Limited impact of sulfate-driven chemistry on black carbon aerosol aging in power plant plumes

Journal article

The aging of refractory black carbon (rBC) aerosol by sulfate-driven chemistry has been constrained in coal-fired power-plant plumes using the NOAA WP-3D research aircraft during the Southern Nexus (SENEX) study, which took place in the Southeastern US in June and July of 2013. A Single Particle Soot Photometer (SP2) determined the microphysical properties of rBC-containing particles including single-particle rBC mass and the presence and amount of internally-mixed non-rBC material, hereafter referred to as “coatings”. Most power-plant influenced air was associated with very slightly increased amounts of non-refractory material, likely sulfate internally mixed with the rBC, however this increase was statistically insignificant even after semi-Lagrangian exposure for up to 5 h. On average, the increase in coating thickness was 2 ± 4 nm for particles containing 3–5 fg rBC. Similarly, the number fraction of rBC-containing particles that could be identified as internally mixed was increased by plume chemistry by only 1.3 ± 1.3%. These direct measurements of microphysical aging of rBC-containing aerosol by power plant emissions constrain the enhancement of sulfate chemistry on both rBC’s column-integrated absorption optical depth, and rBC-containing aerosol’s ability to act as cloud condensation nuclei. Appling Mie and k-Köhler theories to the SP2 observations, permits the resulting effect on rBC ambient light-absorption to be capped at the 2–6% level.

Authors: Markovic, MZ; Perring, AE; Gao, RS; Liau, J; Welti, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: AIMS Press
• Journal: AIMS Environmental Science
• Volume: 5
• Issue: 3
• Pages: 195-215
• Publication date: 2018-06-25
• Acceptance date: 2018-06-18
• DOI: 10.3934/environsci.2018.3.195
• EISSN: 2372-0352
• ISSN: 2372-0344
• Keywords: sulfate chemistry; sulfate; black carbon aerosol; aerosol aging