Black Carbon Aerosols at Mt. Muztagh Ata, a High-Altitude Location in the Western Tibetan Plateau

Zhu, Chongshu; Cao, Junji; Xu, Bin; Huang, Ru‐Jin; Wang, Ping; Ho, Kin-Fai; Shen, Zhenxing; Liu, Suixin; Han, Yongming; Tie, Xuexi; Zhao, Zi-Long; Chen, L.-W. Antony

doi:10.4209/aaqr.2015.04.0255

Cited by 18 publications

(13 citation statements)

References 51 publications

(72 reference statements)

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“…A comparison of the BC or EC measured at different locations is given in Table . The concentrations of BC in the Himalayas apparently decrease sharply with altitude; for example, BC concentrations measured at Lulang were significantly higher than the values reported from Nam Co [ Ming et al ., ], QSS station [ Zhao et al ., ], Hanle [ Babu et al ., ], NCO‐P [ Marinoni et al ., ], and Muztagh Ata [ Zhu et al ., ]. However, the concentrations of BC in urban sites located within high‐altitude basins, as in Lhasa [ Gao et al ., ], can be 5 times higher than that in Lulang.…”

Section: Resultsmentioning

confidence: 99%

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Black carbon aerosol and its radiative impact at a high‐altitude remote site on the southeastern Tibet Plateau

Zhao

Wang

et al. 2017

JGR Atmospheres

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Aerosol black carbon (BC) was measured with an Aethalometer™ at Lulang, a high‐altitude station in southeastern Tibetan Plateau (TP), from July 2008 to August 2009. Daily mean BC loadings varied from 57.7 to 5368.9 ng m−3 (grand average ± standard deviation = 496.5 ± 521.2 ng m−3), indicating a significant BC burden even at free tropospheric altitudes. BC loadings were highest during the premonsoon and lowest during the monsoon, and peaks in BC were coincident with high atmospheric boundary layers. Daily peaks in BC occurred from 08:00 to 10:00 local time with minor fluctuations at other times. The BC mass absorption efficiency (MAE) was calculated from elemental carbon concentrations obtained from a thermal/optical reflectance method and absorption coefficients from the Aethalometer™, and values ranged from 6.1 to 31.7 m2 g−1 (average = 16.6 ± 5.7 m2 g−1). Strong variations in the MAEs during the monsoon can be ascribed to large uncertainties due to low BC and babs and possibly coatings on the BC. High MAEs during premonsoon pollution events were likely due to internal mixing during transport. The mean direct surface radiative forcing (DRF) estimated from a radiation model was −19.9 (±7.4) W m−2 for the full aerosol population and −3.9 (±1.8) W m−2 for a BC only scenario. The BC DRF during a case study (−36.0 W m−2) was much stronger than the typical, and the BC contribution to the forcing was higher (~50%) than usual (~20%). These results show that BC can at times account for a relatively large fraction of the aerosol surface heating over the southeast TP, which may affect both climate and hydrological cycles.

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Section: Resultsmentioning

confidence: 99%

“…The ATN data from the Aethalometer™ are converted to BC mass by assuming a fixed BC specific attenuation cross section of 16.6 m 2 g −1 [ Virkkula et al ., ]. Details of the instrument's operating principles have been presented elsewhere [ Cao et al ., , ; Zhu et al ., ].…”

Section: Methodsmentioning

confidence: 99%

Black carbon aerosol and its radiative impact at a high‐altitude remote site on the southeastern Tibet Plateau

Zhao

Wang

et al. 2017

JGR Atmospheres

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“…The EC and OC levels in KY were also significantly above the mean values, reported by Lim et al (2003), at the background Pacific Ocean (0.09 and 0.21 µg m -3 , respectively), Asian-influenced Pacific Ocean (0.29 and 0.70 µg m -3 ), offshore of Japan (0.27 and 1.00 µg m -3 ) and Sea of Japan (0.66 and 2.43 µg m -3 ). Our EC levels were somewhat higher than the equivalent black carbon (EBC, optical method) reported for a Western Tibetan Plateau site which had the daily levels varying from 33.6 to 330.2 ng m -3 (Zhu et al, 2016) and indeed were much above the EBC levels measured at the South Pole (monthly EBC < 8 ng m -3 ) reported in Sheridan et al (2016). The EC and OC results thus showed that even the KY site was in a relatively remote forest area of Thailand the effects of human activities on pollution levels were still clearly shown as compared to other more "truly" remote areas in Asia reported by Lim et al (2003) or the South Pole (Sheridan et al, 2016).…”

Section: Ec and Oc Compositionmentioning

confidence: 88%

Characterization of Particulate Matter Measured at Remote Forest Site in Relation to Local and Distant Contributing Sources

Oanh

Hang

Tipayarom

et al. 2016

Aerosol Air Qual. Res.

