delta C-13 VALUES IN SIZE-SEGREGATED ATMOSPHERIC CARBONACEOUS AEROSOLS AT A RURAL SITE IN LITHUANIA

The investigations of the carbon isotopic ratio in different size aerosol particles at the Rugsteliskis Integrated Monitoring Station (IMS) at the rural site (Lithuania) during 10-24 July 2008 are presented. Total carbon (TC) concentrations ranged from 0.06 to 0.35 mu g m(-3) and those of elemental carbon (EA) from 0.02 to 0.15 mu g m(-3) in accumulation mode, as well as from 0.06 to 0.14 mu g m(-3) and from 0.02 to 0.06 mu g m(-3) in coarse mode of aerosol particles, respectively. Organic matter (OM) concentration ranged from 1.0 to 25.4 mu g m(-3), with the average value of 5.6 mu g m(-3). Carbon isotopic ratios relative to standard for TC differ significantly in accumulation and coarse modes (-28 and -24%o, respectively) and indicate a different origin of size-segregated aerosol particles. Almost constant organic carbon isotopic ratio (-31.8%a) indicates that OM originates from local vegetation. Organic matter concentrations and the carbon isotopic ratio measurements in the size-segregated aerosol particles allow identifying sources of aerosol particles.