Organophosphate Esters in Vehicle Interior Dust from Chinese Urban Areas: What are the Influencing Factors of the Occurrence?

Abstract

Organophosphate esters (OPEs) are a class of semi-volatile organic compounds commonly added to various products as flame retardants and plasticizers. As one kind of emerging pollutants, OPEs have garnered attention due to their potential impacts on human health and ecosystems. This study collected vehicle interior dust samples from 36 cities in China from December 2020 to May 2021 and detected the concentrations of 11 legacy OPEs. The total OPE concentrations ranged from 5450 ng/g to 63700 ng/g, with the content of three categories of OPEs as follows: ΣChlorinated-OPEs (median: 17420 ng/g) > ΣAlkyl-OPEs (median: 3880 ng/g) > ΣAryl-OPEs (median: 1490 ng/g). In the northern China, the aggregate concentration of OPEs in vehicle interior dust demonstrated the highest levels, while OPE concentrations in the western and mid-southeastern regions of China appeared to be comparable to each other. Coastal and inland cities exhibited differences in OPEs levels, with varying representative OPEs among them. The occurrence of OPEs in vehicle interior dust was closely associated with regional economic development levels, motor vehicle parc, and road density. In contrast to other urban areas, first-tier cities showed the highest aggregate levels of OPEs in vehicle interior dust, with a significant increase observed specifically in the concentrations of Alkyl-OPEs and Aryl-OPEs.

Keywords: organophosphate esters, vehicle, Tris(chloroisopropyl) phosphate (TCPP), dust, socio-economic factors