First Chemical Characterization of Refractory Black Carbon Aerosols

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First chemical characterization of refractory black carbon aerosols and associated coatings over the Tibetan Plateau (4730 m a.s.l) Junfeng Wang, Qi Zhang, Min-Dong Chen, Sonya Collier, Shan Zhou, Xinlei Ge, Jianzhong Xu, Jinsen Shi, Conghui Xie, Jianlin Hu, Shun Ge, Yele Sun, and Hugh Coe Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.7b03973 • Publication Date (Web): 13 Nov 2017 Downloaded from http://pubs.acs.org on November 13, 2017

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Environmental Science & Technology

1

First chemical characterization of refractory black carbon aerosols

2

and associated coatings over the Tibetan Plateau (4730 m a.s.l)

3

Junfeng Wang,† Qi Zhang,‡,† Mindong Chen,† Sonya Collier,‡ Shan Zhou,‡

4

Xinlei Ge,†,* Jianzhong Xu,§,* Jinsen Shi, Conghui Xie,§, Jianlin Hu,† Shun Ge,†

5

Yele Sun, and Hugh Coe#

∥

⊥

⊥

6

†

7

Control, Collaborative Innovation Center of Atmospheric Environment and

8

Equipment Technology, School of Environmental Science and Engineering, Nanjing

9

University of Information Science and Technology, Nanjing 210044, China

Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution

10

‡

11

CA 95616, USA

12

§

13

Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000,

14

China

15 16

Department of Environmental Toxicology, University of California at Davis, Davis,

State

Key

Laboratory

of

Cryospheric

Sciences,

Northwest

Institute

of

∥

College of Atmospheric Science, Lanzhou University, Lanzhou 730000, China

⊥

State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric

17

Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing

18

100029, China

19

#

20

Manchester, UK

21

*Corresponding authors, Email: [email protected]; [email protected]

School of Earth and Environmental Sciences, University of Manchester, M13 9PL,

22 23

Phone: +86-25-58731394

24 25

For Environ. Sci. Technol.

26

ACS Paragon Plus Environment


27

Abstract: Refractory black carbon (rBC) aerosol is an important climate forcer, and

28

its impacts are greatly influenced by the species associated with rBC cores. However,

29

relevant knowledge is particularly lacking at the Tibetan Plateau (TP). Here we report,

30

for the first time, highly time-resolved measurement results of rBC and its coating

31

species in central TP (4730 m a.s.l), by using an Aerodyne soot particle aerosol mass

32

spectrometer (SP-AMS), which selectively measured rBC-containing particles. We

33

found that the rBC was overall thickly coated with an average mass ratio of coating to

34

rBC (RBC) of ~7.7, and the coating species were predominantly secondarily produced

35

by photochemical reactions. Interestingly, the thickly coated rBC was less oxygenated

36

than the thinly coated rBC, mainly due to influence of the transported biomass

37

burning organic aerosol (BBOA). This BBOA was relatively fresh but formed very

38

thick coating on rBC. We further estimated the “lensing effect” of coating

39

semi-quantitatively by comparing the measurement data from a multi-angle

40

absorption photometer and SP-AMS, and found it could lead to up to 40% light

41

absorption enhancement at RBC>10. Our findings highlight that BBOA can

42

significantly affect the “lensing effect”, in addition to its relatively well known role as

43

light-absorbing “brown carbon.”


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1. Introduction

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Atmospheric refractory black carbon particles (rBC), or soot, are a product of

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incomplete combustion of biomass or fossil fuel.1 It is harmful to human health and

47

impacts air quality significantly.1 rBC can affect the radiative forcing by direct

48

absorption of sunlight, or indirectly through alteration of cloud properties as it can be

49

coated with hydrophilic materials and activated into cloud condensation nuclei

50

(CCN).2, 3 Some studies estimate that the positive climate forcing of rBC is second

51

only to CO2.1, 4 In addition, rBC can also deposit on snow and ice, reducing surface

52

albedo and accelerating melting.1,

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Tibetan Plateau (TP), the “Third Pole” of earth,7 as it is the world's third-largest store

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of glacial ice;8 and since TP is in the subtropical latitude, the radiation energy per unit

55

area reflected into space by its glaciers was estimated to be four times more than that

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intercepted between 60 and 70 oN or S.9 However, glaciers in TP are retreating at a

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higher speed than any other part of the world, which may lead to a shortage of

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seasonal fresh water supply for Asian Rivers, and may severely influence the

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Indian/Asian summer monsoon and hence global climate too.10, 11 A recent study

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revealed that rBC and fly ash particles could occupy a large fraction of the cryoconite

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deposited on the TP glaciers.12 rBC has been shown to be an important contributor to

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the TP glacier retreat and Asia monsoon,13 and adds to the much faster temperature

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increase (0.3 oC per decade in the past three decades) in areas above 4000 m than the

64

observed global warming.7

5, 6

This effect is particularly important for the

65

Nevertheless, the climate effects of rBC are highly uncertain, largely due to its

66

interactions/mixing with other aerosol components.1, 14-16 rBC can be co-emitted with

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a variety of species, and become internally mixed with various organic and inorganic

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species through coagulation or condensation processes during atmospheric transport.1,

69

17

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change dynamically during aging and greatly affect the radiative behaviors of

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rBC-containing particles.18, 19 For instance, the radiative absorption of rBC can be

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enhanced due to the non-rBC components coated on rBC cores;4, 20-22 although the

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degree of enhancement is highly variable (from 6%17 to ~200%23) - dependent on the

The chemical composition, optical properties, and thickness of rBC-coating also



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composition, mixing state, coating thickness and volatility of the coating materials.24

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The coating can also alter rBC’s hygroscopicity, for example, increases in water

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uptake and CCN activity have been observed when it is coated with secondary

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species.25-28 Clearly, rBC properties are diverse in different environments, thus

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measurements of the concentrations, compositions, and sources of rBC and its coating

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over TP, are critical to assess its environmental and climate impacts in this region.

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A number of studies have been conducted previously to investigate rBC in TP.

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For example, mean rBC concentrations of 0.75 µg m-3 and 0.50 µg m-3 (both in

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southeast TP, ~3300 m a.s.l.),29 0.36 µg m-3 and 0.16 µg m-3 (both in Qinghai-TP,

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~3200 m a.s.l.),30, 31 0.077 µg m-3 (western trans-Himalayas, ~4520 m a.s.l.)32 and

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0.133 µg m-3 (a western TP site, ~4500 m a.s.l.)33 were reported. A modeling study

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simulated surface rBC concentration of 0.24-0.40 µg m-3 over TP for 1980-2010.34

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Sources of rBC in TP mainly include biofuel/biomass burning from South Asia and

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fossil fuel emissions from South and East Asia.

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dominant contribution from fossil fuel combustion to rBC in northern TP but a more

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significant contribution from local sources (such as yak dung combustion) for rBC in

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inner TP.36 A few studies also investigated the light-absorption characteristics of

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carbonaceous aerosols (including rBC) in TP,30,

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characterize the rBC-coating directly and its influence on the optical properties.

35

A recent report further revealed a

37-39

yet none of these studies

93

To probe the properties of rBC-coating, single particle soot photometer (SP2)40, 41

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is a powerful instrument as it can exclusively detect the rBC-containing particles and

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quantify rBC mass and coating thickness by assuming a core-shell configuration. The

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SP2 can respond to metals and probably some non-rBC refractory material (e.g.,

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hematite), but overall it is very limited in determining the chemical compositions of

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coating. On the other hand, the Aerodyne aerosol mass spectrometers (AMS)42-44 have

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been widely used to determine the fine aerosol composition and some studies45-48 used

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the AMS-measured non-refractory aerosol components to infer sources/aging

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processes of rBC. However, such treatment is largely uncertain as the AMS measured

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the total aerosol species without differentiating the portion that actually coats on rBC.

