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

Drinovec, Luka; Močnik, Griša; Zotter, Peter; Prévôt, A. S. H.; Ruckstuhl, Christian; Coz, Esther; Rupakheti, Maheswar; Sciare, Jean; Müller, Thomas; Wiedensohler, Alfred; Hansen, A. D. A.

doi:10.5194/amt-8-1965-2015

Cited by 788 publications

(729 citation statements)

References 42 publications

(80 reference statements)

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“…The instruments including a Cavity Attenuated Phase Shift Particulate Matter extinction monitor (CAPS-PM ext , Aerodyne Research Inc.) (Kebabian et al, 2007), a CAPS-NO 2 monitor (Kebabian et al, 2008;Ge et al, 2013), and a 7-wavelength Aethalometer 30 (model: AE33; Magee Scientific Corp.) (Drinovec et al, 2015) were equipped in the container for real-time measurements of light extinction coefficient (b ext , λ = 630 nm) of dry fine particles, gaseous NO 2 , and BC with a time resolution of 1 s, 1 s and Atmos. Chem.…”

Section: Experimental Methodsmentioning

confidence: 99%

Vertically-resolved Characteristics of Air Pollution during Two Severe Winter Haze Episodes in Urban Beijing, China

Wang¹,

Sun²,

Xu³

et al. 2017

Preprint

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Abstract. We conducted the first real-time continuous vertical measurements of particle extinction (b ext ), gaseous NO 2 , and black carbon (BC) from ground level to 260 m during two severe winter haze episodes at an urban site in Beijing, China. Our results illustrated four distinct types of vertical profiles: 1) uniform vertical distributions (37% of the time) with vertical differences less than 5%; 2) higher values at lower altitudes (29%); 3) higher values at higher altitudes (16%), and 4) 15 significant decreases at the heights of ~100 -150 m (14%). Further analysis demonstrated that vertical convection as indicated by mixing layer height, temperature inversion, and local emissions are three major factors affecting the changes in vertical profiles. Particularly, the formation of Type 4 was strongly associated with the stratified layer that was formed due to the interactions of different air masses and temperature inversions. Aerosol composition was substantially different below and above the transition heights with ~20 -30% higher contributions of local sources (e.g., biomass burning and cooking) at 20 lower altitudes. A more detailed evolution of vertical profiles and their relationship with the changes in source emissions, mixing layer height, and aerosol chemistry was illustrated by a case study. BC showed overall similar vertical profiles as those of b ext (R 2 = 0.92 and 0.69 in November and January, respectively). While NO 2 was correlated with b ext for most of the time, the vertical profiles of b ext /NO 2 varied differently for different profiles, indicating the impact of chemical transformation on vertical profiles. Our results also showed that more comprehensive vertical measurements (e.g., more 25 aerosol and gaseous species) at higher altitudes in the megacities are needed for a better understanding of the formation mechanisms and evolution of severe haze episodes in China.

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Section: Experimental Methodsmentioning

confidence: 99%

Vertically-resolved Characteristics of Air Pollution during Two Severe Winter Haze Episodes in Urban Beijing, China

Wang¹,

Sun²,

Xu³

et al. 2017

Preprint

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“…We retrieved the å abs from applying a log-log fit to Aethalometer data corrected for filter-loading and multiple scattering effects. In the case of the Aethalometer AE33, the measurements do not require a filter-loading correction because this model uses the dual-spot technology which accounts for this artifact (Drinovec et al, 2015).…”

Section: Aerosol Light Scattering Measurementsmentioning

confidence: 99%

Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

Saturno¹,

Holanda²,

Pöhlker³

et al. 2017

Preprint

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Abstract. The Amazon rain forest is considered a very sensitive ecosystem that could be significantly affected by a changing climate. It is still one of the few places on Earth where the atmosphere in the continent approaches near-pristine conditions for some periods of the year. The Amazon Tall Tower Observatory (ATTO) has been built in central Amazonia to monitor the atmospheric and forest ecosystem conditions. The atmospheric conditions at the ATTO site oscillate between biogenic and biomass burning (BB) dominated states. By using a comprehensive ground-based aerosol measurement setup, we studied the physical and chemical properties of aerosol particles at the ATTO site. This parameterization of å abs as a function of the BC to OA mass ratio was investigated and was found applicable to tropical forest emissions but further investigation is required, especially by segregating fuel types. Additionally, important enhancements of the BC mass absorption cross-section (α abs ) were found over the measurement period. This enhancement could be linked to heavy coating of the BC aerosol particles. In the future, the BC mixing state should be systematically investigated by using different instrumental approaches.

