Influences of Primary Emission and Secondary Coating Formation on the Particle Diversity and Mixing State of Black Carbon Particles.

Autor:	Lee AKY; Department of Civil and Environmental Engineering , National University of Singapore , 117576 , Singapore.; NUS Environmental Research Institute , National University of Singapore , 117411 , Singapore., Rivellini LH; NUS Environmental Research Institute , National University of Singapore , 117411 , Singapore., Chen CL; Scripps Institution of Oceanography , University of California, San Diego , La Jolla , California 92093 , United States., Liu J; Scripps Institution of Oceanography , University of California, San Diego , La Jolla , California 92093 , United States., Price DJ; Scripps Institution of Oceanography , University of California, San Diego , La Jolla , California 92093 , United States., Betha R; Scripps Institution of Oceanography , University of California, San Diego , La Jolla , California 92093 , United States., Russell LM; Scripps Institution of Oceanography , University of California, San Diego , La Jolla , California 92093 , United States., Zhang X; Department of Civil and Environmental Engineering , University of California , Davis , California 95616 , United States., Cappa CD; Department of Civil and Environmental Engineering , University of California , Davis , California 95616 , United States.
Jazyk:	angličtina
Zdroj:	Environmental science & technology [Environ Sci Technol] 2019 Aug 20; Vol. 53 (16), pp. 9429-9438. Date of Electronic Publication: 2019 Aug 02.
DOI:	10.1021/acs.est.9b03064
Abstrakt:	The mixing state of black carbon (BC) affects its environmental fate and impacts. This work investigates particle diversity and mixing state for refractory BC (rBC) containing particles in an urban environment. The chemical compositions of individual rBC-containing particles were measured, from which a mixing state index and particle diversity were determined. The mixing state index (χ) varied between 26% and 69% with the average of 48% in this study and was slightly enhanced with the photochemical age of air masses, indicating that most of the rBC-containing particles cannot be simply explained by fully externally and internally mixed model. Clustering of single particle measurements was used to investigate the potential effects of different primary emissions and atmospheric processes on rBC-containing particle diversity and mixing state. The average particle species diversity and the bulk population species diversity both increased with primary traffic emissions and elevated nitrate concentrations in the morning but gradually decreased with secondary organic aerosol (SOA) formation in the afternoon. The single particle clustering results illustrate that primary traffic emissions and entrainment of nitrate-containing rBC particles from the residual layer to the surface could lead to more heterogeneous aerosol compositions, whereas substantial fresh SOA formation near vehicular emissions made the rBC-containing particles more homogeneous. This work highlights the importance of considering particle diversity and mixing state for investigating the chemical evolution of rBC-containing particles and the potential effects of coating on BC absorption enhancement.
Databáze:	MEDLINE
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