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An advanced instrument, which physically integrates the laser from SP2 into the


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Aerodyne high-resolution time-of-flight AMS (HR-AMS)49, termed as soot-particle

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AMS (SP-AMS),50-55 is the only instrument that can selectively detect rBC and

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simultaneously determine the sizes, concentrations and compositions of its associated

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coating. Of course, single-particle mass spectrometry technique44, 56 can also detect

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rBC and relevant mixed material, but in a much less quantitative manner. So far, only

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a limited number of studies applied the SP-AMS technique to explore the

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rBC-containing particles and/or the light absorption properties, such as in

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California,17, 57, 58 Toronto,59-61 and London.20 This work, for the first time, conducted

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the real-time and highly time-resolved measurement on rBC-containing particles in

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the remote and high-altitude region (central TP). The temporal variations, chemical

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compositions, sources of rBC and its coating are elucidated, and influences of the

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coating on the light absorption of rBC are also discussed.

116 117

2 Experiments

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2.1 Sampling site

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The field measurement was carried out at the Comprehensive Observation Station

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of Chinese Academy of Science in Nam Co (4730 m a.s.l, 30o46’N, 90o59’E, Figure

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S1 of the supporting information (SI)) from May 30 to June 30, 2015. This is the

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highest elevation site in the TP enabling deployment of a suite of real-time aerosol

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monitoring instruments. It is located south of the Lake Nam Co and north of the

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Nyenchen Tanglha Mountains. The surroundings are mainly pastureland with a few

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residents herding yaks and sheep, a tourist resort is situated ~9 km west.

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2.2 Instrumentation

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Besides the SP-AMS, an HR-AMS, and a multi-angle absorption photometer

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(MAAP) (Model 5012, Thermo Scientific Corp., USA) were also operated in parallel.

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This work focused on the SP-AMS data. The SP-AMS and HR-AMS shared the same

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sampling line with a PM2.5 cyclone in front to remove coarse particles and

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subsequently a silica gel diffusion dryer to eliminate moisture. Both AMSs used 130

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µm orifices to maintain ~0.1 L min-1 air flow as the pressure at the site (~56 kpa) is

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much lower than that at sea level. Due to the transmission efficiency of the lens



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system, both AMSs measured submicron particles (PM1).

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The standard SP-AMS is equipped with an intracavity infrared laser vaporizer

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and a thermal tungsten heater.50 However, to exclusively measure rBC-containing

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particles, the tungsten vaporizer was physically removed, since it could still reach

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~200 oC62

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instrument was operated with the laser only configuration throughout the campaign.

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We only collected V-mode data with high sensitivity due to typically low mass

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loadings at this site. Each 5-minute cycle consisted of two menu settings (2.5 minutes

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each) for quantification of concentration/mass spectra and chemically-resolved size

143

distributions, respectively.

even when it was turned off due to heating by the filament. The

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Mass quantification (i.e., ionization efficiency) of the SP-AMS was calibrated

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following the protocol reported in Jayne et al.42 using ammonium nitrate. Relative

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ionization efficiencies (RIEs) of sulfate and rBC to nitrate were determined separately

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by using ammonium sulfate and Regal Black (REGAL 400R pigment black, Cabot

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Corp.),50 respectively. Note under laser-only configuration, direct calibrations using

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ammonium nitrate/sulfate are impossible, thus the calibrations aforementioned were

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performed before removal of the tungsten vaporizer. RIEs of ammonium, nitrate,

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sulfate and BC were determined to be 3.2, 1.05, 1.18, and 0.33, respectively, and RIE

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of organics used the default value of 1.4.43 rBC calibration was repeated under the

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laser-only configuration to determine its IE (IErBC). Based on IErBC, and by assuming

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RIEs of the aerosol species are constants, we can quantify their concentrations.60

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Without the tungsten vaporizer, the SP-AMS rBC quantification is not influenced by

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particle bouncing which heavily affects the collection efficiency in other AMS

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measurements,43 but is mainly governed by the overlap of particle beam and laser

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beam. Size calibration was done by using polystyrene latex (PSL) spheres (100-700

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nm) (Duke Scientific Corp., Palo Alto, CA) before removal of tungsten heater

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according to the method of Canagaratna et al.43

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The MAAP was connected to a separate sampling inlet with a 16.7 L min-1 and 1

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µm size cut cyclone (URG2000-30EHB, URG Corp., Chapel Hill, NC). It determined

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the rBC mass at a single wavelength of 670 nm.


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Concentrations of gases including carbon monoxide (CO), ozone (O3), nitrogen

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dioxide (NO2), and sulfur dioxide (SO2) measured by Thermo Scientific gas analyzers

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were acquired from the Nam Co Observation Station of Tibet Environmental

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Protection Agency (~50 m away from our instruments). Meteorological parameters,

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including temperature (T), relative humidity (RH), visibility (km), wind speed (WS)

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and wind direction (WD) were measured at our site.

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2.3 Data Analysis

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The SP-AMS data were processed by the standard Igor-based AMS analysis

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software.63 All mass concentrations were calculated from the high-resolution fitting of

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V-mode data. Positive matrix factorization (PMF)64 was performed using the PMF

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Evaluation Tool from Ulbrich et al.65 to resolve sources of organics coated on rBC.

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We conducted the analysis on the combined organic and inorganic high-resolution

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mass spectra (HRMS) using the method described in Sun et al.66 and Zhou et al.67

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Different solutions were evaluated carefully according to the procedures outlined in

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Zhang et al.68 Finally, the 4-factor solution was deemed as optimal, and after

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exclusion of the inorganic ion fragments, we were able to identify four distinct

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organic aerosol (OA) factors including a transported biomass burning OA (TBBOA),

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a regional background oxygenated OA (RBOOA), a semi-volatile oxygenated OA

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(SVOOA), and a low-volatility oxygenated OA (LVOOA). Key diagnostic plots of

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this solution are presented in Figure S2. Results of the 3-factor and 5-factor solutions

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are shown in Figures S3 and S4: the 3-factor solution was unable to well separate

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RBOOA and SVOOA, while the 5-factor solution presented clearly a splitting of

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LVOOA.

187 188

Backward trajectory analysis was conducted by using the HYSPLIT4 model (http://www.arl.noaa.gov/ready/hysplit4.html).69

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3．．Results and Discussion

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3.1 Mass concentrations, size distributions of rBC and rBC-coating species

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In Figure 1a, we present the highly time-resolved mass concentrations of both

193

rBC and its coating (sum of organics, sulfate, nitrate, chloride and ammonium)



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determined by the SP-AMS. A detailed combo plot depicting the temporal changes of

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meteorological

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contributions of individual components throughout the sampling period is provided in

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Figure S5. The campaign-averaged concentration of rBC-containing particles (= rBC

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+ coating) was 1.06 µg m-3, and the most abundant component was organics, followed

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by sulfate (Figure 1b). The average (±1ơ) concentration of rBC was 0.12(±0.085) µg

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m-3, close to the average concentration of elemental carbon (0.09 µgm-3) measured in

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PM1 during 2012 at the same location.70 An elevated PM pollution event occurred

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from June 10 to 13, during which the average concentrations of rBC-containing

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particles and rBC increased to 2.70 µg m-3 and 0.26 µg m-3, respectively, with

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maximums reaching 7.24 µg m-3 and 0.54 µg m-3, respectively. This episode was

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associated with transport of biomass burning emissions (details in Section 3.2). In

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addition, the coated BC particles were overall neutralized since the mean equivalent

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molar ratio of the major cations (SO42-, NO3- and Cl-) to NH4+ was very close to 1

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(Figure S6; slope of 0.95 and r2 of 0.97).

parameters,

gaseous

species,

concentrations

and

fractional

209

Our measurement period covered a transition from pre-monsoon to monsoon on

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June 14 based on the changes of meteorological conditions (Figure S5). Before

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monsoon, the rBC-containing particles had a higher mass loading (1.70 µg m-3) and

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the particles were thickly coated with an average RBC (mass ratio of coating to rBC)

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of 8.9; while during monsoon, the concentration was notably low (0.31 µg m-3) and

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the coating appeared to be relatively thin (average RBC of 4.5). The air mass back

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trajectories showed that the air parcels arriving at the site in general had longer

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transportation pathways before monsoon than those during monsoon (Figure S7).

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Overall, this result indicates that the properties of rBC-containing particles before

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monsoon were heavily influenced by long-range transported air pollutants whereas the

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low mass loading and thin coating during monsoon was likely caused by strong

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scavenging of thickly coated rBC particles,71 and influences from local/regional

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sources.

