Quantification of polycyclic aromatic hydrocarbons and aliphatic hydrocarbons in air particulate samples in homes

Quantifications of 10 polycyclic aromatic hydrocarbons (PAHs) and 13 aliphatic hydrocarbons (AHs) ranging from n-C20 to n-C32 were reported in 17 homes and their adjacent outdoor environment in Hong Kong. It was found that PAHs were predominantly associated with PM_1.9, which contributed about 98 and 97% to the indoor and outdoor PM₁₀ PAHs, respectively. Also, indoor PAH levels seemed to be lower than outdoor PAH levels, both in the fine mode and in the coarse mode particles. The mean total PAH content in the indoor PM₁₀ was found to be 3.42 ng·m^-3 and it was 5.18 ng·m^-3 in the outdoor PM₁₀. It might demonstrate that there was no presence of indoor PAH sources in these homes. In contrast to PAH, AH levels were found to be higher indoors both in the fine mode and in the coarse mode particles. In addition, the concentrations of indoor and outdoor AH were significantly higher than their corresponding PAH levels. The mean total AH content in the indoor PM₁₀ was 104.42 ng·m^-3 and 94.06 ng·m^-3 in the outdoor PM₁₀. For PM_1.9, the total indoor AH content was 80.40 ng·m^-3 and the outdoor content was 70.55 ng·m^-3 on average. The distribution patterns of the indoor and outdoor AHs were similar, with maximum AH concentration varying from n-C27 to n-C31. The carbon preference indexes, which ranged from 0.84 to 2.62 for indoor and from 1.13 to 3.89 for outdoor environment, indicate the mixed origin of biogenic and anthropogenic sources in these homes.