿度和能见度进行划分,且阈值没有统一,轻雾和霾难以划分。本文通过大量气象和环保第一手... 详细信息

近年来,中国东部和中部地区雾-霾事件频繁发生,造成大气能见度严重下降,对人体健康造成巨大影响。但当前的研究中雾-霾划分方案有多种,多采用相对湿度和能见度进行划分,且阈值没有统一,轻雾和霾难以划分。本文通过大量气象和环保第一手观测数据,研究了相对湿度、能见度和PM浓度之间的相关关系,提出了新的雾-霾相对湿度阈值确定方法,并确定了100μg m为能见度下降至10 km以下的阈值。形成了便于应用的基于能见度、相对湿度、PM质量浓度的雾-霾划分方案,分析了2013-2018年中国霾现象的发生频次以及雾、霾和轻雾的时空变化。结果表明:2013-2016年三种天气现象的出现频率呈增加趋势,在2017年之后呈现降低的趋势。霾现象主要分布在华北平原、华中平原、长江三角洲和四川盆地。中国区域雾现象发生频次较低,从季节分布来看,霾现象集中发生在冬季,而轻雾多出现在春秋两季。清洁雾主要发生在高山站和相对湿度高的清洁区域,污染雾则多出现在人口密集的城市。当前的研究表明黑碳气溶胶可以通过削弱东亚季风进而影响华北区域雾-霾现象,另外考虑到二次气溶胶在雾-霾发生过程中的重要作用,本文订正处理了CAWNET黑碳监测数据以及环保部气溶胶组分网观测的二次气溶胶数据,获得了黑碳气溶胶的浓度分布和长期变化趋势;分析了2016-2018年秋冬季三个典型城市霾日及清洁日的气溶胶主要成分的变化特征。结果表明:在北京,清洁天气所占比例逐年增加。多数雾-霾事件都伴随着强烈的空气污染。霾现象以湿霾为主,其发生和发展通常与气溶胶吸湿性增长有关,相对湿度等气象条件在重污染过程中发挥了重要作用。2017-2018年,霾日的硝酸盐气溶胶浓度上升更为显著,硫酸盐浓度则上升不明显。硝酸盐气溶胶逐渐成为北京区域污染过程中的主要二次气溶胶。黑碳气溶胶变化整体较为平稳。霾日相比于清洁天气:BC气溶胶下降约1%,硫酸盐上升约2-3%,OC占比略有下降,硝酸盐上升约7%。石家庄站的黑碳气溶胶占比更高,直接排放进入大气中的气溶胶浓度是高于北京区域的。太原区域的黑碳气溶胶占比更高,但是霾日相对更少,可能归咎于较低的相对湿度水平。

关键词：雾-霾相对湿度 PM2.5浓度黑碳 aethalometer 时空分布气溶胶

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