Phthalate acid esters in indoor environments: Concentrations, sampling techniques, and health risk assessment

Phthalate acid esters are semi-volatile organic compounds widely used as plasticizers in consumer and industrial products. This review compares indoor PAE concentrations across countries and evaluates sampling techniques, analytical methods, and exposure risks. China accounts for the largest share of studies (37%), followed by the United States, Japan, and other countries, with higher indoor levels in China likely linked to extensive plastic production. Active air sampling was employed in 88% of studies, mainly using vacuum cleaners (45%), polyurethane foam disks (10.6%), brushes (9.1%), low-volume pumps (7.5%), and tubes (4.5%), while 18% used passive techniques. Active methods allow controlled air collection but are limited by equipment cost and energy demand, whereas passive sampling supports longer-term monitoring with minimal environmental dependency. Sampling durations ranged from under 8 to over 72 hours for active methods and several hours to weeks for passive ones. Indoor relative humidity typically ranged from 31% to 50%, with higher humidity enhancing PAE release from plastics. PAE concentrations varied across indoor microenvironments: dust levels ranged from 312 μg/g in schools to 3,893 μg/g in apartments, and air levels from 786 ng/m 3 in homes to 10,204 ng/m 3 in hospitals. DEHP concentrations were higher in dust than air due to low volatility. DEHP and DnBP consistently pose the highest hazards for adults and children, with oral ingestion as the primary exposure route for children. Overall, higher PAE levels were observed in homes, offices, and hospitals due to building materials and furnishings. Risk assessments highlight DEHP as the greatest potential hazard, particularly for children. Indoor PAE contamination is influenced by geography, sampling approach, humidity, and material composition, reflecting widespread plastic use, differences in ventilation and humidity control, and variations in lifestyle and product consumption across regions. • PAEs are a growing concern due to their harmful effects on human health. • The concentrations of PAEs in indoor environments vary depending on specific activities, materials, and products. • GC-MS has been used more than other techniques for the measurement of PAEs. • Children are mainly exposed to PAEs through daily oral ingestion.