Size distribution of atmospheric particulate ionic species at a coastal site in Portugal

Quimica nova

Alves, Célia¹  Campos, Eduarda¹  Barbedo, Patrícia¹  Pio, Casimiro¹ 

[1] Universidade de Aveiro, Aveiro, Portugal

关键词: water soluble ions;    atmosphericaerosol;    size distribution.;   

DOI  :  10.1590/S0100-40422007000800027

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

A Berner impactor was used to collect size-differentiatedaerosol samples from March to August 2003 in the city of Aveiro, on the Portuguesewest coast. The samples were analysed for the main water-soluble ion species.The average concentration of sulphate, nitrate, chloride and ammonium was 6.38,3.09, 1.67 and 1.27 µg m-3, respectively.The results show that SO42- and NH4+were consistently present in the fine fraction < 1 µm,which represents, on average, 72 and 89% of their total atmospheric concentrations,respectively. The NO3-particles were concentrated in the coarse size.Chloride presented the characteristic coarse mode for marine aerosols. Duringsome spring/summer events, an ammonium surplus was observed (NH4+/SO42-molar ratios > 2), possibly due to greater availability of ammonia comingfrom agricultural activities or from the neighbouring chemical industrial complex.During the remaining periods, the aerosol was found to be somewhat acidic andpredominantly in the form of ammonium bisulphate (NH4+/SO42-molar ratios = 0.5-1.25). Samples collected under a major or exclusive influenceof maritime air masses were essentially constituted by coarse particles withenrichment in sea salt, while for air masses of continental origin the contributionof water-soluble ionic species in the fine mode was more pronounced.

【 授权许可】

CC BY