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Istituto sull'inquinamento atmosferico

Torna all'elenco Contributi in rivista anno 2011

Contributo in rivista

Tipo: Articolo in rivista

Titolo: Chemical characteristics of inorganic ammonium salts in PM2.5 in the atmosphere of Beijing (China)

Anno di pubblicazione: 2011

Formato: Elettronico

Autori: Ianniello A., Spataro F., Esposito G., Allegrini, I. Hu M.and Zhu T.

Affiliazioni autori: CNR - Institute of Atmospheric Pollution Research (Rome), CO.R.AM - Consorzio Ricerche Ambientali (Ferrara), State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University (Beijing, China)

Autori CNR:

  • GIULIO ESPOSITO
  • ANTONIETTA IANNIELLO
  • FRANCESCA SPATARO

Lingua: inglese

Abstract: The atmospheric concentrations of gaseous HNO3, HCl and NH3 and their relative salts have been measured during two field campaigns in the winter and in the summer of 2007 at Beijing (China), as part of CAREBEIJING (Campaigns of Air Quality Research in Beijing and Surrounding Region). In this study, annular denuder technique used with integration times of 2 and 24h to collect inorganic and soluble PM2.5 without interferences from gas-particle and particle-particle interactions. The results were discussed from the standpoint of temporal and diurnal variations and meteorological effects. Fine particulate Cl-, NH4+ and SO24- exhibited distinct temporal variations, while fine particulate NO3- did not show much variation with respect to season. Daily mean concentrations of fine particulate NH4+ and SO42- were higher during summer (12.30 ?gm-3 and 18.24 ?gm-3, respectively) than during winter (6.51 ?gm-3 and 7.50 ?gm-3, respectively). Daily mean concentrations of fine particulate Cl- were higher during winter (2.94 ?gm-3) than during summer (0.79 ?gm-3), while fine particulate NO3- showed similar both in winter (8.38 ?gm-3) and in summer (9.62 ?gm-3) periods. The presence of large amounts of fine particulate NO3- even in summer are due to higher local and regional concentrations of NH3 in the atmosphere available to neutralize H2SO4 and HNO3, which is consistent with the observation that the measured particulate species were neutralized. The composition of fine particulate matter indicated the domination of (NH4)2SO4 during winter and summer periods. In addition, the high relative humidity conditions in summer period seemed to dissolve a significant fraction of HNO3 and NH3 enhancing fine particulate NO3- and NH4+ in the atmosphere. All measured particulate species showed diurnal similar patterns during the winter and summer periods with higher peaks in the early morning, especially in summer, when humid and stable atmospheric conditions occurred. These diurnal variations were affected by wind direction suggesting regional and local source influences. The fine particulate species were correlated with NOx and PM2.5, supporting the hypothesis that traffic may be also an important source of secondary particles.

Lingua abstract: inglese

Pagine da: 10803

Pagine a: 10822

Pagine totali: 20

Rivista:

Atmospheric chemistry and physics Copernicus Publ.
Paese di pubblicazione: Germania
Lingua: inglese
ISSN: 1680-7324

Numero volume: 11

DOI: 10.5194/acp-11-10803-2011

Referee: Sė: Internazionale

Stato della pubblicazione: Published version

Parole chiave:

  • Annular denuder; Urban atmosphere; Ammonium nitrate; Ammonium chloride; thermodinamic equilibrium

URL: http://www.atmos-chem-phys.net/11/10803/2011/

Data di accettazione: 21/10/2011

Strutture CNR:

Moduli:

Allegati: acp_2011 (application/pdf)

 
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