Sources of Fine Organic Aerosol. 8. Boilers Burning No. 2 Distillate Fuel Oil

Fine organic particulate matter emitted from an industrial-scale boiler burning no. 2 distillate fuel oil has been characterized on a molecular basis using GC/MS techniques. Most of the identified compound mass consists of n-alkanoic acids (42.0−51.5%), aromatic acids (5.8−22.6%), and n-alkanes (6.7−25.0%). Polycyclic aromatic hydrocarbons (PAH) and oxygenated PAH (oxy-PAH) together comprise 3.1−8.6% of the identifiable mass and together with chlorinated compounds (5.8−16.4%) show the largest variations in emission rates between the two experiments reported here. An increase in chlorinated compound emissions between tests is accompanied by a similar increase in elemental carbon (i.e., soot) and PAH emissions, which may follow the results of laboratory experiments that suggest that the presence of chlorinated compounds can enhance both soot and PAH formation. Differences between the hopanes distribution in the boiler exhaust versus that found in both vehicle exhaust and in the southern California atmosphere suggest that the oil-fired boiler exhaust is at most a minor contributor to the atmospheric aerosol, which is consistent with inferences drawn from local emission inventories.