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We further compared the non-refractory PM1 species (sulfate, nitrate, chloride,

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ammonium and organics) measured by the SP-AMS and HR-AMS in Figure 1c. As


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our laser-only SP-AMS only detected the portion coated on rBC cores, the slope

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represent the average mass ratio of the rBC-associated species to their total mass

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determined by the HR-AMS. Temporal variations of PM1 mass concentrations from

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both instruments generally correlated well (r2 of 0.84), and ~51% of the

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non-refractory PM1 species was mixed with rBC, which is larger than the value of 35%

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observed in California coastal air. 57 Note this ratio varied dramatically, which was on

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average much higher before monsoon (~71%) than it during monsoon (~27%). The

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comparisons for the major species (organics, sulfate and nitrate) are presented in

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Figure S8, which shows that ~55% organics, ~64% nitrate and 46% sulfate were

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internally mixed with rBC, also much higher than 7-20% of those determined for

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urban aerosols in Fontana, California.58 In addition, sometimes the SP-AMS measured

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species had higher concentrations than those from the HR-AMS (above 1:1 line,

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Figures S8 and 1c). This is probably in large part due to measurement uncertainties of

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the two instruments. However, we want to point out that these extra species might be

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real. One reason is that the SP-AMS can measure refractory species (metal

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sulfate/nitrate and refractory organics) while the HR-AMS cannot. Moreover, recent

240

studies21,

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restructuring into compacted spheres. It is possible that not all species inside voids of

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rBC cores (either ones from aging or co-emitted with rBC) are detected by the

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HR-AMS. We propose both hypotheses should be investigated in future.

22, 72

found that BC aging was initiated by the filling of voids and

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The campaign-averaged size distributions of the major species of rBC-containing

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particles are shown in Figure 2a. Nitrate, sulfate and organics all had very similar

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patterns, and their dependences on RBC and the aerodynamic dimeter (Dva) of rBC

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(Figures 2b-d) were also similar. The data strongly indicates that nitrate, sulfate and

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organics were well internally mixed, and thickly coated on rBC, implying a likely

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core-shell configuration of the rBC-containing particles. The data (Figures 2a and S9)

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also shows that large particles were dominated by thickly coated rBC, and only small

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particles (10. In particular, the contribution

361

of transported BBOA to Eabs appeared to be very significant, since the particles with

362

larger mass fractions of the transported BBOA tended to have thicker coating (Figure

363

5).

364

In future, a more accurate quantification of Eabs can be performed by directly

365

comparing the light absorptions of coated rBC to that of uncoated rBC (obtained by

366

using a thermodenuder to remove coating at high temperatures20). Such measurement

367

can eliminate the measurement uncertainties of SP-AMS. In addition, implementation

368

of other photoacoustic absorption measurements can also help to improve the Eabs

369

quantification.

370 371

4. Atmospheric implications

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Our real-time measurement conducted in central TP elucidated for the first time

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the detailed chemical characteristics of rBC and its associated coating. Our results



374

revealed that in TP the thickly coated rBC was not necessarily highly oxygenated,

375

indicating that the rBC aging in remote and clean environment may be diverse, and

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highly dependent upon the pollutants co-emitted with rBC or being intercepted along

377

its way to the receptor site. In our case, BBOA was found to play a vital role: it was

378

relatively fresh but formed very thick coating on rBC, and well mixed with other

379

species (See Figure S11 for the chemically-resolved size distributions of

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rBC-containing particles during the period heavily influenced by the transported

381

BBOA).

382

Moreover, it is relatively well understood that BBOA is an important source of 81, 83-85

383

light-absorbing BrC,

and our analyses of simultaneously collected filter

384

samples indeed revealed that BB was important to the water-soluble BrC in this site.86

385

The findings in this work, on the other hand, underscore that BBOA can also

386

contribute remarkably to the light absorption via “lensing effect” as it can coat thickly

387

on rBC. A previous study87 observed high organic carbon to elemental carbon ratios in

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biomass burning aerosols, here we pinpoint that the BB organics can heavily coat on

389

rBC cores. Nevertheless, the BBOA here was likely attributed to regional biomass

390

mass/yak dung/incense burning. It is essential to conduct further investigations on

391

different biomass burning sources to clarify their specific properties and interplays

392

with the light absorption enhancement of rBC.

393

At last, Mie theory88 assuming a spherical rBC core and a well-defined core-shell

394

structure is currently used in many climate models to evaluate rBC’s climate effects,

395

while our size distribution data of different species likely suggest a well

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internally-mixed structure of the coated rBC in TP. Nevertheless, further analyses

397

including single particle imaging techniques89, 90 and SP2 measurement41 are still very

398

necessary to investigate the morphology and mixing states of rBC-containing particles

399

under different meteorological conditions and locations in TP. Such measurements are

400

the subject of our future work, to further understand the suitability and limitations of

401

Mie theory, and improve the assessment of rBC’s effects in this region.

402 403

List of acronyms


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404

rBC: refractory black carbon

405

BrC: Brown carbon

406

TP: Tibetan Plateau

407

HR-AMS: High-resolution aerosol mass spectrometer (Aerodyne research Inc.)

408

SP-AMS: Soot-particle aerosol mass spectrometer (Aerodyne research Inc.)

409

MAAP: Multi-angle absorption photometer (Thermo Scientific Model 5012)

410

SP2: Single particle soot photometer

411

RBC: mass ratio of rBC coating to rBC core

412

CCN: Cloud condensation nuclei

413

IE: Ionization efficiency

414

RIE: Relative ionization efficiency

415

HRMS: High resolution mass spectra

416

PMF: Positive matrix factorization

417

OA: Organic aerosol

418

SOA: Secondary organic aerosol

419

BB: Biomass burning

420

TBBOA: Transported biomass burning organic aerosol

421

RBOOA: Regional background oxygenated organic aerosol

422

SVOOA: Semi-volatile oxygenated organic aerosol

423

LVOOA: low-volatility oxygenated organic aerosol

424

Dva: Vacuum aerodynamic diameter

425

O/C: Oxygen-to-carbon ratio

426

H/C: Hydrogen-to-carbon ratio

427

OSc: Average oxidation state, equal to 2*O/C-H/C

428

Eabs: Light absorption enhancement

429

MAC: Mass absorption cross section

430 431

Supporting Information

432

Sampling site (Figure S1), PMF results (Figures S2-S4), overview of measurement

433

(Figure S5), ion balance (Figure S6), air mass back trajectories (Figure



434

S7),comparisons of SP-AMS and HR-AMS data (Figure S8), rBC size distribution

435

(Figure S9), average HRMS of total OA (Figure S10) and TBBOA (Figure S11), and

436

size distributions during the BB-influenced period (Figure S12).

437 438

Acknowledgements. This work was supported by the National Key R&D program of

439

China (2016YFC0203501), Natural Science Foundation of China (21777073 and

440

91544220), International ST Cooperation Program of China (2014DFA90780),

441

Jiangsu Natural Science Foundation (BK20150042), and Jiangsu Provincial

442

Specially-Appointed Professors Foundation. J. Wang also would like to thank the

443

support from China Scholarship Council and the Innovative Project for Graduate

444

Student of Jiangsu Province (KYZZ16_0347). We thank the Nam Co Station for

445

Multispheres Observation and Research, Chinese Academy of Science and the Tibet

446

Environment Protection Agency for the supporting data and logistical assistance.

447 448

References:

449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470

1.

Bond, T. C.; Doherty, S. J.; Fahey, D. W.; Forster, P. M.; Berntsen, T.; DeAngelo, B. J.; Flanner, M.

G.; Ghan, S.; Kärcher, B.; Koch, D.; Kinne, S.; Kondo, Y.; Quinn, P. K.; Sarofim, M. C.; Schultz, M. G.; Schulz, M.; Venkataraman, C.; Zhang, H.; Zhang, S.; Bellouin, N.; Guttikunda, S. K.; Hopke, P. K.; Jacobson, M. Z.; Kaiser, J. W.; Klimont, Z.; Lohmann, U.; Schwarz, J. P.; Shindell, D.; Storelvmo, T.; Warren, S. G.; Zender, C. S., Bounding the role of black carbon in the climate system: A scientific assessment. J. Geophys. Res. - Atmos. 2013, 118, (11), 5380-5552. 2.

