Biomass burning source identification through molecular markers in cryoconites over the Tibetan Plateau

AbstractLevoglucosan is a unique marker for biomass burning that can be transported in the atmosphere and preserved in archives such as ice cores. A new method to determine the concentrations of levoglucosan in Tibetan ice-core samples using high-performance liquid chromatography with electrospray ionization mass spectrometry (HPLC-ESI/MS) was developed. Levoglucosan was separated from coeluting water-soluble organic compounds using a C18 column with a gradient program from 50% to 90% methanol in ultrapure water. An external standard calibration curve (R2 = 0.9958) was established by plotting the ion m/z 163 [M+H]+ peak area versus the amount of analyte. The repeatability ranges between 11% and 2% at a concentration around 10 and 150 ng mL−1. The limit of detection was 10 ng mL−1 and the limit of quantification was 40 ng mL−1. Levoglucosan concentrations ranged from 10 to 718 ng mL−1 in the Muztagh Ata ice core and from 10 to 93 ng mL−1 in the Tanggula ice core. These concentrations, up to 1000 times higher than those measured in samples from Antarctic and Greenland, showed the higher vulnerability of the Tibetan Plateau glaciers to biomass burning events.

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Fire, vegetation and Holocene climate in the south-eastern Tibetan Plateau: a multi-biomarker reconstruction from Paru Co

10.5194/cp-2018-19 ◽

2018 ◽

Author(s):

Alice Callegaro ◽

Felipe Matsubara Pereira ◽

Dario Battistel ◽

Natalie M. Kehrwald ◽

Broxton W. Bird ◽

...

Keyword(s):

Tibetan Plateau ◽

Biomass Burning ◽

Fire History ◽

Vegetation Changes ◽

The Tibetan Plateau ◽

Eastern Tibetan Plateau ◽

The South ◽

South Eastern ◽

The Past ◽

High Concentrations

Abstract. The fire history of the Tibetan Plateau over centennial to millennial timescales is still unknown. Recent ice core studies reconstruct fire history over the past few decades but do not extend through the Holocene. Lacustrine sedimentary cores, however, provide continuous records of large-scale and local environmental modifications due to their accumulation of specific organic molecular markers throughout the past millennia. In order to reconstruct Holocene fire events and vegetation changes occurring on the south-eastern Tibetan Plateau and the surrounding areas, we improved and integrated previous analytical methods. The multi-proxy procedure was applied to samples retrieved from Paru Co, a small lake located in the Nyainqentanglha Mountains (29°47'45.6" N; 92°21'07.2" E; 4845 m a.s.l.). The investigated biomarkers include n-alkanes as indicators of vegetation, polycyclic aromatic hydrocarbons (PAHs) as combustion proxies, faecal sterols and stanols (FeSts) as indicators of the presence of humans or grazing animals and finally monosaccharide anhydrides (MAs) as specific markers of vegetation burning processes. Relatively high concentrations of both MAs and PAHs demonstrate intense local biomass burning activity during the early Holocene (10.9–10.7 cal ky BP), which correspond to a drier climate following deglaciation. High concentrations of MAs but not PAHs between 10.7–9 cal ky BP suggest a period of regional biomass burning followed by a decreasing fire trend through the mid-late Holocene. This fire history is consistent with local vegetation changes reconstructed from both n-alkanes and regional pollen records, where vegetation types depend on the centennial-scale intensity of monsoon precipitation. FeSts were below detection limits for most of the samples, suggesting limited direct human influences on fire regime and vegetation changes in the lake's catchment. Climate is the main influence on fire activity recorded in Paru Co over millennial timescales, where biomass burning fluctuates in response to alternating warm/humid and cool/dry periods.

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Light absorption of biomass burning and vehicle emission-sourced carbonaceous aerosols of the Tibetan Plateau

Environmental Science and Pollution Research ◽

10.1007/s11356-017-9077-3 ◽

2017 ◽

Vol 24 (18) ◽

pp. 15369-15378 ◽

Cited By ~ 18

Author(s):

Zhaofu Hu ◽

Shichang Kang ◽

Chaoliu Li ◽

Fangping Yan ◽

Pengfei Chen ◽

...

Keyword(s):

Tibetan Plateau ◽

Biomass Burning ◽

Light Absorption ◽

Vehicle Emission ◽

The Tibetan Plateau ◽

Carbonaceous Aerosols

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Particle number size distribution and new particle formation under the influence of biomass burning at a high altitude background site at Mt. Yulong (3410 m), China

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-15687-2018 ◽

2018 ◽

Vol 18 (21) ◽

pp. 15687-15703 ◽

Cited By ~ 2

Author(s):

Dongjie Shang ◽

Min Hu ◽

Jing Zheng ◽

Yanhong Qin ◽

Zhuofei Du ◽

...

