| Summary: | Carbonaceous aerosols are a major component of fine airborne particulate matter (PM) and play a complex role in the climate system, via their role in light scattering and absorption, cloud nucleation, and the melting of ice- and snow-covered surfaces, and in air pollution and human health. They are removed from the atmosphere via aging and dry and wet deposition. Over the course of one year, we simultaneously analyzed the composition of carbonaceous aerosol in both PM and snow collected at the Dr. Neil Trivett Global Atmosphere Watch Observatory at Alert, Canada. To understand the seasonal variation in the EC (elemental carbon) and OC (organic carbon) burden, we quantified the amount of total carbon (TC) and fraction of light-scattering organic carbon (OC) and light-absorbing elemental carbon (EC) with a Sunset OC/EC analyzer using the EnCan-Total-900 (ECT9) protocol. In addition, we measured the stable carbon value and radiocarbon content of the EC fraction to apportion it into contributions from fossil fuel combustion (gaseous, liquid, and solid fuels such as natural gas, coal, and diesel) and biomass burning (wildfires and biofuel combustion).
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