The filter-loading effect by ambient aerosols in filter absorption photometers depends on the coating of the sampled particles

Drinovec, Luka; Gregorič, Asta; Zotter, Peter; Wolf, Robert; Bruns, Emily A.; Prévôt, Andrê S. H.; Petit, Jean-Eudes; Favez, Olivier; Sciare, Jean; Arnold, Ian J.; Chakrabarty, Rajan K.; Moosmüller, Hans; Filep, Ágnes; Močnik, Griša

doi:10.5194/amt-10-1043-2017

Cited by 71 publications

(73 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, it is often challenging to distinguish between light absorption by BC and by BrC, especially if the BC concentrations are high (e.g., for flaming combustion). Second, most online instruments use 1-7 fixed wavelengths for light absorption measurements (Drinovec et al, 2015(Drinovec et al, , 2017Lewis et al, 2008;Virkkula et al, 2005), which may not be sufficient to fully characterize spectral absorption properties of BB BrC emissions . In contrast to online instruments, the approach used in this study -measurements of BrC light absorption in extracts -eliminates the interference of BC absorption and allows recording high-resolution (i.e., ∼ 1 nm) absorption spectra over a large wavelength range (i.e., 190-900 nm, for this work).…”

Section: Resultsmentioning

confidence: 99%

Light absorption by polar and non-polar aerosol compounds from laboratory biomass combustion

et al. 2018

Self Cite

View full text Add to dashboard Cite

Abstract. Fresh and atmospherically aged biomass-burning (BB) aerosol mass is mostly comprised of strongly lightabsorbing black carbon (BC) and of organic carbon (OC) with its light-absorbing fraction -brown carbon (BrC). There is a lack of data on the physical and chemical properties of atmospheric BB aerosols, leading to high uncertainties in estimates of the BB impact on air quality and climate, especially for BrC. The polarity of chemical compounds influences their fate in the atmosphere including wet/dry deposition and chemical and physical processing. So far, most of the attention has been given to the water-soluble (polar) fraction of BrC, while the non-polar BrC fraction has been largely ignored. In the present study, the light absorption properties of polar and non-polar fractions of fresh and aged BB emissions were examined to estimate the contribution of differentpolarity organic compounds to the light absorption properties of BB aerosols.In our experiments, four globally and regionally important fuels were burned under flaming and smoldering conditions in the Desert Research Institute (DRI) combustion chamber. To mimic atmospheric oxidation processes (5-7 days), BB emissions were aged using an oxidation flow reactor (OFR). Fresh and OFR-aged BB aerosols were collected on filters and extracted with water and hexane to study absorption properties of polar and non-polar organic species. Results of spectrophotometric measurements (absorption weighted by the solar spectrum and normalized to mass of fuel consumed) over the 190 to 900 nm wavelength range showed that the non-polar (hexane-soluble) fraction is 2-3 times more absorbing than the polar (water-soluble) fraction. However, for emissions from fuels that undergo flaming combustion, an increased absorbance was observed for the water extracts of oxidized/aged emissions while the absorption of the hexane extracts was lower for the aged emissions for the same type of fuels. Absorption Ångström exponent (AAE) values, computed based on absorbance values from spectrophotometer measurements, were changed with aging and the nature of this change was fuel dependent. The light absorption by humic-like substances (HULIS) was found to be higher in fuels characteristic of the southwestern USA. The absorption of the HULIS fraction was lower for OFR-aged BB emissions. Comparison of the light absorption properties of different-polarity extracts (water, hexane, HULIS) provides insight into the chemical nature of BB BrC and its transformation during oxidation processes.

show abstract

Section: Resultsmentioning

confidence: 99%

Light absorption by polar and non-polar aerosol compounds from laboratory biomass combustion

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…15 Therefore, it is often challenging to distinguish between light absorption by BC and by BrC, especially if the BC concentrations are high (e.g., for flaming combustion). Second, most online instruments use 1-7 fixed wavelengths for light absorption measurements (Drinovec et al, 2015(Drinovec et al, , 2017Lewis et al, 2008;Virkkula et al, 2005), which may not be sufficient to fully characterize spectral absorption properties of BB BrC emissions . 20…”