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This study characterized the particulate matter (PM) pollution at a forest site in the Khao Yai (KY) National Park of Thailand, 700 m above sea level and 120 km upwind to Bangkok during the dry season. Two dichotomous samplers simultaneously operated on each monitoring day to collect 2 samples (on 2 filter types: quartz and mix cellulose) of 24 h PM 2.5 and 2 samples of 24 h PM 10-2.5 . More focus was on the dry and more polluted season with a longer sampling period (43 days: Jan-Feb 2005) and less on wet season (10 days, Jun 2005). Samples were analyzed for mass, water soluble ions, elements, EC and OC (Sunset analyzer). PM 2.5 levels obtained at KY in the dry period (47 µg m -3 ) were comparable to those in several urban areas in Southeast Asia, but the wet season levels (7 µg m -3 ) were significantly lower. In the dry season, levels of EC associated with PM 2.5 at KY were remarkably lower than but OC were comparable to those found in urban areas which resulted in considerably low EC/TC ratios (0.08). The major mass groups of PM 2.5 in the dry season were organic matter of biomass smoke origin (OM-smoke), secondary inorganic aerosol, organic matter of other origins than smoke (OM-others) and crustal. Similar contributors to PM 2.5 were also found in the wet season but with only a small contribution from biomass burning smoke. Significant contributions from distant sources to PM 2.5 levels measured at KY were also confirmed by the HYSPLIT backward trajectory analysis. The coarse fraction (PM 10-2.5 ) had major mass groups of OM-others, inorganic particles and crustal that were most likely related to local sources, and some amount of aged sea salt indicating a distant source origin.

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“…Although the PSCF model is a practical tool often used to locate potential source areas (e.g., Zhang et al, 2013b;Dimitriou, 2015;Zhu et al, 2016), a restriction of this method is that the same PSCF values may occur in different grid cells when BC loadings at the receptor site are either substantially larger or only slightly larger than the criterion value, which is often derived as the arithmetic mean (e.g., Wang et al, 2004;Xu and Akhtar, 2010;Zhao et al, 2015). This may lead to difficulties in differentiating heavy pollution sources from moderate ones.…”

Section: Bc Potential Pollution Source Areasmentioning

confidence: 99%

Seasonal Characteristics of Black Carbon Aerosol and its Potential Source Regions in Baoji, China

Zhou

Wang

Zhou

et al. 2018

Aerosol Air Qual. Res.

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Continuous measurements of black carbon (BC) aerosol were made at a midsized urban site in Baoji, China, in 2015. The daily average mass concentrations varied from 0.6 to 11.5 µg m -3 , with an annual mean value of 2.9 ± 1.7 µg m -3 . The monthly variation indicated that the largest loading of BC occurred in January and the smallest in June. The mass concentrations exhibited strong seasonality, with the highest occurring in winter and the lowest in summer. The large BC loadings in winter were attributed to the increased use of fuel for domestic heating and to stagnant meteorological conditions, whereas the low levels in summer were related to the increase in precipitation. BC values exhibited similar bimodal diurnal patterns during the four seasons, with peaks occurring in the morning and evening rush hours and an afternoon trough, which was associated with local anthropogenic activities and meteorological conditions. A potential source contribution function model indicated that the effects of regional transport mostly occurred in spring and winter. The most likely regional sources of BC in Baoji were southern Shaanxi province, northwestern Hubei province, and northern Chongqing during spring, whereas the northeastern Sichuan Basin was the most important source region during winter.

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Black Carbon Aerosols at Mt. Muztagh Ata, a High-Altitude Location in the Western Tibetan Plateau

Cited by 18 publications

References 51 publications

Black carbon aerosol and its radiative impact at a high‐altitude remote site on the southeastern Tibet Plateau

Black carbon aerosol and its radiative impact at a high‐altitude remote site on the southeastern Tibet Plateau

Characterization of Particulate Matter Measured at Remote Forest Site in Relation to Local and Distant Contributing Sources

Seasonal Characteristics of Black Carbon Aerosol and its Potential Source Regions in Baoji, China

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