In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 19, No. 1 ( 2019-01-11), p. 447-458
Abstract:
Abstract. Refractory black carbon (BC) is a product of incomplete combustion of fossil
fuel, biomass and biofuel, etc. By mixing with other species, BC can play
significant roles in climate change, visibility impairment and human health.
Such BC-containing particles in densely populated megacities like Beijing may
have specific sources and properties that are important to haze formation and
air quality. In this work, we exclusively characterized the BC-containing
particles in urban Beijing by using a laser-only Aerodyne soot particle
aerosol mass spectrometer (SP-AMS), as part of the Atmospheric Pollution &
Human Health (APHH) 2016 winter campaign. The average mass ratio of coating
to BC core (RBC) was found to be ∼5.0. Positive matrix
factorization shows the presence of significant primary fossil fuel and
biomass-burning organics (64 % of total organics). Yet secondary species,
including sulfate, nitrate and oxygenated organic aerosol (OA) species, could
have significant impacts on the properties of BC-containing particles,
especially for ones with larger BC core sizes and thicker coatings. Analyses
of sources and diurnal cycles of organic coating reveal significant afternoon
photochemical production of secondary OA (SOA), as well as nighttime aqueous
production of a portion of highly oxygenated OA. Besides SOA, photochemical
production of nitrate, not sulfate, appeared to be important. Further
investigations on BC-containing particles during different periods show that,
on average, more polluted periods would have more contributions from
secondary species and more thickly coated BC tended to associate with more
secondary species, indicating the important role of chemical aging to the
pollution of BC-containing particles in urban Beijing during wintertime.
However, for individual pollution events, primary species (fossil fuel, coal
and biomass-burning emissions) could also play a dominant role, as revealed
by the compositions of BC-containing particles in two polluted episodes during the
sampling period.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-19-447-2019
DOI:
10.5194/acp-19-447-2019-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
