Characterization and health risk assessment of PM_2.5-bound organics inside and outside of Chinese smoking lounges

PM_2.5 samples were collected at six indoor public places that contained dedicated smoking lounges. Samples were taken in the smoking lounges, at two indoor locations outside of the lounges, and in outdoor air near the venues. Organic carbon (OC), elemental carbon (EC), and non-polar organic compounds including polycyclic aromatic hydrocarbons (PAHs), n-alkanes (n-C₁₆ to n-C₄₀), iso/anteiso-alkanes (C₂₉ to C₃₃), hopanes and phthalate esters (PAEs) were quantified. Average PM_2.5 levels of 170.2 ± 85.9 μg/m³ in the lounges exceeded limits of 25 μg/m³ set by World Health Organization (WHO); these levels were 5.4 and 3.9 times higher than those indoors and outdoors, respectively. High ratios of OC to PM_2.5, OC to EC, and PAHs diagnostic ratios in the lounges indicated contributions from environmental tobacco smoke (ETS). The maximum carbon number (C_max) and carbon preference indices (CPI) for n-alkanes showed ETS transport from the enclosed lounges to nearby indoor non-smoking areas. Iso/anteiso-alkanes in the lounges were 876.5 ng/m³, ∼80 times higher than outdoor levels. 17α(H)-21β(H),30-norhopane and 17α(H)-21β(H),(22R)-homohopane were much higher in the lounges than outdoor air, but they cannot be directly attributed to ETS. Estimated carcinogenic risks of PAHs in the lounges exceeded the acceptable level of 10^{− 6}.