Phosphorus flame retardants in indoor dust and their relation to asthma and allergies of inhabitants

Organophosphate esters are used as additives in flame retardants and plasticizers, and they are ubiquitous in the indoor environment. Phosphorus flame retardants (PFRs) are present in residential dust, but few epidemiological studies have assessed their impact on human health. We measured the levels of 11 PFRs in indoor floor dust and multi-surface dust in 182 single-family dwellings in Japan. We evaluated their correlations with asthma and allergies of the inhabitants. Tris(2-butoxyethyl) phosphate was detected in all samples (median value: 580 μg/g in floor dust, 111 μg/g in multi-surface dust). Tris(2-chloro-iso-propyl) phosphate (TCIPP) was detected at 8.69 μg/g in floor dust and 25.8 μg/g in multi-surface dust. After adjustment for potential confounders, significant associations were found between the prevalence of atopic dermatitis and the presence of TCIPP and tris(1,3-dichloro-2-propyl) phosphate in floor dust [per log10 -unit, odds ratio (OR): 2.43 and 1.84, respectively]. Tributyl phosphate was significantly associated with the prevalence of asthma (OR: 2.85 in floor dust, 5.34 in multi-surface dust) and allergic rhinitis (OR: 2.55 in multi-surface dust). PFR levels in Japan were high compared with values reported previously for Europe, Asia-Pacific, and the USA. Higher levels of PFRs in house dust were related to the inhabitants' health status.