Henning, S.; Wex, H.; Hennig, T.; Kiselev, A.; Snider, J. R.; Rose, D.; Dusek, U.; Frank, G. P.;

Poschl, U.; Kristensson, A.; Bilde, M.; Tillmann, R.; Kiendler-Scharr, A.; Mentel, T. F.; Walter, S.; Schneider, J.; Wennrich, C.; Stratmann, F., Soluble mass, hygroscopic growth, and droplet activation of coated soot particles during LACIS Experiment in November (LExNo). J. Geophys. Res. - Atmos. 2010, 115. 3.

Dusek, U.; Reischl, G. P.; Hitzenberger, R., CCN activation of pure and coated carbon black

particles. Environ. Sci. Technol. 2006, 40, (4), 1223-1230. 4.

Jacobson, M. Z., Strong radiative heating due to the mixing state of black carbon in atmospheric

aerosols. Nature 2001, 409, (6821), 695-697. 5.

Kopacz, M.; Mauzerall, D. L.; Wang, J.; Leibensperger, E. M.; Henze, D. K.; Singh, K., Origin

and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau. Atmos. Chem. Phys. 2011, 11, (6), 2837-2852. 6.

Gertler, C. G.; Puppala, S. P.; Panday, A.; Stumm, D.; Shea, J., Black carbon and the Himalayan

cryosphere: A review. Atmos. Environ. 2016, 125, 404-417. 7.

Xu, B.; Cao, J.; Hansen, J.; Yao, T.; Joswia, D. R.; Wang, N.; Wu, G.; Wang, M.; Zhao, H.; Yang,

W.; Liu, X.; He, J., Black soot and the survival of Tibetan glaciers. P. Natl. Acad. Sci. USA 2009, 106,


Page 16 of 30

Page 17 of 30


471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514

(52), 22114-22118. 8.

Lami, A.; Turner, S.; Musazzi, S.; Gerli, S.; Guilizzoni, P.; Rose, N. L.; Yang, H.; Wu, G.; Yang,

R., Sedimentary evidence for recent increases in production in Tibetan plateau lakes. Hydrobiologia 2010, 648, (1), 175-187. 9.

Kuhle, M., The pleistocene glaciation of Tibet and the onset of ice ages — An autocycle

hypothesis. GeoJournal 1988, 17, (4), 581-595. 10. Menon, S.; Hansen, J.; Nazarenko, L.; Luo, Y., Climate effects of black carbon aerosols in China and India. Science 2002, 297, (5590), 2250-2253. 11. Lau, K. M.; Kim, M. K.; Kim, K. M., Asian summer monsoon anomalies induced by aerosol direct forcing: the role of the Tibetan Plateau. Climate Dyn. 2006, 26, (7), 855-864. 12. Dong, Z.; Qin, D.; Kang, S.; Liu, Y.; Li, Y.; Huang, J.; Qin, X., Individual particles of cryoconite deposited on the mountain glaciers of the Tibetan Plateau: Insights into chemical composition and sources. Atmos. Environ. 2016, 138, 114-124. 13. Meehl, G. A.; Arblaster, J. M.; Collins, W. D., Effects of black carbon aerosols on the indian monsoon. J. Climate 2008, 21, (12), 2869-2882. 14. Moffet, R. C.; Prather, K. A., In-situ measurements of the mixing state and optical properties of soot with implications for radiative forcing estimates. P. Natl. Acad. Sci. USA 2009, 106, (29), 11872-11877. 15. Ramana, M. V.; Ramanathan, V.; Feng, Y.; Yoon, S. C.; Kim, S. W.; Carmichael, G. R.; Schauer, J. J., Warming influenced by the ratio of black carbon to sulphate and the black-carbon source. Nature Geosci. 2010, 3, (8), 542-545. 16. Gustafsson, Ö.; Ramanathan, V., Convergence on climate warming by black carbon aerosols. P. Natl. Acad. Sci. USA 2016, 113, (16), 4243-4245. 17. Cappa, C. D.; Onasch, T. B.; Massoli, P.; Worsnop, D. R.; Bates, T. S.; Cross, E. S.; Davidovits, P.; Hakala, J.; Hayden, K. L.; Jobson, B. T.; Kolesar, K. R.; Lack, D. A.; Lerner, B. M.; Li, S.-M.; Mellon, D.; Nuaaman, I.; Olfert, J. S.; Petäjä, T.; Quinn, P. K.; Song, C.; Subramanian, R.; Williams, E. J.; Zaveri, R. A., Radiative absorption enhancements due to the mixing state of atmospheric black carbon. Science 2012, 337, (6098), 1078-1081. 18. Adachi, K.; Zaizen, Y.; Kajino, M.; Igarashi, Y., Mixing state of regionally transported soot particles and the coating effect on their size and shape at a mountain site in Japan. J. Geophys. Res. Atmos. 2014, 119, (9), 5386-5396. 19. Ueda, S.; Nakayama, T.; Taketani, F.; Adachi, K.; Matsuki, A.; Iwamoto, Y.; Sadanaga, Y.; Matsumi, Y., Light absorption and morphological properties of soot-containing aerosols observed at an East Asian outflow site, Noto Peninsula, Japan. Atmos. Chem. Phys. 2016, 16, (4), 2525-2541. 20. Liu, S.; Aiken, A. C.; Gorkowski, K.; Dubey, M. K.; Cappa, C. D.; Williams, L. R.; Herndon, S. C.; Massoli, P.; Fortner, E. C.; Chhabra, P. S.; Brooks, W. A.; Onasch, T. B.; Jayne, J. T.; Worsnop, D. R.; China, S.; Sharma, N.; Mazzoleni, C.; Xu, L.; Ng, N. L.; Liu, D.; Allan, J. D.; Lee, J. D.; Fleming, Z. L.; Mohr, C.; Zotter, P.; Szidat, S.; Prevot, A. S. H., Enhanced light absorption by mixed source black and brown carbon particles in UK winter. Nat. Commun. 2015, 6, 8435. 21. Peng, J.; Hu, M.; Guo, S.; Du, Z.; Zheng, J.; Shang, D.; Levy Zamora, M.; Zeng, L.; Shao, M.; Wu, Y.; Zheng, J.; Wang, Y.; Glen, C. R.; Collins, D. R.; Molina, M. J.; Zhang, R., Markedly enhanced absorption and direct radiative forcing of black carbon under polluted urban environments. P. Natl. Acad. Sci. USA 2016, 113, (16), 4266-4271. 22. Liu, D.; Whitehead, J.; Alfarra, M. R.; Reyes-Villegas, E.; Spracklen, D. V.; Reddington, C. L.;



