Size Dependence of the Physical Characteristics of Particles

Subscriber access provided by Columbia University Libraries

Environmental Processes

Size Dependence of the Physical Characteristics of Particles Containing Refractory Black Carbon in Diesel Vehicle Exhaust Chong Han, Shao-Meng Li, Peter Liu, and Patrick Lee Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.8b04603 • Publication Date (Web): 05 Dec 2018 Downloaded from http://pubs.acs.org on December 5, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 24

Environmental Science & Technology

1

Size Dependence of the Physical Characteristics of Particles Containing Refractory

2

Black Carbon in Diesel Vehicle Exhaust

3 4

Chong Han, Shao-Meng Li*, Peter Liu, Patrick Lee

5 6

Air Quality Research Division, Environment and Climate Change Canada, 4905 Dufferin

7

Street, Toronto, Ontario M3H 5T4, Canada

8 9

Abstract

10

The number and mass size distributions of refractory black carbon (rBC) cores in particles

11

emitted from a diesel vehicle were investigated as a function of particle mobility diameter

12

(dmob) using a single particle soot photometer (SP2) and a differential mobility analyzer

13

(DMA). The thickness and mass of coatings on the rBC cores were characterized. Based on

14

the SP2 and DMA results, the physical properties of particles containing rBC, including

15

effective density (ρeff), mass-mobility exponent (Dm), dynamic shape factor (χ) and mass

16

absorption cross section (MAC) were derived as a function of dmob. At each dmob, the count

17

median diameter (CMD) of the rBC cores was essentially the same as their mass median

18

diameter (MMD), which increased linearly with dmob. The mass of the rBC cores was

19

proportional to the cubic of their dmob. However, coating thickness on rBC cores remained

20

unchanged with dmob, with an average thickness of (28.72±4.81) nm. For particles containing

21

rBC, ρeff decreased and χ increased with dmob. The Dm of particles containing rBC was

22

calculated to be 2.09. At 355 and 532 nm wavelengths, the MAC of the diesel particles

23

containing rBC was inversely dependent on dmob.

24 25 26 27 28 29 30 1

ACS Paragon Plus Environment


31

TOC Art:

32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 2


Page 2 of 24

Page 3 of 24

56


Introduction

57

Black carbon (BC) originates from incomplete combustion of fossil and biomass fuels and

58

represents an important constituent of atmospheric aerosols, with an estimated global

59

emission rate of 4.3-22 Tg·year-1.1 BC is responsible for significant environmental effects on

60

regional and global scales. As an efficient light absorber, BC plays an important role in

61

climate change, ranking as the second strongest contributor to global warming after carbon

62

dioxide.2, 3 BC has the potentials to act as cloud condensation nuclei (CCN) and ice nuclei

63

(IN), influencing cloud formation and precipitation.4-7 Due to its large specific surface area,

64

BC can provide reactive sites for heterogeneous reactions of various species, such as ·OH,8

65

O3,9-12 NO2,13-15 HNO3,16 and H2SO4.17 In addition, BC may cause adverse health effects by

66

penetrating into human pulmonary and vascular systems, resulting in respiratory and

67

cardiovascular diseases.18-20

68

Diesel engines contribute about 37% of energy-related BC emissions on a global basis.21

69

BC particle emissions from diesel engines depend on fuel composition, engine operating

70

conditions, exhaust after-treatment technologies, and driving and environmental conditions.

71

For example, the changes in the ratio of biodiesel to diesel in engines affect the particle

72

number concentrations.22, 23 Particles of higher elemental carbon contents are produced at

73

high diesel engine loads, whereas the particles of higher organic carbon contents are

74

generated at low diesel engine loads.24 Fuel injection pressure and timing have an impact on

75

the combustion process in engine cylinder and thus influence the size distributions of diesel

76

exhaust particles.25-27 The use of diesel particulate filter effectively removes particulate

77

matter from diesel exhaust and significantly reduces the particle number and mass

78

concentrations,28, 29 leading to variations of nucleation mode particles.30 Other factors, such as

79

road gradient and traffic density, change driving patterns and have been shown to affect the

80

diesel engine particle emission characteristics.31

81

The climate effects associated with BC particles are sensitive to their sizes.32 In model

82

calculations, ignoring changes in the size distributions of BC particles can result in high

83

uncertainties in predicting BC-induced CCN concentrations and precipitation.32-34

84

Size-dependent single scattering albedo of fresh biomass burning particles has been measured

85

by Singh et al.,35 who found significant effects of fresh BC particle size on their intrinsic 3



Page 4 of 24

86

optical properties. The radiative properties of BC aggregates are also related to the monomer

87

size distributions; it has been reported that aggregates with different-sized monomers

88

exhibited stronger scattering and absorption than that with same-sized monomers.36

89

Studies have suggested that wet deposition is a dominant mechanism to remove BC

90

particles, which determines their atmospheric lifetime and transport.37 Size-dependent wet

91

removal of BC has been found, which indicates that particles containing larger BC are

92

preferentially removed.37, 38 Upon emission into the atmosphere, BC particles undergo aging

93

processes such as phase partitioning of organic species and heterogeneous reaction with

94

oxidants,39-42 leading to changes in BC particle properties such as morphology, composition,

95

hygroscopicity, single scattering albedo, and chemical reactivity.5,

96

depends on their original sizes at the emission point. For example, during BC particle aging

97

by condensable species, the evolution in the particle size, mass and morphology is dependent

98

on the sizes of freshly emitted BC particles.41, 42 Such dependency shows that the changes in

99

the environmental effects of BC particles resulting from aging also rely on the sizes of freshly

100

emitted BC particles. To better evaluate the degree of changes of BC particle properties in the

101

atmosphere, it is important to measure the dependence of the composition and morphology of

102

freshly emitted particles containing BC on their sizes.

41-44

BC particle aging

103

In this work, the size distribution of particles in diesel truck exhaust was monitored by a

104

scanning mobility particle sizer (SMPS). By coupling a single particle soot photometer (SP2)

105

to a differential mobility analyzer (DMA), the number and mass distributions of the refractive

106

black carbon (rBC) cores in particles were investigated as a function of mobility diameter.

107

The coating thickness on the rBC cores was also characterized by the SP2. Mass-mobility

108

relationships were estimated for particles containing rBC, and their physical properties, such

109

as effective density, dynamic shape factor, and mass absorption cross section, were derived as

110

a function of mobility diameter.

111 112

Experimental Section

113

Particle Generation. A diesel truck (GMC, 2004, TopKick, C7500), equipped with a diesel

114

engine (Caterpillar C7, 7.2 L, Diesel I-6), was used in the experiments. Measurements were

115

made with the Canadian Regional and Urban Investigation System for Environmental 4


Page 5 of 24


116

Research (CRUISER). The vehicle idle mode exhaust was drawn into a specially designed

117

flow tube where it was diluted with zero air supplied by a pure-air generator (AADCO

118

Instrument, Cleves, OH, USA). The flow tube consisted of a stainless steel cylinder (20 cm

119

inner diameter and 127 cm length) and two stainless steel cones (20 cm inner diameter and 45

120

cm length each) connected to the cylinder on both ends. The exhaust flow rate into the flow

121

tube was 0.1-0.9 L min-1 and was diluted by 27 L min-1 of zero air, resulting in a dilution ratio

122

of 30-270. The residence time in the flow tube was 1.8 min.

