Characterization and comparison of speciated atmospheric carbonaceous (soot) particulates and their polycyclic aromatic hydrocarbon contents in the context of the Paso del Norte airshed along the U.S.-Mexico border
Carbonaceous (soot) particulate matter (PM) was collected by both a thermal precipitator (TP) and a high volume air sampler with fiber filters from specific source streams and examined by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Soot PM from burning tires (TPM), a heavy duty diesel truck (DPM), wood burning (WPM), candle burning (CPM), and various natural gas burner combustion regimes along with black carbon (BC) exhibited similarities in PM microstructure, and average primary spherule diameters, which ranged from an average of 30 nm for DPM to 45 nm for BC. The spherule structures consisted of curved graphene fragments and intercalated PAHs. Polycyclic aromatic hydrocarbon (PAH) concentrations were measured (by GC/MS) and compared for these soot PMs, including PAH diagnostic ratios; and these data were compared with outdoor filter collection PM data for El Paso, TX, and a dozen other cities and regions world wide. TPM was observed to contain a wide range of PAHs with high concentrations (from naphthalene to dibenz[a,h]anthracene (MW 128-278)) while DPM and WPM contained lesser concentrations and a smaller PAH range. Candle and natural gas PM as well as commercial BC and carbon nanotube aggregates contained only small concentrations of low MW PAHs. An analysis of PAH carcinogenicity either as a carcinogenicity index or a potency equivalency factor from literature data indicated that only the TPM PAH content would pose any significant long term, carcinogenicity threat. The prospects for utilizing carbonaceous PM source (PAH) markers for discriminating soot PM PAH concentrations in the indoor and outdoor air and the soil is discussed. ^
Environmental Sciences|Engineering, Environmental
Shi, Ye, "Characterization and comparison of speciated atmospheric carbonaceous (soot) particulates and their polycyclic aromatic hydrocarbon contents in the context of the Paso del Norte airshed along the U.S.-Mexico border" (2007). ETD Collection for University of Texas, El Paso. AAI3242140.