515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558

Kong, S.; Williams, P. I.; Ting, Y.-C.; Haslett, S.; Taylor, J. W.; Flynn, M. J.; Morgan, W. T.; McFiggans, G.; Coe, H.; Allan, J. D., Black-carbon absorption enhancement in the atmosphere determined by particle mixing state. Nature Geosci. 2017, 10, (3), 184-188. 23. Cui, X.; Wang, X.; Yang, L.; Chen, B.; Chen, J.; Andersson, A.; Gustafsson, Ö., Radiative absorption enhancement from coatings on black carbon aerosols. Sci. Total Environ. 2016, 551–552, 51-56. 24. Fierce, L.; Bond, T. C.; Bauer, S. E.; Mena, F.; Riemer, N., Black carbon absorption at the global scale is affected by particle-scale diversity in composition. Nat. Commun. 2016, 7, 12361. 25. Saathoff, H.; Naumann, K. H.; Schnaiter, M.; Schöck, W.; Möhler, O.; Schurath, U.; Weingartner, E.; Gysel, M.; Baltensperger, U., Coating of soot and (NH4)2SO4 particles by ozonolysis products of α-pinene. J. Aerosol Sci. 2003, 34, (10), 1297-1321. 26. Tritscher, T.; Juranyi, Z.; Martin, M.; Chirico, R.; Gysel, M.; Heringa, M. F.; DeCarlo, P. F.; Sierau, B.; Prevot, A. S. H.; Weingartner, E.; Baltensperger, U., Changes of hygroscopicity and morphology during ageing of diesel soot. Environ. Res. Lett. 2011, 6, (3), 034026. 27. Zhang, R.; Khalizov, A. F.; Pagels, J.; Zhang, D.; Xue, H.; McMurry, P. H., Variability in morphology, hygroscopicity, and optical properties of soot aerosols during atmospheric processing. P. Natl. Acad. Sci. USA 2008, 105, (30), 10291-10296. 28. Liu, D.; Allan, J.; Whitehead, J.; Young, D.; Flynn, M.; Coe, H.; McFiggans, G.; Fleming, Z. L.; Bandy, B., Ambient black carbon particle hygroscopic properties controlled by mixing state and composition. Atmos. Chem. Phys. 2013, 13, (4), 2015-2029. 29. Cao, J.; Tie, X.; Xu, B.; Zhao, Z.; Zhu, C.; Li, G.; Liu, S., Measuring and modeling black carbon (BC) contamination in the SE Tibetan Plateau. J. Atmos. Chem. 2011, 67, (1), 45-60. 30. Wang, Q.; Schwarz, J. P.; Cao, J.; Gao, R.; Fahey, D. W.; Hu, T.; Huang, R. J.; Han, Y.; Shen, Z., Black carbon aerosol characterization in a remote area of Qinghai–Tibetan Plateau, western China. Sci. Total Environ. 2014, 479–480, 151-158. 31. Wang, Q.; Huang, R.; Cao, J.; Tie, X.; Ni, H.; Zhou, Y.; Han, Y.; Hu, T.; Zhu, C.; Feng, T.; Li, N.; Li, J., Black carbon aerosol in winter northeastern Qinghai–Tibetan Plateau, China: the source, mixing state and optical property. Atmos. Chem. Phys. 2015, 15, (22), 13059-13069. 32. Babu, S. S.; Chaubey, J. P.; Krishna Moorthy, K.; Gogoi, M. M.; Kompalli, S. K.; Sreekanth, V.; Bagare, S. P.; Bhatt, B. C.; Gaur, V. K.; Prabhu, T. P.; Singh, N. S., High altitude (∼4520 m amsl) measurements of black carbon aerosols over western trans-Himalayas: Seasonal heterogeneity and source apportionment. J. Geophys. Res. - Atmos. 2011, 116, (D24), D24201. 33. Zhu, C.; Cao, J.; Xu, B.; Huang, R.; Wang, P.; Ho, K.; Shen, Z.; Liu, S.; Han, Y.; Tie, X.; Zhao, Z.; Chen, L. W. A., Black carbon aerosols at Mt. Muztagh Ata, a high-altitude location in the western Tibetan plateau. Aerosol Air Qual. Res. 2016, 16, (3), 752-763. 34. Mao, Y.; Liao, H., Impacts of meteorological parameters and emissions on decadal, interannual, and seasonal variations of atmospheric black carbon in the Tibetan Plateau. Adv. Climate Change Res. 2016, 7, (3), 123-131. 35. Zhang, R.; Wang, H.; Qian, Y.; Rasch, P. J.; Easter, R. C.; Ma, P.; Singh, B.; Huang, J.; Fu, Q., Quantifying sources, transport, deposition, and radiative forcing of black carbon over the Himalayas and Tibetan Plateau. Atmos. Chem. Phys. 2015, 15, (11), 6205-6223. 36. Li, C.; Bosch, C.; Kang, S.; Andersson, A.; Chen, P.; Zhang, Q.; Cong, Z.; Chen, B.; Qin, D.; Gustafsson, Ö., Sources of black carbon to the Himalayan–Tibetan Plateau glaciers. Nat. Commun. 2016, 7, 12574.


Page 18 of 30

Page 19 of 30


559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602

37. Li, C.; Yan, F.; Kang, S.; Chen, P.; Hu, Z.; Gao, S.; Qu, B.; Sillanpää, M., Light absorption characteristics of carbonaceous aerosols in two remote stations of the southern fringe of the Tibetan Plateau, China. Atmos. Environ. 2016, 143, 79-85. 38. Li, C.; Chen, P.; Kang, S.; Yan, F.; Hu, Z.; Qu, B.; Sillanpää, M., Concentrations and light absorption characteristics of carbonaceous aerosol in PM2.5 and PM10 of Lhasa city, the Tibetan Plateau. Atmos. Environ. 2016, 127, 340-346. 39. Zhu, C.; Cao, J.; Hu, T.; Shen, Z.; Tie, X.; Huang, H.; Wang, Q.; Huang, R.; Zhao, Z.; Močnik, G.; Hansen, A. D. A., Spectral dependence of aerosol light absorption at an urban and a remote site over the Tibetan Plateau. Sci. Total Environ. 2017, 590–591, 14-21. 40. Schwarz, J. P.; Gao, R. S.; Fahey, D. W.; Thomson, D. S.; Watts, L. A.; Wilson, J. C.; Reeves, J. M.; Darbeheshti, M.; Baumgardner, D. G.; Kok, G. L.; Chung, S. H.; Schulz, M.; Hendricks, J.; Lauer, A.; Kärcher, B.; Slowik, J. G.; Rosenlof, K. H.; Thompson, T. L.; Langford, A. O.; Loewenstein, M.; Aikin, K. C., Single-particle measurements of midlatitude black carbon and light-scattering aerosols from the boundary layer to the lower stratosphere. J. Geophys. Res. - Atmos. 2006, 111, (D16), D16207. 41. Liu, D.; Allan, J. D.; Young, D. E.; Coe, H.; Beddows, D.; Fleming, Z. L.; Flynn, M. J.; Gallagher, M. W.; Harrison, R. M.; Lee, J.; Prevot, A. S. H.; Taylor, J. W.; Yin, J.; Williams, P. I.; Zotter, P., Size distribution, mixing state and source apportionment of black carbon aerosol in London during wintertime. Atmos. Chem. Phys. 2014, 14, (18), 10061-10084. 42. Jayne, J. T.; Leard, D. C.; Zhang, X.; Davidovits, P.; Smith, K. A.; Kolb, C. E.; Worsnop, D. R., Development of an aerosol mass spectrometer for size and composition analysis of submicron particles. Aerosol Sci. Tech. 2000, 33, (1), 49 - 70. 43. Canagaratna, M. R.; Jayne, J. T.; Jimenez, J. L.; Allan, J. D.; Alfarra, M. R.; Zhang, Q.; Onasch, T. B.; Drewnick, F.; Coe, H.; Middlebrook, A.; Delia, A.; Williams, L. R.; Trimborn, A. M.; Northway, M. J.; DeCarlo, P. F.; Kolb, C. E.; Davidovits, P.; Worsnop, D. R., Chemical and microphysical characterization of ambient aerosols with the aerodyne aerosol mass spectrometer. Mass Spectrom. Rev. 2007, 26, (2), 185-222. 44. Li, Y.; Sun, Y.; Zhang, Q.; Li, X.; Li, M.; Zhou, Z.; Chan, C. K., Real-time chemical characterization of atmospheric particulate matter in China: A review. Atmos. Environ. 2017, 158, 270-304. 45. Shiraiwa, M.; Kondo, Y.; Moteki, N.; Takegawa, N.; Miyazaki, Y.; Blake, D. R., Evolution of mixing state of black carbon in polluted air from Tokyo. Geophys. Res. Lett. 2007, 34, (16), 16803. 46. Metcalf, A. R.; Craven, J. S.; Ensberg, J. J.; Brioude, J.; Angevine, W.; Sorooshian, A.; Duong, H. T.; Jonsson, H. H.; Flagan, R. C.; Seinfeld, J. H., Black carbon aerosol over the Los Angeles Basin during CalNex. J. Geophys. Res. - Atmos. 2012, 117, (D21), D00V13. 47. Wang, Q.; Huang, R.; Cao, J.; Han, Y.; Wang, G.; Li, G.; Wang, Y.; Dai, W.; Zhang, R.; Zhou, Y., Mixing state of black carbon aerosol in a heavily polluted urban area of China: Implications for light absorption enhancement. Aerosol Sci. Technol. 2014, 48, (7), 689-697. 48. Wang, Q.; Huang, R.; Zhao, Z.; Cao, J.; Ni, H.; Tie, X.; Zhao, S.; Su, X.; Han, Y.; Shen, Z.; Wang, Y.; Zhang, N.; Zhou, Y.; Corbin, J. C., Physicochemical characteristics of black carbon aerosol and its radiative impact in a polluted urban area of China. J. Geophys. Res. - Atmos. 2016, 121, (20), 2016JD024748. 49. DeCarlo, P. F.; Kimmel, J. R.; Trimborn, A.; Northway, M. J.; Jayne, J. T.; Aiken, A. C.; Gonin, M.; Fuhrer, K.; Horvath, T.; Docherty, K. S.; Worsnop, D. R.; Jimenez, J. L., Field-deployable, high-resolution, time-of-flight aerosol mass spectrometer. Anal. Chem. 2006, 78, (24), 8281-8289.



