Webinar: Measurement of Organic Carbon and Elemental Carbon (OCEC) Aerosols

December 2, 2020

The ability to accurately measure atmospheric concentrations of carbonaceous species is extremely important to many researchers. Differentiating between organic and elemental carbon in a particulate-laden sample can be achieved using a thermal-optical analysis. The Sunset Laboratory, Semi-Continuous Organic and Elemental Carbon (OCEC) Instrument has the capability of collecting particulate samples and analysing them on a selected time period. Sunset OC/EC instrument has been widely used throughout the world. For urban areas like Delhi, short collection periods may be needed. The instrument provides integrated measurements of OC and EC on a customizable sampling time (such as hourly or 2-h intervals) and flow rate (2–9 lpm) via a thermal method, as well as an optical EC (OptEC) measurement that is based on transmission of 660-nm wavelength light through the filter. However, the collection periods can be two hours (or more) for areas that envisage less concentrations of OCEC. Summed together, OC and EC provide a measurement of total carbon (TC).

Carbonaceous aerosol is a significant, and often the largest, component of fine particulate matter less than 2.5 microns in diameter (PM2.5). It is composed of organic and elemental carbon (OC, EC), but its composition, sources, and spatiotemporal variations are not well-characterized. OC comprises thousands of individual compounds that can be directly emitted as primary emissions or can be formed in the atmosphere from semi volatile and gaseous precursors over the course of minutes to days. EC is directly emitted from combustion processes, such as from mobile sources or from biomass burning. While it is well-established that elevated PM2.5 levels are associated with many health effects, such as respiratory and cardiac disease, the complex interaction of specific health effects from individual compounds or PM2.5 components, such as OC and EC, are less well understood. OC measurements have typically been comparable to other measurements of carbonaceous aerosol, such as from the Aerodyne Aerosol Mass Spectrometer (AMS).

Sunset Laboratory OC/EC monitor, with improved NDIR, oven, and software is a viable instrument for field deployment at Chemical Speciation Network sites and in routine monitoring networks. The software corrects for instrument drift, identify and quantify the uncertainty in the OC/EC split point achieving better measurements of OC, EC, and total carbon mass in aerosol samples.

We hoped you enjoyed our webinar “Measurement of Organic Carbon and Elemental Carbon (OCEC) Aerosols” as much as we did! If you weren’t able to make it, catch our replay.