123

Particle Measurements. The number and mass size distributions of the diesel particles were

124

determined using a scanning mobility particle sizer (SMPS, TSI model 3080), which

125

consisted of a differential mobility analyzer (DMA, TSI model 3081) and a condensation

126

particle counter (CPC, TSI model 3775). The rBC cores in the particles and the coating

127

thickness on the rBC cores were measured by a single particle soot photometer (SP2; Droplet

128

Measurement Technologies). In addition, particles in the exhaust were first size selected by a

129

DMA, and the monodisperse particles were directed to the SP2 to measure their rBC core

130

masses and coating thickness. This was repeated for particles of different mobility diameters.

131

The principles of the SP2 have been described in detail elsewhere.45, 46 Calibration of the

132

SP2 was performed for the incandescence and scattering signals using fullerene soot particles

133

(Alpha Aesar; Lot #FS12S011) and polystyrene latex spheres (Thermo Scientific),

134

respectively. The mass of rBC cores was proportional to the incandescence signals of the SP2.

135

Mass equivalent diameter (DMEV) of the rBC cores can be calculated using the measured rBC

136

mass and a recommended rBC density of 1.8 g cm-3.47 DMEV is referred as the diameter of a

137

sphere containing the same mass of rBC as measured in the particle.

138

The SP2 scattering signal amplitudes from rBC-containing particles were obtained by a

139

leading-edge-only (LEO) fitting method,48 which were further used to determine the optical

140

diameter (Dp) of the particles. A concentric core-shell spherical structure for the particles

141

containing rBC was assumed to determine the Dp using Mie theory calculations.49, 50 The

142

thickness (Tcoatings) of the coatings on the rBC cores was calculated by (Dp-DMEV)/2. For the

143

same scattering amplitude measured by the SP2, the optical size of a truly spherical particle is

144

smaller than a particle with the same mass but of other shapes because a sphere has a larger

145

scattering cross section compared to other shapes.48 Hence, the core-shell structure 5



146

assumption may lead to a lower estimation for the coating thickness.

147

Morphology. Several parameters, including effective density, mass-mobility scaling

148

exponent and dynamic shape factor, are used to characterize the morphology of the diesel

149

exhaust particles containing rBC. The particle effective density (ρeff) links mobility size with

150

particle mass, and the ρeff is defined as

151

 eff 

6m 3  d mob

(1)

152

where m is the mass of a particle containing rBC from the sum of the rBC core and coating

153

masses; dmob is the mobility diameter of the particle determined using the DMA. The rBC

154

core mass is measured by the SP2, and the coating mass is determined from

155

ρπ((DMEV+2Tcoatings)3-(DMEV)3)/6, where ρ is the density of the coating and is taken as 1.3 g

156

cm-3.21 The mass-mobility scaling exponent (Dm), which describes how the mass of a particle

157

scales with its mobility diameter, is determined using the equation 2,

158

Dm m  Cd mob

(2)

159

where C is a coefficient obtained by fitting the data. The irregularity of the particle shape can

160

be characterized using the dynamic shape factor (χ),

161



d mobCd ve d veCdmob

(3)

162

where dve is the volume equivalent particle diameter, and Cdve and Cdmob are the Cunningham

163

slip correction factors for dve and dmob, respectively. The dve can be obtained by the following

164

equation, 1/3

165

6 m  m d ve    rBC  coating         rBC  coating  

(4)

166

where mrBC and mcoating are the masses of the rBC core and coating in the particle, respectively;

167

ρrBC and ρcoating are the densities of the rBC core and coating, and are 1.8 g cm-3 and 1.3 g

168

cm-3,21 respectively.

169

Optical Properties. Diesel particles containing rBC usually consist of chain aggregates of

170

spherules.51 In order to exactly calculate the absorption cross sections of rBC-containing

171

particles, the Rayleigh-Debye-Gans (RDG) approximation is used to simulate the 6


Page 6 of 24

Page 7 of 24


172

rBC-containing particle aggregates as a cluster of rBC spherules coated by organic carbon

173

(OC). The absorption cross section (σabs, cluster) of the aggregate can be obtained by21

174

 abs,cluster  N spherule  R

175

where Nspherule is the number of spherules, Rspherule is the radius of each spherule, Qabs, Rayleigh is

176

the absorption efficiency of the spherule, λ is the radiation wavelength, and nspherule is the

177

complex refractive index (RI) of the spherule. Based on the spherule size ranges reported,21, 52

178

Rspherule is assumed to be 25 nm. It is noted that larger Rspherule leads to larger σabs, cluster and a

179

slight increase of the mass absorption cross section (MAC).21 The number of spherules is

180

determined by

181

N spherule 

2 spherule

Q

mrBC

abs,Rayleigh

 Nspherule  R

2 spherule

4

2 Rspherule



2   nspherule  1   Im  2    nspherule  2  

(5)

(6)

mrBC,spherule

182

where mrBC is the rBC mass in the particle measured by the SP2, and mrBC, spherule is the rBC

183

mass of each spherule, which is calculated by the mass ratio of rBC to coatings in the

184

spherule. In the RDG calculation, it is assumed that the mass ratio of the coatings on each

185

spherule is the same as that on the whole rBC particle measured by the SP2. In the equation

186

(5), the refractive index (nspherule) of the spherule can be calculated using the Gladstone-Dale

187

equation,

188

nspherule  1

spherule

 ncoating  1   n 1   rBC  Pcoating  PrBC     rBC coating    

(7)

189

where the refractive index of rBC is set to be nrBC=1.85+0.71i at the wavelength of 355 and

190

532 nm, and that of the coating is set at ncoating=1.527+0.108i and ncoating=1.519+0.048i at 355

191

and 532 nm, respectively;21 PrBC and Pcoating are the mass ratios of rBC core and coating to

192

spherule, respectively; ρspherule is the spherule density determined by the density and mass

193

ratio of rBC cores and coatings. The mass absorption cross section (MAC) is defined as,

194

MAC 

 abs,cluster mrBC

(8)

195

where the rBC mass rather than the total particle mass is used as divisor to be consistent with

196

previous studies.21, 53, 54

197 7



198

Results and Discussion

199

Size distribution of rBC cores. Figure S1 shows the mobility size distribution of all particles

200

in the diesel vehicle exhaust. A mode for number size distribution was observed in the 10-500

201

nm range, with a mode diameter of 55 nm and a geometric mean diameter of 55.7±3.6 nm

202

(Figure S1A). In comparison, the mode diameter for the mass size distribution was 175 nm

203

(Figure S1B). This suggests that although smaller particles (100 nm) are the main contributor to the mass concentration.