603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646

Page 20 of 30

50. Onasch, T. B.; Trimborn, A.; Fortner, E. C.; Jayne, J. T.; Kok, G. L.; Williams, L. R.; Davidovits, P.; Worsnop, D. R., Soot particle aerosol mass spectrometer: Development, validation, and initial application. Aerosol Sci. Tech. 2012, 46, (7), 804-817. 51. Wang, J.; Ge, X.; Chen, Y.; Shen, Y.; Zhang, Q.; Sun, Y.; Xu, J.; Ge, S.; Yu, H.; Chen, M., Highly time-resolved urban aerosol characteristics during springtime in Yangtze River Delta, China: insights from soot particle aerosol mass spectrometry. Atmos. Chem. Phys. 2016, 16, (14), 9109-9127. 52. Wang, J.; Onasch, T. B.; Ge, X.; Collier, S.; Zhang, Q.; Sun, Y.; Yu, H.; Chen, M.; Prévôt, A. S. H.; Worsnop, D. R., Observation of fullerene soot in eastern China. Environ. Sci. Technol. Lett. 2016, 3, (4), 121-126. 53. Ge, X.; Li, L.; Chen, Y.; Chen, H.; Wu, D.; Wang, J.; Xie, X.; Ge, S.; Ye, Z.; Xu, J.; Chen, M., Aerosol characteristics and sources in Yangzhou, China resolved by offline aerosol mass spectrometry and other techniques. Environmental Pollution 2017, 225, 74-85. 54. Ye, Z.; Liu, J.; Gu, A.; Feng, F.; Liu, Y.; Bi, C.; Xu, J.; Li, L.; Chen, H.; Chen, Y.; Dai, L.; Zhou, Q.; Ge, X., Chemical characterization of fine particular matter in Changzhou, China and source apportionment with offline aerosol mass spectrometry. Atmos. Chem. Phys. 2017, 2017, (4), 2573-2592. 55. Ye, Z.; Li, Q.; Liu, J.; Luo, S.; Zhou, Q.; Bi, C.; Ma, S.; Chen, Y.; Chen, H.; Li, L.; Ge, X., Investigation of submicron aerosol characteristics in Changzhou, China: Composition, source, and comparison with co-collected PM2.5. Chemosphere 2017, 183, 176-185. 56. Pratt, K. A.; Prather, K. A., Mass spectrometry of atmospheric aerosols—Recent developments and applications. Part II: On-line mass spectrometry techniques. Mass Spectrom Rev 2012, 31, (1), 17-48. 57. Massoli, P.; Onasch, T. B.; Cappa, C. D.; Nuamaan, I.; Hakala, J.; Hayden, K.; Li, S.-M.; Sueper, D. T.; Bates, T. S.; Quinn, P. K.; Jayne, J. T.; Worsnop, D. R., Characterization of black carbon-containing particles from soot particle aerosol mass spectrometer measurements on the R/V Atlantis during CalNex 2010. J. Geophys. Res. - Atmos. 2015, 120, (6), 2014JD022834. 58. Lee, A. K. Y.; Chen, C.; Liu, J.; Price, D. J.; Betha, R.; Russell, L. M.; Zhang, X.; Cappa, C. D., Formation of secondary organic aerosol coating on black carbon particles near vehicular emissions. Atmos. Chem. Phys. Discuss. 2017, 2017, 1-20. 59. Lee, A. K. Y.; Willis, M. D.; Healy, R. M.; Onasch, T. B.; Abbatt, J. P. D., Mixing state of carbonaceous aerosol in an urban environment: single particle characterization using the soot particle aerosol mass spectrometer (SP-AMS). Atmos. Chem. Phys. 2015, 15, (4), 1823-1841. 60. Willis, M. D.; Healy, R. M.; Riemer, N.; West, M.; Wang, J. M.; Jeong, C. H.; Wenger, J. C.; Evans, G. J.; Abbatt, J. P. D.; Lee, A. K. Y., Quantification of black carbon mixing state from traffic: implications for aerosol optical properties. Atmos. Chem. Phys. 2016, 16, (7), 4693-4706. 61. Healy, R. M.; Wang, J. M.; Jeong, C. H.; Lee, A. K. Y.; Willis, M. D.; Jaroudi, E.; Zimmerman, N.; Hilker, N.; Murphy, M.; Eckhardt, S.; Stohl, A.; Abbatt, J. P. D.; Wenger, J. C.; Evans, G. J., Light-absorbing properties of ambient black carbon and brown carbon from fossil fuel and biomass burning sources. J. Geophys. Res. - Atmos. 2015, 120, (13), 2015JD023382. 62. Willis, M. D.; Lee, A. K. Y.; Onasch, T. B.; Fortner, E. C.; Williams, L. R.; Lambe, A. T.; Worsnop, D. R.; Abbatt, J. P. D., Collection efficiency of the soot-particle aerosol mass spectrometer (SP-AMS) for internally mixed particulate black carbon. Atmos. Meas. Tech. 2014, 7, (12), 4507-4516. 63. Sueper,

D.

ToF-AMS

Analysis

Software,

available

http://cires1.colorado.edu/jimenez-group/ToFAMSResources/ToFSoftware/index.html.


at:

