| Samples of atmospheric aerosol particles were collected in Valladolid, Spain,
during the winter of 2003-2004. The measurements were made with a Dekati
PM10 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 size
and shape of the particles were analyzed with a scanning electron microscope
(SEM) and elemental analysis was done with an energy dispersive x-ray
analysis (EDX). We present an evaluation by size, shape and composition of
the major particulate species in the Valladolid urban atmosphere.
The total aerosol concentration is very variable, ranging from
39.86 µg·m-3 to 184.88 µg·m-3 with the coarse
particles as the dominant mass fraction. Emphasis was given to fine particles
(<1 µm), for which the visible (400 nm to 650 nm) light absorption
coefficients were measured using the integrating plate technique. We have
made some enhancements in the illumination system of this measurement system.
The absorption coefficient, σa, is highly variable and ranges from
7.33×10-6 m-1 to 1.01×10-4 m-1 at a
wavelength of 550 nm. There is an inverse power law relationship between
σa and wavelength, with an average exponent of -0.8. |