Preprints
https://doi.org/10.5194/egusphere-2023-351
https://doi.org/10.5194/egusphere-2023-351
27 Mar 2023
 | 27 Mar 2023

Black carbon content of traffic emissions impacts significantly on black carbon mass size distributions and mixing states

Fei Li, Biao Luo, Miaomiao Zhai, Li Liu, Gang Zhao, Hanbing Xu, Tao Deng, Xuejiao Deng, Haobo Tan, Ye Kuang, and Jun Zhao

Abstract. Both the size and mixing state of black carbon (BC)-containing aerosols are crucial in estimating the environmental, health and climate impacts of BC. Traffic emissions are a major global source of BC, however, parameterization of BC mass size distributions and mixing states associated with traffic remains lacking due to its dependence on vehicle types and driving conditions. To investigate BC mass size distributions and mixing states associated with traffic emissions, a field campaign was conducted in Guangzhou urban area during winter, which used a system coupling a differential mobility analyzer (DMA) and single-particle soot photometer (SP2) to measure BC mass size distributions in the range of 100 to 700 nm. The resolved primary organic aerosols were hydrocarbon-like organic aerosols (HOA) and cooking-like organic aerosols (COA), refractory BC (rBC) which was detected by the DMA-SP2 and correlated highly with HOA (R2=0.88), confirming that traffic emissions are the dominant source of atmospheric BC during the observations. The BC mass size distribution was found to be best fitted by a lognormal distribution, with a geometric mean (Dg,BC) of 258±16 nm, varying between 200 and 300 nm. During daytime, active formation of secondary nitrate and organic aerosols was observed, but it had little effect on the variations of BC mass size distributions. Further analyses revealed that Dg,BC was highly correlated with rBC/HOA (R=0.66) in a linear form of Dg,BC= 34×rBC⁄HOA+177, demonstrating that the BC content of traffic emissions significantly impacts the BC mass size distributions. In addition, the size-dependent fractions of BC-containing aerosols in all types of aerosols (fBCc) and the fraction of identified externally mixed (bare/thinly coated) BC particles in all BC-containing aerosols (fext) were also characterized. It was found that the daytime secondary aerosol formation reduced both fBCc and fext, with the decrease of fext being more pronounced for larger particles, possibly due to the higher relative coating thickness. Variations in fext during nighttime were mainly controlled by the emission conditions. For example, fext for 600 nm particles decreased from 0.82 to 0.46 as rBC/HOA increased from 1 to 3.5 while the mass ratios of secondary aerosols to rBC varied little, demonstrating that the BC content also significantly affects the mixing states of freshly emitted BC from traffic emissions. This study suggests that BC content likely plays a key role in parameterizing both mass size distributions and mixing states of BC from traffic emissions and hence has significant implications for accurate representation of BC from different sources when modeling the impacts of BC.

Journal article(s) based on this preprint

14 Jun 2023
Black carbon content of traffic emissions significantly impacts black carbon mass size distributions and mixing states
Fei Li, Biao Luo, Miaomiao Zhai, Li Liu, Gang Zhao, Hanbing Xu, Tao Deng, Xuejiao Deng, Haobo Tan, Ye Kuang, and Jun Zhao
Atmos. Chem. Phys., 23, 6545–6558, https://doi.org/10.5194/acp-23-6545-2023,https://doi.org/10.5194/acp-23-6545-2023, 2023
Short summary

Fei Li et al.

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-351', Zezhen Cheng, 17 Apr 2023
    • AC2: 'Reply on RC1', Ye Kuang, 04 May 2023
  • RC2: 'Comment on egusphere-2023-351', Anonymous Referee #1, 19 Apr 2023
    • AC1: 'Reply on RC2', Ye Kuang, 04 May 2023
  • RC3: 'Comment on egusphere-2023-351', Anonymous Referee #3, 04 May 2023
    • AC3: 'Reply on RC3', Ye Kuang, 08 May 2023

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-351', Zezhen Cheng, 17 Apr 2023
    • AC2: 'Reply on RC1', Ye Kuang, 04 May 2023
  • RC2: 'Comment on egusphere-2023-351', Anonymous Referee #1, 19 Apr 2023
    • AC1: 'Reply on RC2', Ye Kuang, 04 May 2023
  • RC3: 'Comment on egusphere-2023-351', Anonymous Referee #3, 04 May 2023
    • AC3: 'Reply on RC3', Ye Kuang, 08 May 2023

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Ye Kuang on behalf of the Authors (10 May 2023)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (15 May 2023) by Yuan Wang
AR by Ye Kuang on behalf of the Authors (15 May 2023)  Manuscript 

Journal article(s) based on this preprint

14 Jun 2023
Black carbon content of traffic emissions significantly impacts black carbon mass size distributions and mixing states
Fei Li, Biao Luo, Miaomiao Zhai, Li Liu, Gang Zhao, Hanbing Xu, Tao Deng, Xuejiao Deng, Haobo Tan, Ye Kuang, and Jun Zhao
Atmos. Chem. Phys., 23, 6545–6558, https://doi.org/10.5194/acp-23-6545-2023,https://doi.org/10.5194/acp-23-6545-2023, 2023
Short summary

Fei Li et al.

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Short summary
A field campaign was conducted to study black carbon (BC) mass size distributions and mixing states connected to traffic emissions using a system that combines a differential mobility analyzer and single-particle soot photometer. Results showed that the black carbon content of traffic emissions has a considerable influence on both BC mass size distributions and mixing states, which has crucial implications for accurately representing BC from various sources in regional and climate models.