Keyword(s):

Tibetan Plateau ◽

High Altitude ◽

Size Distribution ◽

Biomass Burning ◽

Particle Number ◽

Global Climate ◽

Particle Formation ◽

The Tibetan Plateau ◽

Upper Troposphere ◽

Number Size Distribution

Abstract. Biomass burning (BB) activities have a great impact on the particle number size distribution (PNSD) in the upper troposphere of the Tibetan Plateau, which could affect regional and global climate. An intensive campaign focused on the measurement of the PNSD, gaseous pollutants, and meteorological parameters was conducted at Mt. Yulong, a high-altitude site (3410 m a.s.l.) on the southeastern Tibetan Plateau during the pre-monsoon season (22 March to 15 April). During this period, intensive BB activities in southern Asia were detected by fire maps. The long-range transport of BB pollutants can increase the accumulation mode particles in the background atmosphere at Mt. Yulong. As a consequence, the cloud condensation nuclei (CCN) concentration was found to be 2–8 times higher during BB periods than during clean periods. Apart from BB, variations of the planet boundary layer (PBL) and new particle formation (NPF) were other factors that influenced the PNSD. However, only three NPF events (with a frequency of 14 %) were observed at Mt. Yulong. The occurrence of NPF events during clean episodes corresponded to an elevated PBL or transported BB pollutants. Due to the lack of condensable vapors including sulfuric acid and organic compounds, the newly formed particles were not able to grow to CCN size. Our study emphasizes the influences of BB on the aerosol and CCN concentration in the atmosphere of the Tibetan Plateau. These results also have the potential to improve our understanding of the variation of the particle concentration in the upper troposphere, and provide information for regional and global climate models.

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Influence of biomass burning from South Asia at a high-altitude mountain receptor site in China

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-6853-2017 ◽

2017 ◽

Vol 17 (11) ◽

pp. 6853-6864 ◽

Cited By ~ 17

Author(s):

Jing Zheng ◽

Min Hu ◽

Zhuofei Du ◽

Dongjie Shang ◽

Zhaoheng Gong ◽

...

Keyword(s):

Tibetan Plateau ◽

South Asia ◽

Biomass Burning ◽

Monsoon Season ◽

Organic Aerosol ◽

Submicron Particles ◽

The Tibetan Plateau ◽

Anthropogenic Aerosols ◽

Air Masses ◽

Average Mass

Abstract. Highly time-resolved in situ measurements of airborne particles were conducted at Mt. Yulong (3410 m above sea level) on the southeastern edge of the Tibetan Plateau in China from 22 March to 14 April 2015. The detailed chemical composition was measured by a high-resolution time-of-flight aerosol mass spectrometer together with other online instruments. The average mass concentration of the submicron particles (PM1) was 5.7 ± 5.4 µg m−3 during the field campaign, ranging from 0.1 up to 33.3 µg m−3. Organic aerosol (OA) was the dominant component in PM1, with a fraction of 68 %. Three OA factors, i.e., biomass burning organic aerosol (BBOA), biomass-burning-influenced oxygenated organic aerosol (OOA-BB) and oxygenated organic aerosol (OOA), were resolved using positive matrix factorization analysis. The two oxygenated OA factors accounted for 87 % of the total OA mass. Three biomass burning events were identified by examining the enhancement of black carbon concentrations and the f60 (the ratio of the signal at m∕z 60 from the mass spectrum to the total signal of OA). Back trajectories of air masses and satellite fire map data were integrated to identify the biomass burning locations and pollutant transport. The western air masses from South Asia with active biomass burning activities transported large amounts of air pollutants, resulting in elevated organic concentrations up to 4-fold higher than those of the background conditions. This study at Mt. Yulong characterizes the tropospheric background aerosols of the Tibetan Plateau during pre-monsoon season and provides clear evidence that the southeastern edge of the Tibetan Plateau was affected by the transport of anthropogenic aerosols from South Asia.

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Influence of biomass burning from Southeast Asia at a high-altitude mountain receptor site in China

10.5194/acp-2016-1117 ◽

2017 ◽

Author(s):

Jing Zheng ◽

Min Hu ◽

Zhuofei Du ◽

Dongjie Shang ◽

Zhaoheng Gong ◽

...

