- Polycyclic organic matter (POM) : A Polycyclic organic matter (POM) is Defines a broad class of compounds that includes the polycyclic aromatic hydrocarbon compounds (PAHs). POM compounds are formed primarily from combustion and are present in the atmosphere in particulate form. Sources of air emissions are diverse and include, vehicle exhausts, forest and wildfires, asphalt roads, coal, coal tar, coke ovens, agricultural burning, residential wood burning, and hazardous waste sites. Because of limited emissions data, for this assessment Polycyclic organic matter (POM) data have been limited to either the group of 7 or group of 16 individual PAH species referred to as 7-PAH and 16-PAH, respectively. In this assessment POM refers to 16-PAH. The 16-PAH group includes the 7-PAH group.