DBPapers
DOI : 10.5593/sgem2012/s06.v2008

MAGNETIC PARTICLES AND POLLENS IN INDOOR AND OUTDOOR SETTLED DUST FROM SEVERAL BULGARIAN CITIES – ENVIRONMENTAL IMPLICATIONS

P. PETROV, R. YANKOVA, D. JORDANOVA, N. JORDANOVA, T. TSACHEVA
Wednesday 1 August 2012 by Libadmin2012

References: 12th International Multidisciplinary Scientific GeoConference, www.sgem.org, SGEM2012 Conference Proceedings/ ISSN 1314-2704, June 17-23, 2012, Vol. 2, 593 - 600 pp

ABSTRACT

Dust is the most important factor determining urban air quality. Pollens also cause
respiratory allergic diseases in sensitized people, especially in industrialized cities
where pollen’s reactivity is enhanced by increased air pollution. In our study, a
combination of magnetic methods, aerobiological studies and microscopic observations
on settled dust from indoor and outdoor environment is presented. Magnetic
susceptibility of outdoor dust is always higher than that of the indoor dust, suggesting
that the major indoor magnetic component comes from outdoor dust, which penetrates
inside. The amount of mineral particles of sizes less than 3 microns, normalized to the
total number of inorganic particles, was found roughly proportional to registered
monthly PM10 variations in each city. The main magnetic mineral in outdoor dust,
identified by thermomagnetic analysis of magnetic susceptibility, is magnetite (Fe3O4).
Bulk magnetic susceptibility does not show seasonal variations, in contrast to pollen
abundance. In all cities peaks in pollen abundance are registered in months April-June.
SEM observations coupled with EDX analyses show the presence of several fractions in
outdoor dust: combustion-derived spherical metallic particles; lithogenic irregularlyshaped
particles, as well as plentiful pollen grains with welded metallic small grains on
their surfaces. This finding suggests that significant part of anthropogenic metallic
particles is absorbed on pollens’ surface and possibly increases pollens’ allergic
reactivity.

Keywords: settled indoor and outdoor dust, magnetism, pollen abundance