In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 20, No. 9 ( 2020-05-08), p. 5425-5436
Abstract:
Abstract. The high contribution of secondary organic aerosol to the
loading of fine particle pollution in China highlights the roles of volatile
organic compound (VOC) oxidation. In this respect, particulate active metallic
oxides in dust, like TiO2 and Fe ions, were proposed to influence the photochemical reactions of ambient VOCs. A case study was conducted at an urban site in Xi'an, northwest China, to investigate the origin and transformation of VOCs during a windblown dust-to-haze pollution episode, and the assumption that dust would enhance the oxidation of VOCs was
verified. Local vehicle exhaust (25 %) and biomass burning (18 %) were found to be the two largest contributors to ambient VOCs. In the dust
pollution period, a sharp decrease in the loading of VOCs and the aging of their
components were observed. Simultaneously, the secondary oxygenated VOC
fraction (i.e., methylglyoxal) increased. Source strength, physical
dispersion, and regional transport were eliminated as major factors for
the variation of ambient VOCs. In another aspect, about a 2- to 3-fold
increase in the loading of iron (Fe) and titanium (Ti) was found in the airborne particles, together with a fast decrease in trans-/cis-2-butene ratios, which demonstrated that dust can accelerate the oxidation of ambient VOCs and the formation of secondary organic aerosol (SOA) precursors.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-20-5425-2020
DOI:
10.5194/acp-20-5425-2020-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2020
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
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