Section: Resultsmentioning

confidence: 99%

Light absorption by polar and non-polar aerosol compounds from laboratory biomass combustion

Sengupta¹,

Samburova²,

Bhattarai³

et al. 2018

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Fresh and atmospherically aged biomass-burning (BB) aerosol mass is mostly comprised of black carbon (BC) and organic carbon (OC) with its light-absorbing fraction -brown carbon (BrC). 10There is a lack of data on the physical and chemical properties of atmospheric BB aerosols, leading to high uncertainties in estimates of the BB impact on air quality and climate, especially for BrC. The polarity of chemical compounds influences their fate in the atmosphere including wet/dry deposition and chemical and physical processing. So far, most of the attention has been given to the water-soluble (polar) fraction of BrC, while the non-polar BrC fraction has been largely ignored. In the present study, 15 the light absorption properties of polar and non-polar fractions of fresh and aged BB emissions were examined to estimate the contribution of different-polarity organic compounds to the light absorption properties of BB aerosols.In our experiments, four globally and regionally important fuels were burned under flaming and smoldering conditions in DRI's combustion chamber. To mimic atmospheric oxidation processes (5-7 20 days), BB emissions were aged using an oxidation flow reactor (OFR). Fresh and OFR-aged BB aerosols were collected on filters and extracted with water and hexane to study absorption properties of polar and non-polar organic species. Spectrophotometric measurements over the 190 to 900 nm wavelength range showed that the non-polar (hexane-soluble) fraction is 2-3 times more absorbing than the polar (water-soluble) fraction. However, an increased absorbance was observed for the water 25 extracts of oxidized/aged emissions while the absorption of the hexane extracts was lower for the aged emissions. Comparing the absorption Ångström Exponent (AAE) values, we observed changes in the light absorption properties of BB aerosols with aging that was dependent on the fuel types. The light Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2018-161 Manuscript under review for journal Atmos. Chem. Phys.

show abstract

“…Light-absorbing organic aerosols are also known as brown carbon (BrC) since they absorb blue light significantly but have practically zero absorption in the red band, yielding brownish colours . The distinction between the light absorption by BC and BrC in field and laboratory studies has relied on the explicit assumption that no carbonaceous particle type except BC absorbs solar radiation at a wavelength of ∼ 700 nm or larger (Bahadur et al, 2012;Kirchstetter and Thatcher, 2012;Lu et al, 2015;Drinovec et al, 2017). This common assumption has been used in spite of the finding by Alexander et al (2008), who showed a sizable absorption by a specific class of BrC at longer wavelengths.…”

Section: Introductionmentioning

confidence: 85%

Brown carbon absorption in the red and near-infrared spectral region

Hoffer¹,

Tóth

Pósfai

et al. 2017

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Abstract. Black carbon (BC) aerosols have often been assumed to be the only light-absorbing carbonaceous particles in the red and near-infrared spectral regions of solar radiation in the atmosphere. Here we report that tar balls (a specific type of organic aerosol particles from biomass burning) do absorb red and near-infrared radiation significantly. Tar balls were produced in a laboratory experiment, and their chemical and optical properties were measured. The absorption of these particles in the range between 470 and 950 nm was measured with an aethalometer, which is widely used to measure atmospheric aerosol absorption. We find that the absorption coefficient of tar balls at 880 nm is more than 10 % of that at 470 nm. The considerable absorption of red and infrared light by tar balls also follows from their relatively low absorption Ångström coefficient (and significant mass absorption coefficient) in the spectral range between 470 and 950 nm. Our results support the previous finding that tar balls may play an important role in global warming. Due to the non-negligible absorption of tar balls in the near-infrared region, the absorption measured in the field at near-infrared wavelengths cannot solely be due to soot particles.

show abstract

The filter-loading effect by ambient aerosols in filter absorption photometers depends on the coating of the sampled particles

Cited by 71 publications

References 70 publications

Light absorption by polar and non-polar aerosol compounds from laboratory biomass combustion

Light absorption by polar and non-polar aerosol compounds from laboratory biomass combustion

Light absorption by polar and non-polar aerosol compounds from laboratory biomass combustion

Brown carbon absorption in the red and near-infrared spectral region

Contact Info

Product

Resources

About