205

Figure 1A shows the number size distribution of the rBC cores in the diesel exhaust

206

particles, exhibiting a single mode from lognormal function fitting, with a geometric standard

207

deviation of 1.15 for the lognormal function. The count median diameter (CMD) of the rBC

208

cores was 176 nm, which was larger than that those (100-150 nm) reported for rBC from

209

biomass burning.37 As seen in Figure 1B, the mass size distribution of the rBC cores also

210

exhibited a lognormal pattern, with a geometric standard deviation of 1.16. The mass median

211

diameter (MMD) of the rBC cores was 190 nm. This value was slightly larger than that (180

212

nm) measured for heavy-duty diesel vehicles on road,55 which may be attributed to the

213

dependence of the rBC core size distribution on driving conditions. Larger black carbon

214

particles have been observed for a diesel engine and a gasoline vehicle in idle.56, 57 It was

215

found that congested conditions on a highway, where vehicles were operated at low speeds or

216

idle conditions, led to the largest MMD of rBC, compared to free flowing traffic on the same

217

highway.58 The MMD of the rBC cores measured in the present study was greater than

218

on-road measurements (120-150 nm),55, 58 which may be related to the type of fuels used in

219

the vehicles or the engine operation conditions.59 Liggio et al. found that with progressively

220

lower fractions of heavy-duty diesel vehicles on road, the mode diameter of rBC cores shifted

221

to smaller sizes.55

8


Page 8 of 24

Page 9 of 24


222 223

Figure 1. Number (A) and mass (B) size distributions of the rBC cores in particles from the

224

diesel vehicle idle exhaust measured by SP2. Red lines are the lognormal fittings to the data.

225 226

Figure S2A-F and Figure S3A-F summarize a series of number and mass size distributions

227

of the rBC cores as a function of mass equivalent diameter for six sets of monodisperse diesel

228

engine exhaust particles at different dmob that were pre-size selected by the DMA. The

229

number and mass size distributions exhibited a two-mode lognormal distribution representing

230

singly and doubly charged particles formed during the DMA selection process. The present

231

analysis focuses on the singly charged particles. As expected, the mode positions of both

232

number and mass distributions on the mass equivalent diameters of the rBC cores changed

233

with dmob, shifting to larger mass equivalent diameters with an increase in dmob. As shown in

234

Table S1, The MMD of the rBC cores shifted from 85 nm mass equivalent diameter at 125

235

nm dmob to 173 nm at 300 nm dmob. It is noteworthy that the value of CMD is close to that of

236

MMD at the same dmob. Additionally, Figure S4A-J and S5A-J showed that the CMD and

237

MMD values of the rBC cores remained essentially unchanged as the exhaust was diluted at

238

different ratios.

239

As shown in Figure S2 and S3, the mode ranges of the number size distributions of the rBC

240

cores were similar to those of the mass size distributions. Thus, MMD is used as the main

241

physical property parameter in the following analysis and discussion. Figure 2 displays the

242

MMD evolution of the rBC cores as a function of particle mobility diameter dmob. The MMD

243

depended linearly on the dmob. The corresponding mass of the rBC cores at the MMD also

244

had an increasing trend with increasing dmob. As seen in Figure 2, the mass of the rBC cores 9



245

at the MMD was proportional to the cubic of dmob. It increased from 0.58 fg at 125 nm dmob to

246

4.88 fg at 300 nm dmob.

247 248

Figure 2. The MMD and the corresponding mass (mrBC) of rBC cores in particles as a

249

function of mobility diameter (dmob)

250 251

Size Dependence of Coating Thickness and Mass on rBC cores. Figure 3A shows that the

252

coating thickness remained unchanged within uncertainties with increasing dmob. This agrees

253

well with the observations of Fujitani et al. using transmission electron microscopy, who

254

found an independence of coating thickness of particles emitted from diesel engines on

255

dmob.60 The average coating thickness at different dmob was calculated to be (28.72±4.81) nm.

256

This value was markedly smaller than the coating thickness (50-130 nm) of urban particles

257

associated with traffic emissions, which are atmospherically aged, resulting in much thicker

258

coatings.61 As shown in Figure 3B, the relative coating thickness, defined as the ratio (Dp/Dc)

259

of particle diameter (Dp, from coating thickness plus core diameter) to rBC core diameter

260

(Dc), had a small decreasing trend with increasing dmob. Dp/Dc slightly reduced from

261

(1.64±0.20) at 125 nm dmob to (1.39±0.18) at 300 nm dmob.

262

Assuming a coating density of 1.3 g cm-3,21 the coating mass can be calculated on the basis

263

of average coating thickness and rBC core diameter at the MMD. Figure 3C displays that the

264

coating mass increased as a function of dmob. The coating mass at 300 nm dmob was

265

(5.93±1.59) fg and larger by a factor of 4.1 than that at 125 nm dmob. Nevertheless, the

266

coating to rBC core mass ratio exhibited a decrease with dmob (Figure 3D). It was (2.48±0.62) 10


Page 10 of 24

Page 11 of 24


267

and (1.22±0.33) at 125 and 300 nm dmob, respectively, which were in the reported range

268

(0.27-5.5) of the coating to rBC core mass ratio.21, 62, 63

269 270

Figure 3. (A) average coating thickness, (B) ratio of particle diameter (coating plus core, Dp)

271

to rBC core diameter (Dc), (C) coatings mass, and (D) coating to rBC core mass ratio as a

272

function of mobility diameter (dmob). The diameter and mass of rBC cores are those at the

273

MMD. Error bars were derived from the standard deviation of the average coating thickness.

274 275

Size Dependence of Morphology of Particles Containing rBC. Figure 4A shows the

276

effective density of particles containing rBC as a function of dmob. The effective density was

277

observed to decrease with dmob, which was related to the fact that larger BC aggregates have

278

more branched and open structures than smaller BC aggregates.64, 65 The effective density

279

(ρeff) decreased from (1.97±0.33) g/cm3 at 125 nm dmob to (0.77±0.13) g/cm3 at 300 nm dmob.

280

Figure 5A shows that the effective density markedly increased with increasing the coating

281

to rBC core mass ratio in the particles. Rissler et al. also found larger effective densities for

282

particles with higher OC mass contents generated from diesel engines.62 By filling the

283

internal voids of rBC aggregates, the coatings on diesel particles can lead to increases in the

284

effective density. The trend of increasing effective density with increasing coating mass is

285

similar to observations of gradual increases in the effective density of soot particles during

286

atmospheric aging process, which is attributed to the restructuring of black carbon aggregates

287

by the condensation of secondary organic aerosols (SOA) produced from the oxidation of 11



288

precursors.41-43

289 290

Figure 4. (A) the effective density of particles containing rBC as a function of mobility

291

diameter; (B) the mass-mobility relationship of diesel particles containing rBC; (C) the

292

dynamic shape factor of particles containing rBC as a function of mobility diameter. The

293

mass of particles containing rBC was the total mass of the rBC core at the MMD plus that of

294

the coating. Error bars were derived from the standard deviation of the mass of coatings.

