HR: 0800h
AN: GP31B-0837 [Abstracts]
TI: Magnetic Characterisation and Mapping of Urban Dust in Madrid, Spain.
AU: * McIntosh, G
EM: gregc@fis.ucm.es
AF: Depto de Geofisica y Meteorologia, Universidad Complutense de Madrid, Facultad de CC Fisicas, Avda
Complutense s/n, Madrid, 28040
Spain
AU: Gomez-Paccard, M
EM: miriam.gomez@univ-rennes1.fr
AF: Geosciences, Universite de Rennes 1 bat. 15, Campus de Beaulieu, Rennes, 35042
France
AU: Osete, M
EM: mlosete@fis.ucm.es
AF: Depto de Geofisica y Meteorologia, Universidad Complutense de Madrid, Facultad de CC Fisicas, Avda
Complutense s/n, Madrid, 28040
Spain
AU: Villasante, V
EM: vicvilla@fis.ucm.es
AF: Depto de Geofisica y Meteorologia, Universidad Complutense de Madrid, Facultad de CC Fisicas, Avda
Complutense s/n, Madrid, 28040
Spain
AB:
Air quality and particulate loadings are important contemporary issues, and their characterisation is of great interest. A
study of the magnetic properties of dust deposited on horizontal surfaces and tree leaves across the main urban area of
Madrid, Spain, has been carried out. In both cases the magnetic signal is dominated by a similar, low coercivity component,
which temperature-dependent susceptibility and remanence measurements identify as oxidised magnetite or maghaemite. Subtle
coercivity variations are seen in the samples, showing both tree species and time dependencies. Evergreen (pine) needles
exhibit higher coercivities than deciduous leaves, whilst the coercivity of deciduous leaves increases with time. This can be
ascribed to the progressive oxidation of the magnetic phase. Isothermal remanence intensity and susceptibility decrease as
the distance from traffic-bearing roads increases, indicating traffic as the main source of the magnetic signal. City-wide
maps highlight magnetic "hot-spots" where the accumulation of magnetic material is more pronounced. Sample collection,
measurement and map production are quick and easy and provide a useful tool for delineating time-averaged pollution loadings.
DE: 1505 Biomagnetism
DE: 1512 Environmental magnetism
DE: 1540 Rock and mineral magnetism
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0400 Biogeosciences
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting