Indoor and outdoor concentrations of organic and inorganic molecular markers: Source apportionment of PM2.5 using low-volume samples

Concentrations of PM2.5, elemental carbon (EC), organic carbon (OC), 30 organic source markers (13 alkanes, 14 polycyclic aromatic hydrocarbons and ketones, and 3 hopanes) and 19 inorganic source markers are reported from residential indoor, residential outdoor, and ambient microenvironments from a nine home pilot study conducted in Tampa, Florida. Mean daily PM2.5 concentrations were 9.3 μg m−3 for residential indoor, 11.3 μg m−3 for residential outdoor, and 12.7 μg m−3 for ambient microenvironments. The EPA Chemical Mass Balance Model (CMB8.2) was used for source apportionment of PM2.5 residential outdoor samples. Four main sources of PM2.5 were identified: sulfate (55±6%) (average outdoor PM2.5±S.D.), gasoline-powered motor vehicles (32±4%), diesel-powered vehicles (8±2%), and road dust (5±1%).