Air pollution caused by phthalates and cyclic siloxanes in Hanoi, Vietnam: Levels, distribution characteristics, and implications for inhalation exposure

Contamination status and distribution characteristics of ten phthalic acid esters (PAEs) and three cyclic volatile methyl siloxanes (CSs) were determined in the air (gas and particle) samples collected from indoor and outdoor spaces of several chemistry laboratories, offices, and homes fromurban area of Hanoi, the capital city of Vietnam. Air concentrations of Sigma 10PAEs (median 688; range 142-2390 ng m(-3)) and Sigma 3CSs (171; not detected-1100 ng m(-3)) in the indoor air samples were significantly higher than those measured in the outdoor ones (Sigma 10PAEs: 161; 34.1-515 ng m(-3) and Sigma 3CSs: 43.2; not detected-258 ng m(-3)), partly suggesting the predominance of indoor emission sources of these substances. Therewere significant positive correlations in total air concentrations of phthalates and siloxanes between the indoor and outdoor air samples. The most predominant phthalates were diethyl-, di-n-butyl-, diisobutyl-, and di(2-ethylhexyl) phthalate. For siloxanes, D5 and D6 were more abundant than D4 in most samples. Except for di(2-ethylhexyl)- and di-n-octyl phthalate in some locations, almost all the compounds were likely associatedwith gas phase than particle phase. Daily intake doses of airborne phthalates and siloxanes, and non-cancer and cancer risks of selected phthalates were estimated for different exposure groups such as adults, children, and university subjects (e.g., laboratory staff and students), indicating relatively low levels of risk. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the contamination status and distribution characteristics of phthalic acid esters and cyclic volatile methyl siloxanes in indoor and outdoor air samples collected from chemistry laboratories, offices, and homes in urban areas of Hanoi, Vietnam. The results showed higher concentrations of the substances indoors compared to outdoors, indicating indoor emission sources are predominant. Positive correlations were found between total air concentrations of phthalates and siloxanes in indoor and outdoor air samples.