295 296

Figure 4B shows that the mass-mobility relationships of the diesel particles containing rBC

297

can be well described using a power law function, which allowed the mass-mobility exponent

298

(Dm) of the particles containing rBC to be derived at 2.09 using Eq 2. A Dm value of lower

299

than 3.0 indicates a fractal and non-spherical morphology of particles containing rBC.

300

The dynamic shape factor (χ) represents an important parameter to characterize the

301

morphology of rBC-containing particles. The value of χ is 1 for a spherical particle without

302

cavities. Figure 4C shows the changes in χ of particles containing rBC as a function of dmob.

303

The χ exhibited an increasing trend with dmob, indicating more non-spherical shape for larger

304

particles. The χ increased from (1.60±0.20) at 125 nm dmob to (2.23±0.29) at 300 nm dmob.

305

As shown in Figure 5B, the coatings played an important role in the shape factor χ. The

306

value of χ decreased with an increase in the coating to rBC core mass ratio. This suggests that

307

the particles with a higher coating to rBC core mass ratio have a more spherical shape. There

308

are two processes that may cause the decrease in χ due to an organic coating increase: (1)

309

organic materials may fill the voids between monomer rBC granule aggregates and smooth

310

the particle surfaces; and (2) the organics may cause the restructuring of the rBC cores.42 The

311

second process is likely less important for freshly emitted diesel particles; it has been

312

reported that insignificant restructuring occurred for fresh BC particles of variable intrinsic 12


Page 12 of 24

Page 13 of 24


313

OC content.66 This suggests that the first process is likely the major factor in the decrease of χ

314

and a more spherical shape.

315 316

Figure 5. Plot of the effective density (A) and the dynamic shape factor (B) versus the coating

317

to rBC core mass ratio in the particles of different mobility diameters. Error bars were

318

derived from the standard deviation of the mass of coating.

319 320

Size Dependence of the Optical Properties of Particles Containing rBC. On the basis of

321

the RDG calculations, Figure 6A displays the absorption cross section (σ) of the diesel

322

particles containing rBC at 355 and 532 nm as a function of dmob. The σ showed an increasing

323

trend with increasing dmob. The σ at ultraviolet wavelength (355 nm) was larger than that at

324

visible wavelength (532 nm).

325

Figure 6B shows the mass absorption cross section (MAC) of diesel particles containing

326

rBC at 355 and 532 nm as a function of dmob. The MAC at 355 nm was higher than that at 532

327

nm, which is attributed to the wavelength dependence shown in Equation 5. For either light

328

wavelength, the MAC of the particles was dependent on dmob. The derived MAC value was

329

9.79 and 7.97 m2 g-1 for 125 nm dmob at 355 and 532 nm, respectively, whereas it decreased to

330

7.75 and 6.91 m2 g-1 for 300 nm dmob at 355 and 532 nm, respectively.

331

Intrinsic OC has an important influence on the optical properties of fresh soot. As shown in

332

Figure 6C, the MAC increased with an increase in the mass ratio of coating to rBC core,

333

which may be attributed to the lensing effect of the coating. Absorption enhancement of soot

334

particles containing rBC has been reported due to organic coatings generated during

335

atmospheric aging process.42, 67, 68 For example, a coating of toluene-OH oxidation products 13



336

or succinic acid increased the light absorption of soot particles by 5%.42, 69 The enhancement

337

from secondary organic aerosol (SOA) coatings was attributed to lensing and restructuring

338

effects, which required a sufficient OC coating thickness.69, 70

339 340

Figure 6. (A) Absorption cross section (σ) and (B) mass absorption cross section (MAC) of

341

diesel particles containing rBC as a function of mobility diameter at 355 and 532 nm. (C) Plot

342

of the mass absorption cross section (MAC) versus the coating to rBC core mass ratio in the

343

particles of different mobility diameters. The mass of particles containing rBC was the mass

344

of the rBC core at the MMD plus that of the coating. Error bars were derived from the

345

standard deviation of the mass of coating.

346 347

Discussion and Implications. Based on the SP2 and DMA results in this work, the effective

348

density, mass-mobility exponent, dynamic shape factor, and mass absorption cross section of

349

particles containing rBC from a diesel engine were derived at different dmob. In previous

350

studies, these properties of particles emitted by diesel engines and other fuel combustion,

351

containing rBC or not, have been investigated by different combinations of instruments, such

352

as an aerosol particle mass analyzer (APM)42, 62, 71-74, a centrifugal particle mass analyzer

353

(CPMA)43 or an aerodynamic aerosol classifier (AAC)75, all coupled with a DMA. It should

354

be pointed out that SP2 was highly sensitive to particles containing rBC, while APM, CPMA

355

or AAC cannot distinguish particles with and without rBC. Although the values of properties

356

derived by the combination of SP2 and DMA were close to those obtained through APM,

357

CPMA or AAC, the former detected particles containing rBC specifically while the others

358

measured all particles including rBC and non-rBC particles. Recently, the morphology and

359

density of ambient aerosols containing rBC have been measured using the DMA-SP2 14


Page 14 of 24

Page 15 of 24


360

instrument combination.76 Here, this system was used to characterize the size distribution and

361

coating thickness of the rBC cores in the particles generated from a diesel truck, the results of

362

which were used to evaluate the morphological and optical properties of the rBC particles

363

only. The results increase current outstanding of the physical and optical nature of particles

364

containing rBC in the diesel exhaust.

365

The characterization of morphology and optical property of diesel rBC particles can be

366

compared with those from diesel engines and fuel flame sources. The ρeff (0.77-1.97 g/cm3)

367

was larger than those in previous measurements of soot from diesel engines (0.30-0.82 g/cm3)

368

and propane flame (0.18-0.41 g/cm3) and of aerosols in urban environment (0.26-1.40 g/cm3)

369

dominated by traffic emission.62, 73 The Dm (2.09) was slightly lower than the reported Dm

370

range (2.28-2.56) of particles emitted from light-duty and heavy-duty diesel vehicles at

371

idling,62 and smaller than the Dm (2.40) of particles sampled on road in an urban center.73 The

372

χ (1.60-2.23) was within the χ range (1.02-4.61) of particles generated from the shock-tube

373

combustion with diesel as fuel at variable temperature.72

374

The MAC value (6.91-7.97 m2 g-1) at 532 nm was close to that (6.76-7.02 m2 g-1 at 532 nm)

375

of BC particles in other diesel vehicle exhaust, calculated by the same RDG method.21 It was

376

also in agreement with the reported range (7.5±1.2 m2 g-1) for MAC of freshly emitted

377

particles comprised of light-absorbing carbon from fossil fuel combustion.47 Zangmeister et

