[en] This project is concerned with the electronic properties and reaction pathways of polycyclic aromatic hydrocarbons (PAH), and particulates thereof, which are of environmental concern and which are byproducts of the combustion of fossil fuels. The interaction of radiation with PAH molecules, or solid PAH systems, is the basis of a series of closely related experimental and theroretical approaches which are being utilized in this work. These related research problems include the following subjects: (1) mechanisms of energy transport in PAH crystals, particularly the migration of triplet excitons studied by optical detection of magnetic resonance techniques; (2) mechanisms of emission of photoelectrons from micron-sized PAH particles, demonstrating exoemission by energy transport; (3) electrochemical reactions of anthracene radical cations with aqueous ammonia solutions; (4) exciton-exciton interactions and annihilations in PAH systems subjected to high intensity laser radiation; (5) computer modeling calculations of particle coagulation and scavenging and, finally (7) the reaction mechanisms of PAH model metabolite compounds with nucleic acids, utilizing spectroscopic techniques to study reaction pathways and the structure of the DNA adducts. 52 references, 21 figures