Size distribution of carbonaceous aerosols at a high-altitude site on the central Tibetan Plateau (Nam Co Station, 4730ma.s.l.)

Wan, Xin; Kang, Shichang; Wang, Yuesi; Xin, Jinyuan; Liu, Bin; Guo, Yujun; Wen, Tian; Zhang, Guoshuai; Cong, Zhiyuan

doi:10.1016/j.atmosres.2014.08.008

Cited by 89 publications

(79 citation statements)

References 58 publications

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“…The MAC rBC can be calculated by dividing the absorption coefficient measured with the PAX by the rBC mass concentration from the SP2 (MAC rBC = [Absorption] / [rBC]). Due to the difference in cutoff size for PAX (< 2.5 µm) and for SP2 (< 1.0 µm), the MAC rBC may be overestimated by ∼ 13 % given that BC concentration in PM 1.0 accounted for ∼ 85 % of PM 2.5 in the Tibetan Plateau (Wan et al, 2015). Figure 6a and b show histograms of the MAC rBC values during clean days and the pollution episode, respectively.…”

Section: Optical Properties Of Rbc Aerosolmentioning

confidence: 99%

Black carbon aerosol in winter northeastern Qinghai–Tibetan Plateau, China: the source, mixing state and optical property

et al. 2015

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Abstract. Black carbon (BC) aerosol at high altitudes of the Qinghai-Tibetan Plateau has potential effects on the regional climate and hydrological cycle. An intensive measurement campaign was conducted at Qinghai Lake ( ∼ 3200 m above sea level) at the edge of the northeastern QinghaiTibetan Plateau during winter using a ground-based single particle soot photometer (SP2) and a photoacoustic extinctiometer (PAX). The average concentration of refractory BC (rBC) and number fraction of coated rBC were found to be 160 ± 190 ng m −3 and 59 % for the entire campaign, respectively. Significant enhancements of rBC loadings and number fraction of coated rBC were observed during a pollution episode, with an average value of 390 ng m −3 and 65 %, respectively. The mass size distribution of rBC particles showed log-normal distribution, with a peak diameter of ∼ 187 nm regardless of the pollution level. Five-day backward trajectory analysis suggests that the air masses from north India contributed to the increased rBC loadings during the campaign. The potential source contribution function (PSCF) model combined with the fire counts map further proves that biomass burning from north India is an important potential source influencing the northeastern Qinghai-Tibetan Plateau during the pollution episode. The rBC mass absorption cross section (MAC rBC ) at λ = 532 nm was slightly larger in clean days (14.9 m 2 g −1 ) than during the pollution episode (9.3 m 2 g −1 ), likely due to the effects of brown carbon and the uncertainty of the MAC rBC calculation. The MAC rBC was positively correlated with number fraction of coated rBC during the pollution episode with an increasing rate of 0.18 (m 2 g −1 ) % −1 . The number fraction of coated rBC particles showed positive correlation with light absorption, suggesting that the increase of coated rBC particles will enhance the light absorption. Compared to rBC mass concentration, rBC mixing sate is more important in determining absorption during the pollution episode, estimated from the same percentage-wise increment of either rBC mass concentration or the number fraction of coated rBC. The estimated BC direct radiative forcing was +0.93 W m −2 for the pollution episode, which is 2 times larger than that in clean days. Our study provides insight into the potential climatic impacts of rBC aerosol transported to the Qinghai-Tibetan Plateau from south Asian regions, and is also useful for future modeling studies.

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Section: Optical Properties Of Rbc Aerosolmentioning

confidence: 99%

Black carbon aerosol in winter northeastern Qinghai–Tibetan Plateau, China: the source, mixing state and optical property

et al. 2015

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“…In addition to this, they have capacity to change the radiative balance of the atmosphere by absorbing and scattering solar radiation. They also change the microphysical process of clouds and perform as ice nuclei (IN) and cloud condensation nuclei (CCN) (Ramanathan et al, 2001;Wan et al, 2015;Zhang et al, 2015). This phenomenon varies widely depending on particle size, characteristics and chemical compositions of APM (Muller et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Seasonal Chemical Characteristics of Atmospheric Aerosol Particles and its Light Extinction Coefficients over Pune, India

Pipal

Tiwari

Satsangi

2016

Aerosol Air Qual. Res.

