First nationwide survey of phthalic acid esters (PAEs) in Vietnamese dust samples: Insights into spatial trends, indoor-outdoor differences and human exposure implications

Distribution patterns of 16 phthalic acid esters (PAEs) were investigated in 159 indoor/outdoor dust samples collected from three regions (northern, central, and southern) of Vietnam. Total concentrations of PAEs dust samples ranged from 278 to 2.280.000 ng/g (mean/median: 123.400/39.100 ng/g). The highest concentrations of PAEs were found in indoor dust samples collected from northern areas (mean/median: 276.000/113.000 ng/g), followed by southern (mean/median: 161.000/76.500 ng/g) and central areas (93.100/43.400 ng/g). PAE concentrations in indoor dust were found to be approximately two to four times higher than in outdoor dust, and exhibited a geographical distribution across the country in the descending order of northern > southern > central areas. PAEs measured in dust samples collected in homes were significantly higher than those in workplaces and schools in the northern and central regions. For samples from the southern region, however, a distinct distribution was observed, with PAE concentrations in dust decreasing in the order of workplaces (mean/median: 286,000/282,000 ng/g) > schools (110,000/80,700 ng/g) > homes (51,300/44,800 ng/g). The correlation of PAEs concentrations among indoor/outdoor dust sample pairs collected at each location in all three regions was moderate (r = 0.456). Among the 16 PAEs, DEHP was measured at the highest concentrations in all dust samples, followed by DBP and DEP. Estimated human exposure doses to PAEs through dust ingestion for indoor areas were higher than those for outdoor areas. Infants were at higher risk of exposure than other age groups.