When burning pyridine, the primary polycyclic aromatic hydrocarbons (PAHs) formed are likely to be compounds like naphthalene, acenaphthene, and fluorene. These compounds can undergo further reactions to form polycyclic aromatic compounds (PACs) or polycyclic aromatic dioxins (PCDDs). The specific PCDDs produced would depend on the conditions of combustion and the presence of other compounds or contaminants in the burning process.