Comparison of Thermal Protocols for the Determination of Carbon in Particulate Matter

Abstract

Daily samples of PM1.0 particulate matter fraction were collected from 1 January to 31 March at an urban background station in Zagreb, Croatia. Elemental (EC), organic (OC) and total (TC) carbon were analyzed by thermal-optical transmittance method by two different thermal protocols (NIOSH-like QUARTZ and EUSAAR_2) and the results were compared. Mass concentrations of PM1.0 ranged from 4.7 µg/m3 to 58.9 µg/m3. Very good agreement was observed for TC (slope = 1.0, R2 = 0.99). EC mass concentration levels were found to be lower for QUARTZ than for EUSAAR_2, due to differences in the heating profiles. The EUSAAR_2 protocol with a rather low peak temperature in the inert mode generally classified more carbon as EC compared to the QUARTZ protocol. The slope between ECE2 and ECQ following transmittance correction was 1.5 (R2 = 0.88), while the slope between OCE2 and OCQ was 1.0 (R2 = 0.98).