title: Chemical composition of fine particles in fresh smoke plumes from boreal wild-land fires in Europe.
abstract: A series of smoke plumes was detected in Helsinki, Finland, during a one-month-lasting period in August 2006. The smoke plumes originated from wildfires close to Finland, and they were short-term and had a high particulate matter (PM) concentration. Physical and chemical properties of fine particles in those smokes were characterised by a wide range of real-time measurements that enabled the examination of individual plume events. Concurrently PM(1) filter samples were collected and analysed off-line. Satellite observations employing MODIS sensor on board of NASA EOS Terra satellite with the dispersion model SILAM and the Fire Assimilation System were used for evaluation of the emission fluxes from wildfires. The model predicted well the timing of the plumes but the predicted PM concentrations differed from the observed. The measurements showed that the major growth in PM concentration was caused by submicrometer particles consisting mainly of particulate organic matter (POM). POM had not totally oxidised during the transport based on the low WSOC-to-OC ratio. The fresh plumes were compared to another major smoke episode that was observed in Helsinki during April-May 2006. The duration and the source areas of the two episode periods differed. The episode in April-May was a period of nearly constantly upraised level of long-range transported PM and it was composed of aged particles when arriving in Helsinki. The two episodes had differences also in the chemical composition of PM. The mass concentrations of biomass burning tracers (levoglucosan, potassium, and oxalate) increased during both the episodes but different concentration levels of elemental carbon and potassium indicated that the episodes differed in the form of burning as well as in the burning material. In spring dry crop residue and hay from the previous season were burnt whereas in August smokes from smouldering and incomplete burning of fresh vegetation were detected.
authors.affiliation: Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland. karri.saarnio@fmi.fi
authors.forename: Karri
authors.initials: K
authors.lastname: Saarnio
authors.forename: Minna
authors.initials: M
authors.lastname: Aurela
authors.forename: Hilkka
authors.initials: H
authors.lastname: Timonen
authors.forename: Sanna
authors.initials: S
authors.lastname: Saarikoski
authors.forename: Kimmo
authors.initials: K
authors.lastname: Teinilä
authors.forename: Timo
authors.initials: T
authors.lastname: Mäkelä
authors.forename: Mikhail
authors.initials: M
authors.lastname: Sofiev
authors.forename: Jarkko
authors.initials: J
authors.lastname: Koskinen
authors.forename: Pasi P
authors.initials: PP
authors.lastname: Aalto
authors.forename: Markku
authors.initials: M
authors.lastname: Kulmala
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kukkonen
authors.forename: Risto
authors.initials: R
authors.lastname: Hillamo
mesh_terms: D001272:Atmosphere / Q000737:chemistry*; D004784:Environmental Monitoring; D005387:Finland; D005390:Fires; D052638:Particulate Matter / Q000737:chemistry*; D012906:Smoke / Q000032:analysis*
chemical_list: D052638:Particulate Matter; D012906:Smoke