Keyword(s):

Tibetan Plateau ◽

Southeast Asia ◽

Biomass Burning ◽

Monsoon Season ◽

Organic Aerosol ◽

Submicron Particles ◽

The Tibetan Plateau ◽

Anthropogenic Aerosols ◽

Back Trajectories ◽

Average Mass

Abstract. Highly time-resolved in-situ measurements of airborne particles were made at Mt. Yulong (3410 m above sea level) on the southeastern edge of the Tibetan Plateau in China from 20 March to 14 April in 2015. Detailed chemical composition was measured by a high-resolution time-of-flight aerosol mass spectrometer together with other online instruments. Average mass concentration of the submicron particles (PM1) was 5.7 ± 5.4 μg m−3 during the field campaign, ranging from 0.1 μg m−3 up to 33.3 μg m−3. Organic aerosol (OA) was the dominant component in PM1, with a fraction of 68 %. Three OA factors, i.e., biomass-burning organic aerosol (BBOA), biomass-burning-influenced oxygenated organic aerosol (OOA-BB) and oxygenated organic aerosol (OOA), were resolved using positive matrix factorization analysis. The two oxygenated OA factors accounted for 87 % of the total OA mass. Three biomass burning events were identified by examining the enhancement of black carbon concentrations and the f60 (the ratio of the signal at m/z 60 from the mass spectrum to the total signal of OA). Back trajectories of air masses and satellite fire map data were integrated to identify the biomass burning locations and pollutants transport. The western air mass from Southeast Asia with active biomass burning activities transported large amount of air pollutants, resulting in elevated organic concentrations up to 4-fold higher than that of the background condition. This study at Mt. Yulong characterizes the tropospheric background aerosols of the Tibetan Plateau during pre-monsoon season, and provides clear evidence that the southeastern edge of the Tibetan Plateau is affected by transport of anthropogenic aerosols from Southeast Asia.

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Strong Light Absorption Induced by Aged Biomass Burning Black Carbon over the Southeastern Tibetan Plateau in Pre-monsoon Season

10.5194/acp-2020-1150 ◽

2020 ◽

Author(s):

Tianyi Tan ◽

Min Hu ◽

Zhuofei Du ◽

Gang Zhao ◽

Dongjie Shang ◽

...

Keyword(s):

Tibetan Plateau ◽

Black Carbon ◽

Biomass Burning ◽

Climate Warming ◽

Light Absorption ◽

Monsoon Season ◽

Absorption Enhancement ◽

The Tibetan Plateau ◽

Mixing State ◽

Strong Light

Abstract. During the pre-monsoon season, biomass burning (BB) activities are intensive in southern Asia. Facilitated by westerly circulation, those BB plumes can be transported to the Tibetan Plateau (TP). Black carbon (BC), the main aerosol species in BB emissions, is an important climate warming agent, and its absorbing property strongly depends on its size distribution and mixing state. To elucidate the influence of those transported BB plumes on the TP, a field campaign was conducted on the southeast edge of the TP during the pre-monsoon season. It was found that the transported BB plumes substantially increased the number concentration of the atmospheric BC particles by 13 times, and greatly elevated the number fraction of thickly-coated BC from 52 % up to 91 %. Those transported BC particles had slightly larger core size and much thicker coatings than the background BC particles. However, the coating mass was not evenly distributed on BC particles with different sizes. The smaller BC cores were found to have larger shell/core ratios than the larger cores. Besides, the transported BB plumes strongly affected the vertical variation of the BC's abundance and mixing state, resulting in a higher concentration, larger number fraction and higher aging degree of BC particles in the upper atmosphere. Resulted from both increase of BC loading and aging degree, the transported BB plumes eventually enhanced the total light absorption by 15 times, in which 21 % was contributed by the BC aging and 79 % was contributed from the increase of BC mass. Particularly, the light absorption enhancement induced by the aging process during long-range transport has far exceeded the background aerosol light absorption, which implicates a significant influence of BC aging on climate warming over the TP region.

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Characteristics of PM2.5 at a High-Altitude Remote Site in the Southeastern Margin of the Tibetan Plateau in Premonsoon Season

Atmosphere ◽

10.3390/atmos10110645 ◽

2019 ◽

Vol 10 (11) ◽

pp. 645

Author(s):

Zhuzi Zhao ◽

Qiyuan Wang ◽

Li Li ◽

Yongming Han ◽

Zhaolian Ye ◽

...

