『Abstract
　The impact of biomass combustion on atmospheric particulate matter was investigated at Central and Northern European urban background sites (Duisburg, Prague, Amsterdam, Helsinki) in 2002-2003. In Helsinki, additional 4-week sampling campaigns were carried out during the four seasons in 2003-2004. During campaigns fine particles (PM2.5) and size-segregated samples were collected with a virtual impactor and a ten-stage Berner low-pressure impactor, respectively. From the aerosol samples monosaccharide anhydrides (MA) were determined as source specific tracers for biomass combustion. MA comprised 0.29-6.3％ of the PM2.5 mass and 0.45-7.3％ of its organic carbon content. According to size-segregated samples, the mean diameter of a prominent MA mode coincided with the accumulation mode of particulate mass, except for Prague where the MA mode appeared in a slightly smaller particle size range than the mass. The estimated contribution of biomass combustion to the OC and PM2.5 mass concentration was the highest in wintertime Prague, 79％ and 37％, respectively. It seems that, in addition to traffic in densely populated areas, incomplete biomass combustion with current heating appliances can be a major source of particulate pollution both at local and regional scales.

Keywords: Biomass combustion; Domestic heating; Fine particles; Monosaccharide anhydrides; Organic carbon; PM2.5』

1 Introduction
2 Experimental methods
　2.1 Sampling sites and instruments
　2.2 Gravimetric and chemical analysis
　　Gravimetric analysis
　　Ion chromatography (IC)
　　High-performance liquid chromatography mass spectrometry (HPLC-MS)
　　Thermal-optical transmission (TOT) method
3 Results and discussion
　3.1 MA, potassium, OC and PM2.5 concentrations
　3.2 Mass size distribution of MA and PM
　3.3 Ionic markers of biomass combustion
　3.4 The contribution of biomass combustion to OC and PM2.5
4 Conclusions and implications
Acknowledgement
References