Hygroscopic Properties of Atmospheric Aerosol Measured with an HTDMA in an Urban Background Site in Madrid

3rd Iberian Meeting on Aerosol Science and Technology

Alonso-Blanco, E.^1 ; Gómez-Moreno, F.J.^1 ; Becerril, M.^1 ; Coz, E.^1 ; Artíñano, B.^1

Department of Environment, CIEMAT, Madrid, Spain^1

关键词: Atmospheric conditions;    Atmospheric stability;    Hygroscopic growth;    Hygroscopic growth distribution;    Hygroscopic growth factor;    Hygroscopic properties;    Inorganic fractions;    Meteorological condition;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/28/1/012002/pdf
DOI  :  10.1088/1755-1315/28/1/012002

来源: IOP

【 摘 要 】

The observation of high aerosol hygroscopic growth in Madrid is mainly limited to specific atmospheric conditions, such as local stagnation episodes, which take place in winter time. One of these episodes was identified in December 2014 and the hygroscopic growth factor (GF) measurements obtained in such episode were analysed in order to know the influence of the meteorological conditions on aerosol hygroscopic properties. The prevailing high atmospheric stability triggered an increase of the particle total concentration during the study period, with several peaks that exceeded 4.0 104particles cm-3, as well as an increase in the inorganic fraction of the aerosol, the NO3-concentration, which in this case corresponded to 25% of the total PM1non-refractory composition. The aerosol hygroscopic growth distribution was bimodal during the episode, with an average GF around 1.2 for the five dry particle sizes measured and an average GF spread ≥ 0.15. In addition, it is important to note that when a reduction in the concentrations of NO3-is observed, it coincides with a decrease of the GF and its spread. These data suggest, on the one hand, a high degree of external mixing state of the aerosol during the episode and, on the other hand, a notable association between the GF and the inorganic fraction of the aerosol.