Emissions of polycyclic aromatic hydrocarbons from combustion of agricultural and sylvicultural debris

In this work, 28 parent and substituted-polycyclic aromatic hydrocarbons (PAHs) have been quantified in 76 smoke samples produced by burning pine wood, pine needles, prickly pear and almond skin using two different kinds of combustion devices. The results show a great variability in the total concentrations of the PAHs, while their proportions in the different samples are practically independent of the type of biomass that is burned. Just a few PAHs with low molecular weight—naphthalene, 1- and 2-methylnaphthalene, acenaphthylene and phenanthrene—are the most common in the different smoke samples, representing between 61% and 72% of the total. The high correlation coefficients between naphthalene and the total concentrations of PAHs, or between naphthalene and the concentrations of PAHs grouped by number of rings, demonstrate that all combustion processes studied are equally affected by the variables that regulate those processes. The results underscore the important role that naphthalene plays in the formation of higher molecular weight PAHs by pyrosynthesis and show that the naphthalene concentration can be used as an indicator of the total hydrocarbons content in the smoke.