Morphological, chemical and optical absorbing characterization of aerosols in the urban atmosphere of Valladolid
[摘要] Samples of atmospheric aerosol particles were collected in Valladolid, Spain,during the winter of 2003-2004. The measurements were made with a DekatiPM
10 cascade impactor with four size stages: greater than 10 µm,between 2.5 to 10 µm, 1 to 2.5 µm and less than 1 µm. The sizeand shape of the particles were analyzed with a scanning electron microscope(SEM) and elemental analysis was done with an energy dispersive x-rayanalysis (EDX). We present an evaluation by size, shape and composition ofthe major particulate species in the Valladolid urban atmosphere.
The total aerosol concentration is very variable, ranging from39.86 µg·m-3 to 184.88 µg·m-3 with the coarseparticles as the dominant mass fraction. Emphasis was given to fine particles(<1 µm), for which the visible (400 nm to 650 nm) light absorptioncoefficients were measured using the integrating plate technique. We havemade some enhancements in the illumination system of this measurement system.The absorption coefficient, σa, is highly variable and ranges from7.33×10-6 m-1 to 1.01×10-4 m-1 at awavelength of 550 nm. There is an inverse power law relationship betweenσa and wavelength, with an average exponent of -0.8.
