Stable carbon and nitrogen isotope ratio in PM1 and size segregated aerosol particles over the Baltic Sea
Keywords: PM1 and PM0.056–2.5, stable carbon and nitrogen isotope ratios, source apportionment, southeastern Baltic Sea region
AbstractWe analysed δ13C of total carbon (TC) and δ15N of total nitrogen (TN) in submicron (PM1) and size segregated aerosol particles (PM0.056–2.5) collected during a cruise in the Baltic Sea from 9 to 17 November 2012. PM1 were characterized by the highest δ13C (–26.4‰) and lowest δ15N (–0.2 and 0.8‰) values when air masses arrived from the southwest direction (Poland). The obtained δ13C values indicated that combined emissions of coal and diesel/gasoline combustion were the most likely sources of TC. The depleted δ15N values indicated that TN originated mainly from liquid fuel combustion (road traffic, shipping) during this period. The lowest δ13C and highest δ15N values were determined in PM1 samples during the western airflow when the air masses had no recent contact with land. The highest δ15N values were probably associated with chemical aging of nitrogenous species during long-range transport, the lowest δ13C values could be related to emissions from diesel/gasoline combustion, potentially from ship traffic. The δ13C analysis of size-segregated aerosol particles PM0.056–2.5 revealed that the lowest δ13C values were observed in the size range from 0.056 to 0.18 µm and gradual 13C enrichment occurred in the size range from 0.18 to 2.5 µm due to different sources or formation mechanisms of the aerosols.