Indoor airborne phthalates in university campuses and exposure assessment

Abstract

Phthalates are widely used as plasticizers in consumer products and are ubiquitous in indoor environments. Undergraduates spend a high amount of time indoors, however, little is known on the pollution characteristics and exposure to phthalates in indoor air in a university setting. In this study, passive air samplers measured the concentrations of phthalates in air from dormitories, classrooms, computer rooms, laboratories, and offices of a university in Beijing, China. A Monte-Carlo simulation was used to estimate the undergraduates’ exposure via inhalation based on air concentrations. Six phthalates were detected, including Dimethyl phthalate(DMP), Di (isobutyl) phthalate(DiBP), Di (n-butyl) phthalate(DnBP), Di (2-Methoxyethyl) phthalate(DMEP), Di (2-n-Butoxyethyl) phthalate(DBEP), and Di (2-ethylhexyl) phthalate(DEHP). Sampling rates of polyurethane foam (PUF) were obtained from a calibration study by co-deploying passive and active air samplers in offices and laboratories, and the average sampling rate was 0.62 ± 0.33 m3/day. DnBP and DMEP were the most abundant phthalates in total investigated environments at the university. DMP, DnBP, and DMEP air concentrations showed significant differences in different indoor environments (p < 0.05). All phthalate concentrations were not significantly different between the sunny sides and shadowy sides of rooms (p > 0.05). DMP concentrations were significantly different between male and female dormitories (p < 0.05). Correlation analysis suggests that DiBP, DnBP, and DMEP may originate from the same sources, while DBEP and DEHP may originate from a separate common source. The daily intake of phthalates via inhalation in dormitories is greater than in classrooms, except for DMP, which may lead to higher carcinogenic risks for undergraduates.