 |
| Titel |
Characteristics and formation mechanism of continuous hazes in China: a case study during the autumn of 2014 in the North China Plain |
| VerfasserIn |
Y. R. Yang, X. G. Liu, Y. Qu, J. L. An, R. Jiang, Y. H. Zhang, Y. L. Sun, Z. J. Wu, F. Zhang, W. Q. Xu, Q. X. Ma |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 14 ; Nr. 15, no. 14 (2015-07-23), S.8165-8178 |
| Datensatznummer |
250119924
|
| Publikation (Nr.) |
 copernicus.org/acp-15-8165-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Four extreme haze episodes occurred in October 2014 in the
North China Plain (NCP). To clarify the formation mechanism of hazes in
autumn, strengthened observations were conducted in Beijing from 5 October
to 2 November. The meteorological parameters, satellite data, chemical
compositions and optical properties of aerosols were obtained. The hazes
originated from the NCP, developing in the southwest and northeast directions,
with the highest concentration of PM2.5 of 469 μg m−3 in Beijing. The NCP was dominated by a weak high pressure system during
the haze episode, which resulted in low surface wind speed and relatively
stagnant weather. Moreover, the wind slowed down around Beijing city. The
secondary aerosols NO3− was always higher than that of
SO42−, which indicated the motor vehicles played a more important
part in the hazes in October 2014, even though the oxidation rate from
SO2 to SO42− was faster than that of NOx to
NO3−. Sudden increases of the concentrations of organic matter,
Cl− and BC (black carbon) before each haze episode implied that
regional transport of pollutants by biomass burning was important for haze
formation during autumn. A satellite map of fire points and the backward
trajectories of the air masses also indicated this pollution source. The
distinct decrease in the PBL (planetary boundary layer) height during four
haze episodes restrained the vertical dispersion of the air pollutants.
Water vapor also played a vital role in the formation of hazes by
accelerating the chemical transformation of secondary pollutants, leading to
hygroscopic growth of aerosols and altering the thermal balance of the
atmosphere. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|