A review of organophosphate flame retardants and plasticizers in the environment: Analysis, occurrence and risk assessment.

During passive air sampling, the amount of a chemical taken up in a sorbent from the air without the help of a pump is quantified and converted into an air concentration. In an equilibrium sampler, this conversion requires a thermodynamic parameter, the equilibrium sorption coefficient between gas-phase and sorbent. In a kinetic sampler, a time-averaged air concentration is obtained using a sampling rate, which is a kinetic parameter. Design requirements for kinetic and equilibrium sampling conflict with each other. The volatility of semi-volatile organic compounds (SVOCs) varies over five orders of magnitude, which implies that passive air samplers are inevitably kinetic samplers for less volatile SVOCs and equilibrium samplers for more volatile SVOCs. Therefore, most currently used passive sampler designs for SVOCs are a compromise that requires the consideration of both a thermodynamic and a kinetic parameter. Their quantitative interpretation depends on assumptions that are rarely fulfilled, and on input parameters, that are often only known with high uncertainty. Kinetic passive air sampling for SVOCs is also challenging because their typically very low atmospheric concentrations necessitate relatively high sampling rates that can only be achieved without the use of diffusive barriers. This in turn renders sampling rates dependent on wind conditions and therefore highly variable. Despite the overall high uncertainty arising from these challenges, passive air samplers for SVOCs have valuable roles to play in recording (i) spatial concentration variability at scales ranging from a few centimeters to tens of thousands of kilometers, (ii) long-term trends, (iii) air contamination in remote and inaccessible locations and (iv) indoor inhalation exposure. Going forward, thermal desorption of sorbents may lower the detection limits for some SVOCs to an extent that the use of diffusive barriers in the kinetic sampling of SVOCs becomes feasible, which is a prerequisite to decreasing the uncertainty of sampling rates. If the thermally stable sorbent additionally has a high sorptive capacity, it may be possible to design true kinetic samplers for most SVOCs. In the meantime, the passive air sampling community would benefit from being more transparent by rigorously quantifying and explicitly reporting uncertainty.

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Passive air sampling for semi-volatile organic chemicals

Organophosphate esters (OPEs) were measured in atmospheric vapor and particle samples collected at six sites in the Laurentian Great Lakes basin every 12 days from January to December 2017 (inclusive). Median total OPE concentrations (∑OPEs) ranged from 41.2 pg/m3 at Eagle Harbor, Michigan to 1320 pg/m3 at Cleveland, Ohio. Tris(1-chloro-2-propyl) phosphate (TCIPP) was the most abundant OPE measured in these samples and contributed 26% to ∑OPE concentrations. The spatial distribution of OPEs among the sites suggests that OPEs with longer atmospheric half-lives and relatively high octanol-air partitioning coefficients (KOA) are likely to have a greater potential to undergo long-range atmospheric transport. OPE particle-phase partitioning fraction (Φ) significantly and positively correlated with KOA, but declined with increasing relative humidity. Φ values varied seasonally and were lower in the summer for volatile OPEs. In addition, samples collected in the summer had significantly higher levels of ∑OPEs than samples collected in the winter. The estimated dry deposition flow of ∑OPEs to the Great Lakes was 1.22 tons/year, exceeding the corresponding flows reported for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs).

Spatioseasonal Variations and Partitioning Behavior of Organophosphate Esters in the Great Lakes Atmosphere.

https://digital.csic.es/bitstream/10261/231246/4/Enviromental%20Pollution%282020%29.pdf

GAPS-megacities: A new global platform for investigating persistent organic pollutants and chemicals of emerging concern in urban air

Contamination profiles and potential health risks of organophosphate flame retardants in PM2.5 from Guangzhou and Taiyuan, China.

Flame retardants in urban air: A case study in Toronto targeting distinct source sectors.

Direct measurements of polyurethane foam (PUF) ‒ air partitioning coefficients for chemicals of emerging concern capable of equilibrating in PUF disk samplers.

Jenna Clarke

Papers

Flame retardants in urban air: A case study in Toronto targeting distinct source sectors.

Direct measurements of polyurethane foam (PUF) ‒ air partitioning coefficients for chemicals of emerging concern capable of equilibrating in PUF disk samplers.