Field investigation on phthalates in settled dust from five different surfaces in residential apartments

Phthalate esters (PAEs) are widely used as household and industrial products in residential apartments. Sixteen PAEs in the settled dust from five surfaces in 17 residential apartments in Xi'an, China were investigated from February 2019 to August 2019. A hairbrush and vacuum cleaner were used to collect the dust samples. Four PAEs, namely dimethyl phthalate, diisobutyl phthalate, dibutyl phthalate, and bis (2-ethylhexyl) phthalate (DEHP), were detected in the dust. DEHP was the most predominant compound in the settled dust (median value of 965.1 μg/g). The total PAEs concentrations in the settled dust on the five different indoor surfaces were significantly different. The highest concentration was found for dust samples on equipment surfaces where dust can easily deposit (median value of 3442.5 μg/g), which was nearly 3 times higher than that from infrequently swept surfaces (median value of 1297.0 μg/g). The PAE concentration in dust from the frequently swept surfaces (median value of 2299.8 μg/g) was significantly higher than that from the infrequently swept surfaces. The composition profile of PAEs in dust from the five surfaces was completely different. Therefore, settled dust on different surfaces should be distinguished when conducting field investigations. In addition, increased concentrations with increasing temperature were found for dust from the infrequently swept surfaces, thereby suggesting that temperature may influence the phthalate concentrations in dust.