378

al. summarized that the reported MAC range of diesel engine generated aerosol at 514-532

379

nm was 7.4-17 m2 g-1 with an average of (9.5±3.3) m2 g-1.77 In comparison, a MAC value of

380

8.70 m2 g-1 at 532 nm was reported for soot particles from incomplete propane combustion.17

381

For flame soot particles from different fuels (ethylene, kerosene, diesel, and paraffin), MAC

382

ranges between 3.8 m2 g-1 and 8.6 m2 g-1 at 550 nm.77

383

Variations in the morphological and optical properties of rBC-containing particles from

384

different sources may be related to combustion conditions,72 such as fuel/oxygen ratio and

385

nature of fuels, which significantly influenced the size, composition and structure of rBC

386

particles.24, 51, 59 In particular, the properties of rBC particles markedly rely on their size,24 as

387

shown in the present study. The source and size dependent characteristics suggest that climate

388

models on the impact of rBC particles should carefully distinguish assumptions of these rBC

389

particle properties, in order to obtain more exact estimation results. 15



390 391

ASSOCIATED CONTENT

392

Supporting Information

393

Number and mass size distributions of all particles by SMPS. CMD and MMD of rBC cores.

394

Number and mass size distributions of rBC cores in particles of different mobility diameters.

395

Effects of the exhaust dilution ratio on number and mass size distributions of rBC cores. This

396

material is available free of charge via Internet at http://pubs.acs.org.

397 398

AUTHOR INFORMATION

399

Corresponding Author

400

*E-mail address: [email protected]

401

Notes

402

The authors declare no competing financial interest.

403 404

Acknowledgements

405

This project was supported by Environment and Climate Change Canada’s Climate and Clean

406

Air Program (CCAP).

407 408

References

409

(1) Bond, T. C.; Streets, D. G.; Yarber, K. F.; Nelson, S. M.; Woo, J.-H.; Klimont, Z., A

410

technology-based global inventory of black and organic carbon emissions from combustion. J.

411

Geophys. Res. :Atmos. 2004, 109, D14203.

412

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

413

atmospheric aerosols. Nature 2001, 409, 695-697.

414

(3) Ramanathan, V.; Carmicha, G., Global and regional climate changes due to black carbon.

415

Nature Geosci. 2008, 1, 221-227.

416

(4) Wittbom, C.; Eriksson, A. C.; Rissler, J.; Carlsson, J. E.; Roldin, P.; Nordin, E. Z.;

417

Nilsson, P. T.; Swietlicki, E.; Pagels, J. H.; Svenningsson, B., Cloud droplet activity changes

418

of soot aerosol upon smog chamber ageing. Atmos. Chem. Phys. 2014, 14, 9831-9854.

419

(5) Brooks, S. D.; Suter, K.; Olivarez, L., Effects of chemical aging on the ice nucleation 16


Page 16 of 24

Page 17 of 24


420

activity of soot and polycyclic aromatic hydrocarbon aerosols. J. Phys. Chem. A 2014, 118,

421

10036-47.

422

(6) Slade, J. H.; Thalman, R.; Wang, J.; Knopf, D. A., Chemical aging of single and

423

multicomponent biomass burning aerosol surrogate particles by OH: implications for cloud

424

condensation nucleus activity. Atmos. Chem. Phys. 2015, 15, 10183-10201.

425

(7) Friedman, B.; Kulkarni, G.; Beránek, J.; Zelenyuk, A.; Thornton, J. A.; Cziczo, D. J., Ice

426

nucleation and droplet formation by bare and coated soot particles. J. Geophys. Res.: Atmos.

427

2011, 116, D17203.

428

(8) Browne, E. C.; Franklin, J. P.; Canagaratna, M. R.; Massoli, P.; Kirchstetter, T. W.;

429

Worsnop, D. R.; Wilson, K. R.; Kroll, J. H., Changes to the chemical composition of soot

430

from heterogeneous oxidation reactions. J. Phys. Chem. A 2015, 119, 1154-1163.

431

(9) Zelenay, V.; Monge, M. E.; D'Anna, B.; George, C.; Styler, S. A.; Huthwelker, T.;

432

Ammann, M., Increased steady state uptake of ozone on soot due to UV/Vis radiation. J.

433

Geophys. Res.: Atmos. 2011, 116, D11301.

434

(10) Antinolo, M.; Willis, M. D.; Zhou, S.; Abbatt, J. P., Connecting the oxidation of soot to

435

its redox cycling abilities. Nature Commun. 2015, 6, 6812.

436

(11) Han, C.; Liu, Y.; He, H., The photoenhanced aging process of soot by the heterogeneous

437

ozonization reaction. Phys. Chem. Chem. Phys. 2016, 18, 24401-24407.

438

(12) Han, C.; Liu, Y.; Ma, J.; He, H., Effect of soot microstructure on its ozonization

439

reactivity. J. Chem. Phys. 2012, 137, 084507.

440

(13) Monge, M. E.; D'Anna, B.; Mazri, L.; Giroir-Fendler, A.; Ammann, M.; Donaldson, D. J.;

441

George, C., Light changes the atmospheric reactivity of soot. Proc. Natl. Acad. Sci. USA 2010,

442

107, 6605-6609.

443

(14) Han, C.; Liu, Y.; He, H., Role of organic carbon in heterogeneous reaction of NO2 with

444

soot. Environ Sci Technol 2013, 47, 3174-3181.

445

(15) Han, C.; Liu, Y.; He, H., Heterogeneous photochemical aging of soot by NO2 under

446

simulated sunlight. Atmos. Environ. 2013, 64, 270-276.

447

(16) Kleffmann, J.; Wiesen, P., Heterogeneous conversion of NO2 and NO on HNO3 treated

448

soot surfaces: atmospheric implications. Atmos. Chem. Phys. 2005, 5, 77-83.

449

(17) Zhang, R.; Khalizov, A. F.; Pagels, J.; Zhang, D.; Xue, H.; McMurry, P. H., Variability in 17



450

morphology, hygroscopicity, and optical properties of soot aerosols during atmospheric

451

processing. Proc. Natl. Acad. Sci. USA 2008, 105, 10291-10296.

452

(18) Su, D. S.; Serafino, A.; Müller, J.-O.; Jentoft, R. E.; Schlögl, R.; Fiorito, S., Cytotoxicity

453

and Inflammatory Potential of Soot Particles of Low-Emission Diesel Engines. Environ. Sci.

454

Technol. 2008, 42, 1761-1765.

455

(19) Alföldy, B.; Gieschaskiel, B.; Hofmann, W.; Drossinos, Y., Sizedistribution dependent

456

lung deposition of diesel exhaust particles. J. Aerosol Sci. 2009, 40, 652-663.

457

(20) Frank, B.; Schlogl, R.; Su, D. S., Diesel Soot Toxification. Environ. Sci. Technol. 2013,

458

47, 3026-3027.

