PAH Compounda CAS  RN Molecular Weight No. of Ringsb Naphthalene a 91-20-3 128 2 C1-, C2-, C3-, C4-Naphthalenes --- 142,156, 170,184c 2 Benzothiophene 95-15-8 134 2 C1-, C2-, C3-Benzothiophenes --- 148, 162, 176c 2 Biphenyl 92-52-4 154 2 Acenaphthylene a 208-96-8 152 3 Acenaphthene a 83-32-9 154 3 Dibenzofuran 132-64-9 168 3 Fluorene a 86-73-7 166 3 C1-, C2-, C3-Fluorenes --- 180, 194, 208c 3 Carbazole 86-74-8 167 3 Anthracene a 120-12-7 178 3 Phenanthrene a 85-01-8 178 3 C1-, C2-, C3-, C4-Phenanthrenes/Anthracenes --- 192, 206, 220, 234c 3 Dibenzothiophene 132-65-0 184 3 C1-, C2-, C3-Dibenzothiophenes --- 198, 212, 226c 3 Fluoranthene a 206-44-0 202 4 Pyrene a 129-00-0 202 4 C1-, C2-, C3-Fluoranthenes/Pyrenes --- 216, 230, 244c 4 Naphthobenzothiophene 205-43-6 234 4 C1-, C2-, C3- Naphthobenzothiophenes --- 248, 262, 276c 4 Benz(a)anthracene a 56-55-3 228 4 Chrysene a 218-01-9 228 4 C1-, C2-, C3-, C4-Chrysenes --- 242, 256, 270, 284c 4 Benzo(b)fluoranthene a 205-99-2 252 5 Benzo(k)fluoranthene a 207-08-9 252 5 Benzo(e)pyrene 192-97-2 252 5 Benzo(a)pyrene a 50-32-8 252 5 Perylene 198-55-0 252 5 Dibenzo(a,h)anthracene a 53-70-3 278 5 Benzo(g,h,i)perylene 191-24-2 276 6 Indeno(1,2,3-c,d)pyrenea 193-39-5 276 6 aThe US EPA considers these analytes to be priority pollutants. Analytes that are italicized are considered probable human (B2) carcinogens by the USEPA. bNumber of aromatic 5- and 6-carbon rings. Low molecular weight compounds have 2 or 3 aromatic rings and high molecular weight compounds have 4 or more aromatic rings. cThe molecular weights for the alkylated compounds are shown in order of C1, C2, C3, etc.

Table 1: Polycyclic aromatic hydrocarbons (PAHs) quantified in extracts of house dust from two rural villages in Nepal.