Page 21 of 30


647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690

64. Paatero, P.; Tapper, U., Positive matrix factorization: A non-negative factor model with optimal utilization of error estimates of data values. Environmetrics 1994, 5, (2), 111-126. 65. Ulbrich, I. M.; Canagaratna, M. R.; Zhang, Q.; Worsnop, D. R.; Jimenez, J. L., Interpretation of organic components from Positive Matrix Factorization of aerosol mass spectrometric data. Atmos. Chem. Phys. 2009, 9, (9), 2891-2918. 66. Sun, Y.; Zhang, Q.; Schwab, J. J.; Yang, T.; Ng, N. L.; Demerjian, K. L., Factor analysis of combined organic and inorganic aerosol mass spectra from high resolution aerosol mass spectrometer measurements. Atmos. Chem. Phys. 2012, 12, (18), 8537-8551. 67. Zhou, S.; Collier, S.; Jaffe, D. A.; Briggs, N. L.; Hee, J.; Sedlacek Iii, A. J.; Kleinman, L.; Onasch, T. B.; Zhang, Q., Regional influence of wildfires on aerosol chemistry in the western US and insights into atmospheric aging of biomass burning organic aerosol. Atmos. Chem. Phys. 2017, 17, (3), 2477-2493. 68. Zhang, Q.; Jimenez, J.; Canagaratna, M.; Ulbrich, I.; Ng, N.; Worsnop, D.; Sun, Y., Understanding atmospheric organic aerosols via factor analysis of aerosol mass spectrometry: a review. Anal. Bioanal. Chem. 2011, 401, (10), 3045-3067. 69. Draxler, R.; Stunder, B.; Rolph, G.; Stein, A.; Taylor, A., HYSPLIT4 user’s guide, version 4, report, NOAA, Silver Spring, MD. 2012. 70. Wan, X.; Kang, S.; Wang, Y.; Xin, J.; Liu, B.; Guo, Y.; Wen, T.; Zhang, G.; Cong, Z., Size distribution of carbonaceous aerosols at a high-altitude site on the central Tibetan Plateau (Nam Co Station, 4730 m a.s.l.). Atmos. Res. 2015, 153, 155-164. 71. Miyakawa, T.; Oshima, N.; Taketani, F.; Komazaki, Y.; Yoshino, A.; Takami, A.; Kondo, Y.; Kanaya, Y., Alteration of the size distributions and mixing states of black carbon through transport in the boundary layer in east Asia. Atmos. Chem. Phys. 2017, 17, (9), 5851-5864. 72. Chen, C.; Fan, X.; Shaltout, T.; Qiu, C.; Ma, Y.; Goldman, A.; Khalizov, A. F., An unexpected restructuring of combustion soot aggregates by subnanometer coatings of polycyclic aromatic hydrocarbons. Geophys. Res. Lett. 2016, 43, (20), 11080-11088. 73. Jimenez, J. L.; Canagaratna, M. R.; Donahue, N. M.; Prevot, A. S. H.; Zhang, Q.; Kroll, J. H.; DeCarlo, P. F.; Allan, J. D.; Coe, H.; Ng, N. L.; Aiken, A. C.; Docherty, K. S.; Ulbrich, I. M.; Grieshop, A. P.; Robinson, A. L.; Duplissy, J.; Smith, J. D.; Wilson, K. R.; Lanz, V. A.; Hueglin, C.; Sun, Y. L.; Tian, J.; Laaksonen, A.; Raatikainen, T.; Rautiainen, J.; Vaattovaara, P.; Ehn, M.; Kulmala, M.; Tomlinson, J. M.; Collins, D. R.; Cubison, M. J.; Dunlea, E. J.; Huffman, J. A.; Onasch, T. B.; Alfarra, M. R.; Williams, P. I.; Bower, K.; Kondo, Y.; Schneider, J.; Drewnick, F.; Borrmann, S.; Weimer, S.; Demerjian, K.; Salcedo, D.; Cottrell, L.; Griffin, R.; Takami, A.; Miyoshi, T.; Hatakeyama, S.; Shimono, A.; Sun, J. Y.; Zhang, Y. M.; Dzepina, K.; Kimmel, J. R.; Sueper, D.; Jayne, J. T.; Herndon, S. C.; Trimborn, A. M.; Williams, L. R.; Wood, E. C.; Middlebrook, A. M.; Kolb, C. E.; Baltensperger, U.; Worsnop, D. R., Evolution of organic aerosols in the atmosphere. Science 2009, 326, (5959), 1525-1529. 74. Aiken, A. C.; Decarlo, P. F.; Kroll, J. H.; Worsnop, D. R.; Huffman, J. A.; Docherty, K. S.; Ulbrich, I. M.; Mohr, C.; Kimmel, J. R.; Sueper, D.; Sun, Y.; Zhang, Q.; Trimborn, A.; Northway, M.; Ziemann, P. J.; Canagaratna, M. R.; Onasch, T. B.; Alfarra, M. R.; Prevot, A. S. H.; Dommen, J.; Duplissy, J.; Metzger, A.; Baltensperger, U.; Jimenez, J. L., O/C and OM/OC ratios of primary, secondary, and ambient organic aerosols with high-resolution time-of-flight aerosol mass spectrometry. Environ. Sci. Technol. 2008, 42, (12), 4478-4485. 75. Cubison, M. J.; Ortega, A. M.; Hayes, P. L.; Farmer, D. K.; Day, D.; Lechner, M. J.; Brune, W. H.;



691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734

Apel, E.; Diskin, G. S.; Fisher, J. A.; Fuelberg, H. E.; Hecobian, A.; Knapp, D. J.; Mikoviny, T.; Riemer, D.; Sachse, G. W.; Sessions, W.; Weber, R. J.; Weinheimer, A. J.; Wisthaler, A.; Jimenez, J. L., Effects of aging on organic aerosol from open biomass burning smoke in aircraft and laboratory studies. Atmos. Chem. Phys. 2011, 11, (23), 12049-12064. 76. He, L.; Lin, Y.; Huang, X.; Guo, S.; Xue, L.; Su, Q.; Hu, M.; Luan, S.; Zhang, Y., Characterization of high-resolution aerosol mass spectra of primary organic aerosol emissions from Chinese cooking and biomass burning. Atmos. Chem. Phys. 2010, 10, (23), 11535-11543. 77. Lee, T.; Sullivan, A. P.; Mack, L.; Jimenez, J. L.; Kreidenweis, S. M.; Onasch, T. B.; Worsnop, D. R.; Malm, W.; Wold, C. E.; Hao, W. M.; Collett, J. L., Chemical smoke marker emissions during flaming and smoldering phases of laboratory open burning of wildland fuels. Aerosol Sci. Tech. 2010, 44, (9), i-v. 78. Du, W.; Sun, Y.; Xu, Y.; Jiang, Q.; Wang, Q.; Yang, W.; Wang, F.; Bai, Z.; Zhao, X.; Yang, Y., Chemical characterization of submicron aerosol and particle growth events at a national background site (3295 m a.s.l.) on the Tibetan Plateau. Atmos. Chem. Phys. 2015, 15, (18), 10811-10824. 79. Ge, X.; He, Y.; Sun, Y.; Xu, J.; Wang, J.; Shen, Y.; Chen, M., Characteristics and formation mechanisms of fine particulate nitrate in typical urban areas in China. Atmosphere 2017, 8, (3), 62. 80. Kroll, J. H.; Donahue, N. M.; Jimenez, J. L.; Kessler, S. H.; Canagaratna, M. R.; Wilson, K. R.; Altieri, K. E.; Mazzoleni, L. R.; Wozniak, A. S.; Bluhm, H.; Mysak, E. R.; Smith, J. D.; Kolb, C. E.; Worsnop, D. R., Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol. Nat. Chem. 2011, 3, (2), 133-139. 81. Laskin, A.; Laskin, J.; Nizkorodov, S. A., Chemistry of atmospheric brown carbon. Chem. Rev. 2015, 115, (10), 4335-4382. 82. Ahern, A. T.; Subramanian, R.; Saliba, G.; Lipsky, E. M.; Donahue, N. M.; Sullivan, R. C., Effect of secondary organic aerosol coating thickness on the real-time detection and characterization of biomass-burning soot by two particle mass spectrometers. Atmos. Meas. Tech. 2016, 9, (12), 6117-6137. 83. Chakrabarty, R. K.; Moosmuller, H.; Chen, L. W. A.; Lewis, K.; Arnott, W. P.; Mazzoleni, C.; Dubey, M. K.; Wold, C. E.; Hao, W. M.; Kreidenweis, S. M., Brown carbon in tar balls from smoldering biomass combustion. Atmos. Chem. Phys. 2010, 10, (13), 6363-6370. 84. Budisulistiorini, S. H.; Riva, M.; Williams, M.; Chen, J.; Itoh, M.; Surratt, J. D.; Kuwata, M., Light-absorbing brown carbon aerosol constituents from combustion of indonesian peat and biomass. Environ. Sci. Technol. 2017, 51, (8), 4415-4423. 85. Chen, Y.; Bond, T. C., Light absorption by organic carbon from wood combustion. Atmos. Chem. Phys. 2010, 10, (4), 1773-1787. 86. Zhang, Y.; Xu, J.; Shi, J.; Xie, C.; Ge, X.; Wang, J.; Kang, S.; Zhang, Q., Light absorption by water-soluble organic carbon in atmospheric fine particles in the central Tibetan Plateau. Environ. Sci. Pollut. Res. 2017, 24, (26), 21386-21397. 87. Zhang, Y.; Shao, M.; Zhang, Y.; Zeng, L.; He, L.; Zhu, B.; Wei, Y.; Zhu, X., Source profiles of particulate organic matters emitted from cereal straw burnings. J. Environ. Sci. 2007, 19, (2), 167-175. 88. Bohren, C. F.; Huffman, D. R., Absorption and scattering of light by small particles. John Wiley & Sons, Inc.: New York, 1983. 89. Li, W.; Sun, J.; Xu, L.; Shi, Z.; Riemer, N.; Sun, Y.; Fu, P.; Zhang, J.; Lin, Y.; Wang, X.; Shao, L.; Chen, J.; Zhang, X.; Wang, Z.; Wang, W., A conceptual framework for mixing structures in individual aerosol particles. J. Geophys. Res. - Atmos. 2016, 121, (22), 13,784-13,798.