459

(21) Adler, G.; Riziq, A. A.; Erlick, C.; Rudich, Y., Effect of intrinsic organic carbon on the

460

optical properties of fresh diesel soot. Proc. Natl. Acad. Sci. USA 2010, 107, 6699-6704.

461

(22) Ajtai, T.; Pinter, M.; Utry, N.; Kiss-Albert, G.; Gulyas, G.; Pusztai, P.; Puskas, R.;

462

Bereczky, A.; Szabados, G.; Szabo, G.; Konya, Z.; Bozoki, Z., Characterisation of diesel

463

particulate emission from engines using commercial diesel and biofuels. Atmos. Environ.

464

2016, 134, 109-120.

465

(23) Rahman, M. M.; Pourkhesalian, A. M.; Jahirul, M. I.; Stevanovic, S.; Pham, P. X.; Wang,

466

H.; Masri, A. R.; Brown, R. J.; Ristovski, Z. D., Particle emissions from biodiesels with

467

different physical properties and chemical composition. Fuel 2014, 134, 201-208.

468

(24) Lu, T.; Cheung, C. S.; Huang, Z., Sized-resolved volatility, morphology, nanostructure,

469

and oxidation characteristics of diesel particulate. Energ. Fuel. 2012, 26, 6168-6176.

470

(25) Lahde, T.; Ronkko, T.; Happonen, M.; Soderstrom, C.; Virtanen, A.; Solla, A.; Kyto, M.;

471

Rothe, D.; Keskinen, J., Effect of Fuel Injection Pressure on a Heavy-Duty Diesel Engine

472

Nonvolatile Particle Emission. Environ. Sci. Technol. 2011, 45, 2504-2509.

473

(26) Xu, Z.; Li, X.; Guan, C.; Huang, Z., Effects of Injection Pressure on Diesel Engine

474

Particle Physico-Chemical Properties. Aerosol Sci. Technol. 2014, 48, 128-138.

475

(27) Xu, Z.; Li, X.; Guan, C.; Huang, Z., Effects of injection timing on exhaust particle size

476

and nanostructure on a diesel engine at different loads. J. Aerosol Sci. 2014, 76, 28-38.

477

(28) Zhao, H.; Ge, Y.; Wang, X.; Tan, J.; Wang, A.; You, K., Effects of Fuel Sulfur Content

478

and Diesel Oxidation Catalyst on PM Emitted from Light-Duty Diesel Engine. Energ. Fuel.

479

2010, 24, 985-991. 18


Page 18 of 24

Page 19 of 24


480

(29) Bugarski, A. D.; Schnakenberg, G. H.; JR.; Hummer, J. A.; Cauda, E.; Janisko, S. J.;

481

Patts, L. D., Effects of Diesel Exhaust Aftertreatment Devices on Concentrations and Size

482

Distribution of Aerosols in Underground Mine Air. Environ. Sci. Technol. 2009, 43,

483

6737-6743.

484

(30) Herner, J. D.; Hu, S.; Robertson, W. H.; Huai, T.; Chang, M.-C. O.; Rieger, P.; Ayala, A.,

485

Effect of Advanced Aftertreatment for PM and NOx Reduction on Heavy-Duty Diesel Engine

486

Ultrafine Particle Emissions. Environ. Sci. Technol. 2011, 45, 2413-2419.

487

(31) Barrios, C. C.; Domínguez-Sáez, A.; Rubio, J. R.; Pujadas, M., Factors influencing the

488

number distribution and size of the particles emitted from a modern diesel vehicle in real

489

urban traffi. Atmos. Environ. 2012, 56, 16-25.

490

(32) Ma, X.; Liu, H.; Liu, J. J.; Zhuang, B., Sensitivity of climate effects of black carbon in

491

China to its size distributions. Atmos. Res. 2017, 185, 118-130.

492

(33) Pierce, J. R.; Chen, K.; Adams, P. J., Contribution of primary carbonaceous aerosol to

493

cloud condensation nuclei: processes and uncertainties evaluated with a global aerosol

494

microphysics model. Atmos. Chem. Phys. 2007, 7, 5447-5466.

495

(34) Spracklen, D. V.; Carslaw, K. S.; Poschl, U.; Rap, A.; Forster, P. M., Global cloud

496

condensation nuclei influenced by carbonaceous combustion aerosol. Atmos. Chem. Phys.

497

2011, 11, 9067-9087.

498

(35) Singh, S.; Fiddler, M. N.; Bililign, S., Measurement of size-dependent single scattering

499

albedo of fresh biomass burning aerosols using the extinction-minus-scattering technique

500

with a combination of cavity ring-down spectroscopy and nephelometry. Atmos. Chem. Phys.

501

2016, 16, 13491-13507.

502

(36) Liu, C.; Yin, Y.; Hu, F.; Jin, H.; Sorensen, C. M., The Effects of Monomer Size

503

Distribution on the Radiative Properties of Black Carbon Aggregates. Aerosol Sci. Technol.

504

2015, 49, 928-940.

505

(37) Taylor, J. W.; Allan, J. D.; Allen, G.; Coe, H.; Williams, P. I.; Flynn, M. J.; Le Breton, M.;

506

Muller, J. B. A.; Percival, C. J.; Oram, D.; Forster, G.; Lee, J. D.; Rickard, A. R.; Parrington,

507

M.; Palmer, P. I., Size-dependent wet removal of black carbon in Canadian biomass burning

508

plumes. Atmos. Chem. Phys. 2014, 14, 13755-13771.

509

(38) Moteki, N.; Kondo, Y.; Oshima, N.; Takegawa, N.; Koike, M.; Kita, K.; Matsui, H.; 19



510

Kajino, M., Size dependence of wet removal of black carbon aerosols during transport from

511

the boundary layer to the free troposphere. Geophys. Res. Lett. 2012, 39, L13802.

512

(39) Liscinsky, D. S.; Yu, Z.; True, B.; Peck, J.; Jennings, A. C.; Wong, H. W.; Franklin, J.;

513

Herndon, S. C.; Miake-Lye, R. C., Measurement of naphthalene uptake by combustion soot

514

particles. Environ. Sci. Technol. 2013, 47, 4875-4881.

515

(40) Han, C.; Liu, Y.; Ma, J.; He, H., Key role of organic carbon in the sunlight-enhanced

516

atmospheric aging of soot by O2. Proc. Natl. Acad. Sci. USA 2012, 109, 21250-21255.

517

(41) Khalizov, A. F.; Lin, Y.; Qiu, C.; Guo, S.; Collins, D.; Zhang, R., Role of OH-initiated

518

oxidation of isoprene in aging of combustion soot. Environ. Sci. Technol. 2013, 47,

519

2254-2263.

520

(42) Qiu, C.; Khalizov, A. F.; Zhang, R., Soot aging from OH-initiated oxidation of toluene.

521

Environ. Sci. Technol. 2012, 46, 9464-9472.

