Complex sentence: Polycyclic aromatic hydrocarbons (PAHs), also known as poly-aromatic hydrocarbons or polynuclear aromatic hydrocarbons, are fused aromatic rings and do not contain heteroatoms or carry substituents.
Split into simpler sentences: Polycyclic aromatic hydrocarbons (PAHs), also known as poly-aromatic hydrocarbons, are hydrocarbons with multiple aromatic rings. PAHs do not contain heteroatoms or carry substituents.