Absorption coefficients by aerosols in remote areas: a new approach to decouple dust and black carbon absorption coefficients using seven-wavelength Aethalometer data

Fialho, Paulo; Hansen, A. D. A.; Honrath, R. E.

doi:10.1016/j.jaerosci.2004.09.004

Cited by 146 publications

(130 citation statements)

References 18 publications

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“…The BC mass concentration is calculated from the change in optical attenuation at 880 nm in the selected time interval using the mass absorption cross section 7.77 m 2 g −1 . At this wavelength, other aerosol particles (carbonaceous or mineral) absorb significantly less and absorption can be attributed to BC alone (Sandradewi et al, 2008a and b;Fialho et al, 2005;Yang et al, 2009;and references therein). Measurements at distinct spectral regions (370,470,520,590,660,880 and 950 nm) allow for spectral analysis of the data -the analysis of the dependence of absorption on the wavelength can be of importance for research on direct effects of aerosol BC, climate forcing (Bond et al, 2013;IPCC, 2013) or mineral dust detection (Collaud Coen et al, 2004), through the determination of the single scattering albedo dependence on the wavelength, or source apportionment (Sandradewi et al, 2008b).…”

Section: Aethalometer Ae33mentioning

confidence: 99%

The "dual-spot" Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation

et al. 2015

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Abstract. Aerosol black carbon is a unique primary tracer for combustion emissions. It affects the optical properties of the atmosphere and is recognized as the second most important anthropogenic forcing agent for climate change. It is the primary tracer for adverse health effects caused by air pollution. For the accurate determination of mass equivalent black carbon concentrations in the air and for source apportionment of the concentrations, optical measurements by filter-based absorption photometers must take into account the "filter loading effect". We present a new real-time loading effect compensation algorithm based on a two parallel spot measurement of optical absorption. This algorithm has been incorporated into the new Aethalometer model AE33. Intercomparison studies show excellent reproducibility of the AE33 measurements and very good agreement with post-processed data obtained using earlier Aethalometer models and other filterbased absorption photometers. The real-time loading effect compensation algorithm provides the high-quality data necessary for real-time source apportionment and for determination of the temporal variation of the compensation parameter k.

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Section: Aethalometer Ae33mentioning

confidence: 99%

The "dual-spot" Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation

et al. 2015

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“…1, this cannot be expected due to the variable chemical nature of C brown in general and, for biomass burning in particular, due to the dependence of the optical properties of hydrogenated carbon on the encountered thermal annealing temperatures (Smith, 1984). The situation is further complicated by the presence of non-carbonaceous absorbing aerosol components such as soil dust (mainly hematite), which can play a significant role even in locations quite distant from desert regions (Fialho et al, 2005).…”

Section: Problems Related To the Presence Of C Brownmentioning

confidence: 99%

Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols

Andreae

Gelencsér²

2006

Atmos. Chem. Phys.

1,761

1,033

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Abstract. Although the definition and measurement techniques for atmospheric "black carbon" ("BC") or "elemental carbon'' ("EC") have long been subjects of scientific controversy, the recent discovery of light-absorbing carbon that is not black ("brown carbon, Cbrown") makes it imperative to reassess and redefine the components that make up light-absorbing carbonaceous matter (LAC) in the atmosphere. Evidence for the atmospheric presence of Cbrown comes from (1) spectral aerosol light absorption measurements near specific combustion sources, (2) observations of spectral properties of water extracts of continental aerosol, (3) laboratory studies indicating the formation of light-absorbing organic matter in the atmosphere, and (4) indirectly from the chemical analogy of aerosol species to colored natural humic substances. We show that brown carbon may severely bias measurements of "BC" and "EC" over vast parts of the troposphere, especially those strongly polluted by biomass burning, where the mass concentration of Cbrown is high relative to that of soot carbon. Chemical measurements to determine "EC" are biased by the refractory nature of Cbrown as well as by complex matrix interferences. Optical measurements of "BC" suffer from a number of problems: (1) many of the presently used instruments introduce a substantial bias into the determination of aerosol light absorption, (2) there is no unique conversion factor between light absorption and "EC" or "BC" concentration in ambient aerosols, and (3) the difference in spectral properties between the different types of LAC, as well as the chemical complexity of Cbrown, lead to several conceptual as well as practical complications. We also suggest that due to the sharply increasing absorption of Cbrown towards the UV, single-wavelength light absorption measurements may not be adequate for the assessment of absorption of solar radiation in the troposphere. We discuss the possible consequences of these effects for our understanding of tropospheric processes, including their influence on UV-irradiance, atmospheric photochemistry and radiative transfer in clouds.

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“…The nephelometer was available at the wavelengths of 450, 520, and 700 nm and was designed specifically for studies of the direct radiative forcing of the Earth's climate by aerosol particles or studies of ground-based or airborne atmospheric visual air quality. A seven-wavelength Aethalometer™ (Magee Scientific, model AE-31), described by Fialho et al (2005), was used to measure the concentration of BC in units of ng m -3 at the wavelengths of 370, 470, 520, 590, 660, 880, and 990 nm at 5-min intervals from March 2007 to November 2008. We also used multiangle absorption photometer (MAAP) instruments to measure the concentration of BC at the wavelengths of 450, 500, and 700 nm from September 2009 to December 2010.…”

Section: Instrumentationmentioning

confidence: 99%

Size Distribution and Optical Properties of Particulate Matter (PM10) and Black Carbon (BC) during Dust Storms and Local Air Pollution Events across a Loess Plateau Site

Wang

Zhang

et al. 2015

Aerosol Air Qual. Res.

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We analyzed the suspended particle size distribution in the range of 0.5 to 10 µm and the optical properties of the particles from March 2007 to December 2010 at a site on the Loess Plateau (SACOL; 35.57°N, 104.08°E; 1965.8 m a.s.l.) about 48 km southeast of the center of Lanzhou. The results indicated that the variation in PM 10 was much larger in spring than in winter because of frequent dust events or local blowing soil dust during spring. The highest number concentrations of coarse-mode particles were likely attributable to dust events that transported mineral dust or soil dust in the spring season, caused by cold fronts or strong local winds. In contrast, the fine-mode particles that dominated in the cold season at SACOL were probably indicative of anthropogenic sources related to fossil-fuel combustion and biomass burning. The comparison of dust events and anthropogenic air pollution shows a clear distinction of lower PM 10 with higher B ap for pollution episodes and higher PM 10 with lower B ap for dust events. These findings suggest that the results in the cold season were likely attributable to light absorption of black carbon, and the coarse mode particles were dominant during dust events in spring.

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Absorption coefficients by aerosols in remote areas: a new approach to decouple dust and black carbon absorption coefficients using seven-wavelength Aethalometer data

Cited by 146 publications

References 18 publications

The "dual-spot" Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation

The "dual-spot" Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation

Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols

Size Distribution and Optical Properties of Particulate Matter (PM10) and Black Carbon (BC) during Dust Storms and Local Air Pollution Events across a Loess Plateau Site

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Absorption coefficients by aerosols in remote areas: a new approach to decouple dust and black carbon absorption coefficients using seven-wavelength Aethalometer data

Cited by 146 publications

References 18 publications

The &quot;dual-spot&quot; Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation

The &quot;dual-spot&quot; Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation

Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols

Size Distribution and Optical Properties of Particulate Matter (PM10) and Black Carbon (BC) during Dust Storms and Local Air Pollution Events across a Loess Plateau Site

Contact Info

Product

Resources

About

The "dual-spot" Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation

The "dual-spot" Aethalometer: an improved measurement of aerosol black carbon with real-time loading compensation