522

(43) Schnitzler, E. G.; Dutt, A.; Charbonneau, A. M.; Olfert, J. S.; Jager, W., Soot aggregate

523

restructuring due to coatings of secondary organic aerosol derived from aromatic precursors.

524

Environ. Sci. Technol. 2014, 48, 14309-14316.

525

(44) Pourkhesalian, A. M.; Stevanovic, S.; Rahman, M. M.; Faghihi, E. M.; Bottle, S. E.;

526

Masri, A. R.; Brown, R. J.; Ristovski, Z. D., Effect of atmospheric aging on volatility and

527

reactive oxygen species of biodiesel exhaust nano-particles. Atmos. Chem. Phys. 2015, 15,

528

9099-9108.

529

(45) Schwarz, J. P.; Gao, R. S.; Fahey, D. W.; Thomson, D. S.; Watts, L. A.; Wilson, J. C.;

530

Reeves, J. M.; Darbeheshti, M.; Baumgardner, D. G.; Kok, G. L.; Chung, S. H.; Schulz, M.;

531

Hendricks, J.; Lauer, A.; Karcher, B.; Slowik, J. G.; Rosenlof, K. H.; Thompson, T. L.;

532

Langford, A. O.; Loewenstein, M.; Aikin, K. C., Single-particle measurements of midlatitude

533

black carbon and light-scattering aerosols from the boundary layer to the lower stratosphere.

534

J. Geophys. Res.:Atmos. 2006, 111, D16207.

535

(46) Moteki, N.; Kondo, Y., Effects of Mixing State on Black Carbon Measurements by

536

Laser-Induced Incandescence. Aerosol Sci. Technol. 2007, 41, 398-417.

537

(47) Bond, T. C.; Bergstrom, R. W., Light absorption by carbonaceous particles: an

538

investigation review. Aerosol Sci. Technol. 2006, 40, 27-67.

539

(48) Gao, R. S.; Schwarz, J. P.; Kelly, K. K.; Fahey, D. W.; Watts, L. A.; Thompson, T. L.; 20


Page 20 of 24

Page 21 of 24


540

Spackman, J. R.; Slowik, J. G.; Cross, E. S.; Han, J.-H.; Davidovits, P.; Onasch, T. B.;

541

Worsnop, D. R., A Novel Method for Estimating Light-Scattering Properties of Soot Aerosols

542

Using a Modified Single-Particle Soot Photometer. Aerosol Sci. Technol. 2007, 41, 125-135.

543

(49) Schwarz, J. P.; Spackman, J. R.; Fahey, D. W.; Gao, R. S.; Lohmann, U.; Stier, P.; Watts,

544

L. A.; Thomson, D. S.; Lack, D. A.; Pfister, L.; Mahoney, M. J.; Baumgardner, D.; Wilson, J.

545

C.; Reeves, J. M., Coatings and their enhancement of black carbon light absorption in the

546

tropical atmosphere. J. Geophys. Res.:Atmos. 2008, 113, D03203.

547

(50) Laborde, M.; Schnaiter, M.; Linke, C.; Saathoff, H.; Naumann, K.-H.; Mohler, O.;

548

Berlenz, S.; U.Wagner; Taylor, J. W.; Liu, D.; Flynn, M.; Allan, J. D.; Coe, H.; Heimerl, K.;

549

Dahlkotter, F.; Weinzierl, B.; Wollny, A. G.; Zanatta, M.; Cozic, J.; Laj, P.; Hitzenberger, R.;

550

Schwarz, J. P.; Gysel, M., Single Particle Soot Photometer intercomparison at the AIDA

551

chamber. Atmos. Meas. Tech. 2012, 5, 3077-3097.

552

(51) Han, C.; Liu, Y.; Liu, C.; Ma, J.; He, H., Influence of combustion conditions on

553

hydrophilic properties and microstructure of flame soot. J Phys. Chem. A 2012, 116,

554

4129-4136.

555

(52) Saffaripour, M.; Chan, T. W.; Liu, F.; Thomson, K. A.; Smallwood, G. J.; Kubsh, J.;

556

Brezny, R., Effect of drive cycle and gasoline particulate filter on the size and morphology of

557

soot particles emitted from a gasoline-direct-injection vehicle. Environ. Sci. Technol. 2015,

558

49, 11950-11958.

559

(53) Bond, T. C.; Bergstrom, R. W., Light Absorption by Carbonaceous Particles An

560

Investigative Review. Aerosol Sci. Technol. 2006, 40, 27-67.

561

(54) Schnaiter, M.; Linke, C.; Mohler, O.; Naumann, K.-H.; Saathoff, H.; Wagner, R.;

562

Schurath, U., Absorption amplification of black carbon internally mixed with secondary

563

organic aerosol. J. Geophys. Res.:Atmos. 2005, 110, D19204.

564

(55) Liggio, J.; Gordon, M.; Smallwood, G.; Li, S.-M.; Stroud, C.; Staebler, R.; Lu, G.; Lee,

565

P.; Taylor, B.; Brook, J. R., Are Emissions of Black Carbon from Gasoline Vehicles

566

Underestimated? Insights from Near and On-Road Measurements. Environ. Sci. Technol.

567

2012, 46, 4819-4828.

568

(56) Yamada, H.; Misawa, K.; Suzuki, D.; Tanaka, K.; Matsumoto, J.; Fujii, M.; Tanaka, K.,

569

Detailed analysis of diesel vehicle exhaust emissions: Nitrogen oxides, hydrocarbons and 21



570

particulate size distributions. Proc. Combust. Inst. 2011, 33, 2895-2902.

571

(57) Li, T. Z.; Chen, X. D.; Yan, Z. X., Comparison of fine particles emissions of lightduty

572

gasoline vehicles from chassis dynamometer tests and on-road measurements. Atmos.

573

Environ. 2013, 68, 82-91.

574

(58) Holder, A. L.; Hagler, G. S. W.; Yelverton, T. L. B.; Hays, M. D., On-road black carbon

575

instrument intercomparison and aerosol characteristics by driving environment. Atmos.

576

Environ. 2014, 88, 183-191.

577

(59) Cheng, Y.; Li, S.-M.; Liggio, J.; Hayden, K.; Han, Y.; Stroud, C.; Chan, T.; Poitras, M.-J.,

578

The effects of biodiesels on semivolatile and nonvolatile particulate matter emissions from a

579

light-duty diesel engine. Environ. Pollut. 2017, 230, 72-80.

580

(60) Fujitani, Y.; Saitoh, K.; Kondo, Y.; Fushimi, A.; Takami, A.; Tanabe, K.; Kobayashi, S.,

581

Characterization of structure of single particles from various automobile engines under

582

steady-state conditions. Aerosol Sci. Technol. 2016, 50, 1055-1067.

583

(61) Gong, X.; Zhang, C.; Chen, H.; Nizkorodov, S. A.; Chen, J.; Yang, X., Size distribution

584

and mixing state of black carbon particles during a heavy air pollution episode in Shanghai.

