Direct measurements of black carbon fluxes in central Beijing using the eddy covariance method

Joshi, Rutambhara; Liu, Dantong; Nemitz, Eiko ORCID: https://orcid.org/0000-0002-1765-6298; Langford, Ben ORCID: https://orcid.org/0000-0002-6968-5197; Mullinger, Neil ORCID: https://orcid.org/0000-0002-3148-6950; Squires, Freya; Lee, James; Wu, Yunfei; Pan, Xiaole; Fu, Pingqing; Kotthaus, Simone; Grimmond, Sue; Zhang, Qiang; Wu, Ruili; Wild, Oliver; Flynn, Michael; Coe, Hugh; Allan, James. 2021 Direct measurements of black carbon fluxes in central Beijing using the eddy covariance method [in special issue: In-depth study of air pollution sources and processes within Beijing and its surrounding region (APHH-Beijing)] Atmospheric Chemistry and Physics, 21 (1). 147-162. 10.5194/acp-21-147-2021

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Abstract/Summary

Black carbon (BC) forms an important component of particulate matter globally, due to its impact on climate, the environment and human health. Identifying and quantifying its emission sources are critical for effective policymaking and achieving the desired reduction in air pollution. In this study, we present the first direct measurements of urban BC fluxes using eddy covariance. The measurements were made over Beijing within the UK-China Air Pollution and Human Health (APHH) winter 2016 and summer 2017 campaigns. In both seasons, the mean measured BC mass (winter: 5.49 ng m−2 s−1, summer: 6.10 ng m−2 s−1) and number fluxes (winter: 261.25 particles cm−2 s−1, summer: 334.37 particles cm−2 s−1) were similar. Traffic was determined to be the dominant source of the BC fluxes measured during both seasons. The total BC emissions within the 2013 Multi-resolution Emission Inventory for China (MEIC) are on average too high compared to measured fluxes by a factor of 58.8 (winter) and 47.2 (summer). Only a comparison with the MEIC transport sector shows that emissions are also larger (factor of 37.5 in winter and 37.7 in summer) than the measured flux. Emission ratios of BC ∕ NOx and BC ∕ CO are comparable to vehicular emission control standards implemented in January 2017 for gasoline (China 5) and diesel (China V) engines, indicating a reduction of BC emissions within central Beijing, and extending this to a larger area would further reduce total BC concentrations.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.5194/acp-21-147-2021
UKCEH and CEH Sections/Science Areas:	Atmospheric Chemistry and Effects (Science Area 2017-24)
ISSN:	1680-7316
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
NORA Subject Terms:	Atmospheric Sciences
Date made live:	11 Aug 2020 10:29 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/528319

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