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Page 23 of 30


735 736 737

90. Li, W.; Chen, S.; Xu, Y.; Guo, X.; Sun, Y.; Yang, X.; Wang, Z.; Zhao, X.; Chen, J.; Wang, W., Mixing state and sources of submicron regional background aerosols in the northern Qinghai–Tibet Plateau and the influence of biomass burning. Atmos. Chem. Phys. 2015, 15, (23), 13365-13376.

738 739



-3

4

10.1%

6.6% 2.8%

3 2

Monsoon

Pre-monsoon

18.2% 4.3% 2.4% 9.4% 65.7% -3 0.31µg m

13.5% 67.0% 1.70µg m

8

-3

6 4

1

2

0

0 6/3

rBC coating

Mass Conc.(µg m ) rBC

(a)

Page 24 of 30

6/7 6/11 6/15 6/19 6/23 6/27 Date and time (UTC+8)

(c) (b) 11.5% 6.2%

PM1,SP vs.PM1,HR 1:1 2 r = 0.84

2.8%

12.7%

4 2015/6/30 2015/6/20

2

2015/6/10

Date and time

66.8%

Org. 2SO4 NO3 rBC + NH4

SP-AMS

6

2015/5/31

-3

Camp. Avg.:1.06 µg m

740

0 0

2

4

6

HR-AMS

741

Figure 1. (a) Time series of rBC and its coating (sum of organics, sulfate, nitrate,

742

chloride and ammonium) (inset pie charts show the average compositions of the

743

rBC-containing particles before and during monsoon); (b) Campaign-averaged

744

compostion of the rBC-containing particles; (c) Scatter plot of the total PM1

745

measured by the SP-AMS and the HR-AMS (colored by time).

746



-3

6 5

SO4

4

NO3 rBC

0.8

2-

0.3 0.8

5

0.6 0.2

0.6

0.4 0.4

2

0.1

1 2

4

0.0

6 8

100

8

4

6

3

4

2

0.2 0.0

0.0

2 0

100

1000

4

6

Dva (nm)

8

10

12

14

RBC

(c)

1000

9 8 7 6

1000

-

0.1

1.0

4

0.8

3

0.6 0.4

2

100

0.0 100

4

747

)

0.2

0.0

-3

2

5

2-

0.2

-3

3

1.2

SO4 (µg m

0.3

4

Dva (nm)

0.4

5

(d)

9 8 7 6

NO3 (µg m )

Dva (nm)

-3

0.2

6 8

9 8 7 6

1.0

-

3

0

(b)

1000

Org.

Org. (µg m )

dM/dlogDva (µg m )

(a)

Dva (nm)

Page 25 of 30

6

8

10

12

14

4

6

RBC

8

10

12

14

RBC

748

Figure 2. (a) Campaign-averaged size distributions of major species of coated rBC

749

(rBC size distribution was scaled from that of m/z 24), and their dependences on Dva

750

of rBC and RBC (mass ratio of coating to rBC) (b-d).

751



Page 26 of 30

752 O/C = 0.51, H/C = 1.48, N/C = 0.011, OM/OC = 1.82

(a) 10

(e)

TBBOA

Pre-monsoon 3.0

RBOOA

(f)

0.00

-3

5 0 O/C = 0.69, H/C = 1.22, N/C = 0.007, OM/OC = 2.03

LVOOA

4

RBOOA

0.6 0.4 0.2 0.0

(g)

2

1.6

r =0.95

1.2

2-

(LVOOA vs. SO4 )

0.8

(d)

(h)

SVOOA +

+

+

+

+

CxHy CxHyO1 CxHyO2

2 0

2

1.2

r =0.97

0.8

(SVOOA vs. NO3 )

-

40

60

80

m/z (amu)

100

120

0.2 0.1

0.4 0.0

20

0.3

-

HyO1 CxHyNp CxHyOzNp

+

0.0

1.6

NO3

4

2-

0.0

O/C = 0.61, H/C = 1.35, N/C = 0.005, OM/OC = 1.93

0.4 0.2

0.4

0

0.6

SO4

Mass Conc.(µg m

% of total

)

10

2

753

C2H4O2+

0.0

0.02

O/C = 0.48, H/C = 1.31, N/C = 0.004, OM/OC = 1.75

6

(c)

+

(TBBOA vs. C2H4O2 )

1.0

0

(b)

0.04

r =0.96

2.0 5

Monsoon 2

0.0

6/3

6/7 6/11 6/15 6/19 6/23 6/27 Data and Time (UTC+8)

754

Figure 3. (a-d) High resolution mass spectra of the PMF-resolved OA factors, and (e-h)

755

time series of corresponding factors with C2H4O2+, nitrate and sulfate.

756



Pre-monsoon TBBOA 29.6%

40 10 5 20 0

(c)

0 0.24

1.2

0.20

1.0

0.16

0.8

0.12

0.6

(d)

Monsoon

1.2

0.4 0.2

0.3 RBOOA/rBC

0.0

6.5% O3(ppb)

(e)

SVOOA/rBC

0.0

90

0.6

80

0.5

70

0.4

60

0.3

50

0.2 1

757

0.6

0.6

0.4

36.5%

TBBOA/rBC

0.9

0.8

43.4%

13.7%

LVOOA/rBC

1.2

4

8

12

16

20

Hour of Day

2-

-

41.3% LVOOA

8 6 4 2 0

15

60

SO4 /rBC

14.5% SVOOA

o

T( C)

80

RBC

RBOOA 14.6%

(b) RH(%)

(a)

NO3 /rBC

Page 27 of 30

2.5 2.0 1.5 1.0 0.5 0.0 3.6 3.2 2.8 2.4

24 NO2 SO2

758

Figure 4. (a) Average mass contributions of the four factors to the total OA before and

759

during monsoon, diurnal cycles of RH, T and RBC (b), mass ratios of NO3-, SO42- (c),

760

four factors (d) to rBC, and concentrations of gaseous species (O3, SO2 and NO2) (e).

761 762



(b) Monsoon

(a) Pre-monsoon NO3

-

Cl

-

1.0 0.8 0.6 0.4 0.2 0.0

NH4 -0.2 -0.3 -0.4 -0.5 -0.6

LVOOA TBBOA

+

1.0 0.8 0.6 0.4 0.2 0.0

0.0 -0.3 -0.6 -0.9 2 4 6 8 10 12

2 4 6 8 10 12

RBC

RBC

(c)

0.4

OSc

RBC

12 8 4

SVOOA RBOOA 0.3

OSc

Mass Fraction

SO4

2-

Page 28 of 30

(d)

0.0 -0.4 -0.8

0 Neg. Less Sig. BB BB BB

Neg. Less Sig. BB BB BB

763 764

Figure 5. Mass fractions of the non-rBC components coated on rBC cores (left y-axis).

765

and the average oxidation states of organic coating (OSc, right y-axis) as a function of

766

RBC during (a) pre-monsoon and (b) monsoon periods, and box plots of (c) RBC and (d)

767

OSc (d) for periods with negligible BB influences (Neg. BB, June 15-30), less BB

768

influences (Less BB, May 30-June 10), and significant BB influences (Sig. BB, June

769

10-13) (the bounds of boxes represent quartiles, the whiskers indicate the 90th and 10th

770

percentiles, and the lines and dots inside the boxes are median and mean values).

771 772



rBCMAAP/rBCAMS (Eabs)

Page 29 of 30

2.5 0.0

2.0

0.2

0.4

TBBOA/OA

2.5 Sized by conc. of rBC-containing particles 2.0

1.5

1.5

1.0

1.0

0.5

0.5 4

6

8

10

RBC

12

14

773 774

Figure 6. Light absorption enhancement (Eabs) estimated by the mass ratios of rBC

775

measured by MAAP and SP-AMS versus RBC (Only data from pre-monsoon period

776

are included here; data points are colored by the mass fractions of transported BBOA

777

to total organics, and the marker sizes are proportional to the mass concentrations of

778

rBC-containing particles; Symbols of the boxes are the same as those described in

779

Figure 5).

780



781

TOC Chart

782 783


Page 30 of 30

First Chemical Characterization of Refractory Black Carbon Aerosols

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