585

Atmos. Chem. Phys. 2016, 16, 5399-5411.

586

(62) Rissler, J.; Messing, M. E.; Malik, A. I.; Nilsson, P. T.; Nordin, E. Z.; Bohgard, M.;

587

Sanati, M.; Pagels, J. H., Effective Density Characterization of Soot Agglomerates from

588

Various Sources and Comparison to Aggregation Theory. Aerosol Sci. Technol. 2013, 47,

589

792-805.

590

(63) Lough, G. C.; Chrlstensen, C. G.; Schauer, J. J.; Tortorell, J.; Manl, E.; Lawson, D. R.;

591

Clark, N. N.; Gabele, P. A., Development of molecular marker source profiles for emissions

592

from on-road gasoline and diesel vehicle fleets. J. Air Waste Manage. Assoc. 2007, 57,

593

1190-1199.

594

(64) Olfert, J. S.; Symonds, J. P. R.; Collings, N., The effective density and fractal dimension

595

of particles emitted from a light-duty diesel vehicle with a diesel oxidation catalyst. J.

596

Aerosol Sci. 2007, 38, 69-82.

597

(65) Ghazi, R.; Tjong, H.; Soewono, A.; Rogak, S. N.; Olfert, J. S., Mass, mobility, volatility,

598

and morphology of soot particles generated by a McKenna and inverted burner. Aerosol Sci.

599

Technol. 2013, 47, 395-405. 22


Page 22 of 24

Page 23 of 24


600

(66) Khalizov, A. F.; Hogan, B.; Qiu, C.; Petersen, E. L.; Zhang, R., Characterization of soot

601

aerosol produced from combustion of propane in a shock tube. Aerosol Sci. Technol. 2012, 46,

602

925-936.

603

(67) Liu, S.; Aiken, A. C.; Gorkowski, K.; Dubey, M. K.; Cappa, C. D.; Williams, L. R.;

604

Herndon, S. C.; Massoli, P.; Fortner, E. C.; Chhabra, P. S.; Brooks, W. A.; Onasch, T. B.;

605

Jayne, J. T.; Worsnop, D. R.; China, S.; Sharma, N.; Mazzoleni, C.; Xu, L.; Ng, N. L.; Liu, D.;

606

Allan, J. D.; Lee, J. D.; Fleming, Z. L.; Mohr, C.; Zotter, P.; Szidat, S.; Prevot, A. S.,

607

Enhanced light absorption by mixed source black and brown carbon particles in UK winter.

608

Nature Commun. 2015, 6, 8435.

609

(68) Healy, R. M.; Wang, J. M.; Jeong, C.-H.; Lee, A. K. Y.; Willis, M. D.; Jaroudi, E.;

610

Zimmerman, N.; Hilker, N.; Murphy, M.; Eckhardt, S.; Stohl, A.; Abbatt, J. P. D.; Wenger, J.

611

C.; Evans, G. J., Light-absorbing properties of ambient black carbon and brown carbon from

612

fossil fuel and biomass burning sources. J. Geophys. Res.: Atmos. 2015, 120, 6619-6633.

613

(69) Xue, H.; Khalizov, A. F.; Wang, L.; Zheng, J.; Zhang, R., Effects of dicarboxylic acid

614

coating on the optical properties of soot. Phys. Chem. Chem. Phys. 2009, 11, 7869-7875.

615

(70) Cappa, C. D.; Onasch, T. B.; Massoli, P.; Worsnop, D. R.; Bates, T. S.; Cross, E. S.;

616

Davidovits, P.; Hakala, J.; Hayden, K. L.; Jobson, B. T.; Kolesar, K. R.; Lack, D. A.; Lerner,

617

B. M.; Li, S.-M.; Mellon, D.; Nuaaman, I.; Olfert, J. S.; Petäjä, T.; Quinn, P. K.; Song, C.;

618

Subramanian, R.; Williams, E. J.; Zaveri, R. A., Radiative Absorption Enhancements Due to

619

the Mixing State of Atmospheric Black Carbon. Science 2012, 337, 1078-1081.

620

(71) Radney, J. G.; You, R.; Ma, X.; Conny, J. M.; Zachariah, M. R.; Hodges, J. T.;

621

Zangmeister, C. D., Dependence of soot optical properties on particle morphology:

622

measurements and model comparisons. Environ. Sci. Technol. 2014, 48, 3169-3176.

623

(72) Qiu, C.; Khalizov, A. F.; Hogan, B.; Petersen, E. L.; Zhang, R., High sensitivity of diesel

624

soot morphological and optical properties to combustion temperature in a shock tube. Environ.

625

Sci. Technol. 2014, 48, 6444-6452.

626

(73) Rissler, J.; Nordin, E. Z.; Eriksson, A. C.; Nilsson, P. T.; Frosch, M.; Sporre, M. K.;

627

Wierzbicka, A.; Svenningsson, B.; Löndahl, J.; Messing, M. E.; Sjogren, S.; Hemmingsen, J.

628

G.; Loft, S.; Pagels, J. H.; Swietlicki, E., Effective Density and Mixing State of Aerosol

629

Particles in a Near-Traffic Urban Environment. Environ. Sci. Technol. 2014, 48, 6300-6308. 23



630

(74) Leskinen, J.; Ihalainen, M.; Torvela, T.; Kortelainen, M.; Lamberg, H.; Tiitta, P.; Jakobi,

631

G.; Grigonyte, J.; Joutsensaari, J.; Sippula, O.; Tissari, J.; Virtanen, A.; Zimmermann, R.;

632

Jokiniemi, J., Effective density and morphology of particles emitted from small-scale

633

combustion of various wood fuels. Environ. Sci. Technol. 2014, 48, 13298-13306.

634

(75) Tavakoli, F.; Olfert, J. S., Determination of particle mass, effective density,

635

mass-mobility exponent, and dynamic shape factor using an aerodynamic aerosol classifier

636

and a differential mobility analyzer in tandem. J. Aerosol Sci. 2014, 75, 35-42.

637

(76) Zhang, Y.; Zhang, Q.; Cheng, Y.; Su, H.; Kecorius, S.; Wang, Z.; Wu, Z.; Hu, M.; Zhu, T.;

638

Wiedensohler, A.; He, K., Measuring the morphology and density of internally mixed black

639

carbon with SP2 and VTDMA: new insight into the absorption enhancement of black carbon

640

in the atmosphere. Atmos. Meas. Tech 2016, 9, 1833-1843.

641

(77) Zangmeister, C. D.; You, R.; Lunny, E. M.; Jacobson, A. E.; Okumura, M.; Zachariah, M.

642

R.; Radney, J. G., Measured in-situ mass absorption spectra for nine forms of

643

highly-absorbing carbonaceous aerosol. Carbon 2018, 136, 85-93.

24


Page 24 of 24

Size Dependence of the Physical Characteristics of Particles

Recommend Documents