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The present study has been conducted to characterize atmospheric aerosol particles in terms of carbonaceous species and ionic constituents for a yearlong period at Pune, India. This study provides the evidence for the ionic chemistry, secondary aerosols formation, temporal variability and its climatic effect in the atmosphere. The average concentrations of PM 2.5 and PM 10 were 109.6 ± 23.2 and 166.9 ± 4 µg m -3 , respectively, by far exceeding National Ambient Air Quality (NAAQ) and World Health Organization (WHO) standards. Seasonal analyses indicated that PM 2.5 and PM 10 mass concentrations were higher in the post-monsoon followed by the winter season and lower during the monsoon period. The average concentrations of organic carbon (OC) and elemental carbon (EC) were 31.3 ± 7.4 and 4.2 ± 2.4 µg m -3 for PM 2.5 , while, 34.2 ± 6.2 and 5.0 ± 2.3 µg m -3 for PM 10 , respectively. OC and EC data splits into seasons and their mass loadings were in the order of post-monsoon > monsoon > winter > summer for OC and for EC, it was as winter > post-monsoon > summer > monsoon. The overall chemical analysis revealed that particulate matter (PM) consist higher concentrations of OC followed by cations and the lowest one is EC. The ionic composition analysis indicated that cations were the abundant parts of PM in comparison to anions and Na + and SO 4 2-were at a higher concentration amongst all the ionic species. The estimated light extinction coefficient (b ext ) of the aerosol particle was 291.2 ± 55.3 Mm -1 during the study period. Further apportionment of particle extinction coefficient was estimated and the contributions of light scattering coefficient by particles (bsp) were OC (45%), (NH 4 ) 2 SO 4 (17%), NH 4 NO 3 (8%) and coarse mass (12%), while, the contribution of light absorption coefficient by particle (bap) was 18% (EC). This indicates that in the present study the abundance of aerosol particles are more scattering in nature in comparison to absorption. The average value of Aerosol optical depth (AOD) was 0.46 and their positive correlation with anions and relative humidity (RH) showing same properties, while, in the case of EC, it showed contrast nature with respect to climate effect. Trajectory analysis indicated that the air masses appear as a result of long-range transportation during summer and monsoon period while during the winter and post-monsoon seasons local manmade activities showed dominant influence.

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“…The contribution of OC to PM decreases significantly as the size of PM increases, suggesting the contribution from soil deflation to OC was relatively insignificant. Soil deflation is among significant possible sources of coarse mode OC (Wan et al, 2015). Majority of OC in PM <0.95 also indicates that the dominant part of ambient OC comes from combustion source (s) and/or of secondary origin.…”

Section: Carbonaceous Species In Size-segregated Aerosolsmentioning

confidence: 99%

Size-Segregated Characteristics of Carbonaceous Aerosols over the Northwestern Indo-Gangetic Plain: Year Round Temporal Behavior

Singh

Rastogi

Patel

et al. 2016

Aerosol Air Qual. Res.

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Size-segregated aerosol samples (PM <0.95 , PM 0.95-1.5 , PM 1.5-3.0 , PM 3.0-7.2 and PM >7.2 ) were collected over Patiala (30.33°N, 76.40°E; 250 m amsl), a semi-urban city located in northwestern Indo-Gangetic Plain (IGP) during October, 2012 to September, 2013. These samples were analyzed for carbonaceous aerosols (organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC)) to study their temporal variation, prevailing emission source (s) and secondary formation processes. Annual average of total suspended particulates (TSP) concentration, estimated by adding the aerosol concentrations in different size ranges, was found to be 199 ± 82 µg m -3 , varying from 88-387 µg m -3 with majority of particulate mass found in submicron size (PM <0.95 ). ), respectively over an annual cycle. Highest mass fraction of OC (> 75%) and WSOC (> 80%) was observed in submicron size, suggesting that OC mainly comes from combustion and/or secondary source (s). It has been observed that almost half of OC is secondary. On the other hand, climate forcing agent EC in PM <0.95 varied from 1.1 to 9.8 µg m -3 (4.8 ± 2.2 µg m -3 ). High mass ratios of OC/EC (~1.5-7.2) and WSOC/OC (~0.33-0.68) indicate the relative dominance of biomass burning emission over the study region. Total carbonaceous aerosols account for ~10-59% of submicron particulates mass (PM <0.95 ), indicating that fine particulates are enriched with carbonaceous species. These results have implications to regional climate model development and validation.

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Size distribution of carbonaceous aerosols at a high-altitude site on the central Tibetan Plateau (Nam Co Station, 4730ma.s.l.)

Cited by 89 publications

References 58 publications

Black carbon aerosol in winter northeastern Qinghai–Tibetan Plateau, China: the source, mixing state and optical property

Black carbon aerosol in winter northeastern Qinghai–Tibetan Plateau, China: the source, mixing state and optical property

Seasonal Chemical Characteristics of Atmospheric Aerosol Particles and its Light Extinction Coefficients over Pune, India

Size-Segregated Characteristics of Carbonaceous Aerosols over the Northwestern Indo-Gangetic Plain: Year Round Temporal Behavior

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