An analytical method has been developed of elemental carbon in airborne dust samples collected on quarz fiber filters.After organic carbon having been removed from the sample, elemental carbon was determined by use of ultimate analyzer (CHN corder).In order to separate completely organic carbon and to prevent the loss of elemental carbon from the sample, two thermal separation methods were used:(1) heat separation method;(2) oxidation decomposition method. In the method (1), the sample was heated at 900°c for 2 min in purified He. In the method (2), the sample was heated at 390°C-410°C for 6 min in air.It was shown from the results of residual H/C ratios in the samples that these separation methods are useful for the accurate determination of elemental carbon in airborne dust.