Keyword(s):

Tibetan Plateau ◽

High Altitude ◽

Biomass Burning ◽

Mining Industry ◽

The Tibetan Plateau ◽

Remote Site ◽

Source Regions ◽

Potential Source ◽

Southeastern Margin ◽

High Concentrations

The Tibetan Plateau (TP) is one of the world’s most sensitive areas for climate change. Previous studies have revealed that air pollutants emitted from South and Southeast Asia can be transported to and have a negative impact on the TP. However, the majority of the investigators have focused on the pollutant transport processes from South Asian regions (i.e., India and Bangladesh) and parts of Southeast Asia, while the regions adjacent to the southeast fringe of the TP (i.e., Burma and the Sino-Burmese border) have been neglected. Here, fine particulate matter (PM2.5) samples were collected during the period 11 March to 13 May 2018 at Gaomeigu, a high-altitude remote site in the southeastern margin of the TP. Characteristics, sources of PM2.5, and the potential source regions for different chemical components were investigated. During the sampling time, PM2.5 mass loadings ranged from 3.79 to 54.57 µg m−3, with an arithmetic mean concentration of 20.99 ± 9.80 µg m−3. In general, major peaks of organic carbon (OC) and elemental carbon (EC) always coincided with high loadings of K+ and NO3−, which implies that common combustion sources caused these species’ concentrations to covary, while the daily variations of crustal elements showed different trends with the other chemical compositions, suggesting different source regions for crustal materials. Five source factors were identified as possible aerosol sources for PM2.5 by positive matrix factorization (PMF). They are the mining industry (5.3%), characterized by heavy metal elements; secondary formation (18.8%), described by the high concentrations of NH4+ and SO42−; traffic-related emissions (26.7%), dominated by carbonaceous species (especially soot-EC) and some metal elements; fugitive dust (15.2%), represented by crustal elements (Ti, Fe, and Mn), Ca2+, and Mg2+; and biomass burning (34.0%), which is typified by high concentrations of K+, NO3−, char-EC, primary OC, and secondary OC. The concentration-weighted trajectory (CWT) analysis results showed that the northeast part of Burma is the potential source region for high concentrations of EC and NO3− due to biomass burning emissions, while the tourism industry surrounding Gaomeigu gave strong grid cell values of SO42− as well as moderate values of EC and NO3−. Moreover, the mining industry in the southwest direction of Gaomeigu has important impacts on the zinc concentrations.

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Measurement report: Strong light absorption induced by aged biomass burning black carbon over the southeastern Tibetan Plateau in pre-monsoon season

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-8499-2021 ◽

2021 ◽

Vol 21 (11) ◽

pp. 8499-8510

Author(s):

Tianyi Tan ◽

Min Hu ◽

Zhuofei Du ◽

Gang Zhao ◽

Dongjie Shang ◽

...

Keyword(s):

Tibetan Plateau ◽

Black Carbon ◽

Biomass Burning ◽

Climate Warming ◽

Light Absorption ◽

Monsoon Season ◽

Absorption Enhancement ◽

The Tibetan Plateau ◽

Mixing State ◽

Strong Light

Abstract. During the pre-monsoon season, biomass burning (BB) activities are intensive in southern Asia. Facilitated by westerly circulation, those BB plumes can be transported to the Tibetan Plateau (TP). Black carbon (BC), the main aerosol species in BB emissions, is an important climate warming agent, and its absorbing property strongly depends on its size distribution and mixing state. To elucidate the influence of those transported BB plumes on the TP, a field campaign was conducted on the southeast edge of the TP during the pre-monsoon season. It was found that the transported BB plumes substantially increased the number concentration of the atmospheric BC particles by a factor of 13 and greatly elevated the number fraction of thickly coated BC from 52 % up to 91 %. Those transported BC particles had slightly larger core size and much thicker coatings than the background BC particles. However, the coating mass was not evenly distributed on BC particles with different sizes. The smaller BC cores were found to have larger shell / core ratios than the larger cores. Besides, the transported BB plumes strongly affected the vertical variation in the BC's abundance and mixing state, resulting in a higher concentration, larger number fraction, and higher aging degree of BC particles in the upper atmosphere. Resulting from both increase in BC loading and aging degree, the transported BB plumes eventually enhanced the total light absorption by a factor of 15, of which 21 % was contributed by the BC aging, and 79 % was contributed from the increase in BC mass. Particularly, the light absorption enhancement induced by the aging process during long-range transport has far exceeded the background aerosol light absorption, which implicates a significant influence of BC aging on climate warming over the TP region.

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