SOURCES OF FINE ORGANIC AEROSOL .8. BOILERS BURNING NO. 2 DISTILLATE FUEL-OIL

Fine organic particulate matter emitted from an industrial-scale boile r burning no. 2 distillate fuel oil has been characterized on a molecu lar 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) an d oxygenated PAH (oxy-PAH) together comprise 3.1 - 8.6% of the identif iable mass and together with chlorinated compounds (5.8-16.4%) show th e largest variations in emission rates between the two experiments rep orted here. An increase in chlorinated compound emissions between test s is accompanied by a similar increase in elemental carbon (i.e., soot ) and PAH emissions, which may follow the results of laboratory experi ments that suggest that the presence of chlorinated compounds can enha nce both soot and PAH formation. Differences between the hopanes distr ibution in the boiler exhaust versus that found in both vehicle exhaus t and in the southern California atmosphere suggest that the oil-fired boiler exhaust is at most a minor contributor to the atmospheric aero sol, which is consistent with inferences drawn from local emission inv entories.