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“…All Aethalometer data were corrected for filter spot optical loading saturation effects (Drinovec et al, 2015;Park et al, 2010;Virkkula et al, 2007) using the "binned" ap-proach, first described by Park et al (2010), as implemented by version 7.1 of the Aethalometer "data masher" program (Allen et al, 2012). This correction provides a more robust measurement of the DC metric, since the optical attenuation for BC at 370 nm is 2.4 times larger than at 880 nm, resulting in a larger loading artifact at the shorter wavelength.…”

Section: Introductionmentioning

confidence: 99%

Joint measurements of PM<sub>2. 5</sub> and light-absorptive PM in woodsmoke-dominated ambient and plume environments

Zhang

Allen²,

Yang

et al. 2017

Atmos. Chem. Phys.

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Abstract. DC, also referred to as Delta-C, measures enhanced light absorption of particulate matter (PM) samples at the near-ultraviolet (UV) range relative to the near-infrared range, which has been proposed previously as a woodsmoke marker due to the presence of enhanced UV light-absorbing materials from wood combustion. In this paper, we further evaluated the applications and limitations of using DC as both a qualitative and semi-quantitative woodsmoke marker via joint continuous measurements of PM 2.5 (by nephelometer pDR-1500) and light-absorptive PM (by 2-wavelength and 7-wavelength Aethalometer ® ) in three northeastern US cities/towns including Rutland, VT; Saranac Lake, NY and Ithaca, NY. Residential wood combustion has shown to be the predominant source of wintertime primary PM 2.5 emissions in both Rutland and Saranac Lake, where we conducted ambient measurements. In Ithaca, we performed woodsmoke plume measurements. We compared the pDR-1500 against a FEM PM 2.5 sampler (BAM 1020), and identified a close agreement between the two instruments in a woodsmokedominated ambient environment. The analysis of seasonal and diurnal trends of DC, black carbon (BC, 880 nm) and PM 2.5 concentrations supports the use of DC as an adequate qualitative marker. The strong linear relationships between PM 2.5 and DC in both woodsmoke-dominated ambient and plume environments suggest that DC can reasonably serve as a semi-quantitative woodsmoke marker. We propose a DCbased indicator for woodsmoke emission, which has shown to exhibit a relatively strong linear relationship with heating demand. While we observed reproducible PM 2.5 -DC relationships in similar woodsmoke-dominated ambient environments, those relationships differ significantly with different environments, and among individual woodsmoke sources. Our analysis also indicates the potential for PM 2.5 -DC relationships to be utilized to distinguish different combustion and operating conditions of woodsmoke sources, and that DC-heating-demand relationships could be adopted to estimate woodsmoke emissions. However, future studies are needed to elucidate those relationships.

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

Cited by 788 publications

References 42 publications

Vertically-resolved Characteristics of Air Pollution during Two Severe Winter Haze Episodes in Urban Beijing, China

Vertically-resolved Characteristics of Air Pollution during Two Severe Winter Haze Episodes in Urban Beijing, China

Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

Joint measurements of PM<sub>2. 5</sub> and light-absorptive PM in woodsmoke-dominated ambient and plume environments

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

Cited by 788 publications

References 42 publications

Vertically-resolved Characteristics of Air Pollution during Two Severe Winter Haze Episodes in Urban Beijing, China

Vertically-resolved Characteristics of Air Pollution during Two Severe Winter Haze Episodes in Urban Beijing, China

Black and brown carbon over central Amazonia: Long-term aerosol measurements at the ATTO site

Joint measurements of PM&lt;sub&gt;2. 5&lt;/sub&gt; and light-absorptive PM in woodsmoke-dominated ambient and plume environments

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Product

Resources

About

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

Joint measurements of PM<sub>2. 5</sub> and light-absorptive PM in woodsmoke-dominated ambient and plume environments